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Forum topic by Imacman posted 09-04-2010 02:36 AM 1466 views 1 time favorited 27 replies Add to Favorites Watch
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Imacman

55 posts in 2286 days


09-04-2010 02:36 AM

Hello All… wasn’t really sure where to post this, so I’ll try here, seeing as it involves electric power and safety.
My shop is under construction, and I plan on running the wire this weekend. I have more than a basic knowledge of power…but not a whole lot more. here’s my question,.....

• The plan is to install a power inverter in the shop to suppliment my power needs, with the goal being to have a self sufficient building. I will be installing two 100 watt solar cells on the roof that will charge 6 Deep cycle batteries wired in parrallel, In addition to this I will have an “Intelligent Charger” wired to the setup to ensure the batteries are always topped up. I am also running a power cord from the house to the workshop, this cord is on a 15 amp breaker (120v ) inside the house. What I would like to do is have both the power from the inverter, and the power from the house run to a switch that I can switch between “Grid Power” and “Inverter Power”.... the power from this switch would then be routed to a small pony panel, that would in turn be wired to the outlets and lights in my workshop. The pony panel will serve obviously as a power distribution point…but also as a main breaker so I don’t have to leave the shed and go back into my basement every time I pop a breaker…lol…Lazy lazy I know…lol. So my question is this, is there a switch that will do what I require…or will I have to rig something up?.. ( I Know… I don’t like the sounds of “Rig something up” either…lol ) If so what is it called??.. I’m thinking Double Pole, Double throw?? Any help and or suggestions is greatly appreciated!

Thanks

Paul ( Imacman )

Newfoundland

-- It's about the Journey....not the destination.


27 replies so far

View canadianchips's profile

canadianchips

2345 posts in 2458 days


#1 posted 09-04-2010 02:47 AM

Yes there is such a switch.
By code you are required to install a switch that will prevent any power (generator, solar or whatever) entering the grid. IF THE LINEMEN are working on GRID and they cut your power you DO NOT WANT your supply going into their GRID.
f I recall the name of the switch you are wanting to use is aTRANSFER SWITCH. If this is wired properly it should prevent backfeeding into the main line and possibly killing a lineman working.
Contact an electrician ! Do this properly.

-- "My mission in life - make everyone smile !"

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Imacman

55 posts in 2286 days


#2 posted 09-04-2010 02:59 AM

Ahhh very good point, Although I’ll be running the wiring myself, I will have a qualified electrician finish and connect it all, If the information thats been given to me by the “Solar power guys” is accurate I won’t actually need the Grid power… if thats the case, i’ll be having the electrician / power company install a grid tie in, so i can startv selling the excess power back to them!...lol… thanks for the reply.

Paul

-- It's about the Journey....not the destination.

View Chriskmb5150's profile

Chriskmb5150

253 posts in 2536 days


#3 posted 09-04-2010 04:17 AM

I used a double pole, double throw switch similar to THIS ONE in my old house. We get crazy storms around here so I used it on the main to switch between grid power and a 10KW generator when the lights went out. Im a master HVAC mechanic so im familiar with electrical but i made sure to get an electrician to check my wiring as should you.
Good luck

-- Woodworkers theory of relativity - the quality of your scrap is relative to your skill level

View Mark Shymanski's profile

Mark Shymanski

5314 posts in 3173 days


#4 posted 09-04-2010 02:44 PM

200 watts does not sound like a lot of power, will this be sufficient for your shop?

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

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Imacman

55 posts in 2286 days


#5 posted 09-04-2010 06:11 PM

Hi Mark, the Solar Charging Panels are 200 watts total, so that’s 200 watts of charging power, keeping a Battery Bank Charged, The actual power availble to me will be 3500 Watts Continous with 7000 watts Peak, So it would be similar to running off of a 3500 Watt Generator that can actually hand more.. ( Start Up Voltages )

Cheers

Paul

-- It's about the Journey....not the destination.

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Mark Shymanski

5314 posts in 3173 days


#6 posted 09-04-2010 09:04 PM

Ahhh, I thought you would probably have thought about that :-)

-- "Checking for square? What madness is this! The cabinet is square because I will it to be so!" Jeremy Greiner LJ Topic#20953 2011 Feb 2

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GPM

26 posts in 2291 days


#7 posted 09-13-2010 01:56 AM

I don’t know where you live but most utility companies now must allow “net metering” which means you can store your solar power with them instead of batteries. What that means is when you are producing power by the panels and it isn’t needed it turns your meter backwards. So later when you use power you are first using up what you gave to the utility company. In the end this is much cheaper and easier than batteries. Batteries are a pain and require maintenance and constant replacement.

There are complete simple kits to do a utility interconnect. You are allowed to do most of the work yourself and then have an electrician review it. Then the power company will check it and if it is OK they will allow you to connect.

View BertFlores58's profile

BertFlores58

1684 posts in 2383 days


#8 posted 09-13-2010 03:13 AM

I think the best will be a relay contactor. This is very safe because one power can be use in one time. There is no danger of switching both. Single throw and double pole is all you need. There are switches available but very rigid when it comes to bigger power requirements. You can have a relay contactor and the coil switch will just be a normal selector switch needing only a small current. Coil switch can also be fitted with automatic control sensors such as photo sensitive switches, underpower switches (meaning if the power from solar is not enough then switches back to outside power) and many others… However you have to ensure that there must be a delayed loading of your equipments.. otherwise there will be a big surge of current to your lines and contactor which will overload. For added protection to the contactor there are some current rating overload relay that can be connected directly to the relay.. Hope this help.

