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Hi, Private replies have started to arrive pointing out that the capacities of various batteries depend on the discharge rate. I am aware of that and probably should have mentioned it but it was not obvious if the Ah ratings given was at the specified discharge rate or at a nominal discharge rate: as far as I know D/R uses Lead-Cadmium batteries and they are usually not available in 7Ah. Nominal discharge rate is usually the capacity divided by 20 (C/20) i.e. the cell is discharged in 20 hours. Discharging batteries in less than two hours will give substantially less apparent capacity. Someone suggested to me that a typical gelled cell lead-acid will only provide about 65% of the rated capacity when discharged in less than two hours. The non-gelled lead-cadmiums might be a bit better. I have not measured D cells of the NiCads persuation at 4A but I would guess a 4.4Ah cell which provides about 4.0 at 2Amps could maybe give 3.5Ah at 4 Amps for an overall drop of 20%. If the NiCads used by Ikelight were quick charging F cells, 4.5Ah could be the measured capacity. I'll quit guessing now. Interestingly enough, if you have two battery packs, you maximize the available run time by discharging them simultaneously. john 015 cc015012@br*.br*.ed*
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