12.8 Volt Lithium Ion Batteries

[max49]

Hi, I've had my 2018 Georgetown since new. It seems amazing that it has all 3 original batteries, and they are all still working. But, I have'nt boondocked with it without electricity for very long, and of course I used the generator a lot.
My house batteries are 2- 12volt batteries.
Has anyone replaced their original 12 volt lead acid flooded batteries with
1 or 2 100 Amp Hour 12.8 volt lithium batteries without damaging the converter, inverter, or alternator?

Thanks , Max

[DarkSideJeep]

Originally Posted by max49

Hi, I've had my 2018 Georgetown since new. It seems amazing that it has all 3 original batteries, and they are all still working. But, I have'nt boondocked with it without electricity for very long, and of course I used the generator a lot.
My house batteries are 2- 12volt batteries.
Has anyone replaced their original 12 volt lead acid flooded batteries with
1 or 2 100 Amp Hour 12.8 volt lithium batteries without damaging the converter, inverter, or alternator?

Thanks , Max

First you will likely be able to fit 2 200AH LiFePo4 (Lithium Iron Phosphate) batteries in place of your 2 100AH flooded LA batteries. You want LiFePo4 Lithium Batteries. Next LA Batteries are fully charged at about 12.8v Lithium batteries being fully charged at 13.7v to 14.4v. Your chassis alternator may put out as much as 14.0v. I assume your inverter and charger are separate units. You will need to find out whether your charger has a lithium charging profile. My 2018 Thor ACE did not. If I had replaced the batteries with lithium I would have had to replace the charger as well if I wanted to get the Lithium Batteries up to 14.4v. There is a great deal of discussion about Lithium batteries burning out the engine alternator because they will take a charge much faster than LA batteries. While there has been discussion about the possibility, I have not seen any post where it has actually happened. In my view if it is going to happen it can also happen with LA batteries. I once burned out a connector on a 1976 IH Scout after I installed a second battery. Here are the bullet points.

1. In most coaches you can likely fit twice the battery capisity in your current space.
2. At twice the capacity you will have about 1/2 the weight.
3. If your converter charger does not have a compatible lithium charging profile for the batteries you install you will need to install a new Converter/ Charger.
4. Keep in mind that your chassis starter battery will have to remain a LA battery. Because of that it would be best to install a Lithium BIM first to prevent Alternator overload second to provide a way to keep the chassis battery charged without boiling it out when the coach is sitting.
5. If you coach has solar you may need to update the solar charge controller to one that has a solar profile.

I just replaced about 800ah of AGM LA batteries with 900ah of Lithium. During that install I also replaced the 200watts of solar panels with 800watts. The original panels could only supply enough power to keep the batteries charged as long as the coach was not using any other like keeping the refrigerator running. When I installed new solar panels, I then had to install a nigh capacity sola controller. I have since found out that my inverter / charger does not like trying to fully charge up to 14.4v If I were relying on the inverter charger alone I would have had to immediately replace the Inverter / Charger. Since I have the solar to get the batteries up to full charge it is not an immediate concern.

[SafariBen]

It's been mentioned on here that 300AH batteries are a competitive package at the moment, check if they would fit and the pricing still applies.


You need a way to fully charge the Li every "few to 8" months, not every cycle like lead. The stock charger may work for daily recharging as long as you have another method that will fully charge to balance the Li, that can be solar or a much smaller charger while not in daily use.

[Soppy]

I replace my 3 - 100 ah AGM batteries with 3 - 150 ah lithium batteries. My old converter has an output voltage setting of 14.4 v , which works out perfect for lithium. I can also set it to float at 13.2v if I am going to be plugged into shore power for an extended time. With the engine running, my alternator will charge the batteries at 54 amps, so I don"t need a DC-DC charger. My AGM starting battery is paralled with the lithiums when charging. My RV is only connected to shore power when in use and the batteries are disconnected when in storage.

