How to Charge a Lithium Battery House Bank and an AGM Starter Battery at the Same Time?

[@mcjairo96]

In this case we need to use a Battery isolator with two outputz, but one of those must be connected to a DC-DC converter and after to the lithium battery bank, right?

[@emirruzdic2597]

Hello Jeff, thanks for another great video. I have a question. Would you put the Orion DC-DC after the battery isolator or instead of the battery isolator. Is there any benefit to having a battery isolator if you are adding an Orion to charge a new house bank of lithium batteries. This is assuming there is one alternator, one starter and a house AGM battery bank with a battery isolator currently installed.

[@redwood1957]

When you do a system like this do you tie the negative from the lithium togeter with the lead acid battery? Thank you

[@aphrodite3216]

Do you have any drawings of this setup??

[@HansLaaby]

Hei Jeff. I find your "tech talks" very interestig. However I am wondering why you are not proposing the "Alternator to Battery Charger" system as an option. I have installed this type of charger with outputs to my LiFePO4 service battery and to my AGM start battery. The charger has a (dv/dt = const = constant current) characteristic and a constant voltage ( float)/decaying current characteristic for the service battery. The starter battery is, however, charged mainly as it would have been directly from the alternator i.e. suffisient for start, thruster and ankering operation. This solution does not need a DC to DC converter.

[@tracyoliver550]

Sooo confused. I just finished watching another of your videos addressing the charging of lithium house and AGM starter using a battery isolator and a charge relay, but here you say that can’t be done because of charge profiles and you need to use DC- DC charge converter. Is the difference having or not having the proper regulator for the alternator?

[@ericrainey5361]

I have a Rv. how do I charge the agm starting battery and agm deep cycle house batteries with solar?

[@donfoley9732]

Hey Jeff do you have a basic wiring diagram for my 60 horse,on board battery charger,bow mounted trolling motor and battery,fishfinder?the bilge pump,navigational lights,live well are on the dashboard.its a 16ft aluminum.

[@PacificYachtSystems]

Sorry, we don't have a standard diagram, good idea though.

[@henrikh484]

Hi Jeff, thanks for sharing your knowledge - I'll probably never be a customer in your business (live overseas), but I still enjoy your videos. One little suggestion, whenever you make a video like this, a small schematic of your suggested solution would be fantastic, don't need a full CAD or anything like that, a hand drawn sketch would bee good. Example. In this video, you suggest a DC-DC converter (isolated) - but where will you put it (I know for some/most it's obivious, for others that'll be a question) - as said just a suggestion, not a complaint. Thank you

[@PacificYachtSystems]

Duly noted Henrik, thanks for the suggestion, will try to integrate more visuals in the discussion.

[@alexsails80]

Hi Jeff. Can the input of this dc to dc charger come from the output of a battery isolator? So we don’t drain the starting battery by having it as the input of the dc to dc charger? Thank you

[@etownKeystoned]

Most DC to DC charger are also an isolator so I guess unless you just want the redundancy. I would save the money. I have a renogy 40amp dc-dc Charger and it says in description that it also functions as an isolator To protect the starter batteries)

[@ITAOB]

Hello Jeff, have this exact type of set up. However, for solar charging, would I connect my solar charge controller to my AGM start battery and then charge the LifPo4 bank via the DC-DC charger? Thank you,

[@svdelite6394]

At first I would like to wish you and your team Happy New Year. I plan a setup with AGM and LiFePO4. I do understand the function of the DC-DC-charger. If I install a high-output alternator and charge the AGM/Starterbattery first i assume that the charge of the housebank is limited by the DC-DC- charger, e.g. to 30A per hour as per sample device in the video. Is this correct? And if my assumption is correct I believe a high-output alternator does not really make sense. My planned capacity is 70Ah for starter and 280Ah for house

[@waynebilko]

