- How many double 'A' batteries would it take to start a car ?
Voltage wise, 8 or 9 but you need 300-500 Amps to start a car, which your AAs couldn’t produce. A quick google suggests 2.5A max out of a Durcell AA, so you’d need 200 in parallel for 500A x say 9 to get the voltage, so 1800 or so in 9 series banks of 200 in parallelPosted 4 years agomrlugzMember
Rough calculations based on brief googlage.
Based on assumption of fresh Duracells (capable of 2A output)
Nissan Micra battery has 550 cold cranking amps, so you’d need to provide that.
9X aa duracell in series gives (theoretically) 13.5 volts with 2A current.
550 /2 = 275. so youd need 275 rows of 9 cells to give 550amps
so 2475 AA cells is a 9s275p configuration would start your micra.
A BMW 750 battery has 850CCA, so the configuration would be 9s425p or 3825 AA cells.
This is proper rough guesstimation though. 🙂Posted 4 years ago
What we really need to know is the battery pack equivalent series resistance, so we can calculate the voltage sag vs current output. A typical automotive lead acid battery has a very low ESR, and hence is fairly good at providing the high current/high power but low total energy pulse needed to start an ICE.
In reality, i suspect that you could pull a lot more current than 2A for the 3sec required to start the car, and so need far fewer batteries than the above calcs suggest.Posted 4 years ago
I just pulled 3.2A @ 0.86v from a random AA battery found in a drawer, giving a short pulse ESR of 220 mOhm. It easily kept up that output for 5secs. (Cell was floating @1.56v btw)
You need around 10V system voltage during cranking to ensure engine control systems and fuel pumps etc operate (actually, usually, down to ~6v is just about ok, but we will er on the side of caution), so that means 12S156P (1872 cells) for 500A @ 10V.
Mass of my AA cell was 24g, so that’s a battery mass of 44.9kg. Roughly twice that of a typical car battery.Posted 4 years agochrisdieselMember
The Peugeot / citroen hybrid system is 150bhp engine driving the front wheels and a 50 bhp electric motor powering a small gearbox to the rear wheels, in the boot is a battery case with 150 AA BATTERYS case with an Ecu charging and controller. It’s good for about 2/3 mins of driving before the engine kicks in to recharge it.Posted 4 years ago
But it’s many an emissions benefit. Road tax is £10 per yearchrisdieselMember
Stand corrected regard the battery’s just what I was told on the training course.maybe just a flippant comment by the trainer.Posted 4 years ago
No I don’t drive one but work on them regularly. Yes the battery size/power could be better but it does it’s job I.e makes the top of the range fully loaded ds5 hybrid in the £10 a year tax bracket so company car drivers buy them.
Del, incorrect. AA batteries are batteries. They are already a collection of cells. Pull one apart and its a stack of little ‘watch’ type cells.
Don’t think so. I have pulled them apart, and found one cell, but that was a while ago. PP3s are a stack of cells though, that’s why they are 9V.Posted 4 years agotheflatboyMember
Slight thread revival – that Anti Gravity Jump Starter, does anyone know a good price for one or an alternative in the UK, as they’re massively pricier in the UK compared to the States, and I’m also not sure if the mains charger would be UK-compatible.
I’d like to get one as a present for someone, you see.Posted 3 years ago
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