lead acid to lithium battery swap

[youngbuckwithapickuptruck]

i vanlife and charge a lot of my stuff off my lead acid battery and killed another one after only three years. i was suggested replacing with a lithium ion battery, as they are now cheaper than lead acid.

the only caveat is that they require a Battery Management System. are the LiO batteries with the bms cheaper?

 

[pentode]

I don't want to sound negative but I would be very careful with batteries like that for a few reasons. I don't think automotive lithium tech has advanced far enough that a safe lithium car battery will be cheaper than lead acid.

I helped a friend spec out a marine system and I found troubling inconsistencies between sales brochures and data sheets. The battery my friend wanted to use bragged about having a "built in BMS for safety" but when you dug through the tech specs it required an (expensive) external regulator to protect the battery. When he contacted their sales they said "no, the alternator regulator isn't enough, it needs very stable power for charging". And this wasn't cheap Amazon stuff, it was quality marine -grade gear.

Just be really certain of what you're buying and I'd say resist the temptation to go too low on price with lithium - there's just too much dangerous junk out there IMHO. If you need durability that's definitely compatible with vehicle 12v systems, consider an AGM or deep cycle battery depending on your exact use case. Yeah, they're not super cheap but they'll survive deep discharges much better than normal starter batteries.

 

[lil_Blue_Ford]

Yeah, deep cycle batteries are what you need for constant discharge/recharge. Also, no automotive batteries seem to last very long anymore. It’s becoming a problem.

As for cheap Lithium batteries, I’ve seen where people have cut them open to find nothing but rows and rows of cheap like 18650 batteries linked together.

 

[pentode]

Yeah, deep cycle batteries are what you need for constant discharge/recharge. Also, no automotive batteries seem to last very long anymore. It’s becoming a problem.

As for cheap Lithium batteries, I’ve seen where people have cut them open to find nothing but rows and rows of cheap like 18650 batteries linked together.

This is my main worry, especially when you realize how the market is flooded with low quality and counterfeit cells. You could build one like that with real LG or Samsung cells and a proper BMS but it wouldn't cost $80, it would cost $500

 

[youngbuckwithapickuptruck]

can a deep cycle battery that fits the 2000 2.5l ranger be bought at a super walmart? tractor supply co or any other common place?

 

[4x4junkie]

I've actually been researching this a little bit recently myself, and these are some things I've come to find so far:

12V lithium batteries made for vehicle use are not Li-Ion, but rather LiFePO4 (lithium-iron), which is a far less volatile chemistry than Li-Ion.
Four 3.2V nominal (3.6V fully-charged) LiFePO4 cells match up well to sub for a six-cell lead-acid unit.

Lithium batteries of both types cannot tolerate heat well (above 140°F), so not a good choice for under the hood (this limits their use mainly as an auxiliary or "house" battery mounted inside the cabin space or someplace away from the engine).

Lithium batteries cannot be charged if it's 32°F or below (some batteries will activate a built-in self-heating coil when charge voltage is applied, but actual charging won't begin until it's internal temp rises to like 35° or so).

Lithium should outlast lead-acid if it's kept at the right state-of-charge (SoC) level as much as possible (between 50-70%, which is different from lead-acid which lasts longest when maintained at 100% charge).

LiFePO4 batteries should not be paralleled with lead-acid, even with using a relay isolator (if one battery has a very different SoC than the other, can cause a potentially damaging current flow to occur between them when the relay activates). A DC-DC charging system should be used (of course solar can be used with it as well).

As for cheap Lithium batteries, I’ve seen where people have cut them open to find nothing but rows and rows of cheap like 18650 batteries linked together.

That is pretty much is how all EV batteries are currently built, although it appears the cells are up around 38120 (size) now.
Some very early EV batteries I understand originally did use 18650s... That's a lot of freaking cells to build a 60-80kWh battery out of (each 18650 cell I think is like 8-9Wh, so close to 10,000 cells!! ).
Smaller batteries like what is being discussed here are going to have a similar type of construction.

I'm not sure what is holding them back from producing larger cells (ones that hold around 100-200Ah each for an EV battery)... Seems like it would be a lot easier & cheaper to string 1/10th as many of those in series than the same number of "cells" each one consisting of a dozen or so smaller cells in parallel...

can a deep cycle battery that fits the 2000 2.5l ranger be bought at a super walmart? tractor supply co or any other common place?

You may have to modify or replace your battery tray (the '98-'00 trucks (maybe up to '11?) have tiny little trays), but by doing that it should be possible to get a grp-27 under there...
I managed to get a 27 under the hood of my '94 with a bit of modification to the underside of the hood from a hammer.

You live/camp out of your vehicle a lot? Do you have a solar panel setup on it?