3 Ways to Wire Off-Grid Batteries (Add Lithium to your System)

[@kevinmcmanaman7774]

Mine has been operating perfectly at my off grid cabin a couple years now. I have an early version of the Bank Manager, and use a big bistable relay with it to join my Lifepo4 200Ah to my 330 Ah lead acid at 24v. Works fantastic. I have 4 charging sources to my lead bus: 1kw solar on mppt, 1kw solar on a pwm (since panels face east and west on shed roof), a 600w wind turbine, and a small generator Ive frankly never had to use. The Lifepo4 is connected with Bank Manager in parallel with my lead, but doing the vast majority of the work. The Lifepo4 gets fully charged and drops off, typically mid morning, allowing the lead to do absorbtion and float till nightfall, when it reconnects and carries the load till morning. My lead acids were pretty new when i decided to add Lifepo4. Now, the lead protects my wind turbine (always have lead connection, avoiding danger of Lifepo4 only system - no load when bms shuts off), and it keeps lots of power ready when needed. Also, the Lifepo4 charges very quickly with low resistance, so it makes my wind turbine more efficient and effective, collecting more power rather than burning off excess when voltage rises due to lead's resistance (a constant problem with lead only systems). All has operated flawlessly.

[@Clarks-Adventure]

Thanks for the report Kevin, Glad it's working so well for you.

[@ravicabral2522]

Absolutely fantastic vudeo. Ive never seen a more clearly explained and better presented vudeo onbthe subject. Thanks.

[@stuartroberts3612]

So helpful, we have just bought a new to us boat, where the previous owner had a ‘yard’ install a hybrid battery system (3 batteries) that he did not understand. Just looking at the setup didn’t shed any light on it until I watched this video which replicates the system in place and we now have an explanation - thank you!

[@aledwilliams]

Adding a dedicated starter battery - that's the exact info I've been looking for, now it all makes sense, and I can see how 'easy' adding lithium via the BankManager would work for me on a small sailboat - thank you!

[@scottkrebs586]

Yup, one of those that when I get questions I can just link over here and say, "Let Clark tell you how that works." You're making life easier that way lol

[@TrotterDel]

Another happy bunny. Thanks to Dave (Wildebus) my hybrid works brilliantly. That's 200ah lithium and 345 lead carbon, in a Fiat Ducato ( Ram Promaster in the US ) 500w solar + 200w when required, which in an English summer, is very often. regards Trotter

[@Clarks-Adventure]

Last I checked Dave was just selling a voltage sensitive relay as a BBMS. No safeties about connecting charged with discharged banks (fire risk) and no logic to properly charge your lithium (low current overcharge death) Careful

[@stevecurran3007]

Paraphrasing, "If you are not a little afraid of electrical work maybe you shouldn't be doing this." Every electric tech class should start out with that statement.

[@joshuahayes3670]

Informative, understandable, clearly communicated, relatable content. Thank you for making time to create and edit real-life, sustainable, educational content.

[@benkanobe7500]

Just to show how this works in the real world, I ordered the isolator/relay for my dual-battery pickup truck that has a winch connected to the aux battery. I am now (as soon as I wire it in) comfortable that I can abuse my winch battery in an emergency without fear of hurting my start/run battery. Thanks!!

[@sailingsidequest]

Excellent Clark! Just the video we needed. Honestly I know you probably feel like you've made a version of this video 3 times but you could make 10 more and people will still get something else out of it. Thanks for doing this looking forward to getting our Bank Manager hooked up!

[@Clarks-Adventure]

I'll keep cutting the answer in half until I don't get questions. Once you understand something it's hard to know what "dose" of new knowledge is too much at once.

[@virginislandssailingadvent8978]

Excellent demonstration/explanation. You are a true pioneer in battery management. One possible addition you may wish to include, is the alternator considerations if "switchology" and circumstance allow the starter battery (whether dedicated or integrated with house-bank) alternator charging circuit to attempt charging a large bank of seriously depleted batteries.

[@Clarks-Adventure]

I guess I might not have explicitly said it by any charge offered to either of the lead batteries will eventually be shared with all three batteries. If you are referring to damage to the alternator caused by heavy charging I covered that in kzbin.info/www/bejne/oHS9l5Rop5KEg7s

[@Clarks-Adventure]

And thank you

[@mikeg7924]

Another great video! Grateful for good people like you Clark.

[@Clarks-Adventure]

Thank you Mike

[@pauljenkins3258]

Thanks like you so many conflicting info floating around you put to bed For me, the fear of using the two different batteries. Being on a budget this helps me work with what I have

[@bigbones5063]

Great information, I was able to follow along and understand you, which was a big feat because I don't know anything about electric systems. Thank you for making it easy.

[@Clarks-Adventure]

You're very welcome. Have you watched our other videos. We have a playlist full of electrical videos

[@diogenes848]

Very interesting. Very interested in a better break down on how to make a wind generator. You've done some videos on it but I'd like something that more explicit. Your big wind turbine is really cool and I the information on how to build one is a little scant for some of us... I know it is for me. Best wishes.

[@kenmix6974]

I'm getting a boat soon and I plan on putting this system in. I like your explanations. You keep it simple.

[@Clarks-Adventure]

Thanks Ken

[@daniellapain1576]

I just learned that this exists because of your video. I could do so much with this. Though now I only need to figure out a version of this for a dump load. I plan on attaching a grid tie inverter in a way that if your battery is full and the sun and wind is readily available. Your system will use the battery less increasing it's life and making so you need less batteries. Everyone is quick to say no it can't be done but there has to be a way to pull it off safely and I am trying to figure it out.

[@spectralize13]

Absolutely fabulous video. Cleared up a lot of misconceptions for me.

[@SCFoster]

Nice video. Keeping it simple from a hook up perspective.

