The Top 9 Lithium Battery Mistakes for Van and RV Power Systems

[@rosslukeman]

Get the Ultimate Van Power Cheat Sheet: www.rosslukeman.com/vanpower

[@rosslukeman]

@@AkashicSeer great point on the quality of less expensive breakers. I think people worry about the quality of their main components and then are like "oh yeah, breakers" at the end and get whatever is cheap for that part of the build. But as you said some breakers trip before they hit their rating, or don't trip at all and cause fires. This is definitely an area to invest in quality, because we are literally playing with fire. DON'T save money on breakers, is the the advice I would give. Save money somewhere else if you have to.

[@paulhardie9450]

Mate simple solutions to seemingly impossible problems explained in a well and understandable fashion for the layperson to fathom .You give great advice 👍

[@rosslukeman]

Thanks for tuning in Paul, I appreciate the kind words!

[@DougJohns]

It's always nice to hear from someone that has obvious expierience... so many on youtube simply read and repeat without understanding.

[@rosslukeman]

Thanks for the kind words Doug!

[@JackMayer]

Good one. As an installer/designer for 20+ years you are spot on!

[@rosslukeman]

Awesome, thanks for the vote of confidence!

[@quasimodo8215]

I hope that this comment helps you with the algorithm as much as your excellent content helps us. Thank you Ross!

[@rosslukeman]

Hey awesome, every little bit helps! Thanks for tuning in, I'm glad you got something out of it!

[@pteepan2708]

I love my Victron gear but their battery and Battle Born seem SO over priced. Thank for the video, great tips

[@lvtmnts]

Wow nice to see someone on you tube that really knows their stuff. Did cars for 34 years and specialized in electrical and computer system problems but no experience with RV's till I got my own. On my 4th rv and struggling with battery issues as I dry camp most of the time. Have 4 golf cart batteries and 2000w inverter 500W solar on roof and 300w solar external I can move around when camping in tress.. Worked well for couple years but having issues and want a look into something better. This video really helped and I feel I can trust your info because I can tell you really know what your talking about when so many you tube videos the presenters are not very knowledgeable and often suggest things that are dangerous especially to DIY'ers that don't really know what they are doing or have little experiene building fixxing or designing things. Thanks !!!!!

[@nathoilboy2053]

Your fist point is fantastic. So many companies state...well you have LiFePO4 batteries now so you can run anything...checking the maximum constant discharge is key.

[@rosslukeman]

Hey Nathan, glad you got something out of that first point, I thought it was a battery spec that we should pay more attention to. All most of us care about are amp-hours. Thanks for tuning in!

[@makoshark3759]

Ross: You really have enlightened my brain and broaden my vision on things I did not even know, clicking on this post was the best thing I did since last 2 years ,almost every thing I wanted to know about lithium solutions you havegiven the answer for here .... and all in under 30 minutes.. keep up the good work Champ.. God Bless You

[@annehoffman50]

Amazing how clear you are in your descriptions. Wish more technical providers could communicate as well as you.. Ditto for your Van Power Cheat Sheet.

[@davidsapp8666]

Excellent presentation. Thank you for doing a detailed job.

[@rosslukeman]

Thanks for tuning in and for the kind words David. Glad you enjoyed the video!

[@davyp2993]

This confirmed some of the things I had installed, and gave me thought about others I've omitted. I guess I have some wiring to do.! Thanks for the upload.

[@rosslukeman]

Hey, thanks for watching, glad you got some confirmation, and some new ideas from the video!

[@Gary-wh7ce]

Hi Ross, good content. I do have one request and that is mistake 3. Even when you pull positive one on end and the negative on the other end you will will have a major imbalance in load. There was a time I believed in item 3, but NO more! Take a clamp meter and you will see this in real time especially with lead acid. I have since changed over to use a buss bar on all multi-battery banks! LiFePO4 works so much better with a buss bar. The key is to make sure all connections are torqued the same to manufacturer specs and then test it with a clamp meter! AGM and lead will still see fairly un-even swings until the batteries are balanced but over time they self balance! I highly recommend clamp meters, because everything is just guessing without one. Cheers. Gary

[@mickeymouse-lu2yk]

Truly an excellent video that all rv/van/boat electrical DIYers should see - many thanks

[@rosslukeman]

Thanks for tuning in, great to hear you found it helpful!

[@mb-3faze]

Coming down the pike are sodium-based batteries. The really cool thing about sodium-ion based batteries is that they can be discharged to zero (making them very safe for transport). Fingers crossed on industrial production soon. They will solve many issues.

[@Tumbleweed5150]

@@mb-3faze Those can also handle higher temps, if I recall correctly. I could run my BattleBorns down to zero percentage, but not to zero Voltage. I assume you mean percentage also. I do have my Growatts set to shut down the system before the batteries would even come close to thier shut down point, at around 10.5V, as I believe they will last longer if I keep the percentage of charge up as high as I can. I live in the desert where it has gotten as high as almost 130F, so I DO rely on my solar system for two air conditioners, one a 5000 BTU window model, and the other an 8000 BTU portable model. I have around 27K Watt hours available for overnight, and around 7000W of solar so far, all running two 5000W growatts to power my RV and external stuff. I've been off-grid for over 30 years and this is the best system I have had yet, and so far it's handling three fridges, (one a small "apartment size and two smaller, cubical shaped ones), an upright freezer, an air-fyer/toaster oven, an instant pot, , a 6 gallon water heater, plus a couple of water pumps and of course my computer syste, with no problems. Sorry for the long reply, but solar power interests me a lot.

