First test ride today using a single battery. Connected with a lash up very similar to JHRUKs (thanks) but using a chopped up plastic chopping board rather than wood.
Voltage sag was very marked and much shorter range than I expected with 120+ wattH. Recover from the sag was very slow.
Next test will be with 2 batteries in parallel.
Certainly they are adequate as a get u home reserve but based on today I would not suggest using them as a primary battery.
Keith
PS used on a front hub cyclotricity 250 watt kit with 1.5mm cabling and a 15 amp fuse. Nothing got warm!
Although it wouldn't affect performance, 15A is a bit low for the fuse. Your controller may be 15A, so a 25A one might be better. The BMS will have over-current for the battery, so you only need the fuse to protect against a dead short.
Thanks d8veh. 25 amps it will be!
I'm protecting all the batteries with individual fuses and planning a 3 into 1 harness. The fuses make a good switch as I'm not convinced my soldering on the Deans is up to repeated disconnection.
Has anyone some further thoughts on running different capacity batteries in parallel given that they all have a BMS?
I became confused by some of the earlier postings (an age thing) so at the moment am keeping the 9ah battery completely separate.
K
You can run different capacity batteries in parallel, but they must be approximately the same voltage when you connect them and you should disconnect them for charging otherwise one will charge the other through the discharge leads, which might be OK or not depending on how the BMSs work.
Tried 2 in parallel today. Now much better with less sag although not as much "pull" up a slight incline as the original 9ah bottle battery. The (cold) rain stopped any idea of a range assessment.
K
Thin plastic on top to cover terminals.wires no longer cross over as in first pic.Paulhipwood is part of your plan to put wires where I have paced the pens,and sandwich them with another 2 layers.