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Back-up power

Hey there folks! Looking for some advise again. NH just went through the worst power outage in years (maybe history). 6 days without power has me thinking again. I have means of heat (wood stove) and means of cooking (propane) and lighting (candles and my LED projects), but the well pump is a problem. The need of water to flush the toilets came from the stream nearby, all well and good as it was, washing our bodies from buckets has to go. I have learned that my 220vac well pump actually draws it's power from 2 110 vac circuits. If I have this right (which is my first question, is this even possible) I only need a 110vac converter to run this off my batteries. Now, if I'm correct here (second question) a 4amp 220vac pump is 880 watts, then the draw from the 12vdc battery should be 74amps (give a few for losses maybe 80 amps). I only have 2 160AH deep cell batteries running currently. Am I looking at a reality of 2 hrs (half the draw) or 4 hrs use (full draw)? Or, is it even less.... Yup, that was a third question! I just bought a 2500 (5000 max) watt inverter intended for the shop and thought I would use this as my back-up for the winter. Am i even close here?

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jcksparr0w6 years ago
 we had 8 days instead of 7
olddawg (author) 8 years ago
Just completed the test run and here are the results; System is; 2 Werker Type 31 deep cycle batteries Run in parallel To a Cobra CPI 2575 2500 / 5000 max watt inverter Run through a 12g 5ft cord to the utility outlet next to the panel Main is turned off, utility is a 12g wire run through a 20amp breaker This gives me my back feed to power the panel. Basement lights YES! Florescent units run in pairs and 3 sets (wattage aprox. 170 watts) Water heater YES! Ondemand style needing little power to run (looked like 70 watts) Dining Room light YES! 4 CFL's 27(?) watts each Hallway upstairs light (standard 110vac 100watt can light) YES! Good news has now ended..... I ran each circuit that worked separately, then all together and they all worked. But all other circuits failed. I have a kitchen circuit run on 15amp breaker that should have operated a single CFL light (all other appliances unplugged) and it failed. Bath room circuit running 3 CFL's and it failed. Bedroom circut running the alarm clock only! That failed. I'm missing something here and I can not put my finger on it..... I ran one circuit at a time, when it failed, turned off (unplugged) everything possible in that circuit and tried again bringing up the least powerful item first. The failed areas just would not come up.... Any thoughts here? My mind is racing with possibilities, but a clear mind would really help about now......
olddawg (author) 8 years ago
Big test comes tomorrow! Everything is here now and spent the day hooking it all up, including re-wiring the charge controller. I've come into yet another question for ya'll; Is there a basis on the RC rating? I seem to be in a conflict between batteries due to this. Are all RC ratings based on 25amp usage? My Werker batteries state based on 25amp usage. My Eveready (Pep Boys) does not state amperage.....
olddawg (author) 8 years ago
There's been quite a discussion here on my post and I wish to thank you all for your input. My inverter has not arrived yet, bummer, for I was hoping to experiment this weekend and learn the truth of my well power. I have returned to the basement and searched out all the wiring again to find the 220 vac line to the well. I can not find one. What I do have is 2 110vac breakers wired to 12g wire marked well and 1 runs directly to the control box (that gray box), the other runs through an outlet and ends in the same gray box. Today's quest (since the inverter is not here) is to volt test the incoming lines and test the out going to the well. I'll post up the results later.
tech-king8 years ago
discharging a battery fully is hard on a battery. even the best of deep cell units can only handle about 300 full discharge-charge cycles before being ruined.
if the battery is only for backup (not frequent use) then its ok (it got limited lifetime anyway so no justification to save cycles) but if there is a battery why not employ it for full time in some green project ?
yes it does hurt the battery. every full discharge charge cycle lowers the battery ah capacity. if you like, i can even post a graph
i meant something like this your battery is 50 AH. each too deep discharge takes away 0.5 AH. max battery life (in optimal other conditions) is 5 years you use the battery for backup only. you dischage it 10 times a year after year 1 its 45 ah at end of life (when it got high internal resistance and other problems anyway) it still got half its original capacity with less recent outages you use the battery less and it gets to end of life with higher capacity its not justified to save on discharge cycles cause youll recycle the battery anyway before you kill it too much with the discharges BUT isnt it just waste of battery to keep it for backup only ? you better use it all the time for a solar or wind project and do save discharge cycles
30% is enough to lower th ah. i think i will post the graph when i find it
gmoon8 years ago
I heard from a lot of relative in N.E. after the ice storm. Most modern gas furnaces have electric spark starters; my uncle has an old-school pilot light and his gas heat worked fine, while his neighbor froze... Although I have no idea how your pump is wired, it wouldn't be rated 220/240 unless the full voltage was needed. Of course, you cannot take a single 120 line and place it in series with itself and get 240V... ;-) That would result in a short. AFAIK, in the US the mains enter the house as 220-240V with a center tap. Half the 120V house wiring comes from one side of the 240V, half from the other...
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