RE: compatible batteries

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  • Updated 2 years ago
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FYI, I had asked about compatible batteries for the EGO SP lawnmower. I ordered the 5ah recommended for this mower. Works now. I'm confused why my 2 ah would not power the blade but the sp worked. I love my mower.
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Hey jude

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Posted 2 years ago

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TheAtomTwister

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That is odd to me.
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Prairiedog

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Assuming there's nothing wrong with the 2, it's not the compatibility, it's the amps, which reflect power. Like how a car with a low battery will power the lights and radio, but won't turn over. The sp function worked because it takes minimal power compared to running the sp and the blades.


It's the mowing that puts the working load on the power system, and your batteries are also your gas tank. You get farther on a bigger tank. Even if it had worked you would only have gotten a few minutes of mowing at best. For hand tools, the 2s are fine and the compromise between power and carry weight. If you want an Ironman workout, pop a 7.5 in a weedwhacker and do the whole neighborhood. grin.


I think you have made a good comment. Ego should make clearer that while all their battery compartments will accept all their batteries, there are minimum amp thresholds for a machine to work as designed. Batteries are interchangeable going up in power: you can use 7.5s in a machine designed to run on 5, and 5s in a 2 to increase runtime. But going the other way there will be trade offs, like shortened runtime or they just won't perform, as you experienced. Still, the 5s that came with our snowblower will power our sp lawnmower, just not as long. And we do take advantage of the compatibility frequently.
(Edited)
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TheAtomTwister

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As we are reading your reply, we perceive a few problems, and the first is the confusion of the term "amp" (a measure of current (coulombs per second)) and "amp-hour(a measure of charge(coulombs per second times seconds times 3600)).  You will find that on full power, the mower uses somewhere around 1000 watts, which is what the backpack blower uses, and the 2Ah pack works on the backpack blower, but after the first few seconds of running, the battery starts not being able to keep up with the current drain that the backpack blower puts on it, and that has to do with the number of amps the cells can grant (how rapidly they can discharge).  At a 50.4V nominal voltage, 1000W requires just under 20A, which is just a tad bit too much for the cells in the 2Ah pack. With that said, theoretically the 2Ah should power the mower for normal use, where it is using only a fraction of its full 1000W power, hence you can get so much more than 22.5 minutes of runtime off of the self-propelled mower with the 7.5, which is how much you would get if the mower were running continuously at full.  You would still drain the 2Ah pack pretty quickly, though I have never actually tested it myself.  I don't know if this is a function that EGO has started integrating into their mowers to make sure they cannot overdrain the 2Ah packs or not, but it doesn't seem like it. You should be able to use 2Ah and 2.5Ah packs in that mower, hence you can on the chainsaw, which uses much more power, but I would not recommend that as it is better to use the bigger batteries to make sure you get full power and to maximize the longevity of the smaller packs.
(Edited)
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szwoopp, Champion

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Official Response
All ego tools will operate with all ego batteries.  Only the snow blower comes with the recommendation to use 4.0 or higher batteries for optimal performance.

From the 21SP manual

If your mower will not operate with the 2.0 battery you have a malfunction and should contact customer service.
(Edited)
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TheAtomTwister

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That is the way I see it.  I still recommend using the bigger batteries, but all the same, the mower should be working.  I'm not sure why it isn't.
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szwoopp, Champion

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Agree, I would not use a 2.0 regularly for all mowing, but I have used mine to finish the last 5 minutes of mowing.
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Oregon Mike, Champion

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I don't have the SP mower so this is asked out of ignorance, but will the self propel feature work if the handle clamps aren't fully engaged? Wondering if the blade not turning is because the clamps aren't fully engaged, which is the case for all Ego's mowers, but I don't know if the self propel needs the clamps to be fully engaged for it to work.
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szwoopp, Champion

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I have never tested for that, but I believe that safety feature only prevents the blade from engaging.  OP said their mower works with a 5.0, so clamps is not likely their issue.

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TheAtomTwister

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Yeah, that is what I would think, but I wasn't sure if he just happened to have the clamps engaged with the 5 and unknowingly not with the 2.  
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Oregon Mike, Champion

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Perhaps OP will chime in regarding the clamps part of the question. I did miss the "Works Now" part of his post, though. Yeah, as TAT says, maybe OP re-engaged the clamps before using the 5ah battery. Even unintentionally which sometimes happens when pulling the mower backwards.
(Edited)