Will a lithium-ion battery powered lawn mower recharge after sitting idle though the winter

lawn-mower

I've had a corded electric lawn mower for 5 years and I am very pleased with its performance and value. However I am not pleased with the "chain" of the cord. I do not live in the suburbs, I live in the city and do not have a large lawn, so its only annoying for about thirty minutes worth of lawn which I just live with. I am considering a new electric with batteries but herein lies my question.

I live in the north east and I only need to mow the lawn maybe three months our of the year. The rest of the year the mower and its batteries will sit idle in an unheated garage. Will the lithium-ion batteries go flat and not recharge after sitting idle though the cold winter? Will I have to constantly keep them charged wasting money?

I realize I will want to get at least 2 batteries and I'm fine with that investment if its going to worth it. I don't want to have to replace them each year.

I wanted to ask other people who live in similar climates what their experience was before cutting-the-cord, as it were.

Update:
Thanks to all the responders for your expert responses. I maybe posted on the wrong forum tho, because I was looking for people who've actually lived it and done it and not so much theory as to how it "should" work or lessons about batteries. Thx.

Best Answer

Lithium batteries are not lead-acid. They don't have all those "bad habits" like decaying when left in storage.

Tiny palm-sized packs such as for power tools do tend to age like normal power-tool packs and only give you 3-5 years life... but I understand lawnmower packs are bigger.

This assumes you buy quality and not some cheapo piece o' junk off Amazon Marketplace.

However, I gather you have apprehension about large lithium packs. Lithiums do have certain rules.

  • Do not discharge them literally to zero. Now, any competent lithium battery will have a Battery Management System (BMS) to protect the battery from a variety of things (including overcharge)... and it will disconnect the battery and shut down your appliance to protect it from too-deep discharge. That does nothing about self-discharge from long storage, and I'd suggest putting them on charger every couple of months to keep them from reaching zero.
  • Do not recharge them if temp is below freezing. In fact, if you try to recharge a Tesla whose battery has deep-frozen, it will first heat and circulate battery coolant, before it attempts to charge.
  • Never, ever, feed them after midnight. Just kidding!

As far as buying 2 battery packs, if the supplied battery pack lacks the range to cut the whole lawn, just put the battery back on charger and cut the rest of it later.

Lithiums are happiest working in their midrange: 20-80%. Charging is fastest and it does not need to be tapered/limited, like it must for 0-20% and 80-100%. That's the trick about crossing the country in an EV: you can DC fast-charge within that 20-80% range very quickly.

So if it doesn't have range for the full lawn, stop at halfway and recharge... that way you'll be recharging from 20-50% SOC and it will charge pretty fast up to 80%.... then finish.

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