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[tom_001]

Hello every one,

This has been on the back burner for say six years now, I know you can not easily get big nimh batteries and I will not go into that.

I remember weighing up sla and nimh D-F cells, at the time, the size, weight and capacity wear about the same but nimh needed smart charger for parallel strings and it cost lots more also capacity was cut if it was discharged to fast.

Now I see many Chinese 10000mah D cells with 30A max discharge for like £2.50 ech. I'm going to for get them as they are probably AA's in cardboard lol, however Radio Shack are selling own brand 8000mah D cells for just under £5 ech for 250+.
These NiMH cells are twice the capacity and twice the max drain current of the ones in production not so many yearsago.
wanted voltage is 48v, so thats:
40 cells in each string = 48v, 8ah, 20a max (to be safe)
10 strings = 80ah, 200a max (to be safe)
each cell weight about 160g so thats 64 kg excluding connections
dimensions are 3.2x3.2x6 cm so each 40 cell pack is 2.45L or half a gallon and all together 24.5L or 5, one gallon cans.

So 24.5L or 5, one gallon cans with 48v,  80ah and safe 200a max drain weighing 64kg and costs £2,000 from rs lol (or £1000 if these chinese D cells are ok)
I worked it out to be half the volume of sla and about 40% less weight for the same voltage and capacity, but sla has much larger max drain.

Sorry for the funny workings but I think its sound, If not please tel me where i'm going wrong as this is perfect for a planed light 125 super moto conversion with alltrax and 6hp ish continuous motor max 28hp.
Thanks for any help. Regards Tom.

[tom_001]

well never mind, any way, thunder sky a chinese lithium bat is the same price but 20kg lighter than the nimh will have been and the same price, well sort of, now to find them and the bms in the uk...