Hi, could someone be so kind to help me. My brother in law has owned a wisper 905se for less then 2 years, he has only done roughly 60 miles on it, he only really uses it when away in his camper van. He went for ride on his 905 with us on our electric bikes and his few Power bars he had, ran out near home after 15 miles . He tried to charge it at home but the light was flashing on his charger randomly then stopped flashing and his battery did not charge. He gave the battery to me to charge as my partner has a new wisper 705se with the same 575 battery but different charger. I plugged our charger into my brother in law battery and on our charger there was a red power light and a green charge light and the battery did not charge. He has always kept his battery charged when not in use and through the winter. Has anybody got any ideas why the battery won't charge . Thanks for your help.
Assuming its a Li-ion battery, he did not keep it charged all the time. I could make some guesses as to what he did if you wish to hear them....
What is being seen is when a Li-ion battery goes below 30% charge (which is considered to be the discharged point for normal usage), there is circuitry in the battery that stops the normal charger charging anymore.
If the battery is still otherwise in a good condition, then a good bike shop can usually recover the battery with a "Zero Volt Charger". Once done, the normal charger will work once more.
Or you might be able to buy one somewhere, (slightly like finding Hen's teeth for average bikers!), the only supplier I know of is in Sweden, but only has ones for 36 Volt batteries and they cost US$99 plus postage (from memory!).
But letting a battery go below this point does cause long term damage, so its not to be recommended.
I am adding a copy of the documentation of that special charger, when I was lent one, when my bike was so delivered new.
Its obvious just how it works from the table.
regards
Andy
