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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jcksparr0w7 years ago
 we had 8 days instead of 7
olddawg (author) 8 years ago
I'm in total agreement with the disconnect. It has always been my intention to do so once I have accomplished what I'm attempting to achieve. No worries bro, I will protect my linemen! I believe I misunderstood you before, but now get it on the source of the 220vac. I will look into this deeper. I thought of a reason why the other circuits didn't work and just checked out my theory a minutes ago. I will test it this weekend. All circuits that ran were close or next to the supply breaker. All those that didn't were the same or more distance away. My thought is to move up the priority circuits next to the supply breaker (which happens to be at the top of the panel). I'm thinking that each breaker causes an amount of resistance (even if not turned on) and reduced my power enough not to run these circuits (located towards the bottom of the panel.
olddawg (author) 8 years ago
This makes sense to me and it's what I thought (but not knowing) was happening. Now comes the question.... If this is created from 2- 110vac sources (breakers), then is it possible to re-create the same with my battery back-up by supplying only 110vac back to the panel (with wattage being equal to the 220vac consumption)? Until corrected, I believe my well only needs 880 watts to run. 880 watts means 74amps at 12vdc. My batteries should give 170 amps before reaching cut-out. 2500 watt inverter.... Am I undersized???
You have it all backward . This is not created from 2- 110 volt sources, there is 2 - 110 volt sources created from 1- 220 volt source .
Your batteries will power your well pump, No sweat, However the voltage must be 220-240 there is no way to connect 2 - 110 volt circuits to = 220, the white wire is always there. If you join the black leg and red leg You short circuit the transformer, if you use both black or both red with both white then the wires go to the same place and is still 110 volts. 2500 watts is equal to 3 horsepower after electrical losses are satisfied. Your well pump is not likely that big, But some are.
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......
110100101108 years ago
in the battery cells are in series you divide the current by the amount of parallel batteries not cells
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 ?
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