politics123
Active Member
My example is for a sump pump, but really, this is about providing inexpensive back-up power to any small motors, fridges, etc.
My sump pump runs on 120v AC power. We don't lose power often (1-2x per year), but if that were to happen during a rainstorm, my basement would flood with water. In the future, I'll install either a generator or a whole-house UPS (with solar) and also a redundant sump pump, but those projects are expensive, and I'm thinking, in the short-term, I could get by with spending a lot less. I also found a few battery-backup sump pump systems ($500 or so without the battery), all of which require installing a second pump -- which are also expensive, and have questionable pump reliability.
Anyway, I have two options:
A) Connect invert to battery and whenever we lose power, manually turn on the inverter, manually unplug the sump pump from the wall, and manually plug it into the inverter. Then, when power is restored, I can plug the sump pump back into the wall.
B ) Using a 3-way lightswitch, perform all the electrical work, but still have to turn-on the inverter and flip the sump pump to run on its secondary power source.
C ) Automate!
Obviously, since I'm an active participant here, there's only one way to go. Note: I'd like to automate the power supply to the sump pump (but let the sump pump continue to run based on its float switch)
Here's the assets I have:
1) 1/4HP Sump Pump
2) Elk M1 Gold
3) Duracell (Xantrex) 1000 watt inverter (2000 watt surge). Cost me $45 from Amazon from amazon... couldn't refuse, since if this project fails the inverter will also come in handy while camping... you know, to power my portable M1 gold system... I set of strobes and an alarm if any racoons come close to my picnic basket! JK! (PS Not a half-bad idea, though)
Here's the assets I need to acquire:
1) 12v deep cycle battery (since cost is an issue, I'm thinking of either flooded or sealed, not AGM or GELL)
2) relays/switches
3) battery charger
Design Requirements:
1) This is for an existing 1/6HP (120v AC) sump pump, but I'm seriously thinking about upgrading this to a high-quality 1/3 HP
2) Sump should always run on normal household AC when there is AC power to its circuit.
3) Sump should run off of 12v DC battery + Inverter when there isn't AC power to the house. This doens't need to be an instant cut-over... within 60 seconds is fine.
4) When AC power is reestablished after an outtage, the power should revert back to household AC. This also doesn't have to be instant cut-over.
5) At no time should the sump be connected to both AC power and the inverter power (even momentarily).
6) Ideally, the inverter should be disconnected from the battery until power is lost and the inverter is needed. This will prevent unwanted discharge (300mA) when there is no load
7) Also, I'll be acquiring a battery charger. I could spend a bunch of money on a top-end charger that maintains a battery at peak charge, or I can buy a cheapo unit and automate it such that it charges the battery for 24 hrs every 2 weeks.
I attached a quick schematic of how I think this should be connected
Questions
1) Is there a problem connecting the inverter ground to household AC ground?
2) The ELK-912 and 924 relays might work --> they can be powered either from my ELK (with a rule) or from a wall-wart plugged into the same circuit as the sump pump is currently. They support 40amp in-rush and are rated for a 1/4 HP motor... which is what I have. However, if I wanted to upgrade my sump to 1/3 HP, I'd need a different set of relays. Anyone know of a good source for slightly higher amperage, but still inexpensive, relays? These need to be form c relays, right (break before contact)?
3) I can use the ELK-924 as a DPST switch, right? I just don't connect anything to the other pole?
4) Besides relays, does anyone know of a manu-matic switch that could be used. eg: is there a true 3-way automated (eg: zwave) light-switch that can be repurposed as a DPDT switch?
Estimate Project Costs:
Relays: 2-3 relays... around $30
Battery: $50-$100 (depending on reserve capacity and whether I do flooded, sealed, AGL, or GELL)
Charger: $50 or so for Battery Tender (able to leave connected), $15 for cheapo-charger (which I could regulate using an optional SPST switch)
Inverter: $45
Misc Romex cable and a spare power outlet: got plenty
Total between $150 and $250.
