Why won't my new 24v battery charge?

12th Player

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I just replaced the original 12 year old 24V 17.2AH battery in my B&D CMM1000 mower with a set of brand new Werker AGM 12V (2 of them) 18AH batteries. I know I installed the new batteries correctly because I was able to do a full load of mowing after installation (since the batteries came fully charged).

But the mower won't charge the new batteries. I should have guessed I had a problem from the beginning since the charge light on the mower didn't come on once I plugged in the charger. I was hoping it was just the light itself that was broken but alas...after charging for a day or so, I tried to use the mower but the batteries only last for few minutes. I tried charging longer, shorter, etc to no avail.

I spent $150 to replace the batteries instead of getting a new mower (trying to be responsible) and I'm thinking I made a mistake...unless you guys have some thoughts what is wrong and I can fix it easily.

Thanks in advance for your help!
 

1 Lucky Texan

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I guess you double-checked the breaker at the outley you're using? maybe try a different outlet anyway. I've had some odd things happen on GFCI circuits.

Did you perhpas experience a lightning stike when the mower was being recharged?

is there a separate charger only for those batteries available?

anyway, hope you get it sorted out.
 

MowerMike

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Sounds like you may not have made the battery connection to the charging port on the mower. There is typically a separate circuit from the battery charging connector to the battery, such that the battery may be connected to the motor and the mower will run, but the battery won't charge. Also, you may have an internal fuse or circuit breaker that has blown / tripped. I did that on my Earthwise mower battery when I accidentally shorted the charging port, and I could not get a voltage reading there, but still had voltage across the motor connector.

It's also possible that your charger has gone bad. Do you measure voltage at the charger output connector ?
 

Mark Widmer

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I have been away from LMF for a while so I am joining in late here.

If you don't have a way to measure the voltage out of the charger, at least check that the two wires -- one red, one black -- from the charger circuit board are connected to the main mower circuit board.

MowerCMM1000_5177.jpg

Opening up the CMM1000 can be a hassle, it is easy to strain some of the wires when the cover is open and something might have come loose.

MowerCMM1000_5177.jpg
 

joyeall01

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I have watched a video on youtube, just like starting a dead car battery, you need a good one to jump it! (Yea it worked!).
 
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