Adding Lifepo4 battery and leaving lead acid battery installed

**Gearjunkie** · 02-24-2022, 11:18 AM

Hi all, I am planning to add a Lifepo4 battery to our 22MLE. I am not adding solar as we do too much camping in shaded spots. I also don’t want to change the electrical panel at this time.

This is what’s different than what most people do. I plan to leave the Lead acid battery on the tongue and the LA battery wiring will remain the same.

The Lifepo4 battery will be installed under the bench and have a dedicated disconnect switch, and fuse. It will also have it’s own ground to the frame. It will be tied into the main DC line going into the control panel. I have a dedicated charger so it can be charged from AC independently while disconnected from the system.

The plan; When dry camping, use the LAB while driving and once at the campsite, disconnect the LAB and connect the Lifepo4 battery.

I was wondering if anyone else done this?

**MoonShadow_1911** · 02-24-2022, 01:38 PM

Originally Posted by Gearjunkie

Hi all, I am planning to add a Lifepo4 battery to our 22MLE. I am not adding solar as we do too much camping in shaded spots. I also don’t want to change the electrical panel at this time.

This is what’s different than what most people do. I plan to leave the Lead acid battery on the tongue and the LA battery wiring will remain the same.

The Lifepo4 battery will be installed under the bench and have a dedicated disconnect switch, and fuse. It will also have it’s own ground to the frame. It will be tied into the main DC line going into the control panel. I have a dedicated charger so it can be charged from AC independently while disconnected from the system.

The plan; When dry camping, use the LAB while driving and once at the campsite, disconnect the LAB and connect the Lifepo4 battery.

I was wondering if anyone else done this?

As long as you don't try to use the two together, you should be fine. Just sounds like a PITA to keep swapping between the batteries.

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**deeuubee** · 02-24-2022, 02:17 PM

I have done just that. I did it to keep and charge the trolling motor battery in the tongue box.
The lead acid battery is used for travel also for the brake disconnect and stuff.
I installed a marine 1-2-Off switch. When travelling 1 (LA), camping 2(Lithium).
The OEM converter charges the LA, not so much the lithium.
I have a separate plug-in lithium charger for shore power or generator use.

**traveldawg** · 02-24-2022, 02:18 PM

Originally Posted by Gearjunkie

Hi all, I am planning to add a Lifepo4 battery to our 22MLE. I am not adding solar as we do too much camping in shaded spots. I also don’t want to change the electrical panel at this time.

This is what’s different than what most people do. I plan to leave the Lead acid battery on the tongue and the LA battery wiring will remain the same.

The Lifepo4 battery will be installed under the bench and have a dedicated disconnect switch, and fuse. It will also have it’s own ground to the frame. It will be tied into the main DC line going into the control panel. I have a dedicated charger so it can be charged from AC independently while disconnected from the system.

The plan; When dry camping, use the LAB while driving and once at the campsite, disconnect the LAB and connect the Lifepo4 battery.

I was wondering if anyone else done this?

Not sure of the reason to use both. But you'll probably want to make sure the LA battery and its charger is disconnected prior to turning on the independent charger and connecting that Lifepo4 battery to the rig.

Still questioning the expense and logic tho. I don't get the part about wanting to :...change the electrical panel..." as I am not sure what part that plays either. I would have thought it was a simple matter of dropping in the Lifepo4 battery and replacing the charger (assuming the current charger does not support the Lifepo4).

**Gearjunkie** · 02-24-2022, 02:33 PM

Yes, swapping will be a small PITA but it won't be happening that often.

**Gearjunkie** · 02-24-2022, 02:35 PM

Sounds pretty much what I have planned. I'm going to put a 110v port near the Lifepo4 for the charger.
Thanks.

**Gearjunkie** · 02-24-2022, 02:45 PM

Originally Posted by traveldawg

Not sure of the reason to use both. But you'll probably want to make sure the LA battery and its charger is disconnected prior to turning on the independent charger and connecting that Lifepo4 battery to the rig.

Still questioning the expense and logic tho. I don't get the part about wanting to :...change the electrical panel..." as I am not sure what part that plays either. I would have thought it was a simple matter of dropping in the Lifepo4 battery and replacing the charger (assuming the current charger does not support the Lifepo4).

I have a dedicated charger so it can be charged from AC independently while disconnected from the system.

The expense is minimal and a not everyone will understand the logic. My panel is a WF-8735P with a built in charger that will not fully charge a Lifepo4 battery.

**traveldawg** · 02-24-2022, 02:56 PM

ah - got it - thanks. I didn't know about the way the charger was built in.

**Gearjunkie** · 02-24-2022, 03:03 PM

Sorry, I didn't mention the built in charger in my post. I was trying to keep the post short.
I may change the panel down the road but for now this setup works best for me and won't cost much. It's also a fairly easy install.

**Ynot4me2** · 02-24-2022, 07:07 PM

I can see your thinking but find that it would be to much a PITA for the little gain. Your current converter/charger would charge your lithium to roughly 80%. If that's not enough then you could disconnect it while plugged on shore power and use your lithium charger to top it. I'm just about to order my lithium cells for my DIY battery and plan on replacing the LA with it. This first season will be a direct swap and remain (locked) on ghe tongue. I also have a portable lithium charger that I could carry with us in case we need to top it up. The following season I will relocate inside and add the Victron Multiplus II.

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