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HI..question about UPS baterry replacement? Answered

Baterry on my UPS Mustek Power office 650 is old and not working propperly.It is 12V and 7 amps,so I though to put instead a car baterry,also 12V,but 55 amps....can it be done?will .the device operate safely, or will it get damaged?Or my computer?P.S. I don`t care about esthetic,car baterry wil stay next to the UPS,I want to know can UPS hold that much amps?can it give me more authonomy when there is no electric power,and can I damage my computer with that kind of replacement?..Greeetings from Serbia..:)..


Hmmmm....I though it would be simple battery changing...:(((.... Friends,thanks a lot for those answers,I think I`ll hold to the manufacturer`s recommendations and replace it with it`s standard battery...I really can`t afford to make a barbecue of my comp ...Best wishes,Miki from Serbia...

The primary problem with your idea is the charge circuit, which is not designed to handle the loading presented by an automobile battery. The other issues noted in the posts below are just as valid, although not the critical bottleneck and can be circumvented (no pun intended for anyone who caught that one) pretty easily, since the first UPSes actually used automobile batteries. (UPS batteries, btw, are not considered to be deep-cycle, but float). In addition to dealing with venting and the other issues covered, you'll need to provide an alternate charging system and figure out how to circumvent the internal circuitry which will likely register the lack of a battery on its charging system to be a fault.


8 years ago

Yes, you can, but there are some caveats. (Aren't there always?) A regular car battery will probably have a shorter life due the cycle of charge-drain, charge-drain. A deep cycle battery designed for that type of use will fare much better. There is possibility of battery leakage, even in a sealed battery, if it overheats. The load on your charging unit in the UPS may cause it to overheat while recharging the heavier car battery. (Maybe rig up an old pc fan in the UPS to add a little airflow across the circuitry.) Find an old Tupperware or plastic container that will hold the battery and catch any leakage, just in case. Make sure the battery terminals are protected from shorting out if something were to fall or be laid across the terminals.

It would probably work fine for a while. But, it probably won't charge correctly. Now you have hydrogen gas near electrical equipment not designed to be near hydrogen gas. You now have a pint or so of sulfuric acid in you house. If you want more power either get a bigger ups or try using 2 lead acid batteries.

Gel-cell batteries -- which is what the UPS was designed to use -- are a bit safer, and are available in sizes that will work better with the UPS circuitry. Getting the right battery may actually be cheaper, and certainly easier. If you really want to use a car battery... I would suggest making much larger changes to the UPS, charging the battery through a charger designed for that purpose and using only the output (inverter) stage of the UPS to go from that to the outlets. Remember that the charger has to be able to provide the maximum _combined_ current that will be drawn by the battery and the inverter. (I've seen some UPS's that actually have a 12V input which lets you feed them from additional batteries. But even there, I'd think it would be simpler to just leave them on a separate trickle-charge and connect them up only when needed.)