Has anyone swapped their lead acid batteries for lithium motorcycle battery? Specifically, for SR3. Does or will the stator keep a 12V (12.8V?) lithium battery charged? Any problems or issues to know about in consideration of using a lithium battery for race cars?
Plenty do in the UK without any issues. The charging system will cope with it fine so no problems. You have to be on top of the system as Lithium does not like being discharged (like a failed charging loom or reg/rec) and also will not cope with being over charged.
In the UK there are specific manufactures that you must use when racing, all of which have been tested and approved.
I have seen the odd issue with Lithium though. We recently had a customer with a Caterham who had a battery go up and he had to bury it in sand and then salt water for days until it was fully discharged - the neighbour had called the fire brigade due to the smoke and smell! We haven't seen the car yet but I do wonder if the battery had discharged and then being used as the starter for 24V so pulling 12V in through the negative had caused something to react!
Im running 2x12v lithium with total of 20ah in serial, + 1 extra in the back for my 24v starter system
all 3 batteries in total weight aprox 2.6kg. Works perfectly. Except ive had alot off issues with mye aftermarked stator.. not producing enough power for all my components
I tried two Anti-Gravity AG-1601 batteries last year in place of the AGM lead batteries in my SR3. It did not work out -- both failed within 10 to 20 hours of use, and one was visibly expanded which sounds a little dangerous. The specs on these batteries indicate that they have sufficient amp-hours and cold cranking amps, so I am unsure what caused the failures. On my FE2 (open wheel race car), I used the same lithium battery all year without a problem and it is still going strong.
My race crew says they have had better success with Braille lithium batteries.
@davidf Was the expanded battery the main one on the bulk head? And yes that sounds super dangerous!!! Guessing if it caught fire that would be the end of your car.
I fitted a pair of Lithium batteries from Jack Webb Motorsport in the UK to a customer’s SR3 at the beginning of the year. I decided to put the main battery in the sidepod, as the batteries have a thermal cut out, and I wanted to get it away from the exhaust primaries. This car is also running a Simpson/RLM stainless steel exhaust system, which runs even closer to the battery than the standard primaries, so even with the standard agm battery it needed to run heat protection as it was melting/expanding the battery. Took a bit of work to move the battery into the pod, but seems to be ok at the mo.
Also another thing I did was to check with Radical that the slave battery charger was actually safe/compatible to use with Lithium batteries, which I don’t believe anyone else had bothered to do before fitting them 🙈 Turns out they are 👍
@davidf I have found that both batteries need to be in a good state otherwise it doesn’t like cranking. Not sure how the slave battery goes down, but they do go down eventually (although should be way more than 10-20 hours). I wonder if because one battery is down, it has dragged the other one down somehow (even though they are not on the same charge circuit). That goes a little bit beyond my knowledge.
Are you going to try Lithium batteries again or stick with agm? I would certainly advise either getting adequate heat shielding over the main battery, or just move it altogether if you’re gonna use Lithium 👍
Thanks for the info Alex. For now I will go with the agm batteries in Radical. If I do try the lithium again, I will shield it.
The battery for the FE2 is holding up well but it makes me quite nervous because the battery is mounted just below my foam seat.
When rebuilding my latest sr3 acquisition I was being quite weight conscious about everything that went back in the car. Cutting off unneeded brackets, re-building the loom with thinner wire, spending days making replacement carbon fiber tabs and such. The one thing i DID NOT do was replace the battery with a Lithium unit- I instead down size to a pc680 AGM to save weight. Li-PO are just not an option, aside from the pricetag for a 'quality' unit and specific charger (about 2.2k for the pair) I feel you get an inferior battery as far as discharge, peak, overall life and poor discharge in colder weather. I have been involved in 2 lipo melt downs in other racecars and have seen about 10 more through the years at race track and events I attend. One was an explosion after jumping the battery (correctly may I add) and the other was normal track driving and it ranaway and melted down.
I do motorsports wiring on the side and always recommend an non lipo battery to clients, to me its just not worth the risk. Saying nothing of the inextinguishable fire potential, the white smoke that immediately billows in a melt down is about the worst stuff you can breath. Gases such as hydrogen fluoride HF, phosphorus pentafluoride and phosphoryl fluoride and fluorine. Even if you manage to pull over off the track quickly, undo your belts and get out within 20 seconds you're still exposed to some pretty nasty neurotoxins.
