What alternatives would you recommend? I have found the 40152S marked as headway but it's very cheap.cheapcookie wrote: ↑Jun 23, 2018 4:52 amyou can find them pretty easily in the us, although they are better alternatives, especially from the automotive industry.
They are known as Headway cells, are from China.
The LTO thread is pretty interesting, much better power density than Liion, probably better than these as well.
Do you have any actual experience with the headway cells? I ran and started a 4 cyl on 6Ah shorai with less discharge rating for over a year with no jumpstarts. Anyway, demand is supplied by the alternator while the car is actually running, the battery just makes up spikes if there's heavy demand. So if these cells aren't too overburdened by starting the car it should be no problem.flippy wrote: ↑Jun 23, 2018 3:50 pmdont, those headway cells are crap. no way they still work after 6 months in a 1P setup.
better: https://www.ev-power.eu/LiFeYPO4-batter ... .html#tab2
this has the grunt to actually get the motor turning. the current while cranking might be 100~150A but the initial inrush current is usually around 300~400A. that will kill those poor headway's in just a few months.
i have used this battery for 3 years in a heavy 3.2L V6 (alfa) and now it's cranking a transit engine.
if you have a N54/N55 you need to focus on all the other crap that also pulls on the battery. no way that a single headway is going to keep that stuff running and still start that lump of metal. you need something more beefy. 60Ah like i linked above is what you would need and not have the car die because you left the radio on for 15 minutes.
dont forget that the ECU craps out at 9V.
just fyi: i installed this battery 5 years ago or so in a S55 (the M3 engine) and it is kinda on the lower limit to feel comfortable.
Uh, thanks but where can they be purchased???bigmoose wrote: ↑Jun 28, 2018 7:33 amI think you should take a look at the classic A123 LiFePO4 pouch cells. IIRC they are spec'ed to around 300 amp peak discharge.
The problem will be if you have almost discharged battery for some reason. After start, generator will try to push in all Amps it can generate. You can end up with a very sad battery under your passenger.
No need whatsoever. Aside from sag under load when starting, the only chance for that is if I leave the car sit. The alternator charges it continuously while the engine is running. Right now I drive the car every day. If I don't I will either disconnect the battery or put it on a charger.