Lithium car batteries; 1 3rd the weight

[Logic]

These Lithium batteries seem to be popular in racing circles at one third the weight.
https://antigravitybatteries.com/pro...es/automotive/
(They'll lighten your wallet even more! )

There are plenty of reviews and talk on them if you search.

I'm guessing the casing used is mostly empty, so there's a space saving to be had by using the 'smaller' models too.

Anyone here using them?
Or making their own??

[serialk11r]

If you search you'll find a lot of posts.

Antigravity marks things up about 2.5x in exchange for good customer support. High current BMS with bluetooth costs about 100 bucks and the cells cost on the order of $2/Ah these days (30Ah x 4 in series = about $240). You can get them even cheaper on Aliexpress but the cells may have reduced capacity from being used or QC rejects.

There's zero reason to assemble the pack yourself nowadays, as they make plastic casings that fit standard car/motorcycle battery sizes with standard size terminals.

Another thing to beware of is electronics may not play nice with the BMS' charging cutoff. I have small ultracapacitors in parallel on my car to provide momentary backup power to avoid pissing off the car.

If you don't have freezing temperatures go LFP, otherwise you need LTO. Even though they work at much lower charge than lead acid, I would still have 20Ah at a bare minimum on a car so you don't have a dead battery if you go on vacation.

[alexshock]

There is also another brand LITHIUMAX.

But again... this is only an option for sunny California, not for regions with sub-zero seasons.

Also, there is a classic alternative: Optima Yellow Top, which is a little bit lighter than regular lead.

[serialk11r]

Optima batteries are just overpriced lead acid.

Lithium titanate for cold weather, that's what I have (I bought it more because I can, not because I actually anticipate driving below -5C frequently).

[alexshock]

Originally Posted by serialk11r

Optima batteries are just overpriced lead acid.

They use some proprietary tech for wrapping up internals that results in 10-15% weight gain with same specification.

Originally Posted by serialk11r

Lithium titanate for cold weather...

Did you built it yourself or any know brands that we can buy?

[serialk11r]

Originally Posted by alexshock

Did you built it yourself or any know brands that we can buy?

Got it on Aliexpress. Paid 350 for 40Ah and a 200A rated BMS.

[Ecky]

I've used one of the 20Ah batteries from here for years:

https://www.batteryspace.com/li-ion-...lead-acid.aspx

[redpoint5]

Originally Posted by serialk11r

If you search you'll find a lot of posts.
There's zero reason to assemble the pack yourself nowadays, as they make plastic casings that fit standard car/motorcycle battery sizes with standard size terminals.

Except I can get 7 Ah cells for $3.50 apiece on Aliexpress. I load tested the cells and found them to very nearly get the claimed capacity, which is always hit or miss, especially on Chinese sourced cells.

A 4s4p config would cost $56, 28 Ah, and 200+ short duration discharge capability.

One can scale as needed to achieve their capacity and power requirements.

Originally Posted by Ecky

I've used one of the 20Ah batteries from here for years:

https://www.batteryspace.com/li-ion-...lead-acid.aspx

Same. Spent like $120 and didn't even add balancing or BMS of any sort. 6 years trouble free in the Prius so far.

[serialk11r]

Ah, I never bothered checking the prices of individual cells haha. 7Ah for 3.50 is a good deal, 4S6P would be 84 bucks so much less than 200 for the assembled pack.

I also realize people use batteries in far more demanding settings with no individual cell balancing, but... it's "correct" to use a BMS and not fair to compare directly to BMS equipped batteries.

In a car, I think having the original fitment plastic case, SAE post terminals, and a BMS, all assembled, is well worth an added 120 bucks.

[Isaac Zachary]

I'm very interested in LiFePO4 batteries for mobile amateur radio in the car. The problem is we get lots of cold weather and charging LiFePO4s in the cold ain't good for them.

LTO is another alternative, but the voltage of LiFePO4 is perfect whereas LTO is too low with 5 cells and too high with 6.