Cordless electric enthusiast, new to forum.

[rscamp]

Here's the mower just before starting the first mow with the Lithium Polymer battery.

Here's some data from the Whattmeter.

Initial rest voltage was 40.3V.

Running the self-propel drive alone without load consumed a surprisingly high 2.5A / 107W. High speed self-propel drive alone uphill consumed more than double this at 250W.

Running the main cutting motor alone consumed 7.2A / 293W.

All cutting was done at height setting 4 (lowest recommended for mulching) except as noted. This isn't particularly short. After cutting the front lawn, 2.485Ah was consumed and the rest voltage was 39.3V. Average power consumption ranged between 400 - 600W when cutting. Maximum power observed in some thick grass was around 900W.

At this point I threw in the freshly charged Pb battery that came with the mower and the speed was a bit slower going by the sound. So even after mowing a fair bit the lithium pack has higher voltage. I can't say I noticed a lot of difference in the amount the motor slowed down between the two packs suggesting the motor/wiring is limiting. Of course when the original Pb battery would be dying the LiPos are less than half done.

I stopped again at 5.036Ah consumed and the rest voltage was 38.8V. All parallel cell groups were in near perfect balance ranging between 3.80V and 3.81V.

 

[rscamp]

Here's the mower after mowing the entire lawn once and the back yard a second time at a height setting of 2 which is fairly low. The original Pb battery is in the foreground.

The closeup of the Whattmeter and a balancer shows the rest voltage was 38.1V, the capacity consumed was 9.834Ah (which is less than half of the absolute maximum capacity) and near perfect balance of cell groups.

In short, with these new batteries, there is NO RANGE ANXIETY. Range is now similar to a full tank on the gas mower!

The mower is a pleasure to use as it loses about 10 pounds (5kg) with the battery conversion. It is now significantly lighter and more maneuverable than the old gas mower.

Not everything is as good as it could be, however. Although the mower is a bit stronger with the LiPos, the motor is still a limiting factor in its power. Once electrical power consumption exceeds about one horsepower (750W), the motor begins to struggle. The batteries hold a high voltage so they are not the issue. The switch to LiPos would be perfect if combined with a stronger motor.

 

[Willyvon]

Rob, what's the scoop on that watt meter. I need to measure and monitor the performance of a redesigned blade for my 8 y/o Neuton EM 4.1. I had planned to get a remote display Fluke clamp-on to operate on a loop installed on my security key / removable breaker. The meter is in the $500 range. If this is something I can wire in series without affecting current flow and at a significantly lower cost it's for me!

 

[Willyvon]

My simple auditory test results suggest the blade design concept might provide the cutting efficiency necessary to make the need for a better motor in your test mower moot.

 

[rscamp]

Rob, what's the scoop on that watt meter. I need to measure and monitor the performance of a redesigned blade for my 8 y/o Neuton EM 4.1. I had planned to get a remote display Fluke clamp-on to operate on a loop installed on my security key / removable breaker. The meter is in the $500 range. If this is something I can wire in series without affecting current flow and at a significantly lower cost it's for me!

I recommend this HobbyKing R/C Hobby Store : Watt Meter & Power Analyzer /Watts up (Ver. 2)

It is a power/energy/capacity/voltage/current meter. It needs to connect to both + and - lines to make both the parallel connection to measure voltage and the series connection to measure current.

 

[earthworm]

Re: CMM1000 replacement brushes

Now Black and Decker says the CMM1000 brushes are backordered until 3/8/2012. Waiting 9 months for parts is not exactly consumer friendly. I'm ordering the MM1800 brushes. It only costs $16 to find out if they work.

Probably too late now, but our local ACE sells a great many brush sets generically.
And at, IMO, a fair price...
Of course, they do not have everything...
IMO, Black and Decker are typical American; bad attitude...all profits..

 

[Augi]

Thanks for the welcome twall!

Looks like mine is comparable to the Neuton CE6: 19" blade, rear-mounted bag, and rated for mowing 1/3 acre**. But my CMM1000 runs on 24 volts while the CE6 used 36 V. Also, the CE6 battery is easily removable (unlike mine), easy to swap in a 2nd battery for cutting larger lawns ... a newer Black and Decker model has the swappable battery as well.

**These manufacturers' acreage ratings must be under pretty ideal conditions. In practice I can't finish my yard on a single charge, and we have a 1/4 acre, not all of which is grass. Needs a 2 hour recharge halfway through mowing in order to finish up.

I'm thinking about buying my first cordless mower: B&D SPCM1936. I'm wondering about real life battery life, too. We have about 1/4 acre lot with virtually no slope (back yard has a slight slope for drainage) and it's flat. I had a gas Toro I used for about 10 years; self-propelled, too. It would take me at least an hour or 1.5 hrs. to cut, bag, and empty the bag about 4 times. I'm glad to hear that if I have to, I can get a half charge in 2 hrs. Though that's not cool because ...well just because. Anyone had any experiences with the durability and performance of the B&D SPCM1936 or its cousin the CM1936? Thanks.

 

[rscamp]

I'm thinking about buying my first cordless mower: B&D SPCM1936. I'm wondering about real life battery life, too. We have about 1/4 acre lot with virtually no slope (back yard has a slight slope for drainage) and it's flat. I had a gas Toro I used for about 10 years; self-propelled, too. It would take me at least an hour or 1.5 hrs. to cut, bag, and empty the bag about 4 times. I'm glad to hear that if I have to, I can get a half charge in 2 hrs. Though that's not cool because ...well just because. Anyone had any experiences with the durability and performance of the B&D SPCM1936 or its cousin the CM1936? Thanks.

Based on my experience with the original battery this mower would only cut 1/4 acre if the grass wasn't long, wet and/or the cut height was set high. In other words, most of the time it would not finish cutting this size of lawn.

I don't think this is a bad mower and with a better battery it doesn't perform too badly, but to be realistic it has these limitations:

- limited range with the stock battery - this range varies drastically with cut height and the condition of the lawn
- narrower cut width than the average gas mower
- less power than the average gas mower (due to having a lower power motor due to not being supplied with a good battery)

With regard to the last point, with a better battery it could be fitted with a more powerful motor and then there would be no sacrifice in performance compared with a gas mower.

 

[Augi]

Based on my experience with the original battery this mower would only cut 1/4 acre if the grass wasn't long, wet and/or the cut height was set high. In other words, most of the time it would not finish cutting this size of lawn.

I don't think this is a bad mower and with a better battery it doesn't perform too badly, but to be realistic it has these limitations:

- limited range with the stock battery - this range varies drastically with cut height and the condition of the lawn
- narrower cut width than the average gas mower
- less power than the average gas mower (due to having a lower power motor due to not being supplied with a good battery)

With regard to the last point, with a better battery it could be fitted with a more powerful motor and then there would be no sacrifice in performance compared with a gas mower.

Thanks for the response. You said "stock" battery. Is there another B&D battery that is high capacity for the SPCM1936?

 

[rscamp]

Thanks for the response. You said "stock" battery. Is there another B&D battery that is high capacity for the SPCM1936?

No. Not that I know of. Mine is home brew. It triples the range at lower weight and provides slightly higher voltage.

I forgot to mention another characteristic of this mower. The self-propelling feature is too fast. It can't be slowed down enough for thick grass. It is easy to push so it isn't a major problem. But it is a bit baffling...