My Night rider (wisper 905e) has been pulled out of its mothballs after a 6 mouth rest in the spare bedroom, this was my first ebike back in 2006 and still going strong I am getting around 16 miles in pedelec mode and 10 miles with throttle only,well after 3 charges in the last week tonight the charger has stopped working, I have an ultra duo plus 30 Charger which can charge up-to 10 lithium ion cells, am I right in thinking there are 10 cells in a wisper 36volt battery? dose any one no if this can be used safely to charge the 36v wisper battery?.
The Wisper charger has a charging voltage of 42 volts and is rated at about 2.5 amps continuous. It reduces its output voltage if the battery attempts to draw more than the rated output so it is to all intents and purposes protected.
I assume when you say it's stopped working that it's electrically dead. Do you get any lights when you turn it on without it being plugged into the bike? If you get a green light and a red light then it's working but you should check with a voltmeter. If the fuse is blown you'll still get the red and green lights but of course no output - if it's connected to the bike you STILL get red and green lights irrespective of the state of the battery if this fuse is blown. You get red and yellow lights while it's charging and for the first couple of seconds after switching on even if it's NOT charging.
If you want to use something else the most important thing is the 42 volts output when not connected. Any replacement should also current limit at around 2.5 amps. Other than that, the charger doesn't have to be too smart - the battery's BMS determines when the battery is full and stops the charge - the charger merely detects this cut-off and switches from yellow to green.
You'll note I've carefully avoided saying 'Yeah, plug in your spare charger and it'll be fine' because of course while I mean to be helpful there are of course no guarantees. However, if you're still on a 2006 battery then you don't have an awful lot to lose as it's certainly well past its 'best before' date!
Rog.
