Dustin1824

iTrader: (2)

Sounds like alot of fun! Did you use their balance charger occasionally to make sure the cells were balanced?

I knew that Ballistic used the A123 cells, but doing a DIY job with the same level of packaging would be difficult, for me at least.

What size is the wires coming off of that cell you linked? Using a SB style connector with this battery would be a really clean install, and easy to remove every once in a while for balance charging.

Leafy

iTrader: (1)

I used the ballistic balance charger, I wish I didnt since there's is some other brand with just a sticker over the original logo and a price markup. The hobbyking batteries combined with a small auto balance board havent come far enough out of balance to need to be put on a real balance charger yet.

The size wires coming off the is either 6 or 8ga. I forget. The 5.5mm bullet connectors work really well and it wasnt hard to solder some 4ga wire onto the car side bullets.

Frankie4Fingers

Great points: Where did you relocate yours to? -Is your car track-only?

Leafy

iTrader: (1)

Mine is yet to be relocated. And has only started my personal car twice so far. But we've put a few in other street driven cars locally now. Including the aforementioned civic daily driver who left his headlights on. Passenger footwell would be my choice with a second set of high amp terminals like an anderson connector right near it in case you needed to jump to switch to a different battery in an emergency.

miata2fast

iTrader: (2)

The wiring you are referring to is not even close to 10 lbs. I am in the process of relocating mine, and I would guess it's under 2 lbs. Maybe I should weigh it to know for sure.

Leafy

iTrader: (1)

God damn the internet. Does no one have accurate scales?

miata2fast

iTrader: (2)

LOL. It is a pretty skinny wire after all. I am being speculative on weight, but if I recall, I was thinking I would save ounces in relocating the wire.

I planned to leave the battery in the back and relocate the wire to the driver compartment thus removing just a few feet of wire.

Dustin1824

iTrader: (2)

Look up the weight of wire by foot, 10 feet of 0 gauge wire weighs about 3.5 lbs.

I'm going to estimate the wiring is more like 6GA, so it probably won't even weigh 3.5lbs.

This is actually surprising, I thought it would be heavier.

Leafy

iTrader: (1)

2 is probably closer than 10. 4ga copper wire is ~1/8lb/ft without insulation. and 1 wire runs the full length and a 2nd wire runs part of the length.

ds0440

+1 more for the lawn mower battery.

jeff_man

iTrader: (7)

My friend's WRL car has a 3.4lb battery tender lithium starter battery. Said it was $120ish and wont get off his *** the get the parts number they are using.

Batteries

I know you do have to cut power to it when the car is not running as if it drains 100% the battery is dead forever.

sixshooter

iTrader: (12)

$41
15lbs
230CCA
Super Start Lawn & Garden U1RH - Lawn & Garden Battery | O'Reilly Auto Parts

For comparison, the standard Miata battery, which is already quite small, is
$105
25lbs
320CCA

Stealth97

iTrader: (5)

I'm leaning on the EXT20 now, since I can't get the Yuasa cheap without paying $13 shipping.. at that point I may as well get the legit one for $100. I have no need for anything drawing dark power so I'm going with a cutoff switch as well. Since my head has been in the machine shop for nearly a month and I havent gotten an ETA or even an estimate I haven't thought about it much lately. I'll just buy when I get the head back.

I'm staying away from flooded cell batteries to that leaves out the good, uber cheap lawnmower batteries. No leaking on my rust free chassis.

Ryephile

iTrader: (1)

The Deka's are good AGM's. They're basically generic branded Braille. Anything cheaper will be a lead-acid and/or not worth your time.

Most motorcycle batteries don't have the CCA needed for a car engine plus all the additional loads versus almost none on a bike, save a Gold Wing et al.

If you wanted to go into LiFePO4 territory, you're going to spend more coin. Shorai's LFX36 is a great battery that I used in my Lotus with excellent success, $265 via Amazon Prime. I also just rebuilt my Chimera [4S2P] with Headway 38120HP cells plus top-down balancers and it was around $200, not including that I already had the CF case, cell holders and copper bus bars.

The difference between lead-acid/AGM and LiFePO4 is if you don't drive the car everyday. Storage battery tenders need to be different, as a lead-acid tender will smoke a LiFePO4 in short order.

jeff_man

iTrader: (7)

Voltage: 12V
Cold Cranking Amps: 360
Case Dimensions: 6.49” (165mm) length x 3.38” (86mm) width x 5.11” (130mm) height
Operating Temp: 0 - 140°(F)
Weight: 2.6 lbs

Ryephile

iTrader: (1)

That is most likely a 4S3P of A123 26650's, given the rated amperage of 360A [120A x3]. 1.9 lbs would be the 12 cells, the case and terminals the balance. 7.5Ah is pretty small, your alternator had better be in top shape and your electrical loads minimal.

The price is excellent though, so it has that going for it. The equivalent [actually pretty much identical in terms of cells] Ballistic Evo2 12-cell is much more expensive.

Leafy

iTrader: (1)

7.5Ah isnt all that small. Especially for a miata. If your alternator crapped out you should still be able to drive ~20 minutes with the headlights off.

If you want to DIY your own version of that battery the cells cost ~$7.75 a piece if you buy them with tabs already spot welded on so that you can make the battery pack with solder.

Failure

Nope, prismatic cells. I'll try and find my source again.

Edit: found this Amazon Q&A, but somewhere I saw a forum thread where someone dismantled one.

jeff_man

iTrader: (7)

Only have ECU, brake light, injectors, spark plugs, fuel pump, motor sensors, and wide band to power.

Maybe headlights and turn signals somewhere down the line.

Stealth97

iTrader: (5)

That battery tender was one I was considering. I have a fun street car, not a race car, so after getting a special charger, etc. the cost wont be worth it.