Hi, Jeff. You confirmed what I have in mind. In fact, I've purchased the Orion 12-30. However, what I'd like to know is which way to charge, 150-amp alternator to 600 ah house bank, then DC-DC to 100-amp AGM starter, or the other way around. I suppose this is the tricky part, because I've heard good arguments both ways -- faster charging straight to lithium, thus saving engine run time, but harder on the alternator and possibly the lithium batteries. With a Balmar 614 regulator, incl. alternator temp sensor, this shouldn't be too hard on the alternator, but is it still better to slow-charge the lithium bank for longer life? It's a real conundrum! Oh, and I also have a Sterling APD coming to protect the alt. Love your vids, even attended a seminar or two a few years back. Glad you're still having fun!!

[@valerianvoegele8766]

Hi Wayne, We charge the AGM starter first. Couple of reasons for that: 1. We dont have a smart alternator. 2. We prioritise the starter for obvious reasons. Not sure how the Orion works but the Sterling we use stops converting if the input voltage drops below a certain level Hope that helps

[@JPJCH1]

Charging a Lithium battery with an alternator is not the best solution, a lithium battery has a BMS that can disconnect the charging side, if no preventive measures are taken, your alternator will be damaged.

[@waynebilko]

@@JPJCH1 That’s precisely why I’ve ordered the Sterling Alternator Protection Device, along with my smart regulator. Still hoping for an answer to my question!

[@PacificYachtSystems]

What a hard question, pros and cons on each side. Most boaters will go with charging the AGM engine battery first.

[@etownKeystoned]

​@PacificYachtSystems •▪︎●■ i've got two AGM crank batteries going to an 140 amp isolator then to an AGM house battery then to: fuse box - toggle switches - load (well, it's a dual purpose battery that I can hopefully use to jump the 2 starter batteries in a pinch if they are run down by the radio/headlights or something). Because it is not a specifically designed due cycle i'm adding a LiFePo⁴ 100AH house battery. I purchased Renogy 40amp DC-DC charger with the intention of putting it after the AGM (which is going to remain on the isolater which cuts in at 13.3 & out below 12.8) and move the load to the Lithium battery. Is there any reason to be concerned? (I'm going to put 60amp in line Fuses on either side of the charger for a little assurance but my main concern is charging). Should I put the charger first, then the lithium and put the agm next (with or without the isolator?) My research indicates that going to the a GM first is ideal. And I think that is what my question is summarized as "go to the a g m first or go to the lithium first?"

[@stormer6364]

Thanks for the video Jeff 👍. I have a question, so in this instance which bank would you charge with the alternator and which bank with the dc-dc charger?

[@JPJCH1]

Best to charge the agm battery with the alternator and the Lithium one with the DC/DC charger as this charger will be programmed to the specific needs of lithium batteries

[@stormer6364]

@@JPJCH1 thanks for the reply, that makes sense 👍 do you know how much current are the larger dc to dc chargers capable of these days in the instance you have a large house battery bank? Regards Stormer

[@JPJCH1]

@@stormer6364 I am planning to get a 30A charger for a 100 Ah battery, both from Victron. Or the same from Sterling Power. The recomendation I have read is the charger should be sized at around 25% of the battery capacity. That said I have not seen bigger DC/DC charger from Victron but a 60A from Sterling Power does exist. I understand that you can also wire two chargers in parrallel if needed. In any case I will buy both charger and battery from the same supplier after submitting my wiring diagram for approval.

[@PacificYachtSystems]

Good exchange everyone, agree with JPH recommendation.

[@stormer6364]

@@JPJCH1 sounds good, thanks for the reply, it's nice to know what these chargers are capable of. Many thanks for your time. Best Regards

[@samb9409]

Thanks Jeff! In the middle of designing my system. I haven’t found a good proxy for how to size your dc to dc charger. I have an 85 amp alternator, is running two dc to dc chargers for 60 amp output something you’ve seen? Or would you stay below the 50% rated max output of the alternator?

