Switching from lead-acid to lithium

Time has come to replace the lead-acid deep cycle house batteries. The question is with which type? We have a converted e350 with a high top. Our house electrical is fairly simple- Norcold 12v fridge, 12v water pump, led lights for night time, Espar heater, Fantastic Fan, propane sensor, inverter for plug in stuff (slow cooker, coffee grinder, coffee maker), cpap that runs on 12v. We have a 1x10 Norco smart charger for when we can use shore power, or rely on the van charging system when we are on the road. There is a voltage sensing relay that controls where the charging power should go. The house batteries are located under the cabin, in boxes tucked up on a shelf near the rear axle.
We bought the van in 2021, and the batteries came with it. They are 2- group 31, 100ah hybrid/deep cycle, and one of them has definitely died. I think it died during our last trip because the charging levels were all screwy, despite being plugged in every night. Anyway, the time has come to replace at least one, probably both. So is it also the time to change types? Have heard that it can be difficult to charge lithium when it is cold. We live in Montana, and don’t travel too much when it is really cold, but even in nice temps it can drop below freezing when up in the mountains. Have also read that we would need a charger controller to protect the alternator. Anybody know anything about them?
Any other issues to know about if we switched?

I’m not an expert, and have little experience with this sort of thing.

But it is well known that lithium batteries have a lot of trouble with cold and hot weather. It isn’t just a matter of trouble charging - cold weather can effectively discharge them, and a little colder can destroy them.

I’ve had lithium cell phone batteries destroyed by cold that were left in my vehicle in the mountains of West Virginia, while I went skiing, at least twice - and I haven’t been in weather as cold as parts of Montana sometimes get.

I’ve also had lithium cell phone batteries destroyed by hot weather, that were left in the vehicle too.

On the other hand, I used to have a VW camper bus with a deep cycle marine battery on a battery isolator circuit. AFAIK, it didn’t go bad, due to weather. Lead acid handles temperature extremes somewhat better. (Nickel Cadmium does even better in temperature extremes - but you would need really huge, heavy, and terribly expensive Ni-Cd batteries to handle what you want. Fine for electric shavers and toothbrushes, but not practical for a house car camping supply.)

I’m curious how old your lead acid batteries were when they died. I.e., were they new when you bought the vehicle? Kead acid batteries can be harmed simply by being fully discharged, and of course, like most batteries (including lithium), they slowly discharge themselves over time. It is conceivable that is what destroyed your battery. If you don’t use them much, it may be a good idea to sometimes trickle charge them. Of course, if your battery was on a battery isolator circuit, and you drove the van at least once every few weeks, that would have kept them charged, so no trickle charging is needed.

BTW, “Lithium” batteries encompass many somewhat different chemistries. Some can take cold weather, and hot weather, better than others. Lithium batteries do have the advantage of taking more charge/discharge cycles, and they are much lighter and more compact than lead acid.

Now I’ll leave the rest of this topic to people with more knowledge and experience than me.

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I have no experience with large lithium batteries for running a camper. I have lots of experience with flooded lead acid and sealed lead acid batteries. All batteries lose charge when in extreme cold temperatures and all batteries will get damaged in extreme high temps. All batteries will discharge over time.

It’s best to have them somewhere the temps are regulated. Like compartments connected and enclosed next to the cabin which is temperature controlled. The heat and cold from the cabin should stabalize the temps in your battery compartment to safe levels. Especially if you insulate the battery compartment from the outside but not on the connecting wall to the cabin. Or you can install some type of heat strip to help keep the battery warm. Some LiPo4 batteries have built in heaters for this reason.

If you know your going to be in cold temps, get a lithium phosphate battery with a built in heater. If you choose to switch.

In my experience, I like the regular deep cycle batteries that are standard in every RV made in America. They don’t cost a lot and if no one is intentionally sabatoging your charging device, they should last between 5-10 years at roughly 70-80% of their new capacity. Slowly decreasing over the time you own and use them, and NOT in 6 months of use.

The advantage I like about the LiPo4 battery is that it holds 12 volts better than an acid battery. I have read they will keep 12 volts until they are almost fully discharged. I also have heard they can be discharged further than an acid battery giving more power between charges.

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Our approach was to make sure our elec needs were minimal - an Iceco JP50 fridge, draws 32w when running, which is only 20% of the time, and some charging needs, and a couple of LED lights. We have done multiple week trips in both hot and cold weather with only a Bluetti EB150 (1500 watthours storage) for battery storage. It alone will run the fridge for 5 days. No problem with outside temps down to 10 at night, inside not much above the couple nights we stayed in hotels, and I just avoided using the Bluetti until after we were driving the next day and the van had warmed up - no need to power up the fridge, it was plenty cold already! $50 inverter under the drivers seat, cabled to the battery (inverter has its own fuses), and we use that to recharge the Bluetti every couple of days when driving with the regular 110v wall charger for the Bluetti. No solar panels needed, no wiring complexity, interconnect, charge controllers etc. Easy. One self contained unit for $1000 has the battery, charger, charge controller, inverter, AC, DC and USB output, with peak power of 1500w. And yeah, it’s LiFePo4, so you get to use 1470 of the 1500 watts stored in there, at constant voltage. The old lead acids drop voltage with every electron you take out, and by the time they get down to 10.5v or so, having used 15% of nominal capacity, your fridge and everything else will shut off. No matter what config you use, standalone Li batteries, or a self contained like Bluetti, go lithium. Oh, and Bluetti is 50% the cost per stored watt compared w Jackery or Dometic. and I can pull it out of the van in 2 minutes for use in the house during an outage, to do construction away from power, or take it into the woods to run amplifiers for music or whatever. Works for us. Just sayin.

If that’s not enough power storage, you can gang a couple of Bluetti’s together, still simpler than a home built elec panel. And yes,. if you have existing solar panels, the panels can trickle charge the Bluetti(s).

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You will have to switch both to lifpo4 batteries. You cannot mix and match house batteries. Most of the previous responses are outdated info. Lifepo4 batteries have no issues in heat and newer versions are self heating in cold weather allowing continued charging capability and bluetooth monitoring via app on your smartphone.

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