Is it OK to run the batteries until they are fully or nearly fully discharged?

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Per title, got my first EGO products this summer, the 21" mower and the trimmer.  Very happy with both and impressed with the battery life - get ~3.5 rounds of mowing and trimming out of each before the batteries need recharging, and that's letting the grass get a bit shaggy.  My initial understanding is that I can run both batteries (7.5A and 2.5A) til they are basically dead w/out negatively impacting battery life or ability to fully charge.  However reading some of the comments here it sounds like maybe that's not the case and I should be fully charging both batteries after each use.  So what's better - run until the are dead, or charge after each use?
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gregrapp

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Posted 9 months ago

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Blue Angel, Champion

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My personal choice is to use them, store them, then charge right before the next use. In theory this is better for the cells than sitting fully charged all the time, however the impact is likely very small.

If you can get multiple uses out of a single charge I think that’s the right way to go. Keep on keeping on. :-)
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Blue Angel, Champion

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Oh, and to answer your other question, no problem running the batteries all the way down, however I wouldn’t let them sit fully discharged for long periods before charging them.
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gregrapp

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Yeah, my basic use model so far has been to leave them on the tools until the light flashes red or until they actually quit, then charge 'em.  If the light is red when I finish I charge them right away, so they are never sitting around fully discharged.  And since I mow and trim every other week at a minimum they aren't sitting around w/a low charge for very long either.
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Blue Angel, Champion

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Sounds like you’ve got it all figured out! :-)
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gregrapp

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lol.  I'm trying.  I really like the products and system, hopefully they'll last a long time.  I might be a bit less happy if I have to replace that 7.5A battery in a couple of years!
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Maybe torches and rakes at Egos doors as the villagers revolt if that happens.
Looking forward to 5 - 10 years of battery life.
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Summary: Thoughts on running the battery all the way down to flashing RED

Regarding running the battery all the way down, my personal choice is to NOT do that if possible. 

Here is the primary reason, after installing a volt meter both my charger and mainly the mower, I noticed that the point at which a battery will first go RED, and then go flashing RED happens at different times for different tools and battery sizes.  The onboard battery management system (BMS) for each battery should be designed to "cut-off" at the same voltage, but based on manufacturing tolerances (of the electrical components), as well as the cells themselves, the cut-off voltage can vary.  Refer to my related threads, I've measured a battery voltage as low as 39.9v (2.85v/cell).  The only other reported voltages have been around 45v (3.21v/cell).

And here's where I become a little concerned, the further you discharge your battery, the more you're potentially affecting long term life.  So I have two 5.0 AH batteries, and when I get one down to about 25%, which is above the GREEN/RED transition of 15%, I will stop using that one and change over to the secondary one.  Same basic approach for the string trimmer; and the only time I'll run it down to red is if I'm rather far from the house, and I want to finish up that last bit of trimming without having to walk back twice.  For the 535cfm blower, I'm very cautious to not run that down to red, especially when using turbo because you are drawing a lot of power out of the battery in a short amount of time; yes, it can handle that, but at what cost to long term battery life (put in that second battery if you have it).


Related threads:

Ego Battery Review from a Battery Engineer
https://community.egopowerplus.com/ego/topics/ego-battery-review-from-a-battery-engineer

HOW-TO: Add a digital volt meter to the CHARGER
https://community.egopowerplus.com/ego/topics/how-to-add-a-digital-volt-meter-to-the-charger

HOW-TO: Add a digital volt meter to the MOWER
https://community.egopowerplus.com/ego/topics/how-to-add-a-digital-volt-meter-to-the-mower


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szwoopp, Champion

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"For the 535cfm blower, I'm very cautious to not run that down to red, especially when using turbo because you are drawing a lot of power out of the battery in a short amount of time; yes, it can handle that, but at what cost to long term battery life (put in that second battery if you have it)."

Is this why my 2.0 and 2.5 batteries sometime show red when on the blower and then if I stop blowing and restart the battery will display green ?
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gregrapp

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I saw this as well.
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(a)Typical Engineer

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Here's the mower ran down until it went RED; I immediately stopped and recorded the voltage/capacity, then let the mower sit for 10 minutes idle (battery inserted), and the battery voltage went up from: 47.5 to 48.2v, and capacity from: 4 to 10%.  Noticed the light went from RED to GREEN.



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(a)Typical Engineer

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Blue, technically speaking, I could measure the cut off voltage for my mower (but have not done so yet). =)

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Blue Angel, Champion

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Ah yes, I forgot you have that voltage display installed!