CMM1200 Type 1 mower won't start

AJtony

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My CMM1200 Type 1 mower won't start. I read a few of the issues posted on this site that were similar but I'm not certain if this is strictly a dead battery issue, a charger issue, or possibly both.

I kept the mower connected to the charger when not in use (I'm in California so we do use it year round).
The green LED on the charger was always lit so I expected that the battery was charged.
I just measured 5 volts across the top cell and about 2.5 volts across the bottom cell with an inexpensive analog volt meter.
If the green LED on the charger is lit, does this mean that the charger is no longer functioning properly due to the low voltage across the battery cells? , ...., and should it be replaced along with what I assume to be a dead battery. I'm pretty sure that the battery is over 5 years old, as this mower is a hand me down from a friend when the switch lever on my old B&D MM850 broke.

I'd hate to purchase and install a new battery if my existing charger were part of the problem as well. Any thoughts on how I might take this a bit further to see if I need to replace the charger as well or other things I should consider here?

Thanks, Tony
 

Filek

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Aug 23, 2015
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My CMM1200 Type 1 mower won't start. I read a few of the issues posted on this site that were similar but I'm not certain if this is strictly a dead battery issue, a charger issue, or possibly both.

I kept the mower connected to the charger when not in use (I'm in California so we do use it year round).
The green LED on the charger was always lit so I expected that the battery was charged.
I just measured 5 volts across the top cell and about 2.5 volts across the bottom cell with an inexpensive analog volt meter.
If the green LED on the charger is lit, does this mean that the charger is no longer functioning properly due to the low voltage across the battery cells? , ...., and should it be replaced along with what I assume to be a dead battery. I'm pretty sure that the battery is over 5 years old, as this mower is a hand me down from a friend when the switch lever on my old B&D MM850 broke.

I'd hate to purchase and install a new battery if my existing charger were part of the problem as well. Any thoughts on how I might take this a bit further to see if I need to replace the charger as well or other things I should consider here?

Thanks, Tony

Welcome to the CMM1200!

The charger works as follows: red light - fast charging, battery is low and receiving relatively large current. Green light - battery is mostly charged or completly charged and is now being trickle charged at a low current.

Are you certain that your voltmeter works correctly? Those voltages are amazingly low. Quite often when these batteries are at then end of their life they will still charge up to 12.7 volts, but that voltage will drop dramatically and quickly when you run the lawn mower. Could be that some cells shorted or something of the sort, but if your measurements are correct, then those batteries are finished.

If your multimeter can measure voltages higher than 30 volts, then you could measure the voltage that the charger is putting out. Before I converted my CMM1200 to lithium ion, I measured the charger's voltage by carefully plugging the multimeter into the end of the charger's plug and it measured 29 volts DC. If yours also measured around the same number then it's a good sign that your charger is probably OK. Just make sure that you are not trying to measure current from the charger!

Keep us in the loop on what you find out.
 

Glenn Boothe

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I am having this exact same problem - the charger is green even though the battery is low.

Was a resolution for this ever found?
 
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