help j-lcd king meter error 21

Nealh

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Ab current usually means over current and a controller issue, likely the controller has got to hot and has thermally cut. Usually once cooled will work again.
Under what circumstances did the error occur ?
 

garysnooker

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Sep 10, 2020
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Ab current usually means over current and a controller issue, likely the controller has got to hot and has thermally cut. Usually once cooled will work again.
Under what circumstances did the error occur ?
Thanks for your help on this Nealh what happened a spoke on my wheel broke I decided to replace it and whilst the wheel was of I thought I would wash the bike when I put the back wheel back on and put the power on Error 21 came up , I turned the power back on and the Motor made a thud noise the display was normal but when I tried the throttle and peddled nothing happened
 

Nealh

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Current is dealt with the controller and is often a short circuit so either Mosfet issue or a phase circuit issue, again the latter is a short of the circuit.

Having washed the bike has water ingressed in to the controller or the motor phase cable connector.
A manual check can be carried out by hand to see if there is a phase issue.
With the motor wheel connected up to the controller and with the battery off/removed, does the motor wheel rotate quickly hand or does it offer up hard resistance. Or in English does it freewheel quite nicely.
 
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Nealh

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As the bike wasn't being ridden when the error showed up, then we can assume it is a phase shorting issue.
 

Nealh

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If you did what I said in #4 and the motor wheel turns by hand quite fast then one can usually rule out a phase wire issue.
One can try testing for a duff mosfet with voltage meter with the dial set to 20 ohms but depends on the type of controller connector used.
 

garysnooker

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Sep 10, 2020
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If you did what I said in #4 and the motor wheel turns by hand quite fast then one can usually rule out a phase wire issue.
One can try testing for a duff mosfet with voltage meter with the dial set to 20 ohms but depends on the type of controller connector used.
i have a voltage meter pic of the controller
 

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Nealh

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That white box thing isn't a digital multimeter, I have never seen one in the flesh or used one so no idea what it can test for. All I know is it can't tell one the status of a mosfet with a resistance reading.
 

Nealh

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I have explained how to carry out mosfet testing so many times it gets tedious.
Follow the instructions in the link.
Set you dial to the left on to 20k in the Green section.
BlownMosfets.cdr (ebikes.ca)
 

Nealh

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2.29 never had a reading that low, always been about the 9.9k mark. Though they are consistently the same for the Low side. The one reading is fine for the High side.
Each mosfet type have an RDS (drain source resistance), most ebike controller one's are of the 9 - 14k range.
 
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garysnooker

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Hi nealh the motor phase cable connector.was wet inside the plug do you think i could have blown some think up in the motor
 

Nealh

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Try again with the motor disconnected and/or a dried out connector.
The only thing to test for in the hub are the Hall sensors, if you use the link I gave go to ebikes.ca and select trouble shooting in the learn drop down box. Then select the relevant pdf to open.