[@langstonholland9272]

In about a year from now I'm planning to replace my sailboat's house and start 12V AGM batteries with LiFePO4. There are a handful of LiFePO4 advertised to work for engine starting. I'm sure there will be a lot more in the next year or so. It seems to me that an all LiFePO4 system would simplify some of this charge/discharge juggling required in hybrid systems. Love these videos - thanks!

[@Clarks-Adventure]

I'd stay with lead for starting. If for no other reason as it keeps some dependable batteries on the boat. If you go all Li there is no way to charge them properly. My BankManager requires some lead

[@schussy]

Good review. Info on voltage sensing relay ( VSR=battery combiner) is also very helpfull/intresting. I have a house bank, have a windlass/bow thruster bank and smart battery combiner (ME-SBC) for lead to lead acid batteries . I now am also the proud owner of a lithium iron phosphate battery and a Battery Bank Manager. I thought i would have to stop using the VSR/combiner. But it may still be helpfiull to keep. Will check it out. Clark, thanks for the steer to this video based on comments from other videos.

[@wojtekbratek5156]

For the hell of it! Less telling about what you will be showing and more specifics. We have the only one Life!

[@Clarks-Adventure]

Better find another channel then

[@MiQBohlin]

I’m a bit behind in your releases. This is a good walkthrough since I’m about to build a new battery system for the whole boat. So I need Pb for starter, LiFePo for house bank and probably a carbon lead for my windlass 🤔

[@BoatDawg]

Thanks for the video. Considering a Bank Manager for my Catalina 30.

[@kenatkins620]

Nice work Clark. Thank you.

[@tracyoliver550]

Straight forward, clear and concise as usual!

[@Clarks-Adventure]

Thanks Tracy

[@benkanobe7500]

Another outstanding video on this specific topic of The Bank Manager and combining Lead and Li (I just wish I knew what to do with the two resistors that came with my Bank Manager).

[@johndixon5097]

Clark really enjoyed your explanation of the electrical system hookup. You made it very easy to understand. Thank you for your videos and time.

[@Clarks-Adventure]

Your welcome, John

[@livingsimplytosimplylive6817]

I shall call you, Captain Knowledge lol

[@mikebindley4567]

Rule of thumb with negative ground engine systems is to connect the positive terminal first when connecting battery and when disconnecting battery remove negative first to avoid shorting positive to ground in either case. Cheers

[@stillwatersailor665]

Noticed that also.

[@Clarks-Adventure]

But my dining room table isn't negative ground. :)

[@tvonzweck]

Great video Clark. I have messaged you a few times in the past 18mos and threatened to buy the Bank Manager (your responses were prompt, thank you). Well, I wish I had done the battery upgrades. I now sit in on anchor in Puerto Vallarta, Mexico where all boat parts, especially batteries are outrageously expensive and my house bank of the now infamous FireFly Oasis batteries has crapped out. I'll be watching this video again and designing a system that utilizes the Lithium /lead combo via your Bank Manager w/ a dedicated start battery. I will wait until I sail the boat to Arizona😂 ,or almost, and haul out in a few months at Puerto Peñasco so I can buy all the parts while in the US and drive them over the border from California. I have told dozens of cruisers about the Bank Manager and your channel's videos describing it. Most cannot get their heads around the reality and beauty of it.

[@Clarks-Adventure]

Thanks for spreading the word. I really enjoyed my time in Puerto Vallarta. Do cruisers still hang out at los Crusis? And I really hope you spent some quality boobie time at isla Isabella!

[@tvonzweck]

@@Clarks-Adventure Yes, I am anchored at La Cruz awaiting a haul out to make a necessary "do it now repair". It is a great little village that sees the majority of the cruisers heading to French Poly and other points W and S stop, load up and wait for the trades to build. The anchorage sucks though and teaches one how let go of their needs for comfort while on anchor. I typically don't spend more than a few days here, my haul out date has me waiting a month on anchor with no engine. Do not come to Banderas Bay for a haul out. My 37' monohull fee is $1050, plus $50/day while on the hard, cannot sleep on the boat. I have been to Isla Isabel five times in the last 2 1/2 years, it is glorious. I am simply amazed at how many cruisers will not go there due to the little bit of extra finesse it takes to anchor between the boulders that are known to want to keep anchors.

[@jasonpotts6490]

Thank you for the informative videos. I'm learning a lot!

[@Clarks-Adventure]

You're welcome Jason. Glad you are enjoying our work.

[@bradgreene3340]

Thanks for this. Simple, clear and helpful. Seriously considering your BBMS for a LiFePO4 upgrade later this year.

[@dennishively5994]

Another great video & explaining, thank you

[@Clarks-Adventure]

Thanks

[@raireva4689]

This is great video! Thank YOU!!

[@therokenman2594]

Please keep making these videos! Love learning this info!

[@Clarks-Adventure]

Will do Thero And please share links with your friends.

[@yannkitson116]

Great video, thanks for sharing!

[@Clarks-Adventure]

You're very welcome

[@malcolmdavid722]

Excellent with clarity for a novice like me !

[@williamsanford7472]

Just discovered your channel. Thanks for the content.

[@Clarks-Adventure]

You're welcome

[@alanwheelock1460]

nice work Clark

[@Clarks-Adventure]

Thanks Alan

[@mullerenergy]

Always interesting to see how the competition does things! We do it a slightly different way. We do it by disabling the discharge on the BMS (assuming the lithium battery has the higher voltage initially) and then connect both of them together in parallel and putting them on charge. Once the battery voltages are the same, you can enable to discharge again on the lithium BMS. Obviously both ways have their advantages.

[@Clarks-Adventure]

I guess I don't understand your approach. You do this every charge cycle? With discharge deactivated what happens when the charge source isn't large enough to handle a big electrical load? Won't system voltage crash? Oh, I guess you use lead for big loads while charging. How do you deal with the "low current overcharge" issue of the lithium. If you don't remove the li from elevated voltage after it saturates how do you keep it from being damaged? Do you deactivate the BMS charge capability? Could work.

