Community Forums

kovalsmt · 01-28-2023, 12:30 PM

I am considering changing my lead acid batteries with new Lithium batteries. I have a Magnum MS 2000 inverter charger with the Intellect control panel and 2 each 190w solar panels with a Go Power controller. Can I just install the new batteries, or will other changes be required?
And if other technical changes are required who would be most competent to make the changes?

Thanks to all for sharing your experience.

Kovals
2009 42' Monaco Camelot PDQ
425 Cummings ISL
F-150 Towd

jacwjames · 01-28-2023, 06:26 PM

I haven't installed lithium but read posts on people who have.
My understanding is that you'll have to isolate the house and chassis batteries otherwise you will burn up the alternator as it will have to work to hard. There are ways to charge the house from the alternator, you'll have to decide what would work for you.

Lithium batteries don't like cold weather so you'll have to locate them in a controlled space and if you live/camp in colder weather my have to add heat.

Lots of good info out there, I've watched several videos, read several articles, and monitor a couple RV forums. I've decided that lithium would be nice but not a necessity for me.

markpj23 · 01-29-2023, 06:42 AM

Lots of expensive mistakes to be made if you don't thoroughly understand what's involved. Several threads discuss in detail.
Here's a good place to start: https://www.irv2.com/forums/f106/lit...in-603442.html

Sinyyl · 01-30-2023, 12:01 AM

I just replied a post a few days back about this. I have done an extensive remodel of my electrical system. A short answer is: Yes, your new lithium battery will stop charge at 80％ full, which is not a bad thing. Just pick a name brand like battleborn and do a drop in replacement.

A bit more explaination: Lithium battery run at a higher voltage than lead acid battery. Charge them using the same charger and algorithm will not fully vhatge them. But charged lithium to 100％all the time will shorten it's life anyways.

So if you don't cycle your batteries that often (like once a day everyday), it is totally ok. One last thing, if you frequently use in below freezing temp, and you don't want to do too much remodel, maybe lithium is not for you. Lithium is not as ragged as lead acid battery, they can't be charged below freezing temp.

I am hoping to make a video on Youtube introducing my system. I will make a post here maybe that can earn me a few subs. I have 15kwh @24v battery with 3800w solar and 2x3kw@240v inverter. If anyone cares, I can share a bit more info.

153stars · 02-01-2023, 06:53 AM

Is this your controller to change charge profile. Check the listed inverters.
https://acrobat.adobe.com/link/revie...3-1a29eb5805f6

Persistent · 02-01-2023, 08:09 AM

Yes, your new lithium battery will stop charge at 80％ full, which is not a bad thing. Just pick a name brand like battleborn and do a drop in replacement.

Actually this depends on the specific Li battery you choose and the specific charger you have available. Older RV battery chargers will not work acceptably. It also depends on the pattern of use you follow. With these and other variables all making a difference, only general advice can be given.

What Li battery would you choose?
Exactly what model number of Magnum 2000 do you have?
How will you use the new battery? Discharge, recharge cycle patterns, etc.
What kind of 12 volt system are you using.
What make and model of solar controller are you using?

A bit more explaination: Lithium battery run at a higher voltage than lead acid battery. Charge them using the same charger and algorithm will not fully vhatge them. But charged lithium to 100％all the time will shorten it's life anyways.

Actually charging them to 100% and holding charging for a specific period is required for long life (cell balancing). However, storing them at less than full charge will increase the already long life a little.

So if you don't cycle your batteries that often (like once a day everyday), it is totally ok. One last thing, if you frequently use in below freezing temp, and you don't want to do too much remodel, maybe lithium is not for you. Lithium is not as ragged as lead acid battery, they can't be charged below freezing temp.

Li batteries are much better at frequent cycling than lead acid batteries. Li batteries are what they are. They can be rugged or delicate depending on how you use them. NASA uses them in Space where temperatures drop below -200 degrees often. The technology to manage them is available. The choice to use that technology rests with the battery and system builders.

Battle Born is a good company to work with for RV'ers who have limited knowledge about drop in Li batteries. They provide extensive advice on what works with specific legacy hardware. They will review your plans and make suggestions.

Generally one or two 100 amp hour Battle Born batteries will work with many modern lead acid battery chargers found in travel trailers. Some of the low end chargers with a minimum of bells and whistles work OK.

Larger battery banks usually require other system changes to protect the RV and to get reasonable performance from the expensive Li battery bank.

