battery power question

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Old 04-16-14, 04:49 AM
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battery power question

I have a couple of extra sump pumps here so I don't need like a watchdog system however I would like to power one by battery.

What do I need to do that?

I was thinking a standard marine battery installation or maybe even a power inverter for my truck.... I have no idea where to start though and when I search I just keep coming up with the entire system pump and all.
 
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Old 04-16-14, 05:54 AM
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An inverter would work if you get the proper size. Don't forget the extra current a motor needs when starting and whatever amps your pump needs at 120 volts will be multiplied by 10 at 12 volts then add in the inefficiency of the inverter. You will need a lot of battery to run an AC pump for even a short while.

A 1/2 hp sump pump pulls about 5 amps when running (not starting) so that's about 50 amps from the battery. Then guess 20% conversion inefficiency for a good inverter and your pulling 60 amps from the battery. For the cost of batteries and an inverter I think a generator is a better way to power your sump pumps.
 
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Old 04-16-14, 09:27 AM
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avoid the watchdog systems like the plague. they are junk.

to inverter or not depends on your needs. do you expect long periods of time where the pump runs continuously under heavy water flow? if so, get a whole house generator that automatically kicks in (not the kind that requires you to throw a switch or something). this will cost you a lot of money. professional install, etc.

battery powered inverter systems are good for when you only expect intermittent pump loads -- say 10% duty cycle for up to several days, or continuous operation for less than a couple hours. (10% duty cycle is like the pump running once every 60 seconds, and draining the pit in 6 seconds while it runs). a marine deep cycle battery-powered inverter system can run a typical 1/2hp sump pump for 2-3 days at 10% duty cycle, with no household power. longer if you use more than 1 battery. I have such a system running a 1/2hp Zoeller M98 pump, and it has performed perfectly during power outages.

a few key points:
1. you need to get an inverter/charger. not just an inverter. the ones with built in 3-stage chargers will keep the battery properly charged during normal operation.

2. you need to get an inverter with a built-in automatic transfer switch. this keeps the pump connected to regular household power during normal operation, and automatically switches it over to inverter power when the power goes out.

3. you will need at least a 1200 watt inverter that can deliver at least 2x its rated power for short bursts. Tripplite inverters fit this bill nicely. such as the APS1250 for example.

4. get the marine batteries at Walmart. get fresh stock (they are date stamped). get group size 31 - they are the largest capacity. you can also use multiple batteries for extended runtime.

5. you will need very heavy gauge hook up wire for the batteries. 2/0 gauge. wire that thick is not easy to crimp a connector to. you will need to buy large crimp connectors and a tool called a swedge-on tool to make the crimps. like a lenco swedge on tool. get the wire on ebay. get the swedge-on tool at a welding supply house.

6. or you can buy an inverter that includes hook up cables, like Royal Power inverters, such as the Royal Power PIC-2000. they are lower quality than Tripplite, though. I have both a Royal Power and a Tripplite. they both work, but I trust the TL more.

if you search you'll find a thread where I posted all the details and pics of my setup. good luck.
 
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Old 04-17-14, 09:10 AM
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here's my setup:



- used (and donated) 48v APC battery backup unit
- 4 12V deep cycle marine batteries (these: Staab Battery Co Group 27DC Deep Cycle)
- dual 1/3 hp pumps, staggered in the pit (these: http://www.menards.com/main/plumbing...017-c-8673.htm)


I installed last Oct and haven't had an outage yet. The batteries are the highest AH rating I could find locally, at 105AH each. The pumps are rated at 4.1 amps each and since their staggered only 1 will run at a time. I haven't done the calculations, but I should get some good run times in the event of an outage.
 
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Old 04-22-14, 08:03 AM
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(10% duty cycle is like the pump running once every 60 seconds, and draining the pit in 6 seconds while it runs). a marine deep cycle battery-powered inverter system can run a typical 1/2hp sump pump for 2-3 days at 10% duty cycle, with no household power.

Read more: http://www.doityourself.com/forum/ne...#ixzz2zcxmyTP3
Skyjumper....I was thinking of doing the same thing as the OP and I want to make sure I'm understanding your information correctly. You're saying that if my sump pump was running once every minute, it could run for 2-3 days with only a single marine deep cycle battery and a power inverter? (I have a 1/2 hp pump). Thanks!!
 