[@mb-3faze]

@@Tumbleweed5150 Most excellent. You're probably more of an expert than the 'experts'. I read only today about iron-air battery technology (commercial storage) being implemented and supported by big names like Gates. With luck that promises to be very cheap. Soon you'll have even more options for your system.

[@RowanHawkins]

​@@Tumbleweed5150I realize the small fridge is for space, I did some testing a few years ago with a kilowatt meter and learned that a dorm fridge has almost the same power usage as a full size standard fridge.

[@fratermus5502]

Thanks, failure analysis is important for full understanding. I warm my LFP to 50F (pads) after poring over a bunch of cell spec sheets showing allowable C rates at different temps. Seems to me that the self-heating ones miss out on charging opportunities because they allow the batt to get cold in the first place, then disable charging while the internal heating runs.

[@rosslukeman]

Thanks for watching, yes interesting point on the self-heating batteries. I suppose the other argument is you could accidentally use battery power as they heat themselves, even if you don't have charge sources present. Perhaps both methods have their advantage.

[@Justthe2ofUs843]

I am an installer and I approve this video. Good job.

[@rosslukeman]

Thank you!

[@mgysgtk8835]

Great points. I glad you covered fuses,

[@cawangankejuruteraanelektr735]

0:28 Mistake 1 - BMS Capacity 4:42 Mistake 2 - DC Ripple 6:55 Mistake 3 - Battery At The End Of The Line 8:01 Mistake 4 - Fuses! At The Battery Bank 9:00 Mistake 5 - Wrong Fuse Rating 12:31 Mistake 6 - Loose Connections 14:28 Mistake 7 - Increasing Battery Bank Voltage 18:33 Mistake 8 - No Cold Weather Provision 22:27 Mistake 9 - No External Battery Monitor

[@kryptosyt8171]

thx man

[@biffmacatawa]

Great content. I winter van camp In the rockies. Heat and insulation for the Battleborn Lithium is a must. A cheap indoor/outdoor thermometer is an easy way to monitor house battery temp. Just slide the external temp probe down inside the battery box. Good luck with your adventures.

[@rosslukeman]

Hi Biff, thanks for tuning in and for sharing your experience! Great idea with the indoor/outdoor thermometer, love that. Have fun up in the Rockies, sounds awesome!

[@PSD9737-ML]

I have a fairly decent knowledge in this area but still learned from this video. Great job!

[@edwardlord3632]

Thanks for the reminders as I get ready to order my battery bank next week!

[@rosslukeman]

Thanks for watching Edward, great to hear this video came at the right time!

[@TheCornucopiaProject-bd5jk]

I still like a insulated box for my batteries best. Add a heating blanket or heat mat to get the inside temp up during the coldest part of the night (on a timer). I’m not a fan of expensive self heating batteries.

[@raystanton238]

I use a pair of 12 volt rv holding tank heaters and added bypass switches.

[@petekeener8943]

Thank you so much for solving my problem. 200 amp L battery kept shutting down on me and no one around this town in Oklahoma knew anything about Lithium batteries. My battery, after I looked after you told about it, had a 100 amp BMS and I thought the battery had gone bad and had ordered a new LiTime battery but just looked and it has a 200 amp BMS! Have been tearing my hair out for the past couple weeks over this and no luck until seeing this video!!! Btw, I used to live in Houston and wish I'd been there to consult you!!!

[@rosslukeman]

Hi Pete, awesome to hear this video helped you solve the issue! I know it is frustrating when everything mysteriously turns off. Glad you got a new battery that will do the job. Thanks for tuning in!

[@walrus10001]

Really interesting and very helpful. Great presentation style. Thank you!

[@rosslukeman]

Thanks Peter, I'm glad that was helpful! I appreciate you tuning in-

[@JohnSmith-zk5pq]

Good job & great info. I just sent the link to a buddy who is considering LiFoPo4 batteries.

[@rosslukeman]

Hi John, I appreciate that, great to hear you got value out of it!

[@philc.9280]

Another mistake is paying an enormous amount of money on Battleborn batteries. Sure, they're great but the competition has come so far and just a fraction of the cost.

[@Ajjakakkaka]

Agreed. Victron’s Smart lithiums with external BMS is way ahead of anything battleborn has

[@americafirst8201]

Watt cycle are killer for the price.. I said what I said!

[@lawrencewiddis2447]

Buy 3 batteries or one Battleborn? Same price.

[@rudiwiedemann8173]

EXCELLENT and very understandable and practical technical explanation!

[@rosslukeman]

Thank you Rudi!

