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I have a CMM 1200 I bought new maybe 5~6 yrs ago. A 1st gen model I believe. I've had to fix a broken hinge pin so far.

I got back from vacation and the unit will not mow for more than 30 seconds. I always leave it on the charger whn not in use.

When connected to the charger no lights come on.

The battery cold is 24v and maybe 19~20v under load.

Is it the charger, circuit breaker or something else?

How could I test either to verify?

Thanks,
Chip

First 5 or 6 years on a battery is very good. If you think it is a house breaker then plug a light or any thing that runs off electricty into same whole the charger is in. If it works the electricity to plug is good. Replace battery to see if charger is working. Im betting the battery is just dead.

chipazzo said:

I have a CMM 1200 I bought new maybe 5~6 yrs ago. A 1st gen model I believe. I've had to fix a broken hinge pin so far.

I got back from vacation and the unit will not mow for more than 30 seconds. I always leave it on the charger whn not in use.

When connected to the charger no lights come on.

The battery cold is 24v and maybe 19~20v under load.

Is it the charger, circuit breaker or something else?

How could I test either to verify?

Thanks,
Chip

Click to expand...

I have a similar situation with a CMM 1200 approximately the same age. The battery seemed to be running down more quickly and I was having to jiggle the charger connection to get the red light to come on to start re-charging. Finally, no red light at all, so I replaced the battery thinking it had died. After replacing the battery, the mower starts, but still no light comes on when I plug in the charger.

My question is the same. Is it the charger, the mower's circuit breaker or something else?

So if the mower runs with the new battery then the mowers circuit beaker is not bad. If it is charging the battery then the charger is not bad. Light not coming on on the charger is just that the LED light is not working anymore. Lets not over think this. Unless the new battery can not run the mower after first charge then everything is fine.

Yeah to be honest, I can't rememer the last time I actually looked to see if the charger indicator was working. I just wish I had a way to test it. I could disconnect the batteries and run them on a trickle charger if I wanted.

I decided to give a new pair of batteries a shot. Found an ok deal at Amazon. Free two day shipping will have it here for the weekend. :thumbsup:

Thanks for the advice folks.

Voltage tester will work.

chipazzo said:

The battery cold is 24v and maybe 19~20v under load

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The battery is definitely dead. It should be at least 25.6v fully charged with no load (open circuit) and 24v under load. Also, getting 5+ years from a battery is phenominal.

I think my charger is bad. Green LED comes on, but red never does. It shows 5V, not 26. Should I be able to detect 26V, or does it somehow know that it's not attached to the battery - so it's not trying?

jtellekson said:

I think my charger is bad. Green LED comes on, but red never does. It shows 5V, not 26. Should I be able to detect 26V, or does it somehow know that it's not attached to the battery - so it's not trying?

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I think I have the same issue. I installed new batteries, old ones were 6 years old and would only cut grass for a minute or two. Charger only showed a green light. I put in new batteries it ran fine the first cut but still only a green light on the charger. Now it runs only a few minutes and dies (maybe five minutes) even after charging for several days. The charger has output of 26 volts what wrong? Batteries show 11.7 no load.

I know this is a CMM1200 thread but my CMM1000 is over fifteen years old and still using the original battery. I can still get two mowings (maybe more) on a single charge.

I bought a used CMM1200 last week with a bad battery for $25. The woman said she didn't want to spend $150 for a new battery and she also thought she needed a bigger mower to cut her entire yard. I didn't have the heart to tell her that she could buy an equivalent battery for around $75 or maybe a bit less.

I'm going to swap the battery from my 1000 to the 1200 and then test the charging circuit.

Since there has been no follow-up to my last post I suspect no one cares but I haven't yet done anything with either of the B&D mowers. I DID buy an Earthwise mower (with a dead battery, of course) a couple of weeks ago and I had to totally destroy the plastic shroud to get it off to access the battery. Even then I had to use a pair of large screwdrivers to remove the battery. I ended up scrapping the entire mower except for the motor itself as that was all I really wanted.

