Backup power

[Stormin Mormon]

I'm currently having a negative reaction to your impedence. Impudence. Insignifigance. Some thing like that. Wish more people had power backups at ohm.

[trader_4]

I've never seen one of those for testing 12V lead/acid batteries. But if it exists and works, that would be a solution. Alternatively, he could try to pick up one of the handheld battery testers on Ebay or similar. The battery tester type put a load on the battery while measuring the voltage.

[KenK]

[e-mail] wrote in news:5ktc7apuv9tdp9gkk0ub1o9lq42o251idn@

4ax.com:

Yes. Genuine Battery Tender. That's why I capitalized it.

According to its manual, it should do a good job.

[trader_4]

Yes that's the best test. But the only way he'll know that is to put his load on it and see if it lasts the expected number of hours. I guess doing that once a year isn't a bad idea. But if you do it regularly, every cycle takes more life out of the battery. A battery tester can test it with a short duration load.

Presumably he'd replace the battery if it's no longer adequate.

Only if the light doesn't work after X hours. A mostly bad battery could still light up the light for a brief test and he wouldn't know if it was capable of going the normal length of time in an outage.

[Stormin Mormon]

Termite walks into a bar and asks "is the bar tender here?"

- . Christopher A. Young Learn about Jesus

.

[mike]

I can't say you're wrong...just that you're overthinking it. We don't know the whole story, and you can come up with a counterexample to prove any definitive statement wrong.

I believe there are battery testers that can tell you a lot about the condition of a battery, but are they "worth the cost" in this situation.

Applying some logic...

What is "no longer adequate"? What's the calamity that ensues if the light lasts x-1 hours? x-2 hours? x-3 hours? At what point does the cost of some possible future calamity exceed the current cost of a new battery?

If it's a life-support situation, you replace the battery on a schedule and have an additional battery on standby.

If you used the system frequently, you wouldn't need to test it. In particular, a yearly test suggests that it's more than a year between power outages.

What's the cost, in additional battery degradation due to discharge, of

20 partial discharges over the next 20 years? You don't need to run it flat to learn that it's degrading. Measure the voltage, under load, after an hour and graph the number.

And the system test is of the whole system including source, load, wiring, switches, etc.

I have a UPS on my computer. The battery is not new. Runs for about 5 minutes.

Power outages around here are of two types. Virtually all last less than a second. The rest last for hours.

Replacing the battery with one that runs 10x as long would be of zero benefit.

My first line of defense in a power outage is the nap. Nothing fixes a power outage faster than a long nap.

Second line is two dozen harbor freight free flashlights.

Next is the 12V battery-in-a-box car starting gizmo. Then the car battery. Then the 500W generator. Then, if it's cold and I need to keep the pipes from freezing, I need to run the furnace off the 2KW generator. Then, if I need to power my neighbor's freezers to keep his food from spoiling, I run the 6KW generator.

Can't remember the last time I needed more than the nap and one flashlight. My only excuse is that I acquired all this stuff over 40 years at pennies on the dollar.

Managing expectations is far easier than obsessing over attempting to maintain your full existence during a power outage.

Harbor Freight will sell you a generator for $67 after 25% coupon that will provide REAL backup power if ever needed. And that's probably in line with what you'd pay for a new battery.

[Stormin Mormon]

Ah, bother. Just got off the phone. My train of thought is off in space. I'll write later.

[trader_4]

All I can do is give options that answer the question. IDK what the value is to the OP of being able to test his battery. It's up to him to figure that out and how much a battery tester would cost and how a battery tester fits his requirements versus the putting it through a full cycle test periodically method. There are also options from buying a new battery tester to buying a used one on Ebay. Presumably, the OP, if interested, can research that and figure it out. Someone even pointed out that some multimeters have a battery load test function. I've never seen one, but if they do, then maybe he doesn't have a multimeter, could use one for other purposes too, and that option would work for him.

As to overthinking it, IDK exactly what you mean. You suggested that the best way to test it is to actually make it do what you expect it to do, periodically. All I did was point out that to do that, you'd have to put it through a typical full usage cycle, or at least close to it, and that each time you do that, it lessens the life of the battery. I also said if you do that once a year or so, and that's adequate, it should be fine.

We don't know because that was never given. What the parameters are and how you can test to those parameters are two different things.

And I'm the one that's overthinking things?

That's what a battery tester will do in seconds. Maybe he wants to buy one of those instead? Anything wrong with that?

The rest of the system can be checked with high accuracy in just a few seconds, by turning it on. That isn't the case with a battery, unless you have a load tester.

Irrelevant because your requirements and priorities OP or others.

And I thought the question was about how to test a battery.....

[RobertMacy]

A Rabbi, Priest, Minister, a duck, a rabbit, and a bear all walk into the bar at the same time. The bartender looks up and says, "Is this a joke?"