Ego 7.5AH Battery capacity over time (Battery Degradation over time) – 4 year update

I own three 7.5AH Ego batteries. My earliest had a manufacture date of 2014 (although I purchased it in 2017 with a mower manufactured in 2016). I now have four years of operation on this battery.

As shown in the graph, the capacity dropped off over time (down to a low of 260 watt hours in year 3, which is 63% of the original 410 watt hour capacity), but in year 4 it has actually increased a bit to 290 watt hours (70% of the original capacity).

My 2nd 7.5AH battery was purchased in July of 2018 (manufactured in May of 2018).

As you can see, its graph has gone down, and so far hasn’t popped back up.   At the three year mark it is also down to a 260 watt hour capacity (63% of it’s new capacity).

My third 7.5AH battery has a 2019 manufacture date, but it’s still in its first year of “use”, so I don’t have a fancy graph for it yet, although I have started to include it in the comparison bar graph below:

So far, all three of my 7.5 AH batteries have followed a very similar capacity vs time curve, and you can expect one of these batteries to retain an average of 90% capacity in year 1, 72-75% capacity in year 2, and 63% capacity in year 3.

[Plus, they MAY bounce back up to 70% capacity in year 4, if the other two follow the path taken by my first battery.]

2 thoughts on “Ego 7.5AH Battery capacity over time (Battery Degradation over time) – 4 year update

  1. Love all the Ego stuff you’ve covered.

    What charger are you using?
    What are you using for the Wh calculation?
    What charge state do you keep them in the off season?

    I really wish Ego would add an 80% SOC button and a 30% storage button on their chargers. It would really increase battery life with almost no cost.

    • I use the Ego fast charger for my 5.0 and 7.5AH batteries, and the regular charger for the 2.5ah batteries.
      I use a Kill-a-Watt meter (like this: ) plugged into my fast charger to see how many Wh it takes to re-charge the 7.5 AH batteries (from when they die in my lawnmower).
      In Florida we don’t so much have an “off” season as a “mow every 10 days instead of every 5 days” season….So I never “idle” any of the batteires, just store them fully charged. (If they had an “stop charging at 80%” setting I would use it.)

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