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Nine bot mini not charging after unuse for one year


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3 hours ago, Ritul Thakur said:

I have ninebot mini and I did not use it for one year. After one year when i tried to change the ninebot mini, it is not charging.

in another forum I read that battery disengage if not used for long time. Can some one help me on the issue 

Batteries slowly self discharge, although if in good condition and not left discharged in the first place they should not have got that low in one year, unless stored somewhere quite hot, which in Singapore, I guess, is quite likely!

Lithium Ion battery chargers, or sometimes the BMS (Battery Management System) built into each battery will refuse to charge a battery if the voltage falls too far as low voltage results in the cells tending to grow lithium dendrites that can cause partial shorts within the cells. 

You will find the instructions should have warned you to charge it occasionally if in storage - they tend to recommend at least every 3 months although that much should not be necessary unless using LiFe cells, LiIon cells should have quite low self discharge.

I think your battery is 15 LiIon cells, if so it’s voltage should NEVER drop lower than 45 volts (3V/cell) it might still take charge if it drops to 2.5V/cell - so 37.5V but it is unlikely to work if any lower. Measuring the battery voltage would be a good first step. If it is higher than 45V then either the charger has a problem or one or two cells have failed and the BMS is preventing charge. If lower than 45V it probably is the battery being too low.

One possibility you might try is to leave the charger plugged in for a full 24 hours, it might trickle charge and recover, but do it outdoors or on a non-flammable surface as, if the cells are damaged by over discharge they could suddenly get hot and catch fire - very, very unlikely but best not to take risks.

There are ways to put a boost charge into the cells through the power output side (rather than the charging side) thus bypassing the BMS, Some have done this by driving the devices wheel so as to feed the regenerative braking voltage back into the battery. You only need to raise the voltage to the minimum the charger will accept, then it can be charged normally,.

Bottom line though is that if the battery has got significantly lower than 2.0V/cell for a significant time, even if you manage to recover the battery it will not be much use - poor voltage holding, high self discharge, very little capacity, poor maximum current are all likely to be symptoms. You may find you have to replace the battery.

Edited by Keith
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On 12/16/2017 at 4:33 AM, Ritul Thakur said:

I have ninebot mini and I did not use it for one year. After one year when i tried to change the ninebot mini, it is not charging.

in another forum I read that battery disengage if not used for long time. Can some one help me on the issue 

Did u ever get your answer?

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