well backup system

[HuntingHawk]

Backround first. I have a deep well with 2" case pipe. Its a J-pump. 2HP 3 stage Starite.
Pump is 240VAC with surge power draw of 11.5amps.

I want to put together a solar emergency backup system for. Don't have the money for the build right now but would like to get it all figured out & get an idea of the price involved as well as some technical stuff.

I've thinking a 2000/4000watt inverter would be good enough alittle larger would be better but definately wanting pure sinewave & 60hz versus 50hz.

48 to 240 inverter is cheaper but I think I would be money ahead going with 12 to 240 just because I already have some solar that is 12VDC. Common parts such as solar panels & controlers can be a big asset down the road.

Anyone have any thoughts?
Ross

[J R Adams]

Backround first. I have a deep well with 2" case pipe. Its a J-pump. 2HP 3 stage Starite.
Pump is 240VAC with surge power draw of 11.5amps.

I want to put together a solar emergency backup system for. Don't have the money for the build right now but would like to get it all figured out & get an idea of the price involved as well as some technical stuff.

I've thinking a 2000/4000watt inverter would be good enough alittle larger would be better but definately wanting pure sinewave & 60hz versus 50hz.

48 to 240 inverter is cheaper but I think I would be money ahead going with 12 to 240 just because I already have some solar that is 12VDC. Common parts such as solar panels & controlers can be a big asset down the road.

Anyone have any thoughts?
Ross

Can four 12v pannels be wire in series to provide a 48v panel? I would think that the higher the DC voltage the lower the current, allowing the use of smaller wire.

[HuntingHawk]

You can purchase 48v panels then would need a 48v controller & those items wouldn't be interchangeable with the rest of the solar stuff I have.

Ross

[HuntingHawk]

Plus there would be a huge loss in the batteries. If I took four 12v 125AH batteries & wired them in series I would end up with 48v but only 125AH.

Take the same four batteries & wire them in parallel & you have 12v but 500AH.

I just think cheaper & more efficient to use the inverter to convert 12v to 240 rather then the loss in the battery AH to convert the batteries to 48 then inverter from 48 to 240.

Ross

[HuntingHawk]

Well, I called Sta-Rite to get a clarification on the power needs of the pump. The 11.5amps is the running amperage.

[HuntingHawk]

Here's the inverter that would take care of the pump needs.

http://www.topsalesdepot.com/bwapoin12vdc7.html

But this one may be the better choice due to surge amps.

http://www.topsalesdepot.com/bwapoin12vdc8.html

[Westcliffe01]

Nothing is created or lost in your comparison. The POWER available in watt hours is the same either way. But going series will save on copper and there will be less switching losses in the inverter due to the current being reduced by 4x and thus ohmic losses reduced by 16x. (resistance loss =IxIxR). The inverter "should" be cheaper due to the reduced current = smaller switching mosfets.

It "should" also be easier to balance the charging of the batteries when in series, whereas in parallel it can be difficult to balance unless one adds series resistors larger than the battery internal resistance. These then introduce their own losses.

Plus there would be a huge loss in the batteries. If I took four 12v 125AH batteries & wired them in series I would end up with 48v but only 125AH.

Take the same four batteries & wire them in parallel & you have 12v but 500AH.

I just think cheaper & more efficient to use the inverter to convert 12v to 240 rather then the loss in the battery AH to convert the batteries to 48 then inverter from 48 to 240.

Ross

[HuntingHawk]

I am at this time thinking solar electric isn't a good option for me due to what it would cost.

Ross