8fun kit (Bottle battery): Initial conditioning Question...

jackhandy

Esteemed Pedelecer
May 20, 2012
1,820
323
the Cornish Alps
Afternoon all,

I've fitted an 8fun 250w, bottle battery kit to my Carrera Kraken & all went well, with the odd hitch, here & there as expected.

My concern at the mo' is that I'm running the battery "flat", as advised by those who know far more than me; but it just keeps running lower & lower & not cutting off.
I have ridden a 7.75 mile local route, with 500ft. total climb (to give it something to get its teeth into), 3 times this week, on the initial charge: After the second trip, it was down to the lowest led & this started flashing as I started the 3rd trip. Power gradually petered-out on the climb, until the wheel was only just turning (off the ground), with the lowest led still flashing. Having left the bike for 20 minutes, the low led is still flashing & the wheel turns fairly smartly, as I would expect having rested the battery.

The thing concerning me is, should power have cut-of before this? should I have stopped when the led started flashing? is it OK to charge the battery now or have I harmed the battery by running it too low?

The battery instruction booklet says power is cut off @ 30v. to protect the battery, the lowest led indicates 31.55v (0-30%), but no mention of it flashing.

I would appreciate any help,

Pete
 
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NRG

Esteemed Pedelecer
Oct 6, 2009
2,592
10
Most lithium 36v batteries will cut off at at 31.5v. Ride the bike until the motor wont pull or assist you anymore, its flat at this point, charge it... then you are done. Conditioning cycles don't apply other than the first to reset any battery 'fuel' gauge inside the Battery management System (BMS). Capacity of the battery will increase a little over the next few uses of the bike and will perform best in warm weather. If the cells are good expect a good 2 years use from it if treated well.
 

amigafan2003

Esteemed Pedelecer
Jul 12, 2011
1,389
139
Have you measured the voltage when you've run it that low? You could have a duff lvc circuit on your BMS.
 

jackhandy

Esteemed Pedelecer
May 20, 2012
1,820
323
the Cornish Alps
Thanks NRG,
I thought that was the way of things, just a tad dubious the thing was flashing but not cutting out.
Put it on charge about 16.00, still charging @ 22.30, but finished by 00.30, so a long charge.
We'll see what it performs like today,
Pete