[@seekerstan]

Solar charging 48v: Another big issue with higher voltage solar systems is that it forces you to put your panels in series. A problem with this is that any shade on any spot of that group of panels will degrade the output of all of them.

[@rosslukeman]

Good point! Thanks for tuning in-

[@dyslectische]

No its not . The old yes its correct. The new ones have by-pass diodes so it do compensation

[@marksommers6764]

@@dyslectische, read series .

[@dyslectische]

@@marksommers6764 read again and see the info . Old days one panel down hole systeem down. Today new panels only shutdown small parts on one solar panel Pay for a real one make in the E.U and not china shit.

[@michaelphilip3919]

Why not just use a boost charger instead of a buck. Am researching for a 48vdc system on a Sailboat

[@Pauljohn696969]

Excellent tutorial and easy to follow and understand. Thanks.

[@rosslukeman]

Thanks Paul, great to hear you got something out of it! Thanks for tuning in-

[@TK-123]

Unbelievably helpful. Thank you so much.!

[@rosslukeman]

I'm glad that was helpful! Thanks for watching!

[@ScoutyBoyO]

Super helpful for battery power rookies. Thanks a ton.

[@rosslukeman]

I'm glad that was helpful, thanks for tuning in!

[@warlem2638]

Excelente vídeo, as informações sobre esses erros são de extrema relevâncias.

[@rosslukeman]

Obrigado por assistir, fico feliz que você achou relevante!

[@SEANRMZ]

Thanks for this video Ross, I have a nice set up with 400ah bank with a victron MP 2. The system is 12v all hooked up with 4awg wire. I have 1 section 6inch wire between the lynx and switch and the wire heats up. All bolts are torqued to spect and crimp lugs on to perfection using a hydrolique press.. weird

[@rosslukeman]

Hi Sean, sounds like a nice setup, but maybe the wire is a little small? The 4 AWG would be used maybe for a 12V fuse block but the big trunk lines would be larger. Perhaps that is the heat problem...hope that helps, thanks for tuning in-

[@SEANRMZ]

@@rosslukeman thanks ross, the 4awg was wire suggested for anything over 400ah of battery bank. I sent you a small video to your email explaining where section is heating up. thanks sean

[@randolphh8005]

@@SEANRMZare you mixing up “4/0” with “4” in your post? Obviously 4/0 is adequate for most anything, “4” is not for any battery connection of 12 volts.

[@JohnSmith-zk5pq]

@@randolphh8005 That is what I was thinking. I used 4/0 for my 400amp battery bank going to and from inverter via my Victron Distributor.

[@ScottDLR]

Very informative vid, I don't think I will be making any of those mistakes. I do wonder why one can't use a manually resetting breaker (Bussman type III) as the main "fuse".

[@rosslukeman]

Hi Scott, the main fuses shown are approved by the ABYC because of their interrupt rating. You could use something else if you want to I suppose.

[@lyfandeth]

Even a car battery can put out over 3000 amps into a crowbar short. That's enough current to weld a breaker shut, causing a fire. The next step up in DC breakers are the ones with a 5000 amp interrupt current. One of those should protect one lithium battery (which puts out more current than a regular car battery. You really need a UL/CE approved breaker, with an interrupt current of 10,000 A if you want to sleep well. The primary battery should really be your first priority, they'll vaporize and can't weld shut the way breakers can. By the way, at 12v and these amperages, if your wedding ring shorts out a tool handle at the battery? Your finger will literally be blown off. You really want to read up, Nigel Caulder or Charlie Sherman both make boat maintenance guides, and the systems in boats and RVs are basically identical.

[@mick2d2]

Great video, very educational and easy to understand. Thanks!

[@rosslukeman]

Thank you!

[@labcoattheater6161]

Great video. This really helps give me confidence in what I am putting together. Thanks.

[@rosslukeman]

Thank you, great to hear that helped!

[@SuperSushidog]

This video can be invaluable for lithium/solar system newbies. Great job on a difficult, technical subject. One note, ANL fuses are not rated for 48v systems. You must use a T-fuse for anything above 24 volts. I use a 20kva (400v) 300a DC breaker on my battery to inverter line. The inverter is also protected with an internal circuit breaker, but you still need protection for the battery cable. I also have a high voltage (336 vmp) array on my roof, so use a 500V, 32a DC circuit breaker for that down line which doubles as a disconnect switch. This is not to NEC code for grid tied systems though, as they need a “Rapid Shutdown of PV Systems on Buildings," such as a TIGO module for protection in case of fire. I think that's overkill on a van or RV though. BTW, I have a 12v 560ah LiFePo-4 battery and a separate 620w solar array on the side of my MH to run all my 12v appliances, jacks, slides, etc. so no inefficient stepdown converter is needed. I use a 320ah 48v battery charged by a 4,400w rooftop array for whole house 120v AC power. You are correct, 48-volt systems are not practical for vans with smaller battery/solar systems. For temperature protection, our 12v batteries fit perfectly under the steps of our MH where our old pair of GC-2 golf cart batteries used to reside. We insulated the battery compartment, cut a 1" hole in our step risers and installed a tiny computer CPU fan to keep this space at close to room temperature, so we don't have to worry about the BMS shutting down charging if they get too cold - or their life reduced from getting too hot. Our 48v bank resides under the bed of our MH which has a larger computer fan circulating conditioned air in this space as well. We're FTers, so our RV is lived in 365 days/yr. and never sits in storage as some do. Lithium battery heating pads are available for inexpensive batteries or do-it-yourself battery builds like I have, but unnecessary if your battery is kept in an insulated compartment where interior air is allowed to circulate.

