Drill/mower batteries

[phil sommerton]

Hi again. Now I have my kit I'm looking at battery options. I only need 5ah I calculated for my mostly flat 18 Mile daily journey but obviously 10ah would be better. Can you combine two 5.ah 36v drill/mower cells in parallel? Googled this and found examples in series (multiple 16v) but not in parallel 36v. Assuming you'd need a diode or similar to prevent shorting or can they just be wired straight up? Cheers

 

[D8ve]

Wire straight up. It's been done several times

 

[PH001]

Yeh, direct parallel is fine but just ensure they are very close to the same voltage when you first put them together otherwise you might get some high currents flowing. I just wonder how good the cell balancing will be when you charge this lot up as if the cells go a lot out of balance the battery will go off pretty quickly.

 

[craiggor]

I use two 36v lawn mower batteries.Still going well after a year and a half,2132 miles.I charge them separately.I did fancy joining 2 together as D8ve suggested in the small battery bargain thread on here.Using just the one BMS,this would slow the charge rate down to improve battery life.I do not want to open them up till my 2 year guarantee is up.I think I will just check balance then.Bosch have twin 6ah on there professional lawn mowers and twin 9ah planed for the future.