[@mullerenergy]

@@Clarks-Adventure no, you would only do this initially. Once the two voltages are the same, you enable the discharge again and don't ever have to turn it off again (unless you ever run the batteries below 10V, which isn't great). I'm also assuming there's no charging source that charges at over 14.6V. As for the low current overcharge that some people say damages lithium cells at voltages as low as 3.5V, I haven't seen any evidence of that.

[@Clarks-Adventure]

We have seen batteries that were charged to only 13.8 but held there past saturation die in 3 years of use.

[@mullerenergy]

@@Clarks-Adventure I'm defintiely not saying you're wrong, but I have not personally seen this with any of our batteries. How did they die out of interest? Did they just lose capacity? Did they get bloated? Did they start leaking?

[@Clarks-Adventure]

Honestly I haven't personally seen that battery but my friend Conrad has been following this a lot over the years and showed a link to me from a reputable seeming guy back during the beginning of this project. I think it was nordkyndesign.com/charging-marine-lithium-battery-banks/ It should be linked to Conrad's writeup at the bottom of this page www.emilyandclarksadventure.com/bbms From my memory it was prismatic and I believe they swelled.

[@petersongallery]

Thanks Clark ... good video!

[@Clarks-Adventure]

Thanks Bill

[@ravenrorick2772]

Thanks your videos help me so much.

[@Clarks-Adventure]

You're welcome

[@Zbee167]

Good stuff! Thanks for sharing.

[@Clarks-Adventure]

You're very welcome

[@braithmiller]

Great for any starting out. The voltage sensitive relay between the starter and house: check me on my recommendation logic. The battery sense lead should be Y through a 2-way switch, to both the house and starter battery. Sense to starter battery when you are on board ie, the battery gets charged every month. Sense to house when you leave your boat to fend for itself on the hook for months.

[@Clarks-Adventure]

I like the dial sensing versions. kzbin.info/www/bejne/p5TOnqVsgsyEedU That way any charge current gets shared everywhere. You can leave your alternator charging through your starter wire and your li will float your starter batteries for the longest life.

[@chancederosier3378]

Very helpful thanks

[@nodogrunner]

What a great topic and you explained it clearly and simply, even I can understand. Would love to see a how you would build an electric sailboat from a clean slate. I mean, where would you put the batteries, what kind of motor, how you would mount solar panels, wind considerations, what kind of sailboat you would start with? That would be a college level class.😀

[@Clarks-Adventure]

Yes, more than a single KZbin video for sure

[@Clarks-Adventure]

You could watch our old boat tour video. I think we should redo that. A lot has changed

[@nodogrunner]

@@Clarks-Adventure I think I have watched all your videos. I will slide back through the history and make sure. You should never struggle to find content with your skills. -God bless.

[@alanblyde8502]

Clark I can see Emily saying “hope your not scratching our nice table with that battery are you” 😄

[@austinmesta9862]

Very helpful, thank u

[@lukedenbleyker5091]

I love your videos. Super fun all the things I love to learn about. I'm coming to the DR in December. Would love to meet you. Your videos had a lot to do with it. And the fact I love to fish. Thank you and keep them coming.

[@Clarks-Adventure]

Sure stop by. But get your fishing in before you get here. The DR is pretty overfished. Not much here.

[@lukedenbleyker5091]

@@Clarks-Adventure I will.

[@lukedenbleyker5091]

Might have to go out for a day trip. It's the ocean lots of fish out there lol

[@Clarks-Adventure]

Lots of fishermen here. They go to the Bahamas to steal fish. I understand it like a fish dessert around here.

[@lukedenbleyker5091]

@@Clarks-Adventure really weird. Have to figure that out.

[@lenwhatever4187]

Good stuff as always.

[@Clarks-Adventure]

Thanks Len

[@Jaantoenen]

Clark, what ratio of lithium batteries to lead batteries on a 3Kw system do you recommend?

[@Clarks-Adventure]

No ratio but minimums. Sadly the minimums aren't rules but system dependent do no easy answers. Enough Li to get through the night. Enough lead to keep your charge controllers sane and to not have the system voltage crash when your biggest load is put on them alone.

[@djinniferstonecastle7540]

Thanks for the video! I am just starting to study this. So helpful to watch over several times until my brain lightbulb clicks on and I've got it.😂

[@Clarks-Adventure]

Might I suggest this playlists? ELECTRICITY ON BOATS - Clark's Full Masterclass: kzbin.info/aero/PLsT7_jPsZM5ogT6or244F49-Gy7pYFV7V

[@briangaquin1021]

If you have a 12-volt lamp with alligator clips you can test a conductor you are connecting to a battery to verify there is no difference of potential. Lamp on check out why "0" volts all is OK and this will also charge your caps, the lamp will go from bright to out, when the caps are charged.

[@doneddy2204]

If you have a book/pamphlet detailing these methods I would be very interested. I have small sailboat with all lead from early nineties and would like more power since my batteries don’t last more than a day or two.

[@Clarks-Adventure]

There is this. www.emilyandclarksadventure.com/bbms

[@jamesbrown1501]

Great video. Thankyou.I have 2 lead acid batteries which l plan to keep for engine starting. To charge these batteries l have solar and the 20hp diesel engine alternators in my boat which charge these batteries. Im planning to introduce a lithium phosphate battery to power everything, except the engine If l understand correctly the alternators on the engine are set up only to charge the LA batteries and if the alternators connnect directly to LP battery it will damage the alternators in my boat....So the way around this is to charge the LP from the LA batteries with a special charger that will allow the LP to be fully charged from the LA battery ...Am l on the right lines??

