1 Lithium vs 2 lead acid batteries

[Jetboy]

I've generally preferred dual battery configurations for backup and extra juice to run things like snow plows or winches on my various vehicles.

I was curious though - why not use a lithium primary batter with 2-3 times the amp hours of a lead acid and the same weight and size, and back it up with a micro-start type miniature backup lithium battery. It seems like this would be a better solution for at least the later 5th gens like mine without a good place to locate a second battery.

Anyone using a lithium starter battery or have experience with them for winching use? Can they reliably deliver 400 amps for 20-60 seconds without failing?

And just to take this one step further out of the box - it could be very do-able to build a custom batter out of cheap 18650 cells and shape the pack to go just about anywhere - like in the rear side panel or even underneath the vehicle and eliminate the battery under the hood to make room for a nice compressor or similar.

Thoughts? Anyone go this route?

 

[Engineer]

I doubt anyone has gone this route as my undestanding is the LI car batteries are 4x+ the price of a standard lead-acid. But I like the idea

 

[Jetboy]

I have to admit after looking around a bit - they are really $$$ for a pre-made drop in car battery. Pretty easy to spend $1,000 on a battery. Granted they are about equal to 3 lead acid batteries in capacity, that's a lot of cash. Probably much better to spend the money on a high output alternator and stick with what we've got.

 

[Engineer]

It nerver hurts to think outside the box, but I am with you.....I think my ideal set up would be dual battery, maybe high capacity alternator......dont think I need it with current equipment, a shore charger for when camping in non remote areas and then the cats meow would be something like a honda 2000i or smaller generator dissabembled and built into the under carraige to run off the gas tank if you really really wanted extra power that 2 batteries couldnt give through the night....

 

[Semi-Hex]

Tesla, the company who make electric cars are getting into portable power battery packs. It seems they have a good business model and are working on storage for housing with solar electric. Maybe, they will eventually make something a little bit smaller.

 

[KidVermicious]

How do the lithium batteries stand up to abuse? Can they take a beating like an AGM can?

 

[BettysNephew]

I don't think it is as easy as just bolting something into the vehicle. Lion have a very different charge profile and I'm sure there would be at the least an electronic circuit required and possibly a completely different alternator and charging system. There is also the issue of crash worthiness as Lion are a potential bomb if the outer covering is broken. Without proper design, I would steer clear.

 

[Jetboy]

They are already available as direct swaps for regular batteries. Mostly used in racing and boating applications where weight is more important.

As for a custom pack somewhere underneath - probably would end up a lot like a hybrid. They all use the same cells. Sub-c or 18650's I believe. It would require the batteries plus a charge controller and a discharge disconnect - cant run em all the way to zero. Those are both readily available.

I do see a concern with safety, but IMO if they were protected and in a proper sheilded steel housing I think they could be made very safe. At least as safe as having 15 gallons of gasoline in a tank down there. It's also pretty dangerous. If you really wanted to get cute with safety you could attach the battery with a plastic hardware set so that in case of fire it would melt and drop free of the vehicle.

 

[chmura]

LI batteries are expensive that usually have some sort of microprocessor built inside of them.

The 2015 BMW M3/M4 comes standard with an LI battery (weight savings). I priced this battery and MSRP was $1200 for BMW OEM.

 

[NoDak]

outside of the previous comments, what is the viability in temps below say 32F, 0F, -20F?

once November hits, we stay below 32F, some weeks we drop down in the single or negative single digits and hit snaps of 1-2 weeks of -20F.