-- Bert

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TopamaxSurvivor

17654 posts in 3136 days


#9 posted 09-13-2010 09:21 PM

200 watts of charging power isn’t going to keep up with much use off the inverter. I know people who live off the grid. They use generators for most everything that uses a motor. 200 watts isn’t going to power your shop for much more than lighting.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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Imacman

55 posts in 2286 days


#10 posted 09-13-2010 10:23 PM

Thanks For the Info GPM and BERT, I will discuss with the electrician,

TOPMAX, Thanks for the response, I must have not been clear when I worded my “Power Setup explanation”. The available power to me is Not 200 watts… the available power is 3500 Watts Continious with a 7000 Watt Peak for surge & start up voltages… ie a refridgerator will spike to maybe 6000 Watts at startup then settle at it’s nomal operating current draw. The 200 Watts comes from two 100 watt Solar panels… these solar panels are hooked to a charge controller…. that is hooked to 4 Deep Cycle batteries…. these batteries are hooked to my 3500 watt Inverter. The charge controller monitors the batteries, and feeds a 200 Watt charging current to the batteries as needed….once the batteries are full it automatically shuts off. So the 200 watts is charging power. On a sunny day from sun up to say 6:00pm the charge controller will be topping up the storage batteries. Most of my work would be done in the evenings & nights, so the storage batteries will charge up all day with no current being drained from them. In addition I will have an itelligent charger hooked in that I can switch on at any time to charge the storage batteries..for dyas when there is no sun. so the charging current from the solar cells is greatly reduced. Hope this makes more snese.

Paul
Imacman

-- It's about the Journey....not the destination.

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Imacman

55 posts in 2286 days


#11 posted 09-13-2010 10:34 PM

I reread your post Topamax…. I think I see what you’re saying….. I wondered if 200 watts of charge would be enough as well, the Solar cell Company told me that fro my application 200 wats will be more than enough. for example, a fully charged storage battery set up… can run my lights, and say one power tool for maybe 3 hours… doesn’t seem like a long time…. but on any project build, the tools are actually only in operation for only a few minutes and in most cases only seconds. At the end of the day, if the inverter / solar set up can only run my lights and computers I’ll still be happy enough with that. having said that, The Solar Cell company tells me that my set up will be more than adequate…lol… but as they say… ” the proof is in the pudding”. the biggest factor is ofcourse how many Storage batteries are wired together in parrallel…. the more batteries the longer one can operate the inverter..and the less drain on each individual cell. the batts Are about $100 each, I plan on starting with 4 but I’ll probably continue to add Batts until I have enough to not have to worry about it. Any thoughts and suggestions are greatly appreciated.

Paul

Imacman

-- It's about the Journey....not the destination.

View TopamaxSurvivor's profile

TopamaxSurvivor

17654 posts in 3136 days


#12 posted 09-13-2010 10:38 PM

I understood all of that. 200 watts of charging will take quite a while to put 3500 watts of power back into the system. For running small loads like lighting, computers, ect it should be fine. Running motors for shop equipment, i think you will be disappointed with the 200 watt input to this system.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View PurpLev's profile

PurpLev

8523 posts in 3109 days


#13 posted 09-13-2010 10:43 PM

I’ll second Topamax. not only that – Once you discover the power of power (no pun intended) you may want a more powerfull saw, or another power tool to add to the team… add DC to that (which run almost constantly at peak performance and for the longest time in the shop) – and you’ll be running out of batteries quickly.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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TopamaxSurvivor

17654 posts in 3136 days


#14 posted 09-13-2010 10:55 PM

I suppose I should mention I live off the grid in our RV quite a bit of the tiime. I have considered solar charging for our batteries. I usually run the generator at least 2 hours a day for charging. When I see 5 amps on the 120 volt ammeter, I know there is no way I could keep up using solar without a very substantial investment. I would need to have 6 hours of 200 watts minimum and I am not trying to run power saws or other equipment. The other people in the area use generators to pump water from their wells. They don’t try to run power tools off their solar systems. I have talked to them about their experieinces, solar is over rated as to teh ampunt of power you can collect and save even though the cells are 1000 times more efficient than they were 10 years ago.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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Imacman

55 posts in 2286 days


#15 posted 09-13-2010 11:00 PM

lol.. I’ll third the motion!...lol…. charging dead batts with 200 watts will probably take days… no doubt. The viablilty of it will all depend on usage and current drain of course, The Automatic switching between charging devices will hopefully keep the batteries closer to full than empty. the solar cells will have all day to top up the charge and if they don’t do it, the switching circuit as suggested by Bert, will kick in the Heavy duty charger over night to keep them at peak. I’m pretty sure that this set up will at least run my lights and computers and a few small power tools for a few minutes….. but it would be hard pressed to run my 15 Amp table saw for very long I’m sure…lol… All I know is… my; little “Alternate Energy” project is sure to make an interesting one…. next step…. add a DIY HHO Cell to run my 4000 watt Generator!...lol.. I’m reading amazing things about that stuff as well.

Paul

Immacman

-- It's about the Journey....not the destination.

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