[@HelderNevesHelderNeves]

We run a Renogy 50A DC DC charger on a 90A alternator... (Lithium100A+Lead75A) Works amazing. And we rarelly hit the 50A output as our batteries rarelly drain completely. So we believe this setup qualifies as a 50% cap ;) which gives us some peace of mind as we dont have a smart alternator.

[@PacificYachtSystems]

It's a tough question, here are some assumptions. Assuming your alternator is charging your house battery, then the DC to DC charging converter is charging the engine battery, and so can be relatively small, like 20 or 30 amps.

[@HelderNevesHelderNeves]

Final word goes always to master Jeff Cote :) In our case the alternator charges the Lead starter battery and the DC-DC charger charges the Lithium house battery. See diagram here: images.app.goo.gl/Hn46hmPzuTNnbAnz6

[@jasonpoitras4145]

@@HelderNevesHelderNeves broken link.

[@sendeth]

This was oddly specific, yet recently what I was looking for.

[@PacificYachtSystems]

Just great, glad to help.

[@abhorred]

Do you really need a DC DC though v combiner? Say you set your regulator to 14v bulk charge, lithium loves this and pb charges fine here. Then you have 13.2 programmed as float, lithium just sits happily at this voltage and pb float charges fine. Coupled with the fact that this is an AGM starter battery not a deep discharge, what would be the downside of this? Is it the potential that a big V difference between the 2 "banks" becomes a problem due to lithiums high uptake and delivery potential? Use echo-type charger? thanks

[@PacificYachtSystems]

My concern would be that AGM battery will die prematurely if it chronically undercharged.

[@LUCIFERA-TARO]

Hello Jeff Sir! I m from India n I just wanted 2 know weather agm battery can charge lithium ion battery? AGM 6 VOLT BATTERY And Lithium Ion battery?

[@ciscokid2444]

Jeff can you do a video on dc to dc charging converter please. A lot of us have different battery chemistries.

[@PacificYachtSystems]

Good one, will do.

[@dannyjensen4954]

Thanks. I like your coverage of LiFePO4. I’m learning that you aren’t adverse to LFP as I once thought.

[@PacificYachtSystems]

Glad to help!

[@weedknoll]

Hey Jeff. Love your videos. My wife and I are planning on buying a boat to live on in a couple years, after the kids go off to college. We've been looking at boats and I like some boats that are from EU and the UK. If we buy a european boat, and bring it back to the U.S., what kind of modifications are we going to need to do to our electrical system, and what things we should factor in to our budget. We don't want to be surprised. Are there work arounds that work well or are we going to be looking at a full rewire, and all new appliances and electronics?

[@PacificYachtSystems]

Good question. See articles we wrote about this: www.pysystems.ca/search/?q=european

[@mikepulido1721]

Question on shore power charging with AGM start and LiFePO4 house. Say you have AGM for the starts coupled via DC-DC charger to Li house bank for charging while underway. Part of house circuit is an inverter charger on the Li bank. Starter batteries are charged using a standard AGM charger. Any issue with both chargers on at same time since DC-DC charger is connected between banks?

[@PacificYachtSystems]

No issue with running both chargers at the same time as long is your bank is sized t handle the input from both. Starter battery charger is also a back up charger for the house via the DC-DC charger.

[@somebodydoingthings]

what are your thoughts on sterling power products? specifically the alternator to battery charger.

[@PacificYachtSystems]

Great! Very good products.

[@jonsimpson4329]

Sailboat Lithium question. Can I use one Lithium for a starter battery and one lithium for house? Will a Lithium have enough CCA? Would like to deep six my Lead! Thanks for all the great info.

[@PacificYachtSystems]

Generally, we rarely see Lithium as starting battery, usually the starting battery is AGM.

[@FringanSthlm]

Hello Jeff, excellent video! I actually got on KZbin to ask this exact question and it turns out you guys published this video only a day ago! Anyway, I have a follow up question: Assuming this Lead -> DC/DC -> Lithium setup, how should I connect my solar panels to charge (top up) both the lead starter and charge my lithium battery bank on my sailboat? I have 90W+50W+35W panels on my boat right now.

