Battery Charge Reading

[Del 80]

O.k, this might be a dumb question, if I attach a volt meter to my battery, will it give a constant reading ? my battery has the 3 coloured lights on the top.......which are practically useless, it would be useful to know at all times, what the state of the battery is ......ie how much juice left in it...................Del.

 

[Alan Quay]

Really, you need a watt meter (I'll try to put a link in bit).

Voltage will only ever be an aproximation.

But, roughly, on a 36v li-ion:
41v + = 100%
36 = 50%
32 = 0%

Edit: I have one of these:
http://m.ebay.co.uk/itm/261448272501?nav=SEARCH

 

[Del 80]

O.k Mike, thanks for that, so something like that could be attached to the battery.....or somewhere along the wiring, and would give a constant reading while battery is on the bike ?.......Del.

 

[Alan Quay]

Yes, that's the idea. You put it between the battery and the controller. It will measure volts, volt minimum, amps, amps maximum, and it will integrate amp hours, and watt hours.

Amp hours is the one you are probably most interested in, as this as a bit like a fuel gauge.

Others have posted about novel ways to mount it on you handlebars, but I connect mine up at the battery end and use it there.

 

[Deleted member 4366]

These ones are better because they can more easily be mase waterproof and they have a backlight for night-time.:
http://www.ebay.co.uk/itm/New-GT-Power-RC-130A-LCD-Battery-Balance-Watt-Meter-Power-Analyzer-Ver-2-0-dvz-/201048320816?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2ecf69eb30

You wire them between the controller and the battery. It tells you how many amp-hours you've used.

 

[Del 80]

O.k guys, thanks for that, just getting my old Powacycle back on the road, going to use it for work, then hopefully, after retiring next April, will be looking at buying a new E-bike.......any suggestions ?..............Del.