56v, 21" deck mower runs about 10 min b/f running out of juice.

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I have a 56v, 21" deck mower. I've had it a few months & now the battery lasts about 10 min. It is, admittedly, very thick grass, but my old B & D cordless electric mower did a better job. I am regretting this purchase. Any advice?
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Grady Spoonamore

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Posted 1 month ago

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Oregon Mike, Champion

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Hey Grady, which battery are you using? Also if mower and battery/charger are less than 90 days old you can return it to Home Depot for exchange. If over 90 days give customer service a call. Call early in the morning to avoid hold times.
(Edited)
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Grady Spoonamore

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Thanks for the advice! It's older than 90 days, so customer service it is for me!
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Paul Christenson

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Which cutting level are you operating at?
Are you bagging or just mulching?
Have you checked your blade's sharpness?
(Edited)
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Grady Spoonamore

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I am on the lowest cutting setting (deck all the way down). I am just mulching. The blade could use some sharpening, but it is cutting evenly. 
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Bill Menzel

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Setting number one is 11/2 inches.  That is probably to low to cut your grass. I cut my Kentucky blue grass at 312 inches (setting number five).  This way your roots grow deeper and the grass is a lot healthier and thicker.  What kind of grass do you have?  Even so, your battery should last longer than ten minutes, especially since you don't have a self-propelled lawn mower.  Customer Service should take care your problem.
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Ken, Champion

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I agree that the lowest setting is too low for the typical residential lawn. A putting green maybe, but not a typical lawn. I felt like the second setting was scalping my lawn. I was cutting at No. 3 last year, but this year I moved to 4 and my lawn is much healthier for it.
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summetj

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A 2.5 AH battery should get you 7-12 minutes of runtime. If you have a 7.5 AH battery (came with the self propel version) or 5.0 AH battery (came with the non-self propel version) I would certainly expect more than 10 minutes of runtime for just about any amount of grass. 
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Grady Spoonamore

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I believe I have the 5.0 AH battery--I have the non-self propel version.
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summetj

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The number 1 setting is quite low and would typically require more power than what I normally use (3,4,5), but with a 5.0 battery on the push mower I would certainly expect it to last more than 10 minutes, especially if the battery is less than a year old. I assume the grass you are cutting isn't TOO thick, as you say it's "cutting well", and people typically don't use the lowest setting to mow very high grass.

It sounds like either (1) the mower is taking up too much power - check for string or debris around the bottom of the blade and make sure it turns easily by hand (with the battery out!), or (2) the battery doesn't have much capacity. If you have a Kill-A-Watt meter you can run the battery all the way down, and then figure out how many watt hours it takes to re-charge it with the charger.  (My 7.5 AH batteries typically take 330-410 watt hours to recharge, so I would expect a "normal" 5.0 AH battery to take something in the 220-275 range.)

If the mower is taking up too much power due to resistance, either grass too thick/high or debris caught around the bottom of the blade, you may also hear it go into "overdrive" (or just stay in overdrive all the time). And of course, check to make sure grass isn't clumping and stuck onto the bottom of the deck. If it builds up too much the top of the blade starts to hit it and make a thumping/buzz type noise. If that's the case, take the battery out and then use a stick to clean the bottom of the deck.
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Peter Stevenson

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Sounds like a battery failure. Call customer service and have them take you thru an over the phone diagnostic check
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Grady Spoonamore

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Thank you.
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Jacob, Champion

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Sounds like a dull blade to me. Unless it has always been that way. Sharpen it to a razor edge and see if that helps. I have noticed double run time in the past due to sharpening the blade.
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Paul Christenson

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Assuming you have found nothing tangled under the blade or around the shaft...

For pure edification of us(stump the chumps...:) )...could you fully charge your battery...then, while sitting on the driveway...engage the mower...note start time...let it just run until the battery says no more...note that time...then post total run time just cutting nothing...(you could strap the blade engagement to save your hands...:) )
(Edited)
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Grady Spoonamore

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Interesting idea, but I'm not comfortable doing that. Thanks for the input!