How can I test a 40v Li-Ion battery for a Greenworks 25292 cordless mower?

[ilyaz]

FWIW, I just called Greenworks and they gave me the model number of batteries compatible with my mower (25292):

• 29302 (2 amp hours)
• 29662 (4 Ah)
• 29282 (4 Ah)
• 2907002 (5 Ah)

Of course, the smallest one is still $100+ if I buy from them, so I'll do another pass at findings a discounted one somewhere

 

[dougmacm]

Recently bought some Greenworks 40V GMAX tools then found this forum yesterday while searching for pricing / reviews of their 40V Self Propelled 21" mower. I then posted in the "Welcome to the Electric & Battery Operated Equipment Forum!" thread as my into.

Anyway, I then stumbled upon your thread here with the GEN 1 battery problems. As I stated in the other thread, I bought 3 GW tools that came with 4Ah batteries … one of them however came with the WRONG battery, it for some strange reason came with a GEN 1 4Ah battery # 29662. Tool was purchased from HomeDepot.com and it shipped to me from a HD warehouse in Arizona … there was no indication that it was a return or box had been opened and re-sealed, so this battery had to be a factory mistake.

I contacted GW and they sent me the correct battery, so I've now got this brand new GEN 1 battery sitting here that I have absolutely no use for.

This brand new 29662 4Ah / 146Wh Battery has a 12/13/16 date code. It is externally the same, but the terminals are arranged slightly different so it will not click in to a GEN 2 tool, so I can't "run" test it. It displays 4 bars (fully charged) and checked the voltage per MowerMike's post and it shows 30.45V between "+" & "C" and 31.17V between "+" & "ohmega" … quite a bit higher readings than the "approx. 24V" he stated; whether this is good or bad I don't know. I had checked it prior across the "+ & -" terminals and found it strange I got just a small mV reading, so I was happy to see this thread showing the proper way to test it.

So, do you have any interest in this battery ?? Just as you have done, I searched to see what this battery sells for and saw it is around $114.00. I had recently bought a brand new compact 2.5Ah GEN 2 battery from a guy that was parting out a kit on ebay. It regularly sells for around $100 and I got it for $67 delivered … would this be a fair price ?? Let me know, probably can't post pics being a new forum member but could e-mail you some.

Thanks,

Doug

 

[1 Lucky Texan]

Just chiming in here to report my first bad 40V battery. It's a 2Ah. It will charge OK and the leds will report a full charge. But, it has reduced lidespan and any device (well, mower or blower so far) it is in will shut-off with 2 leds still illuminating.

weird thing, it's one of the newer batts I own, manufactured 04/13/2018 . I have others that are close to 8 years old.

 

[MowerMike]

Just chiming in here to report my first bad 40V battery. It's a 2Ah. It will charge OK and the leds will report a full charge. But, it has reduced lidespan and any device (well, mower or blower so far) it is in will shut-off with 2 leds still illuminating.

weird thing, it's one of the newer batts I own, manufactured 04/13/2018 . I have others that are close to 8 years old.

You got a bad one, it happens. Quality control on Chinese li-ion cells can be spotty. It only takes a couple of weak cells to take down the entire battery. Unfortunately, you are outside the Greenworks 2 year warranty. The new generation Greenworks 60 volt batteries now carry a 4 year warranty, which is why I’m now focusing on that lineup.

 

[1 Lucky Texan]

You got a bad one, it happens. Quality control on Chinese li-ion cells can be spotty. It only takes a couple of weak cells to take down the entire battery. Unfortunately, you are outside the Greenworks 2 year warranty. The new generation Greenworks 60 volt batteries now carry a 4 year warranty, which is why I’m now focusing on that lineup.

I THINK, this is one of the 'free' batts I inadvertently got when I purchased my, 'supposedly tool only', 21" MO40L01 from the Amazon Warehouse (the one I had to replace an axle on) so, no great loss really. At first, I though about continuing to use it but have now decided it could be a fire hazard when charging or ???, so, I'm gonna recycle it.

 

[MowerMike]

At first, I though about continuing to use it but have now decided it could be a fire hazard when charging or ???, so, I'm gonna recycle it.

I doubt it would be a fire hazard when charging, as long as the charger shuts off when it reaches the max voltage setpoint or if it overheats. I have experienced SLA batteries overheating and leaking acid when their chargers failed to shut off and overcharged them. I've never seen this happen with a bad Li-Ion battery.