Monster UPS

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Bad Wolf

Minister of Fire
Hearth Supporter
Jun 13, 2008
523
Eastern CT
I just can’t seem to pass up anything free. I somehow decided that my 2 deep discharge batteries weren’t enough backup for my furnace.

They were disposing of the UPS system at work which still had 4 years left on the nominal 10 year batteries. So I took 18 of them and the racking system and set them up downstairs next to the furnace. Each battery is 2 cells of 2 volts, so when you hook them up in series you get a 4 volt 300 Amp/hr battery. So the 18 batteries give me six 12 volt banks for a total of 1800 Amp/hr.
This coupled with a 600 watt pure sine inverter and relay setup from Xantrex and I should be able to go for a couple of days.

One thing I did noticed is when I went to charge them, the charger would hang up at 85% for hours. If I turn it off and back on, it jumps to 95%. Eventually it will show 100% and I get the green light.

Just for fun I plugged the furnace into it the other day and let it run for 40 hours. The only thing calling for heat was the hot tub, and I fired the boiler for about 8 hours to bring the storage up to 175 for DHW. According to the Kill-o-watt meter I used a little over 2000 watts and the voltage never dropped below 12.5.

There are front panels and a top that I attached after I hooked everything up. A nice neat and clean setup.


. [Hearth.com] Monster UPS

BTW a friend took the other 120 batteries and hooked them up to his solar panels at his cabin in Vermont.
 
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Man.. and i thought I was doing good with my little repurposed 1200watt PC UPS.

BUT!!!! I only need about 7 seconds till the 15kw Kohler kicks in. :)

JP
 
You should be using some PV's and running your house on this. That is a lot of capacity!
Great score!

I have a friend who is in the recycling business. When Maine Yankee Nuclear Power Plant closed years ago, he got their backup batteries for the cost of removing them. As I recall, they were 2400 ah, 2volt batteries wet cell lead acid batteries. They were huge and he sold them to people with PV systems.
They are a lifetime battery. Not only because no one in their right mind would want to move them again.
 
Might be a good thing to think about ventilation for that area if you haven't yet. Hydrogen gas is a byproduct of cycling batteries through charge/discharge cycles. Goes boom in a big way if it accumulates.:eek:
 
Might be a good thing to think about ventilation for that area if you haven't yet. Hydrogen gas is a byproduct of cycling batteries through charge/discharge cycles. Goes boom in a big way if it accumulates.:eek:

This is actually code for stationary battery storage/charging in Maine at least. Although I've never seen a problem with people who don't. I thnk hydrogen disipates quickly and doesn't pool on the floor as other flammable gasses do. I'd still build a vented enclosure though, as hydrogen is the most explosive gas known to man!

TS
 
These are sealed batteries that "produce no emissions during normal operation" (from service book) The LEL for hydrogen is 4%, and they further say "normal air circulation in a ventilated facility will preclude any hydrogen build up" .

That said, I will make sure that I have good air flow during charging.
 
It is indeed lighter than air so it rises to the top of the room the batteries are kept in. I remember looking at the set up for a 30KW solar setup and they had the batteries in a sealed cabinet that had small ventilation fans both in and out. Seems like they were controlled by a sensor of some type. It was a professionally installed packaged system and I'm sure it was standard equipment rather than an add-on component.
 
Howdy "neighbor" SE CT here.

Very nice score on the battery bank. Reminds me of what we have at my work just in case the doo-doo hits the fan.
 
your "hanging up" for a long time is the absorbsion time for the charge. the charger will fill them up to a specific voltage, and then hold them there for a while to let the chemistry settle down, and then continue to bulk charge them up towards 100%. if you don't give them time to settle down a bit, you get more electrolysis and more hydrogen and need to add more water more often.

karl
 
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