Reviving a free, dead 12V cordless Black & Decker mower - Page 6

MetroMPG · 07-21-11, 08:19 AM

Not yet (kill-a-watt).

---

Looks like I underestimated the time to cut the entire lawn. It's probably ~25 minutes, front, back & side. There's not going to be enough juice in this pair of 12 Ah batteries to do the job - they're only delivering about 14 minutes run time before voltage is flirting with the 10.5 mark and I shut things down to avoid battricide.

Need to add another battery!

Daox · 07-22-11, 01:27 PM

So, what is the plan? Are you goign to try the 7Ah battery in parallel with the others? I think it should work. It should give you another 5-6 minutes to the run time.

MetroMPG · 07-25-11, 10:17 AM

5-6 additional minutes will still only put me in the "barely able to do ALL the cutting in one charge" territory.

I'll probably try it.

But since it's going to be pretty hard on the pack, I may just do half, recharge and do the remainder. Sort of how you're doing the lawn at your place with the e-riding mower.

MetroMPG · 07-26-11, 11:21 AM

If you haven't laughed at this project yet -- or at the "Mower #2" development part-way through it -- you will laugh at this:

Mower #3 ...

Yesterday I picked up another, free, identical M3300 battery-electric mower (same as Mower #1). Someone had advertised it for sale online, and I contacted him to ask if he happened to have the owners manual.

"No," he said, "but the mower's been for sale for a while now and nobody wants it, so you can have it, if you like."

This one also apparently has a cooked battery, and also possibly a dead charger (preliminary inspection). The mower itself works though - jumper cables to the car battery, a la Frankenstein, and it fired right up.

This gives me the option of going with free, used "15 minute" battery packs in both mowers, but still being able to cut all the grass in 25-30 minutes, by switching mowers half-way through.

Or, I have spare parts.

Either way, I will never need another lawnmower in my life.

Unfortunately, now I need a garden shed to store them all.

Daox · 07-26-11, 11:30 AM

So, you're just going to live with the 15 minute run time? You're not gonna try to add another battery?

MetroMPG · 07-26-11, 11:44 AM

Oh, I'll probably try that too.

Piwoslaw · 07-26-11, 02:51 PM

You're sick, man. I tell you: SICK!!

MetroMPG · 07-26-11, 03:02 PM

Does seem a bit excessive, eh?

MetroMPG · 07-29-11, 08:27 AM

Mission accomplished

So, trying one more new (used) battery arrangement means the mower now has enough juice to do the entire lawn (~20-25 mins).

I now have one 12 amp-hour battery (which seems to have about 2/3 of its rated capacity - delivered ~4 amps for 120 minutes in my inverter test) in parallel with a 7 amp-hour battery that has ~60% of its rated capacity).

They seem to work well together.

At this point, all that's left to do is to tape up a few connections, secure the batteries, and put the "hood" back on. I may lead a pair of wires through the hood so I can easily hook up a multimeter to monitor voltage and keep an eye on that battery pack.

It's safe to say this free mower is back in service with free used batteries (with some time invested testing their capacities). Alternatively, about $120 would have bought a new battery that would have had it back on the road (um, lawn) with little muss or fuss. (But where's the fun in that?!)

MISSION ACCOMPLISHED!

Daox · 07-29-11, 08:31 AM

Great to hear it all worked out, and for free!

