Observing proper safety (ie, not using it inside the home), is there any reason using a car-sized 12v gel-cell (eg, Optima*) would be a Bad Idea (tm)?
Form-factor is not an issue; the battery would be outboard, of course.
Charging time would be much longer considering the modest charge current of the UPS, but so would be the discharge time.
Opinions?
Thanks.
Are you sure the available charge current will exceed the self-discharge of the battery?
Sylvia.
You should use a sealed battery. Car batteries may leak accid and H2 gas. Most UPS I've seen have a fuse in series with the battery. Make sure to retain the fuse. I'm not worried about the charge current. An UPS is usually fully recharged in a couple of hours.
Any deep-cycle LA battery would work.
Assuming that the cooling of the inverter is good enough--not all of them will run at high output for long periods.
Cheers
Phil Hobbs
Actually works fine. BTW, for the UPS, you can use the worn out car battery as well. It has enough of current for this application.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
Should work with out a problem, except for charging. IF you want an indoor friendly battery look at the AGM, they don?t gas like LA's.
Cheers
(tm)?
Good point. Attach a thermistor/thermocouple and a data recorder to the inverter hot spots and see how fast the temp is still climbing when running at rated load with the original equipment battery.
If its still climbing, there could be trouble.
Typical car battery is "start" battery and is not designed to withstand significant discharge. For UPS use one needs "Deep cycle" battery.
On Sun, 26 Jul 2009 04:53:53 -0700, Andrew wrote (in article ):
That's a *great* primer on LA batteries of all types (liquid, gel, AGM, deep-cycle); there's not a type that's not described.
"Myth: The old myth about not storing batteries on concrete floors is just that - a myth. This story has been around for 100 years, and originated back when battery cases were made up of wood and asphalt. The acid would leak from them, and form a slow-discharging circuit through the now acid-soaked and conductive floor."
Thanks!
Heres the real Battery FAQ
Cheers
Checked it. Site degraded by not having enough editorial expertise to not fix the Sb vs Pb symbol error.
You say, "Car-sized"; but you haven't said if it's a car battery or a deep-cycle (RV, Marine, golf cart).
Don't use a car battery. They're good for 600 cold cranking amps, but crap for deep-cycle applications.
If it is, in fact, a deep-cycle battery, then there should be no problem, as long as your UPS can keep it charged, as has been mentioned.
Good Luck! Rich
Have something to add? Share your thoughts — no account required.
Ask the community — no account required