[@Clarks-Adventure]

Sort of... Both batteries types are charged from every charge source. The BankManager is kinda a sub charge controller just for the lithium. So you can leave the rest of your charge system unmodified. marinedcac.com/pages/bankmanager

[@MyNameIsHoward]

HI Clarke , I've been following your tutorials and really appreciate the knowledge I've garnered from them.. I'm looking to convert my leisure AGMs to lithium on my narrowboat here in the Uk. However your battery manager isnt available here in the UK .. Is there an alternative i would be able to find somewhere , Thanks Howard

[@Clarks-Adventure]

We are going through the CE testing process and once completed we will probably get a UK distributor. That is likely to take at least a year. But no need to wait. Lots of narrow boat guys have BankManagers. They just use reship.com or another such organization to provide a US address and handle the import for you.

[@johnnylightning1491]

Good video Clark. I have some questions: 1) do you recommend putting dielectric grease or some other sealant on the battery connection? 2) does a BIRD perform the same function or is it the same thing as a voltage sensitive relay? 3) are Trombetta relays reliable enough for your system? The reason I ask about the Trombetta relays is that I have a spare one and they're a whole lot cheaper but I don't think the one I have is bi-stable. Between you and Will Prowse I'm learning, but I'm not quite there yet. Good stuff buddy, keep it coming.

[@Clarks-Adventure]

1. I use Vaseline for lead batteries. Always have. I've had no issues. I like conductive grease. I go into that in detail in a video, probably the terminal one. 2 what's a BIRD 3 No idea. Never owned one that I know of. The BankManager works fine with monostable relays as well. As long as that one is rated for enough switching current and it doesn't use too much coil current AND is continuous duty it should work I expect. (I'm stocking some $100 monostable Chinese relays rated for 500 (Chinese) amps. They have a built in economizer. They are in stock but not on the "buy" page yet. Also I have a few huge automotive style 250a rated monostable I'd sell for $50 if any of that makes things easier. )

[@johnnylightning1491]

@@Clarks-Adventure A BIRD is a Bi-directional Isolator Relay Device which I think performs the same function as the Voltage Sensitive Relay you were talking about but I'm not sure. The reason I ask is I'm pretty sure I already have one installed in my motor home. Being the cheapskate that I am I have spending money for something I already own. Here's a link to some literature. 8hi01e.a2cdn1.secureserver.net/wp-content/uploads/2022/02/53-00362-000-PRODUCT-BROCHURE-1.pdf

[@scottwolfeil3647]

Learning so much from your video's. Thank you! Quick question. I have (2) batteries currently on the sailboat (House +Starter). They are connected to a manual switch( Off, 1, 2, All). I'd like to connect a Voltage Sensitive Relay. My question is: Does It make any difference whether I connect It DIRECTLY between the battery positives OR between the battery 1 and battery 2 terminals on the switch? Every example I've watched of this setup doesn't show a battery switch in the mix so I'm slightly confused on how the switch will play in this setup. If I have the switch set to "ALL" does it defeat the purpose of the VSR?

[@Clarks-Adventure]

Doesn't matter. Basically put the switch in parallel with the VSR. Switch on - hard on Switch off - auto control Switch off and VSR ground wire switch off - hard off

[@oschonrock]

I am electrical & electronic engineer who has been working on boat electrics in my spare time on and off for my whole life. This Bank manager is all very clever. The only question that keep bugging me is: Why have a hybrid system? Just get rid of the lead. It only lasts a couple of years anyway. The Lithium is smaller, & lighter for the same usable capacity. (starter / windlass / bowthruster batteries are a different story, which has other ways of being addressed, as the video shows). This just feels like a very clever trick "looking for a problem" and making the system more complex? Maybe I am missing something.

[@Clarks-Adventure]

I think you are missing some things First off if you treat lead the way the BankManager does and it will last a really long time. Li has BMSs inside and for most users they are beyond magic. Get hit by lightning expect them to die. Expect the BankManager to die but a big vat of lead and acid, expect them to live. The ISO just asked Emily and I to write a white paper that will be the beginning of their standard on the subject. They are taking this seriously. ABYC states if you use Li you "shall" have a reliable backup power supply for critical systems. (Lead) Many issues with alternators. Many other advantages. Watch through our stuff and read www.emilyandclarksadventure.com/bbms If it interests you.

[@oschonrock]

​@@Clarks-Adventure Thanks for coming back. Really enjoy your videos and love what you are doing. Sure. The lead will last longer if you effectively don't use it. But from the POV of someone putting in Lithium they are almost certainly doing that when their house lead is almost dead, and they probably putting the lithium into the same box where that dead lead is coming out. They will probably triple their usable capacity by switching to lithium, in the same space and with less weight. Firstly, I am not arguing for a pure Lithium system. Lithium is not very good at extreme currents (despite what some new "starter lithiums" now say). So yes, you should still have lead. But IMHO for a simple and effective system, you should just have starter/windlass/bowthruster lead, and NOT house lead. The amount of lead you thus need is very limited, because it is not about capacity, only about max current. Lead is good at that. And you just park it literally.. with a manual switch or with a voltage sensitive relay as you have shown. Secondly, in terms of "backup systems and failing BMS": Yeah that's an issue. but these have much simpler solutions. Have a way of bypassing your BMS. Building your own LiFePO4 instead of those pre-made blocks helps here, but is not required. And/Or have spare BMS, they are relatively cheap compared to the actual battery. And/or have way of switching your starter lead into your house circuit (a simple high current bypass for the voltage sensitive relay). In this case, you will have enough to run essential nav instruments, VHF radio etc. The issue with alternators should be addressed by having lithium compatible regulator or charge limiters (I think these are lame), but in my suggestion they will always have the starter/windlass/bowthruster lead to dump into and regulate off (no spiked diodes when BMS cuts out etc). I think I have read and watched all your Bank Manager content. It's very clever and it looks like a very neat and well made unit. But for me it still seems to be predicated on the need for using LiFePO4 and lead as house batteries in parallel for the "normal use case" (ie not emergency fallback). And I fail to see why that necessary or even what advantage it has. I think you are asking people to keep 2 types of house battery and the space and weight allowance for them and then asking people to buy a very good and clever product to manage that situation. But IMHO you have not explained well, why people would want to do that in the first place.

