What's the smallest (cheapest) battery you can get away with using on an FD race car if the only accessory load you have is the A/C blower?

 

the stock factory installed battery was either a 55C23L or a 65D23L, at 55 amp/hours
that PC680 battery we all used to run (Hawkers other product was the Harrier jet plane, which is kind of neat), and that is only 20amp hours
so somewhere in between is probably good.

as far as price and weight goes, its kind of random. the anti gravity that everyone loves is heavy and expensive
and you should for sure do some searching, there are tons of different brands now, https://no.co/nlp9

(i've had a 1U golf cart battery for 6-7 years now, it was $40!)

 

I recently went w a low cost AGM battery I found on Amazon for $40; installed in driver's side storage bin. Not sure about the overall longevity of this small-ish unit (only been 6 months). But so far, so good.

Mighty Max Battery ML18-12INT - 12 Volt 18 AH, Internal Thread (INT) Terminal, Rechargeable SLA AGM Battery

 

Before anybody starts suggesting using bargain basement (true) lithium batteries remember they're some of the most volatile and energy dense (dangerous) batteries out there - even if the cells seem to the the same as used by other well known brands the load balancing strategies and circuitry to said cells may be half baked. If you really MUST buy cheap, buy LiFePO4 for safety and take the weight hit.

 

I went with a Braille G20. It saved 10lbs over the PC680 it replaced, and has a bit more power. It also is the same size as a PC680, so it fit in the same mount, which was the deciding factor over Anti-Gravity.

 

I used an Odyssey PC545 AGM battery for many years. My usage was basic car driving, headlights at night, heater blower in winter, standard bulbs for lights. This battery is rated as CCA 150 and reserve capacity of 18 minutes, and nominal capacity between 12ah and 13ah. At this capacity I considered it a "healthy car" battery as I had no problems normally. But at this size if I tinkered with the tune via live connection to ECU for more than 30-40 minutes or if fans ran for more than 10 minutes then starting could be difficult.

I would suggest a lithium (or any type) of battery similar to a PC545 is at or near the lower end of practical usability.

This post motivated me to lookup some pricing of lithium batteries and I found that some come in 13.2V and 14V sizes. My gut feeling is these may be a good solution for those of us that have a few seconds of 12.X to 13.XV voltage when we are pushing our IGN-1A coils hard and/or when also night driving. I'll be researching this some more and lacking any serious negative findings I will likely try a 13.2V model such as the E3 Ultra-Lightweight Lithium Battery E3.403 or possibly the E3.402 from summitracing.com, listed at a price of $265 / $230.

 

I think that is the type of battery I was looking at.

I am aware of the potential hazard of lithium batteries. I’m not going for bargain basement, just bang for buck.

 

The NLP9 sounds good to me. It’s available here for less than 20,000 yen, which is a third the price of a typical lithium car-sized “race” battery here. And it’s probably lighter. Just need some terminal adapters…

 

https://www.amazon.co.jp/ECO-WORTHY-...1zcF9hdGY&th=1

This little guy is just 10,000 yen.

I think 20 ah would suffice for pure track use, no? I can always throw my full-sized battery in the car if I need to.

I would probably have to rejigger my battery retention system, but this would save about a year's worth of dieting. Hahaha.

 

LiFEPO4 batteries are awesome with Rotaries as you definately notice the increased cranking speed due to the ability of the battery to supply more current and the higher voltage. we run 20AH LiFEPO4 starting batteries which differ from others due to their ability to deliver over 200A from their BMS. One thing is they need to be charged at around 14.6V compared to 14-14.2v from a conventional Lead battery another big advantage is weight as our 20AH Lifepo4 weighs around 3.5Kg.

 

Wish I had known that before replacing my 6 yr old antigravity battery. I still have the PC680 battery tray.

 

Highly recommend a brand called Lithuimax, Not sure if you have it over in the USA but we use them here in the shop and they are excellent.

 

Local, good race car builder TC Design recommend Antigravity. I wound up with a 21lb Braille in my RX8 race car instead because I'm cheap and didn't want the extra risk of Li.

 

everyone loves the anti gravity, and they have some nice features, but its expensive and they aren't that light. so i don't get it

 

Agreed on the AG price point but not sure which models you saw, the weight on both of mine are definitely under 5 lbs. I just weighed their ATX-12-HD and it's 3.25 lbs! It's kinda wild being able to hold a car battery with one hand no problem like that. I used to run Braille for years but always hated having to worry about maintaining them.

 

So, this is dutch, and I don't know if available locally to you. But this is what I got in my FC, and also used this on a 1.6 common rail tdi endurance racer.
Compared to some of the over-the-top unnecessary-hightech extremely priced alternatives, this is fairly cheap.

https://www.accuserviceholland.nl/lf...epo4-accu.html

Only thing to keep in mind, keep it at charge.
I fucked the second one because I forgot and can buy a new one now

 

To be fair the ATX-12-HD is a battery for small motorcycles.

The comparable battery for an FD in the Antigravity range is the ATX30HD or 51R-30-RS which are heavier than yours (7.81lbs and 11.25 lbs respectively), but that's obviously significantly lighter than AGM battery of equivalent performance.

 

7.81 lbs for the ATX30HD is still quite impressive for the rating imo and to be fair, it's also advertised as being a motorcycle and power sports battery.

One of the main reasons I chose to use the ATX12HD is because I'm one of the crazy people chasing every little last pound to eek out more perceived "performance." But the climate is generally fair all year round in CA where I live so I feel I can get away with it. The 12 has worked without fail for both of my mazdas and must be somewhere around 5 years in the RX and still starting strong.

 

Anyone try a Noco battery yet? Thinking of trying out the NLP30 700amp rated at 2.76lbs

 

+1

LiFePo4 batteries are non volatile and now capable of the input and output amps, personally that would be my choice, however being new tech still there isn't a ton of reputable companies making them, yet. i wouldn't really say there's a weight deficit compared to a stock sized lead acid.

 

i have the nlp30, theres quite a few cheap ones on ebay (mine was 1.5yrs old though).

Turns the car on fine. Also have had the p680 in past, nlp30 seems way better in every aspect. Note im reworking the engine bay so have only been able to turn it on for some drives around the neighborhood. Seems to hold charge way better than the old lead acid or pc680.

 

Apparently an FB caught on fire due to a trickle charger being left on a (cheap?) lithium battery.
So definitely get something with overcharge protection circuitry.

 

I run a noco nlp20 on an 8, turns the car over fine