Upgrading House Battery to Lithium

[TexanRVer]

My first post! Howdy! FINALLY bought a motorhome...been wanting one since I was a kid! Had a blast with my family traveling when I was little, and can't wait to share it with my kids!

Got a question...I am the proud new owner of a 2018 Thor 30FE...and I would like to upgrade the house battery to a 12V Lithium.

Is there anything I need to do before putting it in? I've seen/read some videos/web pages that say you need to switch your converter to see a lithium battery? Is that right? Or can I just drop that lithium in and it work fine?

Thanks for you help!
HW
2018 Thor 30FE

[Judge]

There are hundreds of threads on lithium battery conversions..... so search will be your friend. You may want to read several threads before doing anything.


As a quick answer and suggestions.....


- A lithium conversion is not just dropping in a lithium battery in place of a lead acid battery...... that's why it's called a conversion.

- You need to research your converter and whether it has the capability to charge a lithium battery properly. Most stock converters of cheaper Class C''s don't and will require the replacement of the Converter / Charger/

- If you have a BIM or BIRD so that your alternator can charge the house battery and shore power can charge the chassis battery, you will need to replace the BIM with an LI-BIM 225.

- You need to determine how much power you need based on your camping style and goals.

- If you camp in very cold climates (or you plan to store the coach in cold climates), placement of the battery can be important. When an LiFePO4 battery drops below 32F, the BMS will not allow the battery to charge.

[TexanRVer]

Thanks. Found the issue...need to upgrade the converter that does both Lithium and Lead Acid.

[Judge]

Originally Posted by TexanRVer

Thanks. Found the issue...need to upgrade the converter that does both Lithium and Lead Acid.

The Converter won't be a mixed charging device managing both LiFePO4 and lead acid. The LI-BIM 225 is what moderates the charging between the converter and the chassis battery and the alternator and the house batteries.

[TheGoodLife]

As an alternative consider replacing the OEM flooded lead house batteries (if they are still installed) with AGM, unless you will definitely be needing/wanting lithium.

[Chateau_Nomad]

Originally Posted by TheGoodLife

As an alternative consider replacing the OEM flooded lead house batteries (if they are still installed) with AGM, unless you will definitely be needing/wanting lithium.

I agree with this if you're looking for a "drop in" replacement that's more robust than FLA batteries, simple to do and more affordable. LifePO4 batteries ARE NOT "drop in"... the charging requirements are quite different than lead acid.

If you choose to go the lithium route, do your research! There's quite a bit of "infrastructure" changes to be made. Know in advance the changes (and considerable expense) required to do it properly. Otherwise your new batteries may have their life shortened, and you won't take advantage of the additional amp hours.

[Jimbo56]

Originally Posted by TexanRVer

My first post! Howdy! FINALLY bought a motorhome...been wanting one since I was a kid! Had a blast with my family traveling when I was little, and can't wait to share it with my kids!

Got a question...I am the proud new owner of a 2018 Thor 30FE...and I would like to upgrade the house battery to a 12V Lithium.

Is there anything I need to do before putting it in? I've seen/read some videos/web pages that say you need to switch your converter to see a lithium battery? Is that right? Or can I just drop that lithium in and it work fine?

Thanks for you help!
HW
2018 Thor 30FE

Check with Chateau Nomad. He’s converting his Class C. There’s a thread on the forum.

[Hugh.vines@att.net]

Originally Posted by Judge

The Converter won't be a mixed charging device managing both LiFePO4 and lead acid. The LI-BIM 225 is what moderates the charging between the converter and the chassis battery and the alternator and the house batteries.

Changed my converter and batteries to lithium left everything else the same

[Judge]

Originally Posted by Hugh.vines@att.net

Changed my converter and batteries to lithium left everything else the same

If you have a BIM-160 so your alternator can charge the house batteries and you didn't change it out for an LI-BIM 225, you run the risk of overheating your alternator and shortening it's life.

[Chateau_Nomad]

If you don't need an inverter, I'd do what Hugh did... but like Judge said, I'd upgrade to a Li-BIM 225.

My install was a little more complicated than "drop in" and change a few components. With a smaller coach I worked hard to avoid sacrificing storage space. The original FLA batteries were under the steps (typical class C). I definitely didn't want my LiFePO4 batteries there.

So I cut a back wall out in the large driver-side rear storage, which gave access under the bed platform. It's just a dead space used as a messy wire bundle run. After moving the transfer switch forward, I have room for three 100Ah SOK LiFePO4 batteries - I'm starting with two, but can add a third later if needed. The inverter/charger took some space which was unavoidable.

We wanted a "full coach" inverter, but don't necessarily need to run A/C from the inverter. It will... but 200Ah of batteries is not near enough for that - but perfect for everything else.

2 - 100Ah SOK LiFePO4 batteries
3k Inverter/charger
3 - 200 watt solar panels
Li-BIM 225
Assorted cables, lugs, hardware and tools
Incidental items... solar switch, shunt, etc.

I have about $4k invested in the entire install. To do it correctly required purchasing lug crimpers and a few specialized tools... which I'll probably sell eventually as I'll never use them again. BUT even with those tools, this install (done the way I wanted) was probably half the cost of a professional install.

The install is complete and works fantastic. I've been busy with other mods, and currently doing exterior maintenance/waxing. I'll eventually post pics of the entire setup.