[@Clarks-Adventure]

Also, The "on line" lead was the only way I could solve the low current overcharge issue that every "Li compatible" charge controller out there causes. See Conrad's article at the bottom of this page www.emilyandclarksadventure.com/bbms

[@oschonrock]

​@@Clarks-Adventure OK, just read that. In my book it is the Lithium BMS's job to stop overcharge. It can do that. Conrad says "this is the ejector seat". Correct. No regulator is supposed to detect that. It's at the cell level. However, is it not true that in any net charging situation the starter/windlass/bowthruster/BUFFER battery battery will be connected via the voltage sensitive relay? So the lead can act as the buffer for the solar / wind / alternator regulators. The house consumers would will be directly fed from charge. There is no lead capacity needed for this. Therefore no lead house battery is required? If I am missing something on the above "situation at full Lithium" with BMS cut off, and you think the solution is a lead house bank, then I think it might be worthwhile making that case more clearly to motivate people to reserve the space, weight and cost of an additional permanently connected lead house bank with significant capacity. (and then use your product to manage the charge / discharge in parallel with the lithium) What is much better than the "integrated 12V block LIFePO4 with integrated BMS" is a proper separate BMS with separate charge and discharge contactors which the BMS can separately control. ie when the Li if full just switch off charging to Li, not discharge.

[@Clarks-Adventure]

You seem set on your position. We are all captains of our own ships. Do as you like There are pretty good advantages in this approach hundreds of people are using this approach to good effect. It's being adopted by the ISO, it seems. You will either see it as useful or you won't. I'm not trying to change your mind.

[@helomech1973]

Great video.

[@Clarks-Adventure]

Thanks

[@trevorcronin9249]

Thx for the info. Cheaper to put a decent DC to DC charger between the Pb & the Li?

[@Clarks-Adventure]

Except there are no decent dc-dc chargers. They all charge your Li like lead, to a voltage. If you want long life you need a BankManager.

[@jonghj]

I may be wrong, but... In this setup, the bank manager only adds the lithium bettery to the circuit when it's charging. (both voltages are close to each other) When the charge goes away, the lead battery drops its voltage to 12.8 volts and the bank manager disconnects the lithium (that sits at 13.4 volts) from the circuit. As a result the lead battery will be drained and the lithium is actually the one that is on vacation on vacation...

[@Clarks-Adventure]

Hi Hank, Yep. You got it a little wrong. The batteries disconnect under charge so the lead voltage tends to go up after disconnect. Regardless there are much more complex instructions in the device that keeps it sorted. We have 500 happy customers, we must be doing something right. More detail here. kzbin.info/www/bejne/jIu2o2mlast_fqc

[@jonghj]

@@Clarks-Adventure I see my mistake. 😁 The lead battery is not dropping voltage after charging stops.. After charging both batteries will keep the same voltage because they are connected.. So the bank manager does not disconnect. My bad!

[@Clarks-Adventure]

I'll try to say it another way, It disconnects after the li finishes charging but reconnects once the Pb finishes charging

[@Clarks-Adventure]

I'm obviously still figuring out how to explain it clearly. Thanks

[@jonghj]

@@Clarks-Adventure This guy did an experiment without a bankmanager. What happens is that the lithium after a few minuted is trickle charging the lead battery. And both end up staying at around 13.4 volts. kzbin.info/www/bejne/jna6dniimax2nsUsi=TF6l6ASXTvcBZF6m Btw Thank you for you videos on the subject.. I feel confident to keep my Agm batteries and make them a very useful part of my 24 volt 4 battery 200 ah setup. Before seeing your videos I planned to sell them. 😊

[@mgevirtz]

Can you show us your power supply design? On my boat I am using a 110 volt connected to a very hungry inverter.

[@Clarks-Adventure]

I think you want to look at our other videos. Take a look at our playlists

[@kennyrodg]

Hi from the UK....Great video and thanks for explaining things so well. I have a question if i may.....I have an RV with an auxiliary start system...If the engine starter battery goes flat the system combines the house bank with the starter battery via a relay to give you an emergency boost...My question is, how would this system work if the house is completely Lithium and the engine starter is lead acid. Thanks in advance.

[@Clarks-Adventure]

If you used my BankManager the starter lead would be held to 13.2 until the HOUSE Li went flat. Then it would be disconnected to preserve it for starting your engine so it's EXTREMELY unlikely your lead starter would go flat even if you left the lights on.

[@kennyrodg]

@@Clarks-Adventure Hi and many thanks for the reply, it's appreciated....Being completely honest, by the time I factor in shipping, import duty etc the cost would be prohibitive but for other RV owners this might be an option....I help out on a few American based Facebook groups so this could be relevant and I'd be happy to spread the word.... My scenario then.....I have a split charge relay (voltage sensing ) to keep the starter battery charged when on solar or shore power and I understand that the battery manager would keep the starter battery charged....However, the question still remains in case of emergency as to how you would combine the the two battery sets when using the auxiliary start function that most if not all American manufactured RV's have...Just for info...I am UK based but my RV is American... Thanks again and look forward to hearing from you.

[@Clarks-Adventure]

You could always make a jumper switch that bridges the batteries together if you think that would be useful.

[@Clarks-Adventure]

And yes please spread the work on the BankManager please.

[@gerrys6265]

I have a 100 Ah LiFePo for house bank and an agm for starting. Charging with Alternator and solar with an MPPT controller. Can I ignore first Lead battery in the video and use the voltage sensor relay between the LIFePo and AGM which is a dedicated starting battery? Love your videos Thanks

[@Clarks-Adventure]

No because for this scheme to work some lead has to be guaranteed to always be connected or bad things will happen to your charge controllers. But with a hybrid battery system you really don't need the VSR as much. Since your lead won't really be touched until your li is nearly dead you can use a thin plate starting battery as your lead bank (in fact I recommend it) as it won't cycle much. Just don't let the li go dead and all is well. So in terms of the video, use the two battery model with the lead being a starter battery.

