I have an EGO mower, and generally I like the convenience of not having gasoline. It is much quieter, and you can stow it standing up. It easily mows my yard.

But the battery, which 56V, 7.5 amp hours (not the biggest one they sell, but next to biggest) died after less than a year. It won't charge at all. They are sending a replacement.

I didn't abuse the battery, charged it per the instructions, and the charger is a "smart" charger anyway. It is supposed to monitor the battery, keep it charged, or partially discharge it if you don't use it for a month.

What causes a battery like that to just go bad?

Same thing happened to my Ryobi string trimmer's 40v 2ah battery. Lasted one season.

quote:

Originally posted by jhe888:
What causes a battery like that to just go bad?

Abuse, design defect, production defect--incl. inferior materials.

You claim you didn't abuse it. Unless there's been a raft of complaints about their 56V, 7Ah batteries, it's unlikely a design or common manufacturing defect. So probably you just had the bad luck of getting a bad battery.

Li-Ion batteries are kept happiest if they're not deeply-discharged. So, even if the tool or battery aren't telling you "I need charging," it's best to put 'em back on the charger when they get no lower than 80-70% charge. Reason being is that reduces the charge time, thus the amount of heat generated during charging. It's the heat that reduces their lifespan most.

Aren't most of such batteries a bunch of 18650 batteries - easily available. Can individual cells be replaced? A decent individual 18650 charger would identify a bad cell.

quote:

Originally posted by Ripley:
Aren't most of such batteries a bunch of 18650 batteries - easily available. Can individual cells be replaced? A decent individual 18650 charger would identify a bad cell.

No, this is a big thing, so I don't think it is a bunch of smaller cells. It must weigh 7 or 8 pounds. I assume it is one big battery, and it obviously has some monitoring and protection circuitry built into it as it has an indicator light and can shut itself down.

quote:

Originally posted by jhe888:


I didn't abuse the battery

Did you store your batteries in your basement or other climate controlled area when not in use?

I read that leaving them in a shed or other non climate controlled area to freeze in the winter and bake in the summer is what helps kill them. I keep my Kobalt blower and weed whacker batteries in my basement for this very reason.

quote:

Originally posted by PASig:

quote:

Originally posted by jhe888:


I didn't abuse the battery

Did you store your batteries in your basement or other climate controlled area when not in use?

I read that leaving them in a shed or other non climate controlled area to freeze in the winter and bake in the summer is what helps kill them. I keep my Kobalt blower and weed whacker batteries in my basement for this very reason.

A basement in Houston would be an indoor swimming pool. We don't have them. The battery is in the attached garage. In Houston, this means it will never freeze. Ever. It can get hot, but this battery hasn't even lived through the hottest part of a summer - it is too new.

It’s just a shit battery (shit mfr). I’ve got big lithium batteries in my ski, and all of my motorcycles from Shorai. I don’t even charge them or put them in the maintenance cycle often. 1-2 times a year. The ones in my bikes are approaching 10 years old with no issues.

quote:

Originally posted by jhe888:

quote:

Originally posted by Ripley:
Aren't most of such batteries a bunch of 18650 batteries - easily available. Can individual cells be replaced? A decent individual 18650 charger would identify a bad cell.

No, this is a big thing, so I don't think it is a bunch of smaller cells. It must weigh 7 or 8 pounds. I assume it is one big battery, and it obviously has some monitoring and protection circuitry built into it as it has an indicator light and can shut itself down.

All battery packs are made of smaller individual cells linked up in series for voltage and parallel for current.

Even 300lb ecar batterries are a bunch of smaller cells. >7000 18650s in a tesla battery pack

https://evannex.com/blogs/news...ithium-ion-batteries

Now as to replacing a single cell by the avg joe. No its a non starter. You need a spot welding tool, not to mention the chances of fire and explosion as you are spot welding.

There are companies that do rebuild battery packs. Not sure how economical they are. Last time i priced the service it was for nimh batteries with 25% more capacity. Ran ~60% price of new battery

Probably a defect, one or more of the cells is bad, yes it does have a bunch of smaller batteries inside, it happens.

Neighbor just bought the Ego Riding mower, has a ton of batteries from all the equipment, he put his chargers in the laundry room to have a cooler storage/charge area.

Says the rules are to not put on the charger when done until the battery cools, don't keep on the charger once charged, store in a cool place.

But in the end it's under warranty, just be sure everything you have is registered online with receipts and you won't have warranty issues with EGO, not doing that and they become difficult.

Thanks all. In particular, thanks for the advice about finding a cooler place for storage and charging.

there is a company MTO that I've considered sending back a few 2.5 batteries to, $90 to recondition and repair, I haven't used them, but did find them doing a bit of research when considering the project.

They do all EGO battery, the 7.5 included that is a $400 battery new, so if they let you keep the old one, might look to find someone that can fix it, then you'll have two.

Link

quote:

Originally posted by HRK:
there is a company MTO that I've considered sending back a few 2.5 batteries to, $90 to recondition and repair, I haven't used them, but did find them doing a bit of research when considering the project.

They do all EGO battery, the 7.5 included that is a $400 battery new, so if they let you keep the old one, might look to find someone that can fix it, then you'll have two.

Link

Yes, they are not requiring return. Thanks.

But yoicks, that re-furb isn't cheap at $270. Cheaper than a new battery.

This message has been edited. Last edited by: jhe888,