Homemade Battery Backup

[mralias]

Or this?

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I WANT ONE!

 

[Wilbur Feral]

Now i'm paranoid that my ups is too close to my stove. i actually have it sitting on the left... you can almost see the corner of it in my avatar, that black line is the start of it.

it's been there 2 years now, now hydrogen bomb. should i move it? it's a cyberpower, unmodified.

Is your UPS using the factory battery? If so, it is very likely Absorbed Glass Mat and personally I would not worry as AGM produces very low levels of hydrogen during recharge. That said, I am no expert and you may wish to consult one.

If you use a standard marine battery that is not AGM, (i.e., you modified a UPS to use one), or if like me you have a stove that can run on battery backup (an MVAE), then do NOT recharge near the stove! I recharge in a drafty garage with a fan running.

 

[briansol]

I have not modified the unit in any way. It has stock batteries. I looked at the manual, and it says 'keep away from fire' but that's most things with batteries.

• Battery Size & Type 2x Rechargeable 12V/8.5AH Sealed Lead Acid (User Replaceable)

so they are not AGM.

 

[dlehneman]

I built this battery backup system for my St Croix Hastings after 1 too many short power outages that caused my house to fill up with smoke.

It is simply a store bought APC with it's own internal batteries removed. In their place, I wired in (2) 90AH marine batteries. This sits in a room just below the stove. It's wired through the wall directly upstairs to the outlet the stove plugs into.

This set up will run my stove for about 8 hours in a power outage.

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Hey Tim,
I've been considering a very similar setup for the past year. I actually bought a UPS missing the battery at a thrift shop hoping to try it out, but unfortunately the UPS wasn't charging at all so I didn't get to try it yet.
Anyway, I know you said it would run your stove about 8 hours, but have you ever tested it that long? If not, what's the longest you've tried? Does the UPS try to estimate run time with those batteries or does it just assume factory battery run time?

 

[TimfromMA]

Hey Tim,
I've been considering a very similar setup for the past year. I actually bought a UPS missing the battery at a thrift shop hoping to try it out, but unfortunately the UPS wasn't charging at all so I didn't get to try it yet.
Anyway, I know you said it would run your stove about 8 hours, but have you ever tested it that long? If not, what's the longest you've tried? Does the UPS try to estimate run time with those batteries or does it just assume factory battery run time?

Yes, Ive tried it. I actually measured the voltage on the batteries every 10 minutes for the entire time. After 8 hours, the batteries measured about 11.8V each which represents about 60% discharge. Any further discharge risks damaging the batteries.

The estimated runtime shown on the front of the UPS is based on factory batteries. If you wire in larger batteries like I did, do not rely on it to tell you how much time you have left.

 

[dlehneman]

Thanks!