[@arildred2780]

There are some 80V ANL fuses

[@SuperSushidog]

@@arildred2780 Thanks. I stand corrected. The biggest ones I've seen are 32v. Good to know there are some 80v ones available.

[@andystewart1580]

Great video! Iam glad I met all the bullet points for my system by copying a bunch of your designs. I do have an issue with the system stopping for one minute almost the same time each day here in Phoenix AZ at 14:29 hrs +/- a few minutes. How would I isolate to see if its heat issue /shock issue for a 12v 300ah battery with total of 600w panels for the system. (Chins LiPo Epever 60a mmpt, Renogy 3kw inverter and Renogy 500A battery monitor) when Iam not around. Rv sitting with power on inverter 24/7 internet wifi and alarm system cameras go out and come right back. Temps recorded inside RV are up to 135° and hold where equipent ( battery charge controller inverter) is a tad cooler around 125° the hot part of day is not until about 1600hrs. The renogy battery monitor shunt shows battery charged and only 9W being pulled from system. Thanks !

[@MJ-ge6jz]

Good info! Thx! I need to move my outgoing Neg line to the other end!

[@rosslukeman]

Thank you, great to hear it helped you improve something. Thanks for tuning in!

[@jimsprague7502]

Good Day Sir. I also live in the Houston area. Katy to be specific. We have a new 2024 Jayco 25RB. I am in the process of upgrading the Solar Panels to 495 Watts total,( came with 200 watt panel, I have purchased a 195 watt and 100 watt Bifacial panels to add on the roof. However we are also looking at upgrading the solar charge controller (The Go Solar 30 amp PWM unit that came with it is likely sub par). Im looking at the Victron 100/30 W/ Bluetooth unit. I have also purchased a Furrion Net Zero 1000 Watt inverter (With transfer switch built in) to install in the camper. Its almost 600$ unit and Camping world had it on sale for 40$ so I couldn't refuse that price. The camper is pre wired for an inverter (Although I have questions as to whether that existing wiring is adequate and where in the breaker panel this is connected. I have many questions on the correct way to install this unit, or possibly pay someone who has the technical knowledge to do the job correctly. The unit has mostly 12 volt and propane appliances. The inverter would be for the TV, and Mac Mini. If we need the A/C we would use the inverter generator. Is this something you have experience with? We are also looking into upgrading to Lithium Battery over the stock battery. The Converter has the capability to switch to lithium, however do We also need a 12vDC to 12vDC charger for the connection from the tow vehicle to the camper? Or is that not necessary? Again, I don't have the technical knowledge of these systems.

[@herkko61]

A lot of good information, thank you so much.

[@rosslukeman]

Glad you got something out of it, thanks for tuning in!

[@brianjessen547]

Great info! Thanks for the education.

[@rosslukeman]

Thank you Brian, I'm glad you got some takeaways from the video!

[@olivierbourgeois3230]

Thanks for putting this together

[@rosslukeman]

Hi Olivier, thanks for tuning in, I'm glad you got something out of the video!

[@dragonflytoo]

Very informative. Greatly appreciated. Shared to a few others 👍👍

[@rosslukeman]

Hey there, thanks for tuning in. Great to hear you got something out of it, and thanks for sharing!

[@deanedeane4318]

Excellent video Dude and thankyou !😉🙃😎 NZ

[@rosslukeman]

Glad you got something out of it, thanks for tuning in!

[@Tumbleweed5150]

7:48 The way that you describe is still not the best way, especially when using more than two batteries in a bank. In my experience of three decades off-grid, I have found the best way to hook up multiple batteries in series is to use a "spider". Using equal length cables from each positive to a bus bar, (and the same for negative), THEN to the other parts of the system works much better!

[@GeorgeFerree]

Dope overview. Thank you!

[@rosslukeman]

Glad you liked it, thanks for tuning in!

[@franwellman8328]

I will be at Lake Conroe most on March. I could really use your help. I'm wanting to hook up two 3000 watt Renogy inverters the 65 lb ones that only have one output each to power my whole rv.I have six Ampere Time 100 ah batteries. Hope to ear from you. Thank you, Fran Wellman

[@woodzyfox4735]

Question for you. If my inverter outputs 120V @ 100 amps. How Many amps at 12V will my inverter pull form the battery?

[@K9River]

You can have losses up to 30%. 100 amps increased by 30% would be 130 amps. 30% is a high estimate. Good connections and wire and a quality 3000 watt inverter running an appliance that takes 100 amps would be 10%-15% loss, which would be 110 to 115 amps actually taken from the battery bank.