[@PacificYachtSystems]

Connect solar to one battery bank (probably house) with a controller. Then in turn charger engine battery from house with DC to DC charging converter.

[@dan5641]

@@PacificYachtSystems Hi Jeff, so this solar setup require two DC-DC charger? one for Alternator -->AGM --> DC-DC --> Lithium and one Solar --> Lithium --> DC-DC --> AGM? Or does the DC-DC charger work both ways?

[@SOLDOZER]

@@dan5641 No. Solar Panel--> Solar Controller --> Lithium. Alternator --> Starter Battery --> DC/DC --> Lithium

[@jasonpoitras4145]

@@SOLDOZER Maybe a stupid question, but if I charge up Starter battery while on shore power, am I also going to be charging the Lithium house bank?

[@tracyoliver550]

@@SOLDOZER why not Alternator ->house-> dc/dc -> starter?

[@rodsmith7611]

I use the Victron 12/12-30’s in all my boats. Got sick of ACR/VSR’s not disengaging. Added benefit of the Victron’s is that they have automatic engine shutdown detection; you don’t have to run any wires to the ignition for starting isolation.

[@PacificYachtSystems]

Thanks for sharing Rod.

[@projecttrawler]

Can the Orion's be wired in parallel to get more amperage. I have a 24v system and the Orion'sdont put out anywhere near my 30amp 24v alternator...

[@PacificYachtSystems]

Yep, we have done that before to get more amperage from one bank to another.

[@ante8210]

Hi Jeff. Thanks for another great video. On my boat with 300 HP outboard engine I have AGM for house and starting battery for engine ( not AGM). In this moment I am using a switch to determine which one I will charge with my alternator. I was watching some your previous videos and I thought that solution of my problem would be a battery combiner. But now watching this video I am a bit confused is that a good idea. Any suggestion? Thanks

[@PacificYachtSystems]

Hi Ante, when mixing battery types for charging, use a DC to DC charging converter between batteries.

[@andreruegg9490]

Great video, thanks. These Victron DC/DC chargers are recommended very often. Once I purchased them, I realized that they are only 88% efficient. Sadly, the remaining energy is converted into heat and the chargers are getting very hot. I removed them from the system, and looked for a more efficient set up.

[@PacificYachtSystems]

What did you choose as an alternative?

[@andersfahrendorff9025]

@@PacificYachtSystems I am in the exact same boat:). got 3 x 170Ah lithium batteries from Renogy, and have two wet batteries for engine and windlass on board. Is the DC/DC still the way to go, or is there a better alternative?

[@NICEandEASY024]

@@andersfahrendorff9025 have you found an answer to this? I’m trying to figure out the best way to manage this as well

[@hfed2657]

I looked at a review of a Renogy 20amp dc-dc and it was in the same ball park ( 86% ). Did you find something better? Thanks.

[@philipgarrett1987]

Victron now offers Orion-XS DC/DC chargers which are 98.5% efficient. An added advantage of the improved efficiency is greatly reduced heat during DC to DC conversion.

[@scottwetzel8146]

How would you recommend doing this, but with two engines/two alternators? One for house bank, one for start bank? Or both alternators connected and treating them as one and using a DC-DC charger?

[@PacificYachtSystems]

We like to use battery isolators to share the alternator output to multiple battery banks. We'll be doing a video just on this topic in the near future.

[@scottwetzel8146]

@@PacificYachtSystems thanks for your reply, and love the videos! Looking forward to seeing the video about isolators. Instead of sharing one alternator output to multiple battery banks, how would you recommend using two alternators (twin engine boat) to charge two banks of different chemistry?