Anyway, I later found that the battery had some bulges in the case, probably why I had to pry it out of the holder. Bulging usually denotes a battery that is badly sulphated and while it would take a charge it had no capacity. I connected a battery desulphator to it and I am letting it attempt to repair the sulphation, without having much confidence that it will. I'll leave it on the device for about a month and then do some testing.

Luana said:

Since there has been no follow-up to my last post I suspect no one cares but I haven't yet done anything with either of the B&D mowers. I DID buy an Earthwise mower (with a dead battery, of course) a couple of weeks ago and I had to totally destroy the plastic shroud to get it off to access the battery. Even then I had to use a pair of large screwdrivers to remove the battery. I ended up scrapping the entire mower except for the motor itself as that was all I really wanted.

Anyway, I later found that the battery had some bulges in the case, probably why I had to pry it out of the holder. Bulging usually denotes a battery that is badly sulphated and while it would take a charge it had no capacity. I connected a battery desulphator to it and I am letting it attempt to repair the sulphation, without having much confidence that it will. I'll leave it on the device for about a month and then do some testing.

Click to expand...

Please keep us updated! I would like to know how it goes. I am curious - what do you have planned for the motor from the Earthwise, some sort of upgrade to the 1200?

After about a month, maybe five full weeks, I connected the Earthwise battery to the CMM1200. It did start although it sounded slow. I connected the Earthwise battery condition indicator and when stopped it indicated a full charge but as soon as I started the motor it dropped to the red (dead battery) indication. That meant the month of "rehabilitation", during which I twice used the charger to ensure it was as charged as possible, was a failure.

I took the battery, control board (with charging circuit), upper handle (mechanical control switch) and motor from the CMM1000 and cut up the rest of the old mower. I then brazed the handle bolts onto the inner holes to allow me to more easily unscrew the handwheels for folding the handles. I have set the battery (more than fifteen years old) into the CMM1200 and I also replaced the original black oxide sheet-metal screws holding the upper half to the lower half with stainless steel screws to reduce the chance of rust destroying the head slots. The old screws were Torx head and almost impossible to remove because of rust. I temporarily connected the battery and noticed a fair amount of sparking at the motor brushes so I decided to get a spare set of brushes to see how worn the original brushes have become. Since I received the new brushes I have been plagued with some medical problems and have not been able to do anything with the mower.

what do you have planned for the motor from the Earthwise, some sort of upgrade to the 1200?

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For all intents and purposes the motor from the Earthwise is identical to the motor in the B&D mowers. What I have in mind is using the motor(s) with my gasoline mower/tractor conversion either to use as individual blade motors on a 36-40 inch twin-blade deck or else to use them to power brush-cutter blades that I will mount on a boom from the tractor. The same medical problems I mentioned before have also kept me from that project.

Luana said:

Since there has been no follow-up to my last post I suspect no one cares but I haven't yet done anything with either of the B&D mowers. I DID buy an Earthwise mower (with a dead battery, of course) a couple of weeks ago and I had to totally destroy the plastic shroud to get it off to access the battery. Even then I had to use a pair of large screwdrivers to remove the battery. I ended up scrapping the entire mower except for the motor itself as that was all I really wanted.

Anyway, I later found that the battery had some bulges in the case, probably why I had to pry it out of the holder. Bulging usually denotes a battery that is badly sulphated and while it would take a charge it had no capacity. I connected a battery desulphator to it and I am letting it attempt to repair the sulphation, without having much confidence that it will. I'll leave it on the device for about a month and then do some testing.

Click to expand...

A battery bulging is due to gassing and nothing else.
Gassing comes from overcharging and nothing else.
Automatic battery chargers are notorious for overcharging batteries.
The few batteries that I need to keep fully charges are on a plug in timmer that limits the charging 1/2 hour day

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