7.5ah battery problem

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  • Updated 5 days ago
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I just bought the brand new EGO 21 in. 56-Volt Lithium-ion with 7.5Ah Battery and Charger. I tried mowing my lawn for the very first time, but battery lasts very short time. Less than 30 minutes, more like 20 minutes and it starts to get stuck (and shows less than 25% when charging). After full charge it works again for only about 20 minutes. Is it possible I have a defective battery? Only reviews suggest that it should last 1 hour or so.
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Nikita Kozhekin

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Posted 2 weeks ago

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SCDC, Champion

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Too many variables.  How thick is your grass, how tall, was it wet/damp from recent rains.  Have you tried sharpening the blade. Did you charge to full before your first cut.

Those are the major contributors to short battery life.
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Nikita Kozhekin

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Yeah, my grass is a bit tall, but not super wet. It was displaying red battery level after about 20 minutes though :(
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szwoopp, Champion

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Well you may get better results setting the cut very high (setting 6) for the first mow and basically mowing it a second time immediately or the following day at a regular height (setting 2 or 3).  Also letting it dry should help a lot as well.

Tall and wet are a bad combo for requiring/sucking energy from the batteries.
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sam rosenberry

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I've had a similar problem.  I bought my mower last September and it worked like a champ.  I stored the battery in the basement during the winter per the manual.  This spring I can only cut for about 15 minutes before the solid orange light comes on and it quits.  I start with a fully charged battery and I have the mower on the highest setting and slowed down the self propel speed to no avail.  Blade is sharp as well.  Any suggestions?  I have an email in to EGO, and am waiting to hear what they say.  Thanks!!
(Edited)
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Blue Angel, Champion

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Sam, if you don't hear back from your email request within a day or so I'd give them a call.  If you do call, call early in the morning on a weekday to avoid long wait times.
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sam rosenberry

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Thanks!  Will do.
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summetj

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My 1 year old battery typically gets me 35-39 minutes of runtime, cutting dry grass with a sharpened blade that isn't terribly high (one week of growth).  If you are cutting very thick still dew covered grass, a 20 minute runtime doesn't sound completely unreasonable (is the blade motor constantly "spinning up" to full power or running at full power all the time? If so, a 20 minute runtime would probably be reasonable).  

A year ago I did get a few 50+ minute runtimes was when cutting grass that didn't really need to be cut yet (early season / late season).

If you have a Kill-A-Watt type meter, try measuring how much power the charger is putting back into the battery. The most I've ever measured is 430 watt hours (last year) and this year I'm getting around 390 watt hours.
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Nikita Kozhekin

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Thanks, how do I know if motor is spinning up to the full power or not?
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szwoopp, Champion

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you will hear it speed up / kick into high gear as you mow.  That is the only way to tell.  There are no indicators or lights.  It is supposed to be a temporary thing for tall thick areas of your lawn where the engine power has to increase to keep the blade spinning at the normal high rate.
(Edited)
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Fred Clarke

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Lots of optimists on this list. You can tell if it is working hard by the sound. Start it on the driveway, the go to the grass. The documentation advertises the blade comes very sharp. Ace and other hardware stores will sharpen it. 20 minutes is not acceptable unless your grass is very high and very wet. to bad you can't try another battery. if you live in Denver area you can try mine.
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Oregon Mike

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Although I thought the blade that came with my mower seemed sharp enough out of the box, and it did seem to cut my grass just fine, I can't believe how much better it cut once I went ahead and sharpened it anyway. 
They do tend to lose their sharpness pretty easily and I think it's due to the softness of the blade material. Hardening it more would help hold the edge longer. But, that horse has been kicked and kicked so hopefully EGO is looking into it.
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Nikita Kozhekin

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Thanks :) Sadly I'm very far from Denver!
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Blue Angel, Champion

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Nikita, if you are in a regular weekly routine of cutting your grass and it’s not overgrown or wet you should be getting somewhere between 30 to 60 minutes of useable run time.

A sharp blade will always improve run time as well as improve cut quality, however I don’t believe a dull blade would be responsible for a 20 minute run time.

The next time you cut, try leaving the battery on the charger overnight first to make sure it gets a chance to fully top off. If the mower continues to only run for 20 minutes your next move would be to call Ego Customer Service and have a replacement battery sent.
(Edited)