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Old 04-22-14, 10:01 AM
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jeff I think you're right. i checked my math. with just a single marine battery you will only get 12-15 hours runtime at 10% duty cycle, according to the capacity & load calculations. although I will say this - mine was running on battery power at 10% duty cycle for about 8 hours and the batteries still measured 12.5 volts, which is >90% capacity remaining. and that was with a 3/4hp storm pro pump. but i do have 2 batteries. still, the field measurements would indicate the system could run for 80 hours under those conditions --- or 40 hours with a single battery. i don't know how to reconcile that with the theoretical calculations - maybe the published battery specs are conservative??

if you're worried about runtime you can just add more batteries in parallel.
 
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Old 04-22-14, 12:44 PM
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Sky jumper.....Wow, that's a lot more time than I assumed you'd get from a battery back up. Definitely something I will look into for my basement. Thank you for the information!!
 
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Old 05-13-14, 08:43 AM
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so I just tested this again. we had heavy thunderstorms yesterday and most of the night. I purposely unplugged my main pump/power supply from house power and ran it all night on battery power (driving the inverter). it was running every couple minutes all night.

this morning I checked and it was still pumping, and the batteries still measured 12.71V. which means the batteries are technically still fully charged, even after running a primary pump all night at 2-3 minute intervals. this is 2 marine deep cycle batteries connected in parallel. now, the batteries did measure 12.79V when i first unplugged the inverter from the wall - which means they were >100% charged to begin with. but 12.7V is considered 100% state of charge. these batteries can be discharged down to 11.58V before they need to be recharged.

so I left it unplugged. will check again when I get back from work.
 
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Old 05-14-14, 03:02 PM
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What inverter do you suggest Skyjump?
Can you post a link to a thread with your detailed setup?

I do have a generator but it woiuld be nice to be able to get an inverter setup where I wouldn't have to go outside in the dark if need be and fire up the generator.
 
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Old 05-15-14, 08:40 AM
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for the inverter, if you are using a 1/3hp pump I recommend the Tripp Lite APS1250. if you are using a 1/2hp or 3/4hp pump I recommend the Tripp Lite APS2012. Note that with the APS2012 it needs to be hardwired for the AC input and output, so you will need some wiring skills. both of these units have built in 3 stage battery chargers and automatic transfer switches.

you will see in my past posts that I used to recommend the Royal Power PIC-2000 inverter/charger. I still use mine, but the automatic transfer switch failed. I therefore do not recommend it anymore. I now have to use a separate battery charger to keep it charged. the inverter still works as an inverter.

here's a link with details of how to set up. read carefully. I now have 4 systems (2 in old house, 2 in new house - yes I am the unfortunate owner of 2 houses at the moment). you will see that one of my systems uses 2 golf cart batteries - they work great, but you will have to top up the water every so often as they do outgass while charging. going forward I will just use the standard maintenance free marine deep cycle batteries from walmart or Menards. just get fresh batteries that haven't been on the shelf for more than a couple months (they are date stamped) and pop off the tops when you first get them to ensure they are properly filled with electrolyte.

http://www.doityourself.com/forum/we...sump-pump.html
 
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Old 05-16-14, 04:05 AM
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Thanks Skijumper, I will definetly study your recommendations.

So why not just a portable generator? That is my main backup right now. I have only a single pump in the pit with a spare pump in storage. I have a generator in the garage that I can whell outside and hook up to an inlet on the side of the house which supplies an outlet by the pump.

What I am not thrilled about is that I have to be home and be awake to implement it. Is this a bad idea?
 
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Old 05-16-14, 11:51 AM
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What I am not thrilled about is that I have to be home and be awake to implement it...
that's why not a portable generator. inevitably you will be away from home some day or asleep while your sump gets inundated with water and the power goes out.
 
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Old 05-16-14, 12:53 PM
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I don't think a battery back up to a sump pump is a bad idea if your house is such that damage will result within a fairly short time (only you can decide what damage is acceptable and what time frame fits) of a power or pump failure. If the situation is as critical as you are implying then I would also invest in a power failure/pump failure alarm, preferably one that could call my cell phone, so as to alert me if I was away or wake me if I were asleep.

When I read these posts about sump pumps it makes me thank my lucky stars that I live in a house where a sump pump is unnecessary.
 
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