My sump pump runs on 120v AC power. We don't lose power often (1-2x per year), but if that were to happen during a rainstorm, my basement would flood with water. In the future, I'll install either a generator or a whole-house UPS (with solar) and also a redundant sump pump, but those projects are expensive, and I'm thinking, in the short-term, I could get by with spending a lot less. I also found a few battery-backup sump pump systems ($500 or so without the battery), all of which require installing a second pump -- which are also expensive, and have questionable pump reliability.
Anyway, I have two options:
A) Connect invert to battery and whenever we lose power, manually turn on the inverter, manually unplug the sump pump from the wall, and manually plug it into the inverter. Then, when power is restored, I can plug the sump pump back into the wall.
B ) Using a 3-way lightswitch, perform all the electrical work, but still have to turn-on the inverter and flip the sump pump to run on its secondary power source.
C ) Automate!
Obviously, since I'm an active participant here, there's only one way to go. Note: I'd like to automate the power supply to the sump pump (but let the sump pump continue to run based on its float switch)
Here's the assets I have:
1) 1/4HP Sump Pump
2) Elk M1 Gold
3) Duracell (Xantrex) 1000 watt inverter (2000 watt surge). Cost me $45 from Amazon from amazon... couldn't refuse, since if this project fails the inverter will also come in handy while camping... you know, to power my portable M1 gold system... I set of strobes and an alarm if any racoons come close to my picnic basket! JK! (PS Not a half-bad idea, though)
Here's the assets I need to acquire:
1) 12v deep cycle battery (since cost is an issue, I'm thinking of either flooded or sealed, not AGM or GELL)
2) relays/switches
3) battery charger
Design Requirements:
1) This is for an existing 1/6HP (120v AC) sump pump, but I'm seriously thinking about upgrading this to a high-quality 1/3 HP
2) Sump should always run on normal household AC when there is AC power to its circuit.
3) Sump should run off of 12v DC battery + Inverter when there isn't AC power to the house. This doens't need to be an instant cut-over... within 60 seconds is fine.
4) When AC power is reestablished after an outtage, the power should revert back to household AC. This also doesn't have to be instant cut-over.
5) At no time should the sump be connected to both AC power and the inverter power (even momentarily).
6) Ideally, the inverter should be disconnected from the battery until power is lost and the inverter is needed. This will prevent unwanted discharge (300mA) when there is no load
7) Also, I'll be acquiring a battery charger. I could spend a bunch of money on a top-end charger that maintains a battery at peak charge, or I can buy a cheapo unit and automate it such that it charges the battery for 24 hrs every 2 weeks.
I attached a quick schematic of how I think this should be connected
Questions
1) Is there a problem connecting the inverter ground to household AC ground?
2) The ELK-912 and 924 relays might work --> they can be powered either from my ELK (with a rule) or from a wall-wart plugged into the same circuit as the sump pump is currently. They support 40amp in-rush and are rated for a 1/4 HP motor... which is what I have. However, if I wanted to upgrade my sump to 1/3 HP, I'd need a different set of relays. Anyone know of a good source for slightly higher amperage, but still inexpensive, relays? These need to be form c relays, right (break before contact)?
3) I can use the ELK-924 as a DPST switch, right? I just don't connect anything to the other pole?
4) Besides relays, does anyone know of a manu-matic switch that could be used. eg: is there a true 3-way automated (eg: zwave) light-switch that can be repurposed as a DPDT switch?
Estimate Project Costs:
Relays: 2-3 relays... around $30
Battery: $50-$100 (depending on reserve capacity and whether I do flooded, sealed, AGL, or GELL)
Charger: $50 or so for Battery Tender (able to leave connected), $15 for cheapo-charger (which I could regulate using an optional SPST switch)
Inverter: $45
Misc Romex cable and a spare power outlet: got plenty
Total between $150 and $250.