Rebuilding an Ezee Cadence battery pack with Aldi 'C' cells continued
I posted this in April and need some advice. I did discharge tests on the 64 Aldi C cells and was happy with their 4Ah capacity (although I did manage to overcharge a couple which exploded the plastic insulator end of their cases - still seem to work OK, but presumably now of lower capacity so I wont be using them). I have finally got round to opening up my Li-ion battery case and have a problem - I cant work out how to fit 64 (or 60) cells in it. I always end up with a few that I cant sandwich between the 2 layers and still close the case. I am loathe to throw away the C cells and start again with AA cells as Flecc did So I am wondering what would happen if I substituted some 2500mAh AA cells in the assembly. I have just ordered 32 AA NimH from Hong Kong (eBay) at around £0.50 each. There are various ways I could do it and I would appreciate advice on the following options - originally I was going to connect 2 C cells in parallel and then 30 or 32 duos in series to make 36 or 38.4V, 8Ah:
1. I could make a 6.5 Ah battery by connecting 1 AA in parallel with 1 C, then these duals in series - is there a problem with self discharge between just 2 cells of different capacity?
2. I could probably stretch this idea to C + 2 X AA - would fit I believe.
3. I could substitute triplets of AA cells in parallel (=7.5 Ah) for some of the paired C cells - would this overstress the AA's? - I might be able to squeeze some sets of 4 AA's in parallel which would then presumably be safe from overdischarge
4. I could make a whole bank of AA's in series and parallel it up (via Schottky diodes?) with a bank of C cells.
ps I can post some pics of the Phylion Li-ion cells if anyone is interested - the cases were quite swollen after a year or so of disuse.
pps Flecc - your NimH 'loan' battery is now cutting out regularly after over 2000 miles or so at around 4Ah of discharge - the internal impedance has gone too high, I guess - my Cycle Analyst shows a minimum voltage as low as 25V. I might try and see if the problem is with just a few of the cells, once I've got a working substitute battery.
ppps - thank you Fecn for you confirmation of the performance of Aldi C cells.
Tony
I posted this in April and need some advice. I did discharge tests on the 64 Aldi C cells and was happy with their 4Ah capacity (although I did manage to overcharge a couple which exploded the plastic insulator end of their cases - still seem to work OK, but presumably now of lower capacity so I wont be using them). I have finally got round to opening up my Li-ion battery case and have a problem - I cant work out how to fit 64 (or 60) cells in it. I always end up with a few that I cant sandwich between the 2 layers and still close the case. I am loathe to throw away the C cells and start again with AA cells as Flecc did So I am wondering what would happen if I substituted some 2500mAh AA cells in the assembly. I have just ordered 32 AA NimH from Hong Kong (eBay) at around £0.50 each. There are various ways I could do it and I would appreciate advice on the following options - originally I was going to connect 2 C cells in parallel and then 30 or 32 duos in series to make 36 or 38.4V, 8Ah:
1. I could make a 6.5 Ah battery by connecting 1 AA in parallel with 1 C, then these duals in series - is there a problem with self discharge between just 2 cells of different capacity?
2. I could probably stretch this idea to C + 2 X AA - would fit I believe.
3. I could substitute triplets of AA cells in parallel (=7.5 Ah) for some of the paired C cells - would this overstress the AA's? - I might be able to squeeze some sets of 4 AA's in parallel which would then presumably be safe from overdischarge
4. I could make a whole bank of AA's in series and parallel it up (via Schottky diodes?) with a bank of C cells.
ps I can post some pics of the Phylion Li-ion cells if anyone is interested - the cases were quite swollen after a year or so of disuse.
pps Flecc - your NimH 'loan' battery is now cutting out regularly after over 2000 miles or so at around 4Ah of discharge - the internal impedance has gone too high, I guess - my Cycle Analyst shows a minimum voltage as low as 25V. I might try and see if the problem is with just a few of the cells, once I've got a working substitute battery.
ppps - thank you Fecn for you confirmation of the performance of Aldi C cells.
Tony
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