ups battery

How can I check a rechargeable battery to tell if it needs recharging?

I want to buy a UPS battery to leave in the detached garage to charge my phone while working on the mower and other things. I don't have much luck with batteries. Years ago I used a lot of ups batteries for portable power and had problems keeping them charged. I'd think one was charged and it'd be dead when I needed it.

Will a trickle charger do a good job of charging it without over charging? There isn't any power in the garage so I'll have to bring the battery into the house to charge. It's to far to run an electric cord. I listen to a lot of Internet radio out there.

Maybe you can can suggest some other setup?

Thanks

Reply to
Austin Davis
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It depends on the chemistry. The only sure way is to use a discharge tester. However, that doesn't tell you if it needs a charge. It tells you that your charging method is successful. There are also some tricky ways of measuring SoC (state of charge) by putting a load on the battery for a short period of time, measuring the slope of the discharge curve, and using that information to guess the SoC. APC uses this method in some of the SmartUPS designs. However, it's more of an indication that you're battery needs replacement, than a SoC. Another is a coulomb counter. That's common with LiIon battery systems. In effect, it's a data collector that tabulates the current going in and out of the battery. If the battery charge efficiency is known, the SoC can be calculated.

Let me guess(tm). You were trying to float charge a gel cell or AGM battery with a crude charger? Gel and AGM batteries do not like being overcharged, varying temperatures, or sitting discharged for any length of time. In other words, they're quite easy to kill.

Offhand, I would guess that would be overcharged, and dead fairly soon after. It might also be that you discharged the gel or AGM battery too much. Discharge below about 50% SoC can kill off batteries rather quickly.

No, although that's controversial. My contention is that trickle charging without a full charge cutoff is guaranteed to put a thin coating of lead sulfate on the plates, which if discharged further, will kill the battery. My favored method is the usual 3 stage charger. with a total turnoff when at 100%.

Solar power perhaps?

Google for "portable power station". Get the one that has the biggest battery (heaviest weight on the specs) and claims to have a decent battery charger circuit. This may not be the best, but will probably be the cheapest. It can also be used for other things in the garage. However, don't just leave it in the garage. Bring it into the house and keep it charged to prevent sulfation. The bad news is that if you use it regularly, the typical battery life is about 5-7 years.

Also, if all you want is more runtime from your smartphone, get a LiIon external battery battery for the smartphone. I have several and find them quite handy for 5V (USB) power: They come in different sizes and battery capacities. I can't tell how big a backup you need without knowing your smartphone current drain. There should be an app for determining that on the phone.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

phone > while working on the mower and other things. I don't have much luck with

buy a small solar panel.

Bye Jack

Reply to
jack4747

On 7 Apr 2016, Jeff Liebermann wrote (in article):

How about the ?blue toaster?? (c;

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AC160S/dp/B00SR4HQ62

Li-ion.

Reply to
DaveC

Overkill. He's trying to power a lousy smartphone, not power the entire garage.

Also, I have my doubts about using a LiIon battery for backup power. The problem is that LiIon batteries deteriorate if left at 100% charge full time: Some laptops have a "battery saver" profile, that charges the laptop battery to 50-60% SoC in order to extend the battery life.

APC does offer a LiIon UPS (BG500). I haven't dug into their design yet to see what they're doing: It has a 3 year warranty.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Jeff Liebermann

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