Motor homes may require special modifications with 200 amp hour or larger battery banks. The lead acid start batteries and automotive alternators are a significant issue to be accommodated.

Certainly large Li battery banks can destroy a motor home alternator under certain conditions.

Persistent · 02-01-2023, 08:41 AM

Quote:

Originally Posted by kovalsmt

I am considering changing my lead acid batteries with new Lithium batteries. I have a Magnum MS 2000 inverter charger with the Intellect control panel and 2 each 190w solar panels with a Go Power controller. Can I just install the new batteries, or will other changes be required?
And if other technical changes are required who would be most competent to make the changes?

Thanks to all for sharing your experience.

Kovals
2009 42' Monaco Camelot PDQ
425 Cummings ISL
F-150 Towd

Much more detail is required to provide adequate answers to your questions.

You can probably replace a 100 amp hour lead acid battery with a 100 amp hour drop in lithium battery. A 2009 Magnum battery charger may or may not properly support the lithium battery. The engine alternator with a lead acide start battery is unlikely to adequately support the battery. The solar controller may or may not support the lithium battery. Post exact makes and models of the components for better advice.

The larger the the lithium battery bank is, the more issues will have to be dealt with. At what point the lithium battery may damage the alternator depends on the exact equipment you have. At what point the old charging system may cause poor performance from the lithium battery also depends on the exact equipment.

To be sure a new system will work, you can adopt a new system designed for lithium batteries.

Engine charging of a lead acid start battery and a lithium house battery require separating for good system health. Many people use a battery to battery (B2B) charger to separate them. Some people simply disconnect the bridge circuit that joins the two together.

Drop in LiFePO4 lithium batteries need to be fully charged and held charging for a period of time to balance the cells. Different brands require different balancing times. Usually the balancing voltage must be 14.4 volts or so. Most legacy lead acid chargers will drop to 13.6 volts or so by that time, so balancing never occurs.

With the best built brands of batteries, lack of balancing during charging has less effect than with poorly built brands. But, all require balancing for long life.

So, both legacy chargers and solar controllers need to be capable of delivering more than 14 volts at the end of the charge cycle. I have a 30 amp 2018 WFCO charger. It will provide 14.4 volts for 4 hours maximum.

So the lithium battery would have to be fully charged and balanced with 4 hours. In many charge cycles, the WFCO would work OK with a 100 amp hour lithium battery. My WFCO would not work with a 300 amp hour lithium battery bank. It would almost never balance the battery bank.

Battle Born brand was one of the early drop-in Li battery suppliers. They provide expert advice to customers. They provide a webpage showing various models of legacy chargers that work with their batteries BMI. They also will evaluate your planned installation before you buy.

Many Chinese brands have been proven to be frauds. Batteries may not have advertised functions. They may not have been assembled properly or have other failings.

Certainly they do not provide good advice and warranty is non-existent.

kovalsmt · 02-06-2023, 12:45 PM

Thank you for your time and experience. I asked Battleborn about those questions and got the following reply.

1) You set up will charge to 100%. The Magnum inverter charger has a custom setting that can be deployed for full charging.
2) You can install as large of a bank as you'd like with no repercussions. The biggest misconception about lithium batteries is that they request or draw current from an alternator source; this is not true. If it were, we would simply regulate how much they took and remove the need from a charger in the first place. Battle Born Batteries simply take what they are given from the charging source. So, if in this example you have a small 5a DC to DC charger, the batteries will simply accept that 5a DC to DC charge coming from the starter battery. They will not request more than they are given. Now, one thing you do want to make sure if that this DC to DC charger can DISCONNECT at the right voltage; we like to see something around 13.3v or higher. The reason this is important is secondary to the starter battery(s). Most alternator charging systems disconnect the house batteries from starter battery(s) when the voltage hits around 12.8v. This means you would need to discharge the lithium batteries 80% before it disconnects from the starter battery. I think you are ok with your current set up being used, but wanted to provide some clarity on this topic and what we really look at for proper alternator charging with a lithium battery bank.

Persistent · 02-07-2023, 07:06 AM

Battle Born Lithium LiFePO4 battery charging profile
https://battlebornbatteries.com/char...es-the-basics/

153stars · 02-07-2023, 10:07 AM

A lot is covered already but the solar controller should top off to balance state often enough if MS2000 charge profile doesn't cover it. A Renology 40amp dc-dc charger is only about $120. Since lifepo4 charge and discharge curve is flat it's going to fully recharge pretty fast.