dsullivan wrote:I currently have a brand new eZee 36v 14ah battery pack from ebikes.ca (who helped me design and sold me everything for my first ebike.
*Note - when I received the battery it was holding a charge of 42v. After every charge I give it, it only reaches 37 or 38 volts.
Is this normal or is it a bad sign?
over 3 days I have discharged the battery on rides down around 7 amp hours the first trip
Then I recharged.
7 amp hours again and then I did a 1 hour charge to make sure I would have enough to get to work and home.
a full charge last night.
today I had some running to do so I drove it until cycleanalyst said 11 amphours then it just died.
Showing 32.4V and showing used 11ah I assumed I had about 2.5 to 3 amp hours left.
Not so bad except it died about 3.5kms from my house at the bottom of the biggest hills and I am not the best biker. Actually I am very close to the worst but I have been getting better.
So I walked the hills and biked the last 2 KMS to home.
First thought - Should I be counting AmpHours or Should I be counting WattHours?
Second how low should the BMS Volt cutoff on these eZee batteries be.
Third did I hurt the battery giving it a little 1hour charge the other day.
fourth is there some ritual I should do as a breakin for these batteries or should I just use them? Should I expect it to get better?
PS I am loving this bike.
For the eZee 36V/14Ah LiMn battery 42V is fully charged. If you are reading 37-38V after a complete
charging cycle that is way too low.
First be sure your voltmeter or whatever you're using to check the voltage is working properly ( I use an inline wattmeter during charging).
Second, check the open circuit output of the charger. Some smarty-pants chargers will read a lower open-circuit voltage than they charge at but most will read the voltage they charge to, which in your case should be at least 42.0V. A little more is actually better since it will help the BMS balance the pack, for example my 12S LiPo charger reaches 50.5V or 4.208V/cell and I balance to 4.20V/cell.
Third, if the charger output voltage looks fine then leave it connected to the pack at least overnight to be sure the pack is fully charged AND balanced.
When breaking in a battery limit the depth of discharge until it has had several complete
charging cycles. I stress COMPLETE because if you don't let the battery fully charge AND balance you risk having a low cell which will cause the BMS to cut out prematurely. A BMS will trip out for a number a reasons, one is low overall battery voltage, but it will also trip if just ONE cell goes too low.