Was just looking at those lithium batteries today. Got a "lighter" batt about a year ago.
Didn't even realize these 3 lb batt's exist. How does something like this hold up?

https://www.batterytender.com/Batter...ry-w-Smart-BMS

 

I had issues starting with a 400amp portable battery once, not sure if 360 would cut it.

 

I use a 360 for a while and it was just too close to the limit of capacity. It started great but it was super easy to kill. I did charge it back up several times from dead though.

I have a 480cca (equivalent) antigravity and its been rock solid for 2 years.

 

this one is 3.8lbs with 680cca, with the reserve capacity held - i mean how much lighter do people really need?

https://antigravitybatteries.com/pro...-oem/atx20-rs/

 

I still stand by my Shorai battery. It lasted me about 6 years and I only killed it bc I left the key in ignition and jumped it one too many times. My car used to be my DD and it was more than capable of starting my car on e85 in 0 degree weather.

540CCA 6# and I can get them on on the cheap thanks to a very generous person that works there.

 

i did like mine too, and cost effective, but even leaving mine charged all the time, mine got burned out fast. the antigravity is much more $$ but i like the idea of having the reserve capacity separated out. don't see any downside to that, other than it may need it more often due to restart taking up some of that ah?

 

Too rich for me. If I had the stock weight battery maybe. For that money, I would go with
one the light IC's, since I have a 30ish lb one in there now.

 

same, i've got a deka ext18L in there now, about 20lbs but not awful. maybe next time

 

I use a powersports sized lead acide battery. Weighs right around 9-10lbs and has never had an issue starting my car even after sitting for 8 months without being on a charger. Costs around $120 IIRC

 

Austin, what battery specifically do you use - powersports 10lb?

FYI: I called Shorai, and they advised their batteries were rated up to 30Amp charging, so our alternators are likely to shorten their lives: the person answering the phones here in San Jose area straight up told me not to buy it or use it.

I called Antigravity in Los Angeles, left voice mail, did this maybe 3x different days. Never heard back
So I called again another day and got somebody to answer, she than took my phone and name, advising Senior Tech will call me.
Later that day got a call from Minnesota, spoke to the senior tech, who could not do basic electrical math.

In the past I used PC680 which worked fine 2 years and than started usually have issues, once in a while. I could stretch a PC680 out to 4-5 years of use if I "used it daily".

Miata batteries are nicely sized for Evo, they are more or less exactly like ROW(Rest of the world) Evo batteries, USA gets a ultra sized battery due to some areas having extreme weather conditions.
I researched back and forth, between the slightly smaller 21lb and right on 24-25lb MIata sized batteries.
Original Japanese batteries like Panasonic and Yuasa last for 6-7 years.
Die Hard is really quiet good in all tests.
Finally I decided Deka had great variety and reputation: bought a Deka ETX30L 21lb battery, rated at between 365 and 400 cca - depending who you ask/read.

In the shop they tested it in front of me, it put out 580 cca right in front of me as it got pulled out of the box.
It is going into the trunk of my daily driver Evo, via 2 awg fine strand wire with EPDM insulation.

2 awg wire is heavy in itself.
A lightweight battery say in the 6-10lb mounted in original position, or somewhere close-er to the engine - maybe under passenger seat to get it out of the engine-room heat?- saves weight that we normally pay a lot for. For track oriented car I would prefer that route.

 

This is what I use, it's made by the same company that owns Deka: https://www.sure-power.com/product/e...is-genesis-ep/

I run the smallest one in the photo (G13EP according to their spec sheet).

$130 on Amazon but I do remember seeing it a bit cheaper elsewhere last time I was shopping:
I also really love that the terminals are threaded. I always bolt my cables to the battery after having a clamp become too loose on me at the track.

 

Austin, how do you "treat" your battery?
Just park the car in garage and use sparingly, no battery tender?
Or do you put it on battery tender? Disconnect battery from chassis?

Trying to understand if it would be suitable for regular car, or far too low capacity to be trusted say after 2-3 years, at 32-35F in the morning, after sitting for a week?

PC680 exhibited this type of behavior, was ok for 2-3 years, than it's capacity was borderline to continue cold starts when weather got cooler down to 32-35F, at first when car sat few days, later even overnight was enough to be unreliable.

 

In my mind, if the longevity/economy of the battery is a concern, then the trade off to save some weight does not make sense. There is a trade off with everything.

Not saying you cant, but if I depend on the car to get home from work in the winter I would not choose a battery with weight savings in mind.

 

Winter in San Francisco, not Chicago...

 

Liked the Genesis-Hawker batteries. For a light weight battery (good quality, also like the bolt terminals too) they perform well. Had one in my RS for 3 + years in Sacramento. Temps from mid/low 30's in winter to 100's in summer. Not a track car and was garage kept. Occasionally sat for a week or saw brisk canyon runs in Valley summer heat.Never used a tender and never failed to start.
I personally don't see the gains in getting a lithium batt and paying double price to achieve just 5 lbs in weight in a street car.