[@gerrys6265]

@@Clarks-Adventure Thanks so much!!

[@DGinNC]

So there's a trend in car audio of adding lithium ion banks to vehicles. Would one of your bank managers be practical to achieve this safely. These lithium banks are operating around 15-16 volts and being used to drive high power amplifiers and coupled with high current alternators 300A . Just looking for a way to do this safely or more safe than what I've seen others do.

[@Clarks-Adventure]

I'm not a fan of all li-ion batteries. The BankManager is only configured to run LiFePO4 batteries. Other li-ion cells are prone to thermal run away (especially when charged wrong). LiFePO4 is particularly safe (extra important on a boat) and lasts a lot longer. If you use a BankManager with a LiFePO4 in a car audio system you can charge all your batteries with your alternator while running the engine and assuming you are going to run a relatively small Li bank I added a feature to the menu that can temporarily disconnect the lithium bank while you start the engine. Li really isn't for that kind of load.

[@benpower3331]

Hi Clarke, Another great video, does your bank manager and the inclusion of the lead in your house bank protect your alternator. Is that why you use the lead? I was thinking of getting a dc to dc charger but you don’t seem to lean that way. Ben.

[@Clarks-Adventure]

That's one of the reasons, Ben. kzbin.info/www/bejne/oHS9l5Rop5KEg7s I really think dc-dc chargers solve two problems but introduce like 4 more.

[@sweetescapecutter2823]

If you wanted to increase your amp hours available do you increase the lithium side bank or the lead side bank of batteries or both

[@Clarks-Adventure]

Either. Or both. Generally the smart money goes on the li side

[@clayratliff7727]

Answered all my qestions, very helpful! I do want to double-check one thing- If I have multiple lithium batteries wired in parallel, I would set the BBMS amps to the total capacity? For example, with 2x 200 ah lithium batteries I would set the BBMS bank size to 400 ah, is that correct?

[@Clarks-Adventure]

That is correct

[@pontoonrob7948]

I plan on trying your system. Tell me please about points of failure: 1. Suppose the relay fails either off or on, what possible consequences? 2. Suppose the bank manager fails either joined or apart, again, what possible consequences?

[@Clarks-Adventure]

Well for a bi-stable contactor those are the same. If you fail while connected you stay connected. If you fail disconnected you stay disconnected. For a monostable NO any failure disconnects li bank For a monostable NC any failure connects the li bank If you are disconnected you can't use or charge your Li. If you are connected your Li is slightly overcharged by the lead charge controller as long as it basically stays below 14.6. If it tries to equalize your lead or your Li cells are not balanced your BMS steps in. During this time you are exposing your Li to low current overcharge. This is a slow certain death but you could go a year this way without destroying your Li. The bi-stable contactor has a cycle life large enough that it should outlive you in this application. The BankManager is made as robust as I could make it including having an independent watchdog timer to reboot it if it were to lock up from a software or memory error.

[@foowb]

Would you consider a battery isolator (the one with diodes) in place of a VSR in the setup with a dedicated starting battery? I think I understand the difference between the two, but functionally I couldn’t think of anything working differently in this particular setup with three batteries.

[@Clarks-Adventure]

Diode based isolators were a good idea 30 years ago. Their problem is they induce a voltage drop. This wastes power, that's why they have heat sinks If you use one be very careful where you sense voltage.

[@foowb]

@@Clarks-Adventure thank you! I don't have either right now but looking online lots of stores still seem to be pushing the isolator switches. Good to know, I didn't know they produced a voltage drop, I'll do some more reading. A VSR does seem like a neat idea. Also thank you for making all your excellent videos. Even with a lot of background in EE I'm learning a lot.

[@stevejohn]

I really like the BankManager. have you tried installing it on a larger system? I am considering installing it on a project I am working on. I have 3 starter batteries Port, starboard, engines and gen-set. a 800 amp lead acid house bank and adding a 800 amp LiFiPO4

[@Clarks-Adventure]

No problem Our boat has 1500ah of lead, and then there is this.. kzbin.info/www/bejne/pYiaeJWPiZiimdE

[@johnnychristo4895]

I have a motorbike and would prefer to use a single lithium iron. Is that feasible?

[@Clarks-Adventure]

You can do anything you like. Are you asking will the BankManager operate as a charging device without lead. The Gen3 will have that capability, something I developed for a guy building wheelchairs.

[@johnnychristo4895]

really appreciate reply im sure time is important thanks cobber. Actually i was wondering is the bank necessary can i just put lithium in and use it like a lead.@@Clarks-Adventure

[@Clarks-Adventure]

You mean a little starting battery for a motorbike? Sure just do it. They don't cost all that much and work fine until they die. I have a 1700cc v-twin, I use a little battery. Light and starts so much better than the lead.

[@johnnychristo4895]

@@Clarks-Adventure 1700!! Wow Suzuki boulevard? You tearaway I'm green with envy. Thanks again I'll give a small donation first chance as appreciation. Born to be free you live it

[@Clarks-Adventure]

Roadstar Warrior

[@jeremyshima2888]

Hi Clark, It is my understanding that Li takes a higher voltage to fully charge than lead acid. How does the bank manager deal with that? Do you just not fully charge the Li?

[@Clarks-Adventure]

That's a serious misconception that slowly kills Li. Li just can't be charged "to a voltage" like lead. There is so much more to it. It can be fully charged at 13.7v or it can take power at 14.6 for quite some time depending on other factors. Charging beyond full slowly kills the cathode of your Li cells. Also repeated under charging causes a cell memory condition. If you set the BankManager for 100% it will charge the li fully but no more. For various reasons, but chiefly Li having a lower internal resistance, the li will take power faster and charge before your lead.