[@matthewkorwel1099]

Hi Jeff. What about the scenario where I have a lithium house bank and a group 34 lithium banshee starter battery. I have a multiplus ii 3000 that will trickle charger the starter battery so I am planning on charging the house bank with the alternator. But I'm not sure how to protect the alternator from the bms shutting down. The "wire in a battery isolator so the agm is a fall back" seems like it won't work when the starter is also lithium. Thoughts? I have a balmar alternator with mc614 regulator.I thought I read somewhere I can set that up so the 614 will shutdown the alternator when the battery goes away... Is that Thing? Thanks for all the knowledge you share!

[@PacificYachtSystems]

We haven't done a battery setup where both engine and house are lithium batteries before. Since your battery BMS doesn't communicate with the alternator, not sure how you'll get the alternator to stop charging if ever your engine or house lithium BMS disconnects because of overcharging. What have you found out about this so far?

[@matthewkorwel1099]

@@PacificYachtSystems I have emails out to Balmar and Victron now, waiting on some info. I don't have to stick with the Lithium stater but I'm interested to see if i can get it to work just out of curiosity.

[@ciscokid2444]

Will a blue seas mini add a battery 65Amp kit charge my 12 volt lithium cranking battery and my 24 volt lithium trolling motor battery properly?

[@PacificYachtSystems]

No. A battery combiner, like the blueseas add a battery 65 amp kit is not made to convert from 24 to 12 volts DC. You'll need a DC to DC charging converter for this.

[@BreakingWavesSailing]

another great vid thanks Jeff

[@PacificYachtSystems]

Glad you enjoyed it

[@markscaglione1300]

I want to replace my house battery with lithium. I have 3 Yamaha F300s and each one has its own starting battery AGM group 27 and I want to keep them. My single house battery is an AGM group 31 and I want to replace it with a lithium battery. All 4 batteries run through a BEP switch box with ACRs. They all get charged with the engines running and a 4 bank Powermania charges them at home. Would the Yamahas charge the lithium without any new equipment ? (Plug & Play)

[@PacificYachtSystems]

I would be hesitant to charge it through the bep vsrs. Although I'm sure many are doing it. I would be more inclined to disconnect the vsrs (you could just cut the small ground wires) and instead run a dc to dc converter from each engine battery to the house. IE a victron orion smart 12v / 12v 30a. this will limit each outboard alt to 30a so it won't cook them. But you'll still get 90a into the house bank which is pretty good with only a single battery anyways. won't take long to charge.

[@markscaglione1300]

@@PacificYachtSystems What is your opinion about using the Lithium version of the Yandina combiner ? Its cut-in and cut-out voltages are higher than the BEP vsrs.

[@61Bryantg]

I am doing the same with the use of a dc to dc charger adding 200ah lithium batteries with my lead start battery. My concern is my with this tax the stock alt. on my universal diesel engine? If the DC to DC charger is only 20 amp? I also so a video where someone used a solar charger to do the samething as a DC to DC charger.

[@PacificYachtSystems]

A DC to DC charging converter limited to 20 amps won't be too taxing to a small alternator (e.g. 55 amps)

[@ahhhhhhhhhhhhhhhhhh123]

What happens if you DONT install the DC to DC charging converter? Would the AGM starter battery suffer more or the Lithium (Lifepo4 in my case)? I ask because with my situation I'm willing to just let the starter battery suffer, I dont care. I can replace it. But I wld like to keep the LifePo4 healthy for a while. Is this just not possible without a converter?

[@pauldemontigny1754]

Your alternator would suffer.

[@ahhhhhhhhhhhhhhhhhh123]

@@pauldemontigny1754 but the batteries wld be ok? i dont care abt the alternator really

[@robertlewisvideo]

Should it be non-Isolated or Isolated ?

[@PacificYachtSystems]

Isolated.