[@rosslukeman]

Hey there, if you do 1/10th the voltage, then it's 10X the amperage to produce the same number of watts. So 120V @ 100 amps is the same as 12V @ 1000 amps, either one is 12,000 watts. Inverter losses would require a little more on the 12V situation as @K9River has said.

[@thegettingoveritguy7266]

Nice videos great explanations of victron tech

[@rosslukeman]

Hey there, thanks for tuning in. I appreciate the kind words!

[@enanholbrook9369]

You mentioned that when using solar you need a higher voltage than your system voltage so does that mean there’s an issue with using 12v solar with a 12 volt system

[@rosslukeman]

Hi Enan, the "12V solar panel" is a misnomer. Those panels are actually 20-22 volts typically. They are trying to put it in layperson terms so you know to match that panel to that battery, etc. But if it were actually 12V no power would flow to the battery. Great question, thanks for bringing this up, and for tuning in!

[@enanholbrook9369]

@@rosslukeman thanks! I appreciate the response

[@rudiwiedemann8173]

SUGGESTION: you should do a video on battery “combiners” and “isolators” to protect your engine starter battery SOC.

[@rosslukeman]

Rudi I have to be honest, I said not to use those for lithium batteries in another one of my videos, they don't regulate the current or the voltage. I use DC-DC chargers mostly these days. Thanks for sharing your suggestion though.

[@jeanguillaume4589]

@@rosslukemanare you saying not to charge lithium batteries in camper with the truck being connected to camper to charge batteries or am I not understanding your comment correctly?

[@rosslukeman]

@@jeanguillaume4589 No I was telling him that I don't use combiners and isolators anymore, but DC-DC chargers instead. Charging the camper from the truck is fine.

[@walkerbay6373]

Excellent! Thanks!

[@rosslukeman]

Awesome, glad you got something out of it. Thanks for tuning in!

[@rvfishing8817]

I have two 300 amp/hr LiFePOE with a bluetooth connection to the BMS. The app to connect automatically calculates across the batteries to give a full state of charge for the bank. I am an old programmer, the logic behind this seems fairly straight forward. You want the exact same batteries in the bank and the BMS's will be reporting the same data, so why not. Live in a cold climate so I have internal heating pads, but have separate breaker to the charging source they can all be shut down when winterizing just to be sure.

[@Rebels3000]

I use circuit breaker instead of fuse as protection out of my battery positive. I like this option as apart from fuse like protection, it also allows me to cut off all power if the need arises. Interested to know why this not mentionjed as an option (good or bad), in this video..

[@cabracove]

I do too, I have 4, and it also makes it very easy to isolate any or every part of the system instantly.

[@rosslukeman]

Hi Emilia, thanks for tuning in. I too like to use breakers in my systems so I have a built-in cutoff switch. In the case of overcurrent protection on the battery bank, I don't use breakers because I cannot find a quality DC breaker that is 400 amps with an interrupt capacity of 6000 amps or higher. Good surface-mount breakers have an interrupt capacity that is 3000 amps and this does not meet the ABYC standards for large battery banks. So I don't use breakers in this part of the system because the item I need does not exist or would be a very expensive specialty item. For cutoff, I put a switch next to the fuse. Hope that gives more detail on the subject, thanks again for tuning in!

[@f150bft]

I just want to replace my old lead acid battery in my 5th wheel. It's a 2013 model and I thought i'd get a 100ah battery and be done, maybe get a new converter too. Anything special I need?

[@MichaelCook1981]

I’ve seen people use auto circuit breakers for power systems, you said ANL, terminal fuse and the T fuse. Are auto circuit breakers not approved/ not a good idea to use?

[@peanutblast2709]

Great vid

[@rosslukeman]

Thank you

[@marksommers6764]

Found an (maybe not so unusual ) odd prob .. with accessories running but charging BMS disconnects and solar goes high damaging electronics . Found the wrong controller settings to be the culprit .

[@rosslukeman]

Good catch! Glad you found the culprit and were able to fix it. Thanks for tuning in-

[@funlovingJohn]

When my 5 year old OEM toyota hybrid 12V 56ah lead acid AGM battery gets much older, I am thinking of replacing it with a 12V 50ah lithium battery. I can't find any videos on this. What do you think?

[@ZiggZagg11]

I am using Victron solar controller... I hope I haven't damaged my Battle Born batteries this summer as I haven't put any load on it... But the solar panels have kept it 100% all summer... I maybe should have left it not charge rather than keep it charging to full all the time...? 🤔 👀

[@cayrick]

Very good video. Thanks!

[@rosslukeman]

Thanks!

[@ivecodavey]

Do you have any idea what would cause a CTEK D250SE charger to take power from the start battery when the house battery is charging from solar

[@SolarPowerMyRV]

Excellent advice here 100%

[@rosslukeman]

Thanks!

[@skelafeti]

Class T fuses are the best bet when using lithium batteries. I use it and recommend them to all. They have the best interrupt rating.

