Craftsman Cordless Mulching Mower Not Charging Green Light On

[MikeinDC]

Hi, I have an old Craftsman Cordless Mulching Mower that doesn't charge the battery this year. The moment I plug in the charging cable the light turns green as if fully charged. Was working fine at the end of last season and the motor initially runs when I try to mow, but runs out within minutes when a load is applied. I originally thought it was a battery issue, so ran out and bought new ones ($100, ouch) , but same deal with the brand new battery. It is a model 900.370520, 24 Volt 19". Not a lot of electrical parts to this thing. I've got two of the external power adapters/chargers and have tried both. Is it possible that the electronic module is faulty? I don't see this part for sale online and Sears only offers a kit that has a lot of parts I don't need.

Any ideas or other troubleshooting?

Thanks in advance for your help.

Mike

 

[MowerMike]

Hi, I have an old Craftsman Cordless Mulching Mower that doesn't charge the battery this year. The moment I plug in the charging cable the light turns green as if fully charged. Was working fine at the end of last season and the motor initially runs when I try to mow, but runs out within minutes when a load is applied. I originally thought it was a battery issue, so ran out and bought new ones ($100, ouch) , but same deal with the brand new battery. It is a model 900.370520, 24 Volt 19". Not a lot of electrical parts to this thing. I've got two of the external power adapters/chargers and have tried both. Is it possible that the electronic module is faulty? I don't see this part for sale online and Sears only offers a kit that has a lot of parts I don't need.

Any ideas or other troubleshooting?

Thanks in advance for your help.

Mike

So, is this a SLA 24 volt battery that is removable from the mower ? Can you measure the battery voltage across its terminals ?

 

[MikeinDC]

So, is this a SLA 24 volt battery that is removable from the mower ? Can you measure the battery voltage across its terminals ?

Hi MowerMike, After charging for over 24 hours the battery was still basically drained. Don't remember the exact voltage, but it was in the mid 11's.

Thanks for the response.

Mike

 

[MowerMike]

Hi MowerMike, After charging for over 24 hours the battery was still basically drained. Don't remember the exact voltage, but it was in the mid 11's.

Thanks for the response.

Mike

OK, so I found the manual for your mower, and it looks like the circuitry that controls the battery charging is built into the mower rather than the external charger. This circuitry is malfunctioning such that it is preventing the battery from getting charged, so you will need to either replace it or bypass it to allow the battery to recharge properly.

 

[MikeinDC]

You are correct, 2 batteries wired in series and the charger plugs into the mower.

 

[MowerMike]

You are correct, 2 batteries wired in series and the charger plugs into the mower.

Please see my revised post.

 

[MikeinDC]

OK, so I found the manual for your mower, and it looks like the circuitry that controls the battery charging is built into the mower rather than the external charger. This circuitry is malfunctioning such that it is preventing the battery from getting charged, so you will need to either replace it or bypass it to allow the battery to recharge properly.

I was afraid the charger was in the module. They no longer sell the electric module and only sell an overhaul kit that seems to include an external charger (though there are no details that state this). I'll need to see if I can find the external charger by itself and wire around the internal module, as you suggest. Thanks for the help.

Mike