07-21-11, 08:19 AM	#51
MetroMPG Infrequent noob Join Date: Aug 2008 Location: 1000 Islands region, Ontario, Canada Posts: 402 Thanks: 37 Thanked 20 Times in 19 Posts	Not yet (kill-a-watt). --- Looks like I underestimated the time to cut the entire lawn. It's probably ~25 minutes, front, back & side. There's not going to be enough juice in this pair of 12 Ah batteries to do the job - they're only delivering about 14 minutes run time before voltage is flirting with the 10.5 mark and I shut things down to avoid battricide. Need to add another battery! __________________ . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-22-11, 01:27 PM	#52
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	So, what is the plan? Are you goign to try the 7Ah battery in parallel with the others? I think it should work. It should give you another 5-6 minutes to the run time. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-25-11, 10:17 AM	#53
MetroMPG Infrequent noob Join Date: Aug 2008 Location: 1000 Islands region, Ontario, Canada Posts: 402 Thanks: 37 Thanked 20 Times in 19 Posts	5-6 additional minutes will still only put me in the "barely able to do ALL the cutting in one charge" territory. I'll probably try it. But since it's going to be pretty hard on the pack, I may just do half, recharge and do the remainder. Sort of how you're doing the lawn at your place with the e-riding mower. __________________ . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-26-11, 11:21 AM	#54
MetroMPG Infrequent noob Join Date: Aug 2008 Location: 1000 Islands region, Ontario, Canada Posts: 402 Thanks: 37 Thanked 20 Times in 19 Posts	If you haven't laughed at this project yet -- or at the "Mower #2" development part-way through it -- you will laugh at this: Mower #3 ... Yesterday I picked up another, free, identical M3300 battery-electric mower (same as Mower #1). Someone had advertised it for sale online, and I contacted him to ask if he happened to have the owners manual. "No," he said, "but the mower's been for sale for a while now and nobody wants it, so you can have it, if you like." This one also apparently has a cooked battery, and also possibly a dead charger (preliminary inspection). The mower itself works though - jumper cables to the car battery, a la Frankenstein, and it fired right up. This gives me the option of going with free, used "15 minute" battery packs in both mowers, but still being able to cut all the grass in 25-30 minutes, by switching mowers half-way through. Or, I have spare parts. Either way, I will never need another lawnmower in my life. Unfortunately, now I need a garden shed to store them all. __________________ . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-26-11, 11:30 AM	#55
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	So, you're just going to live with the 15 minute run time? You're not gonna try to add another battery? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-26-11, 11:44 AM	#56
MetroMPG Infrequent noob Join Date: Aug 2008 Location: 1000 Islands region, Ontario, Canada Posts: 402 Thanks: 37 Thanked 20 Times in 19 Posts	Oh, I'll probably try that too. __________________ . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-26-11, 02:51 PM	#57
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 964 Thanks: 190 Thanked 111 Times in 87 Posts	You're sick, man. I tell you: SICK!! __________________ Ecorenovation - the bottomless piggy bank that tries to tame the energy hog.

07-26-11, 03:02 PM	#58
MetroMPG Infrequent noob Join Date: Aug 2008 Location: 1000 Islands region, Ontario, Canada Posts: 402 Thanks: 37 Thanked 20 Times in 19 Posts	Does seem a bit excessive, eh? __________________ . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-29-11, 08:27 AM	#59
MetroMPG Infrequent noob Join Date: Aug 2008 Location: 1000 Islands region, Ontario, Canada Posts: 402 Thanks: 37 Thanked 20 Times in 19 Posts	Mission accomplished So, trying one more new (used) battery arrangement means the mower now has enough juice to do the entire lawn (~20-25 mins). I now have one 12 amp-hour battery (which seems to have about 2/3 of its rated capacity - delivered ~4 amps for 120 minutes in my inverter test) in parallel with a 7 amp-hour battery that has ~60% of its rated capacity). They seem to work well together. At this point, all that's left to do is to tape up a few connections, secure the batteries, and put the "hood" back on. I may lead a pair of wires through the hood so I can easily hook up a multimeter to monitor voltage and keep an eye on that battery pack. It's safe to say this free mower is back in service with free used batteries (with some time invested testing their capacities). Alternatively, about $120 would have bought a new battery that would have had it back on the road (um, lawn) with little muss or fuss. (But where's the fun in that?!) MISSION ACCOMPLISHED! Attached Thumbnails __________________ . To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-29-11, 08:31 AM	#60
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Great to hear it all worked out, and for free! __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.