[Persistent]

Originally Posted by max49

Hi, I've had my 2018 Georgetown since new. It seems amazing that it has all 3 original batteries, and they are all still working. But, I have'nt boondocked with it without electricity for very long, and of course I used the generator a lot.
My house batteries are 2- 12volt batteries.
Has anyone replaced their original 12 volt lead acid flooded batteries with
1 or 2 100 Amp Hour 12.8 volt lithium batteries without damaging the converter, inverter, or alternator?

Thanks , Max

RV lithium batteries use a different charging profile than deep draw lead acid batteries. Lithium need 14.4 volts at the end of the charge cycle. Lead acid can only use 14.4 volts at the beginning of a charge cycle.

Lithium batteries need to be fully charged occasionally. Lead acid batteries need to be fully charged soon after use. They should always be stored fully charged. Lithium can be stored partially discharged.

Your RV has three charging devices. They are converter/charger, solar controller, and engine alternator. They are all programed to provide lead acid charging profile. Either the converter/charger or the solar controller must be changed to provide lithium charging profile.

Damaging existing 12 volt system devices
The only device that may be damaged is the engine alternator. Most do not have over current protection. Deeply discharged lithium batteries may try to draw too much current for too long. Alternator may over heat. It is most vulnerable when idling and charging both start battery and deeply discharged lithium batteries.

A 100 amp hour lithium battery is probably OK. Four 100 amp hour lithium batteries is probably too much. Two 100 amp hour lithium may or may not be an issue. There are various limiting devices available. There are battery to battery chargers that convert the alternator charging profile to lithium and limit current.

I have no way of knowing how much current your RV alternator can safely handle. It has to charge the engine start battery and run all the engine 12 volt stuff. How much capacity will be left over for lithium charging is unknown.

All that said, why do you want to convert to lithium? If the current lead acid batteries are working satisfactorily, why change? After I learned how to maintain my lead acid batteries, they lasted more than 10 years.

[max49]

Although my 7 yr old batteries are still working, although they are getting old and tired, like me maybe.
When I'm without hookups and there is a curfew for generator time, I use my inverter to make coffee in the morning., The batteries don't like it and the coffee pot struggles, the coffee doesn't get hot as normal and the pot shuts down faster than it should. SO I have to replace the batteries and was just considering lithium. Lithium works good for E Bikes but sound like they may be more trouble than the extra benefits they might bring.

[DarkSideJeep]

Originally Posted by max49

Although my 7 yr old batteries are still working, although they are getting old and tired, like me maybe.
When I'm without hookups and there is a curfew for generator time, I use my inverter to make coffee in the morning., The batteries don't like it and the coffee pot struggles, the coffee doesn't get hot as normal and the pot shuts down faster than it should. SO I have to replace the batteries and was just considering lithium. Lithium works good for E Bikes but sound like they may be more trouble than the extra benefits they might bring.

My coach had 4 6v AGM batteries with a total 780ah capacity. those batteries weighed 125# each. I replaced them with 3 300ah LiFePo4 lithium batteries weighing about 75# each. Replacement AGM batteries would have cost me will over $2000.00. The lithium batteries replacements cost only about $1500.00. Since I also installed a solar upgrade as well, I did not need to do anything with my inverter charger. The solar gets the batteries up to 14.4v whenever the sun is out. Frankly I needed to replace the AGM batteries and the Lithium's were cheaper. The OE solar on my coach was completely inadequate and would have needed to be upgraded as well regardless of what batteries I had.

[Sweetbriar]

New to me coach (the Newmar in my signature) still had the six factory installed 12VDC batteries (Newmar added two more to the standard six with the residential fridge option) that would deplete a charge pretty quickly.

Replaced with four Lithium 100 amp/hr batteries. Updated the Magnum MS2012 charging and invertering parameters to match battery manufacture's recommended settings and installed a "Lithium Battery Isolation Manager" to protect the alternator.

Did the work back in March of this year. 3 months later, which includes a 4200 mile road trip, and no problems with the coach or chassis systems or the battery bank. Saved a lot of weight going from 5 lead acid batteries to four lithiums.

[computerguy]

I have a whole thread on it here

[atodalen]

You may find some useful information on this recent thread.
https://www.irv2.com/forums/f101/lit...im-673736.html