[@joebuck49]

good info

[@Clarks-Adventure]

Thanks Joe

[@stillwatersailor665]

I want to have 2 100 amp lithium batts for house and a separate lead starter batt. I plan to have solar to charge the lithium and use engine alt / battery charger (shore power). What options to I have other than a DC to DC charger? My boats on a lake and the most I am off shore power is for 3 to 4 days max.

[@Clarks-Adventure]

Well I obviously like the BankManager. www.emilyandclarksadventure.com/bbms

[@markreynolds8630]

Can I ask. In those systems, where does the output from the alternator feed in? Tnx.

[@Clarks-Adventure]

To the house lead. All charge sources and loads go to the house lead.

[@azul_5157]

Hi Clark, Another superb video for us electrical chickens out here. Quick question, is a voltage sensitive relay the same thing as a battery combiner? I currently have one between my house bank (AGM) and the start battery (pB/A).

[@Clarks-Adventure]

Only one difference. VSRs cost $25 bucks Battery combiners are like $200

[@azul_5157]

@@Clarks-Adventure You are very correct on price. I have the victron one....

[@markandrews7701]

One question I have had since first learning about the BMS is about the ratio of lead to lithium. Is there an optimal ratio or other metric to decide how much lead should be added as the amount of lithium increases?

[@Clarks-Adventure]

There is a minimum. No maximum really except a lot of sick lead will eat power over night being held to 13.2. The minimum is: 1 enough to keep your charge controllers sane. Some make bad decisions or put our really noisy power if connected to small batteries 2 enough to keep the voltage from dropping too fast when a big load comes on with the li disconnected. It's very system specific. Thin plate starter batteries do this job best as long as you don't plan on cycling them. If you are planning on using your lead as a cloudy day backup you will need this plate deep cycle batteries but you will likely want a good amount

[@davidbell4986]

Did you check your shorts after that spark?

[@Clarks-Adventure]

Unexpected sparks around those cells are always terrifying for a second

[@covisko]

What if I want to keep my battery selector switch on the boat? Can I skip this voltage sensitive relay?

[@Clarks-Adventure]

Sure you can do it manually. I personally have both. So I can force the house into the starter even if the voltage is low. Just jump the vsr across the switch terminals

[@benkanobe7500]

I have my Bank Manager ordered for my 36 volt (yes, I know) system. I can not understand the artwork or schematic as to how to wire the included two resistors. Where do they go? Why are they there? Do I wire them in series or parallel? Can someone help as I am NOT technical (but I learn really fast!)?

[@Clarks-Adventure]

Sorry we don't get a lot of 36v guys so I didn't do a special page for you. The bi-stable contactor is a 12v device. The resistors kinda eat up some power so the contactor only sees 12v of your 36v. Each resistor eats up (drops) about 12v. To wire them up go from the lead positive 3/8 contactor terminal through your fuse then through both resistors in series then to the contactor positive coil terminal (small and alone) Mount the resistors to a metal plate to help dissipate heat and protect your boat if things were to go wrong.

[@chriswoodward5368]

On one of your videos you talk of using lead battery to protect the alternator. How small of a lead battery can I use. I will have a bank of 600 or 800 APH 12 Volt battery bank of lithium. It is in a motorhome. Charging comes from 160 amp dedicated alternator or from 2 inverter chargers that get their power from shore or generator. I have looked at DC to DC charge controllers, but most of them seem to max out at about 80 AMP no point with 160 amp alternator. Still no solar as of yet I don’t see the benefit we’re we live.

[@Clarks-Adventure]

It really doesn't take much. Especially if the lead battery in question is a thin plate starter type. I just put an FAQ section on the BankManager website. I talk about this a bit there. www.emilyandclarksadventure.com/bankmanager

[@chriswoodward5368]

@@Clarks-Adventure thanks I will look at it.

[@brettday8450]

Can this device be used for car audio applications?

[@Clarks-Adventure]

Yes. And with a BankManager your alternator can charge the li. I even added a setting that will automatically disconnect the li as you start the engine so the starter doesn't overload the li batteries.

[@terryroth9707]

At what voltage does the controller work with? Are the newer systems moving to 48v and higher, yet? Higher voltages means less current.

[@Clarks-Adventure]

The BankManager runs at nominal 12v, 24v, 36v and 48v systems. My power supply section would fail above 80v so higher than 48v nominal is a total respin of the circuit.

[@cluuck4617]

Is this another version of the BIRD relay, which I have separating my 2 battery banks already? Really like the concept, and would it eliminate the need for a DC to DC charger to protect the alternator?

[@Clarks-Adventure]

I don't know what a BIRD relay is. The BankManager is a new thing. It's a battery bank management system. www.emilyandclarksadventure.com/bbms Here is some useful info on li and alternators kzbin.info/www/bejne/oHS9l5Rop5KEg7s

[@cluuck4617]

@@Clarks-Adventure The BIRD (BI-DIRECTIONAL ISOLATOR RELAY DELAY) performs two important functions. It provides a method of charging the coach battery from the engine alternator and charges the chassis battery from the converter when the coach is plugged into shore power.

[@Clarks-Adventure]

Yep almost the same thing. I bet the big difference is the price.

[@lanceporter994]

i understand but where is the best place to connect the loads

[@Clarks-Adventure]

As I say at the beginning of the video. All loads and charge sources go to the lead. You may want to watch the beginning again

[@jeffmeredith9094]

Will this work for car audio??? Im running a AGM battery under the hood and a 64ah lithium battery in my truck next to my 3 amps

[@Clarks-Adventure]

Yep. I added a special feature so the li gets disconnected when you start your engine automatically so the li isn't asked to do that heavy lifting. Comes back in when the alternator starts charging. With the BankManager you can correctly charge your Li battery off the cars charging system.

