Anthony As we know batteries have a Cold Cranking Amps CCA rating, and this rating should be above what the engine/starter motor draws from the battery to turn the engine over. Measured a B230FT 4 cyl turbo engine on cold crank and the initial Inrush current was 270 Amps. My FT engine has 9.1:1 compression so would imagine a 10:1 comp would require a little more to crank well. So for a vehicle without acessories and one that starts well a 310 CCA should be fine for my purposes.
Vee_Que Because I have a daily 740t, that uses a 600cca battery in order to support the whole car. My 122 with a b20e with 10.5:1 c.r and a 940 starter uses a 550cca battery. Wouldn't care to go smaller with an electric Fan and 100w headlights. Both have a 940 100a denso alternator. I wouldn't go that low on cca unless you're obsessed with weight loss.
Anthony I'm obsessed with weight loss (haha) (motorsport vehicle). On that wavelength some people have been fitting a Harley motorcycle battery - eg Deka ETX20L. Even though their not that large they still weigh 6.5kg. SSB in Australia make a Lithium Ion car battery (Powersport L-HVT-1 or the L-HVT-6) but the price is north of $800 and it weighs around 2.5kg. Thats a bit over the top price wise as we dont really know how long they will last.
tbro Anthony I used HC28 Fullriver gel battery in my 2F Mazda, lasted well over 3 years and is still going strong.. It was layed up for 12 months due to engine blowup, didn't charge it and it started a new motor with 12.5 comp ratio, so last well and plenty of kick. Not light approx. 9kgs but nothing worse than stalling on the grid and not enough battery power to restart. Tezza
deleted_user_160 If it's weight loss your so keen on, just go get a lithium ion and be done with it. 1/4 the weight of an equivalent lead acid battery. 670cca in the 740t with static comp 9.3 Minimum to no accessories.(Hard fast starting)including solenoid bypass relay. 480cca in the 142 with static comp10.5 and a slow old starter. (Definitely struggles)
jamesinc @Anthony you seem nerdy enough to figure out a battery setup using a very small 12V battery that can energise a couple of supercapacitors cranking surely? :|
Philia_Bear The cranking amps in a lead acid are just a byproduct of the surface area of the lead exposed to the acid The Capacity of the battery is a byproduct of the volume of the lead and acid You can get some super high surface area batteries that have >2000CCA but less than 20AH of capacity, they frequently use very small lead pellets that are in a cage instead of as a plate The performance of these batteries deteriorates rapidly with discharges though and may only provide 5-10 full discharges before failing unlike a normal car battery which can survive->100 Ni-CAD and NIMH are far more forgiving than LI-ION and cheaper as well
deleted_user_160 More forgiving? Curious as to why the mass transition from NiCAD, NiMH batteries to lithium ion in the trade tools world?
Philia_Bear blondejay;100396 wroteMore forgiving? Curious as to why the mass transition from NiCAD, NiMH batteries to lithium ion in the trade tools world? They don't catch on fire nearly as easily as LI will :-)
