I'm in need of help with electric mower
 

I'm in need of help with electric mower

Since there is not a newsgroup just on mowers, I am hoping that someone might
be able to steer me in the direction of getting my electric lawn mower working
again. It's a Ryobi electric lawnmower, and I don't have any manuals or
schematics.

I posted some sketches and photos that I hope will help he
http://www.geocities.com/hbcalifornee2002/mower.html

Here's the problem:

This problem started all at once. One day I mowed for an hour with no trouble,
then the next weekend, it would only run 5-10 minutes before draining the
battery. Battery is less than six months old.

Another strange thing is that when I plug the mower in to recharge, the
"charge" light indicates that the battery is fully charged, while the
"Empty/Full" meter shows it as being "Empty." (The "charge" light is connected
to the charger board, and the "Empty/Full" meter is connected to the relay
board.

After charging overnight, the "Empty/Full" meter shows "Full" and the "charge"
light still shows fully charged. After running again for 5 minutes, the meter
goes to "Empty." Plugging in again, and the "charge" light still shows fully
charged.

Please send me an email if you have any idea of what might be causing the
problem.

Thanks very much!

I'm in need of help with electric mower
 

If it is a 24 volt battery (a thing Ididn't know existed -- any time I have
come across 24 systes they have always been 2x12 volt batteries) it needs
about 28 volts output from the charger, and the fully charged battery should
show about 26 volts acroos the termminnals of charge.

It looks to me like one of the dodes is blown in the rectifier pack, i
would just replace with a single solid state rectifier.

I'm in need of help with electric mower
 

Thanks for the info!

After going over the voltages again after dinner, it looks like the charger is
only putting out 18-21VDC, which is too low to give a decent charge. Seems like
I remember troubleshooting something else on this mower a few years ago and it
was putting out 27VDC.

So, I went back and look at the little rectifier board, which is just 4 diodes.
The input there is 35VAC and the output is 107VAC and 46VDC. Does this look
weird? I'm wondering where the AC is coming from and why it's up so high.

The diodes all checked out OK with an ohm meter, but I’m wondering if one of
them is breaking down when AC is applied (?)



"AWM"

If it is a 24 volt battery (a thing Ididn't know existed -- any time I have
come across 24 systes they have always been 2x12 volt batteries) it needs
about 28 volts output from the charger, and the fully charged battery should
show about 26 volts acroos the termminnals of charge.

It looks to me like one of the dodes is blown in the rectifier pack, i
would just replace with a single solid state rectifier.