[@jeffreyumeh8580]

Also if your going with more than 2 batteries in parrellel you should be connecting the batteries to a bus bar with equal length and gauge cables and as you said connect your inverter temnals the the oppsite ends of each bus bar, with lead acid batteries their high resistivity meant that you could link up 4 or even 8 in parallel and the current would much preffer to flow through the cables rather than to dump into 1 battery, but lithium batteries have a lower internal resistence so you need to be super careful about the resistence of the run of cables not being different to different batteries in the chain. In series you don't really have much choice which is why in that case you will need a battery balancer once you get past 2 batteries in series and even then you should top balence your batteries once in a while. Although honestly once your trying to get to 48V, I would suggest 2x 24V batteries or even better a 48V battery, this isn't really a choice for boats because of the high humidity and salt in the air you need a marine grade battery and I haven't personally seen any marine rated batteries in 48V, they probably exist, but I suspect they are a speciality product and are therefore expensive, but if you don't absolutely need the marine rating server rack batteries are CHEAP per kWh and as long as you go with a manufactorer who whelds their cells internally they are going to be good for mobile applications because they use the same method to make EV packs and most server rack batteries are laser welded because at scale it's just the cheapest way to make them and it's super very reliable. Just make sure that the batteries are raised a inch or so off the floor of the camper / van / RV so that in the case of flooding your they will probably be okay as long as they didn't get flooded on in which case you were already pretty screwed considering that the conductors and cables would have gotten water on them... thrid pro tip-or just 🦆ing common sense... don't put plumming near your batteries, thats just dumb. I would be kinda tempted to wire up a 48V battery to an MPPT solar charge controller to a 12V battery.

[@tribalncgaming1091]

DC ripple is also mitigated by increased voltage if i recall.. going from 12v to 24v. ?

[@trevortrevortsr2]

I use 120a BMS and limit my appliances to 900watt on a 1.5kw inverter (3kw surge) - oversized short wire runs ever run fused at its power end. I do not use trip-type fuses as most are for AC current - always preferring bolt-in mega fuses

[@koyaan1sqatsi]

Sigh. You confirmed a concern I had about my new install. 🤔 😊 I put breakers and fuses on everything that charged or discharged the batteries, but only a disconnect switch on the main battery cables, thinking since I had breakers for everything else, it should be fine. But I wasn't totally OK with it, and you pushed me in the right direction. I'm going after one of those fuses that mounts to the battery post, as that looks like the best solution for my system. Great video with clear explanations! Thank you!

[@HDRW]

Lots of useful stuff in here - thanks! Just one thing though, you implied that you could connect two batteries capable of supplying 50A each in parallel, and then draw 100A. I don't think this would work unless the two batteries were *exactly* matched in every way, and if not then one would supply more than the 50A and trip out, then the other would trip out.

[@sergiomomesso1590]

When something pull current, voltage drop on to those batteries to this current demand. The voltage drop on those batteries is the sames, then normally each battery will draw current to their spec in parallel. In counter part in series, it's not the same since each batteries must pull same current. Then, it's problematic to not match batteries in series, again way better is to buy like 48 volts batteries compared to 4 x 12 volts since the BMS of the 48 volts batteries will monitor the 48 volts, not 4 x 12 volts.

[@BarryandKaren]

I dont know much about Battleborn batteries but have never seen any of rhem with a low 0.5C BMS current limit. I thought they were all at least 1C for max charging and perhaps even more for discharge?

[@vincentborrowdale3093]

Good info,,thanx...

[@rosslukeman]

Glad you got something out of it, thanks for tuning in!

[@Oblivionsurveyor]

For my 200amp battery i used a 175amp MRBF fuse because it actually takes more than 175amps to blow those fuses.

[@ManagingFI]

Great content in this video, very helpful. I don't understand why for #8, that you need temperature sensors. If you have no temperature sensors and the chargers stay on but the battery disconnects internally what problem(s) can that cause?

[@rosslukeman]

Hi Aaron, thanks for tuning in, and good to hear you enjoyed the video. In general it can cause voltage spikes when a charger is under load and then the load disappears. Voltage spikes can blow some equipment, such as alternators. Sterling Power makes a "voltage spike absorber" so to speak to counteract this phenomenon. Not a huge deal, your system would probably be okay, but it's not a best practice to have abrupt shutdowns. Better to have the system work in harmony.

[@FutureSystem738]

So, basically if you don’t do your homework you pay the price. Why am I NOT surprised. Great video! 👍

[@garyweber6413]

hey ross thanks for sharing some real world know how

[@rosslukeman]

I'm glad that was helpful Gary, thanks for tuning in!

[@arlendavis]

Thanks for that info.

[@rosslukeman]

Thanks for tuning in!

[@Canthus13]

If you don't have a heater in your battery (Like Chins. Great batteries, but they don't have a heater), Get an RV tank heater for it and keep them in a battery box that you can ventilate in warm weather. It takes a bit of proactive work, but it works fine. Just don't let it kill your batteries or you still might charge it when you shouldn't.

