250 amps for 1 min is a discharge rate of 35C on a 7Ah Battery.

To compare like with like, a 35C discharge rate from a fairly standard robot battery like a Hawker Genesis would mean 1 x 16Ah Hawker being capable of delivering 560amps for say 1 min.

Even the 16Ah Hawker Genesis is only rated for 535 Amps for 5 seconds before the voltage drops to below about 7 Volts, and the voltage heads south from there to the point the battery becomes un-usable.

I did have a whole section of the post where taking into account efficiencies of SLA batteries vs rated capacity and Ah ratings I worked out that if you *really* developed 250amps for 60 seconds, you actually exceeded the rated capacity of the battery, and ended up with the terminal voltage of the battery hitting 0v.... and thats before you look at the size of the terminals ! (so I just decided to delete all the maths as it would have just bored people!)

Bottom line is guys, Im sorry, but theres no way a 7Ah battery can supply 250 amps (or 200 for that matter!) (3Kw of power!!!!) for 60 seconds.....

Ed
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