[@SeanMcChannel]

@@PacificYachtSystems From my research from Victron's website and forums, the isolated Orion DC DC charger converter is more adaptable for a variety of use cases, and provides galvanic isolation between input and outpur terminals. The real benefit of using the ISOLATED Orion DC DC charger converter appears more suited to using the DC voltage converter mode (ie not charger mode) to provide say clean DC voltage power output to some sensitive navigation or other equipment, where the equipment negative terminals need to be isolated from the power source/batteries negatives as clean power level signals are required or as part of some safety requirement. In such cases, using an isolated version makes sense as it provides the isolation between power source and equipment. If you are using the Orion DC DC charger converter to charge say batteries of different chemistries (AGM/Lithium), if your battery banks negative terminals (say starter and house batteries) are connected to a COMMON DC ground bus bar - which is likely connected to say the engine block which in turn may then be connected to sacrificial zinc anodes - then an Orion DC DC ISOLATED charger (in the charger mode) would provide little benefit compared to using the NON-ISOLATED version of the Orion DC DC charger. Yes, using the isolated version works fine in such cases, but you gain no real benefit of the isolation, as negative terminals are connected. Or is my interpretation of Victron's isolated vs non-isolated not accurate?

[@nonetasker4551]

I wonder if anyone makes a unit who measures alternator temp and then adjust the field if the temp goes to high?

[@PacificYachtSystems]

Absolutely, Balmar 614-H does exactly that, measures battery temp and even alternator temp.

[@nonetasker4551]

@@PacificYachtSystems Nice product. A bit expensive maybe. A simple solution decreasing the voltage between the factory regulator and the brushes could do the trick? Need to modify the alternator a bit though. If it works it can be used on any alternator. I don`t know. Not an alternator expert.

[@1fastbuggy502]

Would you use a isolated DC-DC charger or a non isolated DC-DC charger for this mans boat ?

[@PacificYachtSystems]

Isolated.

[@smqueeneyful]

@@PacificYachtSystems why isolated? All of the ground/neg wires are connected on my boat - essentially non-isolated, and the batteries all sit in the same area. Do I need isolated for some reason?

[@ysesq]

use a victron Buck-Boost DC-DC Converter

[@PacificYachtSystems]

Good one.

[@moriver3857]

I guess then, the alternator only directly charges the AGM. I will be in the same predicament within a year. Thanks.

[@PacificYachtSystems]

An alternator can only directly charge one battery bank. To charge multiple banks a sharing device needs to be added. There are many different ways to do it. I'm not sure what your question is.

[@danpease8395]

Jeff, Where so you stand on the idea of having a small amount of lithium permanently combined in parallel with an AGM house bank. Best of both worlds? Have enuf lithium to go overnight at anchor, then AGM starts to contribute. AGM likes to sit at 13.2, and AGM likes to trickle at 13.2. Lithium gets cycled lots of times, AGMs cycled very few times and not very deeply. Charge from externally regulated alternator, (or solar), at 14 volts. Added benefit is that in case of BMS shutdown in the Lithium, the alternator still has someplace to send charge to. Comments, discussion, ?

[@TerrydeAlaska]

Dan, this sounds like what Clark did on Temptress. Seems hard to get experts to weigh in on this idea.

[@JPJCH1]

In a battery bank, all batteries should be of same brand/technology and age. That said and as mentionned you can have a sla battery as your starter battery charged via the alternator, then a DC/DC charger to charge the house battery bank with one or several Lithium batteries. Plus solar pannels to maintain your house bank.

[@danpease8395]

@@TerrydeAlaska Exactly what I was trying for. I’ll try and send Jeff the link so he can watch it.

[@danpease8395]

Jeff, just for the fun of it, give the following a look. Interesting prospect. Sorry I can’t seem to make it a link. kzbin.info/www/bejne/qnLYgZmdj8yLm8U

[@PacificYachtSystems]

Interesting concept, but still curious to find out what we don't know yet. Over the years, learnt the hard way, there is what we know and then there is the world of surprises from doing things for the first time.

[@javierbetancourt9388]

💯

[@PacificYachtSystems]

Thanks Javier.