[@beyondfossil]

It's not hard to get 48V by putting a couple solar panels in series. The larger solar panels already around some 30V open voltage to begin with. Furthermore, 12V is less efficient because of high current (amps) required for mid- to larger size RV power setups. Power loss increases with the square of current, so a 48V system actually has 1/16th the power loss over comparable 12V system. You will wear out your battery and equipment faster. To power a simple toaster with its typical 900W power would require 75A at 12V but only 18.75A at 48V. An induction cooktop would be around 1500W at max which needs a very large blistering 125A continuous at 12V and likely will sag 12V down to 10V requiring even more amps. Other common appliances in the 1500W range include space heater, microwave, kettle, etc. If you want a toy RV setup that will wear out its batteries and equipment faster, go with 12V. If you want a working modern RV setup that will last longer, go with 48V. 🙂

[@jimduke5545]

Another nice video Not a fan of ANL fuses for battery fuse(s). At least mitigate the short circuit risk by sheathing the cable from battery post to the fuse. Better, yet, Class T and sheathing but I get the trade-space.

[@rosslukeman]

Hi Jim, thanks for tuning in, and for sharing your thoughts on the different fuses. A lot of options to consider!

[@mxt4907]

Whew. So every wire connected to the positive battery terminal (besides the charge controller) needs one of those fuses?? I’ve never even seen a fuse like that. I have. So much to learn

[@geerthaemelynck1126]

16:50 : If solar voltage is lower than your battery you could look at Genasun GVB-8-OPE-Li3-51V... it boosts the solar panel voltage...

[@jimpiper5297]

Curious re actual numbers for the DC ripple voltage on the 2/0 cable from the charger/inverter you mentioned. Depending on the on-line source for voltage drop calculators, a 12-ft run of 2/0 cable with a 30A draw will result in a nominal 30mV drop. Given a charge voltage of 14.6 for LiFePO4 batts, just how sensitive is the model of the Victron you mentioned that it would shut down with that modest of a ripple voltage? Else, wire/cable sizing is certainly of paramount importance.

[@DougJohns]

or... what kind of massive load was required to push things to the limit?

[@charlesloeffler333]

I would guess his brief phrase that because of the long wire run, the voltage drop was too high, and that caused the controller to shutdown, rather than a ripple increase

[@QuentinQuark]

If the battery BMS will shut things down if it goes above the rating (as in Mistake #1) then why the need for a fuse at the battery bank (Mistake #4)?

[@rosslukeman]

Because BMS’s fail and it’s ultimately a piece of electronics. Electronics should never be used as your fire prevention method. Omitting over-current devices like fuses is what leads to electrical fires.

[@donpickett202]

can you create a stand alone dc system connected to the start battery, using a li time brand 100 ah lifepo4 battery as a house battery. i dont want converter inverter. be glad to pay you

[@John-ph8rq]

Good info, thanks Ross! Nice arms too, lol

[@rosslukeman]

I'm glad that was helpful, thanks for tuning in! The arms are a work in progress lol.

[@owenparker6651]

Very good info as per usual, Ross. I am assuming that the Overkill BMS on my 24v battery will prevent charging when it is below a specific temperature. I never plan to be anywhere even close to THAT cold, plus I have temperature controlled heating pads between each paid of cells... Is it wrong to rely on the BMS as the last bastion to prevent charging when too cold?? Thanks for sharing...

[@rosslukeman]

Thanks Owen! On the BMS shutdown, I think you are okay. You've got the heating pads to prevent them from getting too cold, and it's okay to use the BMS as the last bastion as you said. It's just iffy with some brands as they don't do the cold-weather shutdown. As long as your brand does, then it's fine. But you said you don't do places that cold, so I think you are good. Thanks for tuning in!

[@owenparker6651]

@@rosslukeman Thanks for the reply. The BMS has two temperature gauges and I tested them to ensure they work. Fingers crossed I never have to find out! :)

[@lesliehunter1823]

You are an effing gold mine Luke!

[@rosslukeman]

Thanks, I appreciate that Leslie!

[@petersimms4982]

The price of lithium batteries have gone down by 25% in the last month in the UK 😊

[@toddgorski7854]

The one you missed is the washers. You need to make sure any cable lugs are not installed with a washer between them. This is an easy mistake to make on an ANL fuse holder where the washer may drop while installing the fuse, but is a mistake you could make anywhere. A washer has much more resistance than the cable lug, especially if it is a stainless washer.

[@rosslukeman]

Good one!

[@atlasyts]

I just replaced the plastic gear. Now my step retracts when I open the door, and extends when I close it. Drives me nuts. What went wrong?

[@rosslukeman]

Hey there, thanks for tuning in! I don't have an immediate answer but it sounds like the signal wires that control the step got reversed or the wire was landed in the wrong terminal. Don't let me send you on a wild goose chase though, perhaps contact the step manufacturer or see if their manual has a list of common troubleshooting issues. Hope that helps!

[@atlasyts]

It turned up a very silly thing. Just had to turn the motor housing cover 180 degrees. That reversed the action 🎉

[@rosslukeman]

@@atlasyts Awesome to hear! I'm glad it was something simple!

[@jacobuszwanenburg1629]

Lithium is the first mistake ! I have little to no issues with lead carbon AGM were good too. Keep the lithium I’ll stay old school

[@sreekumarUSA]

Thanks!