[@slowbrezze]

still leaning appericate wven though more into car auto food info

[@glennvoyer4624]

Hi Clark i really would like to buy your bank manager i live in Western Australia is there going to be a time where i can buy direct from you and get it shipped because at the moment it is very expensive and hard to organise the shiping hope to buy direct and shipping direct from you soon

[@Clarks-Adventure]

As of now it requires a currier. Reship.com was recommended by an Australian and we have been passing that recommendation on. We sell a lot of these to Australia. Your country is just expensive to get things into. Of course you could vote that away. I really don't know how to solve that. I imagine if I had a local distributor there would still be the customs charges but shipping might be less. If someone in Australia wanted to buy at least 10 I'd offer a discount so they could resell. I have a guy doing that in the EU.

[@MNeilGri]

My current battery locker is full, but I have another locked about two-three feet further back (in the quarter birth). As long as I had the correct gauge wire, would using that back locker to store the lithium battery be ok, or would the distance create a problem for your device?

[@Clarks-Adventure]

No problem. And with li being so much lighter and not needing the same ventilation conditions, it can be placed in more places.

[@MNeilGri]

@@Clarks-Adventure thank you

[@bhartley1024]

Can anyone save me a trip to the boat and remind me what size the contactor studs are for the contactor in the video? I think they are 3/8", but I'm not sure.

[@Clarks-Adventure]

Yep 3/8"

[@bhartley1024]

@@Clarks-Adventure Thanks Clark!

[@emilioplentz]

Hi Clark. After the batteries are fully charged (Lithium and Lead) what happens to the energy produced by the solar panels ?

[@Clarks-Adventure]

The solar controller just doesn't let it pass to the batteries. Technically the panel voltage goes up to the point that the light doesn't have the activation energy to overcome it. The energy just heats the panel like it heats anything that color.

[@emilioplentz]

@@Clarks-Adventure Thanks

[@Kantuski]

@@Clarks-Adventure Great videos. In the above scenario, could you use a grid-tied inverter to use the PV input?

[@Clarks-Adventure]

It would be harder than you think to get them balanced when running together. Probably use some kind of voltage sensor on the battery side to flip the mppt/inverter with a relay would be the least technical way to make it work.

[@slowbrezze]

how can use this in car audio i know this about boats or rv storage and going back and fourth ppl seem knowledgeable here. i want to know since auto is burst my goal is to stay above 13 to have optimum burst on bass drops

[@Clarks-Adventure]

I was thinking about car audio when I designed the BankManager. It has some special features that were just for you guys though they turned out to be useful in campers, houses and boats as well. As I understand it a lot of you guys with Li charge the li at home. With the BankManager and the two battery model I show in this video you can charge your Li as you drive with your alternator and the li will be disconnected when you start your engine because Li just isn't for starting loads. So you can run independent of an AC charger. You can expect your amps to see 13v except from when you actually crank your engine to when your alternator kicks in. So you might hear bass clipping for like 5 seconds on engine start. www.emilyandclarksadventure.com/bbms

[@seekerstan]

So, how do you avoid melting down your alternator when the dead Lithium bank connects to your alternator.

[@Clarks-Adventure]

I made this video and the one after it just for you. kzbin.info/www/bejne/oHS9l5Rop5KEg7s

[@Clarks-Adventure]

kzbin.info/www/bejne/jmXCgKJ5dp2HoLs

[@jasonsomerville2504]

Please tell us how we purchase in UK

[@Clarks-Adventure]

Like it says on the buy page . www.emilyandclarksadventure.com/bbms We only ship to US addresses. There is a company called reship.com that can provide you with a US address and handle the customs for you.

[@bradsullivan870]

Is it possible to run a lithium battery in parallel with a LA battery on a diesel truck? If so, how?

[@Clarks-Adventure]

Yep several guys have done it. Take a look at the BankManager install manual. Basically you just put the li in parallel with the lead and a BankManager contactor in the positive cable. That big case alternator will charge everything up when driving and the Li gets used first www.emilyandclarksadventure.com/bbms

[@Clarks-Adventure]

Once you've done that you should consider one of my battery powered air conditioner units for the sleeper. No more apu or engine running if you get one that's full heat pump. MarineDCAC com. (Air cooled unit coming soon)

[@bradsullivan870]

@@Clarks-Adventure Would that work with dual Lifepo4 batteries or would there be an issue?

[@Clarks-Adventure]

@bradsullivan870 no problem. Usually one limits themselves to 4 batteries in parallel. But with multiple BankManagers you can go beyond that.

[@richcherwalk6349]

Why not just get several lithium ion in parallel with a heavy duty bms for starting engine?

[@Clarks-Adventure]

Lead has some serious advantages over Li. And without a BankManager charging incorrectly is basically impossible in a live system.

[@marklapierre5629]

What do I do if I have only a LiFe house battery and a Pb starter battery with no Pb house battery? Why would I want to use up space and weight for a Pb house battery when I have a LiFe house battery?

[@Clarks-Adventure]

I assume you are asking.g because you want to take advantage of the BankManager and it's ability to protect your Li bank. If so as I say in the video use your starter battery as your lead house battery. You won't touch that battery with house loads until your Li is over 80% discharged.

[@marklapierre5629]

@@Clarks-Adventure So there's no way to connect a VSR to protect the starter battery from being discharged without some form of Pb house battery? I guess I'll have to add a tiny AGM battery into the circuit for the VSR to reference from.

[@Clarks-Adventure]

You do understand that your expensive li batteries are being charged wrong, right? I'm going over to a cruising boat today to look at his 1 year old li that has been cooked by Victron gear. We will try to recover some life into the cells and then he's installing a BankManager. Hopefully not too much damage has already happened. I might get a video out of it. Yes you could use a VSR between li and lead. It would turn off if the li was depleted below 20 percent. But any charge going to the lead would also go to the li. Li shouldn't be charged to a voltage limit and it can't be floated. The vsr wont help that.