I like the Headway cells, and they seem to be well thought of. Clearly, I have to do some measuring. At first glance, width is going to be the determining factor. Capacity wise,
Headway cells used to be the only way to get a sensible capacity into a box the same size as the grp24 lead brick, and they are quite high C rate meaning they are safe to use in a small capacity without hurting them. Over the last few years there are MANY new different sized cells appeared. And some allow much higher Ah capacity to be used in the space we have available. So its possible to fit more capacity which has many benefits.
based on the 22NF SLA having a roughly 50AH capacity (manufacturer’s rating),
With lead you only usually get around half to twothirds of that out before the voltage drops, and the internal resistance/peukert means you stop... So your 50Ah lead battery is realy a 30Ah one.
I was thinking of using the Headway 15 AH cells, 8S for 24 volts, and then 4 or 5 banks in parallel, for 60 or 75 AH.
(BM - can you explain your AH numbers? I’m not following.)
Those were the first cells I looked at that I found after a quick search. They should allow you to fit 16 cells. They are 72Ah. So they ill allow 8S and 2 in parallel, giving you 144Ah. Way better than your 60Ah with the headway cells. C rate is lower, but since theres 144Ah then thats still better overall! But it will be tight, as those cells need to be wrapped in something to insulate them electrically or spaced apart with 1mm sheets of plastic.
Shirley may tell us they are bad cells, and or offer something better?