[@rosslukeman]

Thanks, I appreciate that!

[@fredrau5279]

Thank you

[@rosslukeman]

Thanks for tuning in Fred!

[@eugenekochnieff7055]

Please understand, if you are powering an inverter, the current in the battery will follow the power in the load. If you have a nominal 50V battery powering an inverter with 1 kW load there will be an average current of 40 A but it will be varying from a few amps ( inverter quiescent load) to 80 + Amps at twice the frequency of your inverter output. 60 Hz in North America so battery current will be 0-80 A st 120 Hz.

[@gubbernl]

It's absolutely true current follows power demand. But even more important is the increase of current when the battery gets empty. By the way, frequency has nothing to do with it. The correct calculation is: I=P/V Max voltage 58V, min voltage 40V 1000/58= 17.2A (with a full battery) 1000/40= 25A (with an empty battery) + add some amps (5-10%) due to the inefficiency of the inverter.

[@kadmow]

I often critique (hopefully in light hearted ways) people purporting to "educate" on these topics who confude and conflate - something they call "Amps per hour" - Amps and Amp Hours.. lol... ( yes the other thing "doesn't exist" ) Yes I understand Amps are a proxy for power and Amp hours are a proxy for energy capacity (or energy use - as a lot of people may be able to measure amps but can't do maths. Scrimping on leads - big conductors are expensive (but so are Victron inverter-chargers - why would someone mount inverter and batteries a long way apart ??)..

[@Krunch2020]

When connecting two or more batteries together, the BMS cables inside the battery are small so there’s no need to use #2 cable there. It’s more important to keep the charger and inverter (if you use one) close to the batteries.

[@kadmow]

@@Krunch2020 , the BMS leads are sense and sink wires mostly, they hardly flow any current (limited by resistors) balance capacity for many BMSs is limited.

[@rudiwiedemann8173]

QUESTION: Why don’t Lithium battery BMS electronics include an automatic “fold-back” circuit to limit current flow either way instead of requiring an external fuse?

[@Tumbleweed5150]

They do. They are just not as good as putting in your own fuse for safety, especially if you are using more than one battery in a bank. In a parallel set-up to get more Amp-hours, (capacity), the Amps the full bank can put out is the Amps each battery can max out at multiplied by the number of batteries. So, no problem if you are using only one battery, be it a 100Ah or a 300Ah battery, as the BMS WILL shut off the battery at the proper Amperage for THAT battery. But if one has, say, four batteries that can each output 100 Amps, then the battery bank will have the capability of putting out 400 Amps. Even in the case of only one battery, like the man said in the video, it is always better to use something that cut's the output BEFORE the inverter, etc. In his example, one uses a shunt on the negative post of the battery bank, which is set up to report the state of charge, plus all the other info you need for the whole bank, and can be set up to shut down the power before the BMS would to save on other components in your system. (I would use equal length wires from each battery to a bus bar, on both the positive and the negative sides, which not only distributes the power more evenly from and to the batteries, but also gives the ability to disconnect one of the batteries in the system in case of need).

[@rosslukeman]

Answer: I am not sure about the fold-back circuit. Even if components are able to limit current, the fuse would still be needed as its mainly to protect the cable.

[@marccohen5477]

I see some lithiem batteries state that only four batteries can be put in series. A limit on the BMS. Is that true for all lithium batteries?

[@rosslukeman]

Hi Marc, I think the limit of 4 in series has more to do with the BMS not being able to track things in a 60V or higher system. They are saying the BMS knows what's going on in systems up to 48V (4 batteries in series). At that voltage, it still has to track high voltage around 56 volts, and low voltage around 44 volts, so it can do its shutdown thing. They're just saying if you string together a ton of batteries, the BMS will not function at those higher voltages. To answer your question, yes a lot of these mobile systems would top out at 4 batteries in series to make a 48V system. Beyond that if you need more power, you would increase amps and can add many, many batteries together in parallel. Hope that helps, thanks for tuning in!

[@pauldhond4974]

Great. Thanks

[@rosslukeman]

Thanks for tuning in!

[@TimeSurfer206]

Yet another reason for me to get a 48V system. Major drawback there is, when you want to increase your capacity, you need to buy FOUR more batteries. And ah, yes, connections. I remember one rainy night in Georgia, cleaning battery terminals as well as the ground connection to the frame, and the hot lead to the starter. Naturally, it was raining. It was the night before Thanksgiving, and it was for a young Black Mother who was stuck with a dead battery at the supermarket. The battery was fine, the alternator was fine. Both were darn near brand new. The connections were trashed. Yes, both had been replaced at a shop. And they didn't even clean the existing terminal connectors on the cables. Which were clamp ons, and corroded as blazes as well.

[@dianesapp7955]

WTF do we need to know the Person you helped was a young Black Mother. Ya idiot 🤣🤣

[@K9River]

Good thing you mentioned she was black and that you capitalized "B"lack.

[@TimeSurfer206]

@@K9River I'm a Boomer. So sue me.

[@K9River]

@@TimeSurfer206 Boomer = racist? That's a new one.