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Battery not charging for smart step model purchased in July

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My battery will not charge for my Sondors smart step model purchase in July.  My battery was completely depleted.  I hooked up the charger and the charger indicator light started out as red and turned to green after a period of time.  When I disconnected the battery and turned the ebike on, the battery life indicator showed no bars.  When I plugged in the charger, the battery indicator showed green and the battery did not charge.  Any suggestions?

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  • 3 weeks later...

Hi Sean,
Depends on the model Sondors you have but since you posted in a thread about Battery Charging a Sondors Smart Step I’ll assume that’s what you have. 
The Instructions are in the Instruction Section of this forum.  Your Display/LCD is the KD51C



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I have a step and the XS or MXS. The battery specs seem the same for the XS and MXS.....I think.

The charging light on the charger won't move past green. Never turns red. Have not been able to charge the battery since the last full charge about a month ago.

I tried all of the charging tips and no change. Tried another charger - same issue.

Any thoughts? Seems to be one of the more common question/issue.



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I have the same battery, as both the Sondors XS & MSX in my Sondors X. If you’ve followed the Charging Procedures, to the letter, in the Official Sondors charging instructions, https://shop.sondors.com/blogs/news/caring-for-your-sondors-battery
my first suspicion would be the battery fuse. You should get a Multimeter to diagnose all electrical problems on you bikes. I think you can eliminate the charger as fault but check the output voltage from it, just to make sure, it should be about 54Volts. Then check the battery voltage and if it checks, below the recovery threshold, there are unpublished procedures -OR- no voltage at all, you’ll need to open up the battery to look for a disconnected wire. We recently had that discovered when the member reported a problem, like yours and found the loose wire. 
Any voltage below 39.5 would be unrecoverable because the batteries & chargers BMS (battery management system) won’t allow it. But there are work arounds, that I won’t detail here now, but LEMMENO, if you discover low voltage, no matter at what level. 

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If you’re not familiar with the operation of a multimeter, there are good videos on YouTube. I even carried one with my tools on my bike but that was overreach. So I soon abandon the useless practice, 20,000 + miles and never needed one on the road.
Scarlett the Red Border Collie waiting for her morning coffee.


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