Kilowatt hours (kWh) required to fully charge the 5 ah battery

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I love the new snowblower--it's incredible!  Just finished clearing about 2-3" from a driveway for a three stall garage (including the slush by the street left by the snow plow) and the sidewalks of six houses on a single charge of the two 5 ah batteries.

One question remains: Can anyone tell me how many kWh of electricity is required to fully charge a single depleted 5 ah battery?  By doubling number and referring to my electric bill for current rates, I can figure out how much it costs to "fill up the tank" for one full snow blowing session.

Thanks!
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tzeilstra

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Posted 3 years ago

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Blue Angel, Champion

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If we look at the 5Ah rating and then assume 50.4V average, in theory it should take 252Wh to charge a battery, or 0.504kWh to charge the pair.

In reality it gets a bit messy, because Ego doesn't use 100% of the rated cell capacity (in order to extend battery life), and there are inefficiencies due to heat loss while charging (likely around 10%).

I should actually do a discharge test on mine to find out. It will only be as accurate as my energy meter, but it's probably better than a wild guess. :-)
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tzeilstra

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Thanks - I was hoping someone would walk me through the math.  But yes, I would love to get an actual result from an energy meter if someone has one and wants to do an experiment for us...
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I actually measured this for all of my batteries so far, except my 5Ah. This is the tag I keep on a 4Ah:



You can see that when the battery was new it took 0.24kWh to charge, and more recently took 0.23kWh to charge. Since 10Wh is the highest resolution on this meter, and it's a cheapie, I'm not drawing any conclusions yet.

The method I use is to deplete the battery in the blower set to its lowest setting, which is likely the lowest power drain of any Ego tool. Then I charge the battery using the Standard charger (not the Rapid) to minimize heat loss. I measure the total energy with the meter.

I misspoke before... I should have said "charge" test, not "discharge" test. :-)
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That guy calculated the cost. No more math
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If the charger operates at the full 210W for the duration of charging the 5Ah pack, then the energy needed would be (1 + 2/3)*210 watt-hours. The rapid charger is a bit trickier, for the amount of current that it uses to charge batteries wanes as the batteries become more charged. To know for sure exactly how much energy is needed (which really isn't necessary, only an estimate is needed), use an ammeter on the charger's cord, an ammeter that can graph current to time, and a voltmeter that can graph voltage to time. Use the two graphs to calculate the total energy used.

My estimate would be that the 210W charger would be 350Wh, or 0.35kWh, or 0.07kWh/Ah. The rapid charger would use more energy I would assume. 

Sorry Spark, but this math I need to post.

I should note that the energy needed to charge the battery will depend of course on the battery's energy capacity, which will wane as the battery degrades over time.
(Edited)
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So my 5Ah battery took 0.32kWh to recharge from completely dead. This is pretty impressive given that the 4Ah batteries are about 0.24kWh at best. Of course this is not a completely accurate representation of capacity, but it is a 33% increase.
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At 11 cents a kWh... Thats pretty cheap!
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Cars put out slightly more carbon dioxide, motorcycles put out more of everything else measured, and sometimes by several thousand percent. Cars are orders of magnitude cleaner.

I bet an "OHV" lawnmower engine is far dirtier even than a motorcycle, and a two-stroke anything would be off the charts.
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I stand corrected.
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DJDDay

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Cars are an order of magnitude cleaner than motor cycles, but their sheer numbers alone cause them to contribute an astronomically larger amount of pollution into the atmosphere.  And in areas of the world where emission standards are close to non-existent (Mexico, India, China, etc), the types of particulate matter and other pollutants are greater.
(Edited)
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Absolutely, but imagine if even 10% of the North American public were to start riding motorcycles instead of driving cars?

I spent a week in Delhi last October. The level of pollution there is almost unbelievable... to the point where you blow your nose at the end of the day and what comes out is grey or black. The sun disappears into the smog at 5:30 pm; even though it's still high in the sky you can't see it.
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Thankfully gas powered OPE is something that typically gets used only once or twice a week!
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summetj

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As a data point, I have a 7.5 AH battery and charging it on the quick charger from flashing red takes 420 watt/hours. (The battery was manufactured in Dec 2014, but I didn't receive/start using it until 2017.)
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TK

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Warranty starts when you receive it, but I too, would not like to receive a battery that was 3 years old. Would anyone buy a new car battery that was 3 years old?