The 45 lbs. lump of Bosch sitting under my hood is getting a little old and cranky. As long as I'm replacing it, should I be looking for a lighter alternative?
If so, any recommendations? Optima and Odyssey are the only two brands I've heard much about. Any good?
This will go into my racecar, which is an '87 Mercedes 190E 2.3-16 that's often parked outside. If lightweight = big headaches, then it might not be worth it.
If it makes a difference, the car pretty stripped out and running on Weber side-draughts instead of the stock K-Jet system. I suspect that reduces demand on the battery and charging system to some degree.
Shorai
I'm running a Deka ETX9 in my Miata. But with only 120cca, I wouldn't recommend it in a car that required a lot of cranking before it lights off.
If you can get a 14.5 volt voltage regulator (try the Chevy section at your local junkyard), a Zippy 4s2p 8400 lithium iron phosphate battery will start anything up to a LS1 and weighs 2 lbs. $80 at Hobby King.
I have had great luck with daily driving a Hawker Odyssey in two separate cars
Lawn mower battery has done fine for me for a few years.
With little batteries, voltage drop is your opponent. If you can run a 4" 4-gauge cable from positive to starter to terminal, and a 4" 4-gauge cable from negative to the gearbox casting, then wire positive and negative connections to the rest of the car from those terminals, you'd be gratified at how small a battery is needed to start a car.
If you want light, cheap and easy to replace.
Lawn tractor battery, they come in 3 different ratings, get the one with the most CCA's.
It's a race car, so it won't need to start in really cold weather. Keep a jump battery handy just in case, but a good lawn tractor battery will typically be fine.
The nice thing with this option, if for any reason you need a replacement, you can get one anywhere. If the alternator dies, you can pick up a second battery and a charger and keep going to finish the race weekend.
You can find more expensive batteries, and they will be a couple pounds lighter.
I have this one in my LS1 Camaro and Supercoupe. 1.75 pounds, 240 CCA. I usually keep both cars hooked to a trickle charger, but let the Camaro go for 2 weeks unhooked once just to see if it would still work. It did.
I've really liked my Shorai. 5lb. Smart charger works well. I've had it about a year.
Deka ETX 18L. Works like a champ in my racecar.
So, I've heard, once upon a time, about using capacitors to act instead of a battery. I don't remember how much they weighed, but I seem to remember them being pretty light. Pros/Cons?
scardeal wrote: So, I've heard, once upon a time, about using capacitors to act instead of a battery. I don't remember how much they weighed, but I seem to remember them being pretty light. Pros/Cons?
It's possible but not with off-the-shelf technology. A company was once developing addon capacitors for a car battery to take the load of cranking off the battery. This lead crafty people to the idea of using a tiny battery plus a capacitor bank for cranking. Then a company called Ohm tried to commercialize that concept but it's gone nowhere.
Edit: Looks like the Ohm battery project was officially cancelled back in 2015 due to an unspecified problem found in testing with the prototype battery units.
Edit2: Found a guy who managed to DIY a similar setup:
An 87 190E Cosworth! With side-drafts! Holy cow, I think you're entitled to call on Zeus to ignite you with lightning bolts, on demand. Righteous ride.
^^^ The car is pretty cool, if I do say so myself!
I can't describe how badass the engine sounds with the twin Webers. It barks and spits like a rabid Rottweiler. And the throttle response is insane.
third the lawn mower battery. Something like $30 at Walmart and it's my daily driver, going on two years now.
Are the terminals the right size?
I'm using a lawn tractor battery in the F500, I needed to add ballast so the extra weight over the tiny formula car style battery was a plus. I had to make up new terminal ends (eyelet style like GM side mount) but you could use screw on posts.
Tom
U1 size mower batteries run a lead tab with a 1/4" hole in it for bolting an eye terminal to, there are various solutions to hooking car cables to them (get creative), or buy adapters.
$20 at walmart right now:
https://www.walmart.com/ip/EverStart-U1R-7-Lawn-Garden-Battery/16795214#about-item
In reply to LanEvo:
Dude, at least give us an NSFW warning before posting pornographic images 
Sweet car.
I got sick of lightweight batteries dropping charge and leaving me looking for jumpers at an event. Now I use an XS Power AGM battery. It's lighter than a normal battery, heavier than the lithiums and hasn't failed me.
I've all but given up on flooded lead-acid batteries. SLA/AGM is waaaaaaay better at tolerating infrequent use or long periods of non-use. I just had a 2-year old conventional lawn tractor battery die in the JD. Noticed that the SLA's I had scrapped from my old computer UPS were the same size. They've been taking up space in my garage for about a year. Pulled the old battery, popped in the SLA, and she started right up. If I hadn't noticed the old batteries sitting there, I'd have ordered some LiPo's, just 'cause I think it would be neat to start a ICE with a dry cell battery.
I ran a Shuriken BT-20 in the Forte for 3 seasons. Pulled it in the fall for the big battery, put back in the spring. Never had any issues.
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