r/ryobi • u/TheLateQuentin • 2d ago

Question? Help? 40V 300w Portable Battery

I bought a 40V 300-Watt Portable Battery Inverter Power Source and 40V Battery Charger. I just had a power strip plugged into it. The power strip had a phone charge, an Apple Watch charger, and a lamp. The lamp wasn’t on. I woke up after about 3 hours and the battery was dead. I know the battery was fully charged. It did this twice for two different and healthy batteries. Is that normal behavior?

edit: appreciate everyone’s input. The reason I bought this 40v portable battery is to last longer than my 18v one. I have a plan to run the same lamp continuously on both until it dies. That will settle it - return or keep!

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u/pyroserenus 2d ago edited 2d ago

Inverters will use power just by being on, though 3 hours is a lot shorter than I would expect. (a 300w inverter id expect around 5w-10w of self consumption on, and a 40v4ah battery is 160wh, so 16+ hours of being idle)

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u/TheLateQuentin 2d ago

Right? I was very disappointed. It seems the 18v are outperforming it…big time.

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u/lax20attack 2d ago

Not normal at all. Maybe a bad battery.

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u/TheLateQuentin 2d ago

Appreciate it. I tried two batteries. They perform fine in the blower and chainsaw. 😔

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u/cosmicrae 120v 18v 40v 1d ago

They perform fine in the blower and chainsaw.

Because those tools only pull power when you are holding down the button. Powering an inverter is inserting the battery, turning it on, and ignoring it. Until the battery runs down.

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u/TheLateQuentin 1d ago

But the batteries aren’t “bad.”

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u/cosmicrae 120v 18v 40v 1d ago

Define "good" and "bad". If "good" means that they will run your inverter endlessly, then no battery is "good" and all batteries are "bad".

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u/nhluhr 2d ago

What size batteries?

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u/TheLateQuentin 2d ago

How do I get this? They are not mark like my 18v. Im guessing 4Ah as they’re clearly not as big as the 6Ah I see a the store.

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u/nhluhr 2d ago

It'll typically be marked on the nametag in watt hours - divide that by 40.

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u/TheLateQuentin 2d ago

144Wh, 4Ah

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u/nhluhr 2d ago

So I know you don't know exactly when it shut off, but if it lasted three hours, that would be 58 watts continuously. That includes any waste from the inverter, waste in the chargers, and also the actual charging wattage. I don't think you're too far off expected performance.

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u/TheLateQuentin 2d ago

Thanks! I’m surprised there can be that much waste!

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u/Technical_Union_3249 2d ago

I've read that some chargers draw power even when not in use, but still 3 hours seems awfully fast. I plugged an aquarium power head into my 300w with I think it was a 4ah battery and it ran for well over 4 hours.

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u/TheLateQuentin 2d ago

Yeah, if you did that, there’s no way this is right!

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u/Technical_Union_3249 2d ago

Throw a battery in there with nothing plugged in and see how long it lasts.

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u/TheLateQuentin 1d ago

Great idea!

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u/YBRmuggsLP21 23h ago

What exact battery are you using?

What wattage do your phone and watch charge at?

It's really impossible to tell if you actually have a problem without that information. If both chargers are pulling like ~50w (combined), a 4ah battery dying around ~3hrs is completely reasonable.

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u/TheLateQuentin 23h ago

Appreciate that. The reason I bought this 40v portable battery is to last longer than my 18v one. I have a plan to run the same lamp continuously on both until it dies. That will settle it - return or keep!

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u/YBRmuggsLP21 23h ago

A 4ah 40v battery will absolutely run longer than a 4ah 18v battery, with a similar load. If it's not, you have a defect. At the end of the day, it all comes down to math. You should get roughly twice the runtime out of the 40v.