Welcome to the Solar Power (and Rechargeable/Battery/Electric) Mower WikiEdit
Describes finding, modifying, maintaining, and using rechargeable lawn mowers modified for use with solar panels. The focus is on Black and Decker 12 volt lead acid battery driven mowers.
Description of This Wikia TopicEdit
A Personal Note:
This wiki is the outgrowth of my guide posted on ebay.com
As you can read in that link - if it's still good -, it's quite possible that you'll come across a used, tired, dead 12 volt rechargeable mower some day on craigslist, freecycle or while curb shopping. I did this very thing several years ago. After a while, I got it running and have now connected it to a 12v battery charging solar panel. To my pleasant surprise, 10 watts of solar panel power is ideal for maintaining and charging a single 12v battery powered mower, such as Black and Decker's lovely CMM625 and similar mowers - and ideal for mowing small plots like my 6,000 sq ft yard. What follows is my attempt to pass on what I've done. You're welcome to comment or edit, as is usual with wiki knowledge.
History of Rechargeable MowersEdit
(Maybe a reader will fill in)
Basics of Modern Rechargeable MowersEdit
Most battery driven rechargeable mowers use 1, 2, 3 or more 12 volt batteries. Voltage is some multiple of 12 usually. You can tell how many batteries you have to replace/charge by dividing your mower's voltage by 12.
Some modern rechargeable mowers use Lithium battery packs or other chemistry. However, most mowers use lead acid batteries. Such lead acid batteries are specifically designed for constant use or discharge. These may be labelled SLA, AGM, Marine, Golf Cart etc. Vehicle-starting batteries are not designed for constant use and shouldn't be used in mowers.
Problems of Lead Acid Battery Self DischargeEdit
A lead acid battery discharges over time. Worse, if left in a discharged state in the cold, the battery can be damaged. Therefore, most lead acid batteries are kept topped up or trickled charged and will generally last the longest if kept fully charged. Note that overcharging a lead acid battery with a continuous high charge (as opposed to a trickle charge) will also ruin a battery.
Battery Longevity and effects of deeper battery dischargeEdit
SLA/AGM batteries last about 3-5 years. That estimate may be much longer if kept fully charged most of the time with slight usage or be much shorter if a battery is heavily used between charges or not charged to full frequently.
Lead acid batteries in mowers last longest when not exhausted between charges. Leaving 20% will prolong a battery. Even better, not going below 50% will lengthen the battery life even more.
See the Troubleshooting page section.
Basics of Solar PanelsEditA solar panel converts the sun's energy into electricity that can be used to charge a battery or run a device. In the case of
mowers, running the device is not possible because the charge is so small at any given time.
A solar panel charges best when positioned to receive full sun. It would put electricity into a battery during the day and receive it back from the battery at night if a blocking diode wasn't installed between the two. It is very important that a blocking diode be in series between a solar panel and a battery to avoid discharge of the battery.
Panel Voltage and NamingEdit
Panels are often nominally named for the type of battery they are designed to charge - not their actual charge. Similar to water dripping from a higher to a lower bucket, a panel must maintain a higher voltage than the battery it is charging. A 12 volt solar panel will probably actually generate 18-20 volts when measured in full sun with a volt meter.
Combining Solar Panels and Rechargeable MowersEdit
This is what this Wiki is all about.
Combining a 12 volt solar panel with a single 12 volt powered Rechargeable mower is as simple or difficult as the connection between the two. If the battery on the mower is wired simply enough and/or you are very lucky, it is charged by an AC/DC adapter that generates a voltage higher than 12volts DC. If this is the case then the solar panel might be able to supply a charge to the mower's battery with simple physical connections. Some manufacturers may use nonstandard or esoteric DC connectors, which might require you to either fashion your own charge connectors or to seek out the help of Molex.com or some other parts supplier.
Models of Mowers and Their SpecificsEdit
Black and Decker CMM625Edit
A 12volt, 26 amp hour SLA battery powered mower from the 1990s. The model currently used by this Wiki's creator.
Subjective Adaptation Difficulty to Solar Power: VERY EASY
CMM 625 Solar Connection SpecificsEdit
Uses a MOLEX connector () which you might need to buy or fashion if you make a connector for your solar panel - 
assuming you didn't cannibalize your DC adapter's connector. Power is supplied by a no-longer-produced DC adapter. The mower plugs very nicely into a 12 volt 5 or 10 watt solar panel. It recharges on either of those within about 6 days in the summer time. In the winter can happily receive a trickle charge to keep battery maintained from 5 watts.
CMM 625 Mower SpecificsEdit
18 inch cutting path. Most parts no longer available. May take similar B&D parts. Sold as a mulching mower (uses insert) or remove insert to use with B&D side discharge bag.
The motor has carbon brushes and draws about 20 amps when simply spinning the blade. Overload protection occurs at about 40 amps.
CMM 625 DurabilityEdit
Plastic, but satisfactorily medium duty - maybe heavy duty depending on your application.
CMM 625 Manual, Parts and Parts DiagramsEdit
In addition to craigslist and ebay, try the ServiceNet Dewalt / Black and Decker Online Parts Service.
CMM 625/630 Manual (scanned) available at DeWalt/Black and Deker here.
A basic blog for discussion of things on this page is here.