Ryobi One+ Battery Has Only 7v at Contacts

Jan 2, 2020
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United States
I've seen many posts about Ryobi batteries that the charger says are defective. I haven't seen any about my problem.

When I insert my batteries (both originals) into the charger, the green light dims and then brightens slowly indicating a fully charged battery.

When I measure the voltage at the contacts, I get abt 7v.

I took one of the batteries apart. I measured the voltage from the one end of the first cell to the last. It showed 19v.

Evidently the, battery is fully charged, but the tool only "sees" about 1/3 of the voltage at the contacts.

Any thoughts?


Dec 19, 2010
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Firstly, I don't like Ryobi. Every bit of kit I've had with Ryobi has failed. One particular annoyance are the ones where a battery and charger are shared - Plus one? - lose the batteries to failure and you lose the lot.
What battery technology? Lithium, Nicad, Nickel Hydride?. I have replaced defective Nicad and Hydride cells, but I wouldn't touch Lithium. In a battery made up of say nine cells, one defective cell takes the lot down,
Don't place too much reliance on measuring cell or battery voltage. A defective item can show a good voltage when not under load, but it's a different matter loaded.
Even replacing the original cells with better quality cells is not without it's problems. The cells are closely matched to the charger, particularly with Lithium, and really too risky to try.
As a footnote, all batteries have a lifetime however well treated.
With a Ryobi sprayer, I ditched the Nicads altogether and used an external Lead acid battery which are much easier to charge and obtain. The sprayer was still rubbish, so it got binned and was replaced by a car windscreen washer pump attached to a plastic fuel can and a 12-V SLA battery. Cheaper, better, easily fixed or repaired.

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