solar instulation

[tommu56]

RonMar
There is dc brakers box for each load and charge controller to the buss so the cable would have to fail or something like that.

Tom

 

[BTDT]

New co. here in TX may hit it big in solar. They will install enough solar on you roof to generate excess during the day which they sell to grid. At nite you run on grid. No batteries. $500 deposit refunded with interest at end of term (1 to 20 yrs). NO INSTALLATION charge and they gurantee you current electric rate for the term of agreement. They expect to make enough money on excess generated during day to cover your use at nite and show a profit. They could end up with a massive solar field and no land cost. Plant yet to be built so it is to early to know if this is ever even going get off ground

I'm interested. Any more info? Who gets the rebates, installer co. or homeowner?

 

[tommu56]

Hey Tom,
Great pictures man, who took them? Is that you up on that slippery roof? Be careful.
Your system looks pretty good from what I can see. Lots of battery storage. I see you got the spill proof tubs to put them in too. Did you go with the hydrogen caps?
Wish you had a webcam for us to see the whole thing.

Rob
Thanks for the concerin!

Ironically the weekend before I drilled from inside to mark were a joist was so I could mount brackets to them I walked up the roof from the lower roof with out a problem on the way back down I started sliding went off that roof to the lower. It's roof pitch is the other way caugh a rib and started rolling down that roof the hiting the skylight and grabing the ladder kept me from hitting the ground.

I have done it 100's of times on the other side of roof the main roof is 8/12 and and the porch is 4/12 but in the same direction so if I slide I stop on lower pitch with out a proble. I didn't even think about the ridge being 90 off the other roof or the drop from one to the other. I thought I would stop. That is why I put roof brackets and chinken ladders up this weekend.

Yea I didn't find any trays for the batterys yet that would fit in the battery box I'll keep looking.


The guys at backwoods solar didn't recomend the hydro caps but I did ask.

tom

 

[RonMar]

RonMar
There is dc brakers box for each load and charge controller to the buss so the cable would have to fail or something like that.

Tom

Tom
I am trying to get my brain around your system wiring. Do you have a wiring diagram? Is there an individual controller(and associated circuit breaker) for each 12V pair of batteries? Because if not, there is a lot of potential for severe damage. If the 12V pairs are just connected to the main 12V buss, you could in theory disconnect a pair and connect a motor in their place and it would draw power from the buss and three remaining 12V sets, just as your inverters do. A shorted battery or feedline on any of the 12V pairs could do the same thing and with large gauge wires, could draw ALL the available power from the other 3 sets VERY quickly. You have enough arc welding potential there to build a good sized steel structure Without fuses to isolate each cell, it has a VERY large potential for catastrophe. With the battery box lined with foam insulation, you would have a very hot fire. will your main building survive a battery box fire?

 

[tommu56]

Ron

its the same as a Traction battery for a forklift just wired a little different (they usually are in series "18: 2v cells to get 36 volts

Mine are "2" 6 volt in series to get 12volts and 4 sets in parralle to keep 12 volts but the current adds up that way.
Just like in my disel truck 2 12v in parralle for the juce to turn it over.

The invertor has a 12 volt input and an output of 120v at 2800 watts thereis a 250 amp breaker in line to stop that from being overloaded.

The invertor (outback) is protected internally and will shut dow in current or temp gets too high it is also the transfer switch and battery charger the generator hooks to it and will switch load to generator when running and if more generator power is avaiable it can charge at 100 amps back in to bank

tom

 

[RonMar]

That one circuit breaker on the inverter input would be sufficient to protect a single 12V series circuit as if you break a series circuit at any point, you interrupt current flow. But you are feeding yours with four parallel circuits.

Batteries can and do short internally. Without a fuseable link on each of your four 12V series battery pairs, you have the makings for a bomb! If one cell in one of those 12V pairs shorts, or you slip with a tool and cause a short, this will lower the voltage and resistance of that pair below the 12 buss voltage. This lesser voltage and lower resistance will be seen by the other three 12V pairs as an electrical load. Just as a weaker battery in a parallel circuit will suck up more charge current and rob energy from the stronger cells when not charging, the stronger 12V pairs will attempt to power this "load". With approx 1260AH of uncontrolled/unswitchable supply available in the three unshorted 12V pairs, They will feed this need up to the limits of that really large wiring. I would estimate that 1260AH pack can deliver many times that current(5-6 THOUSAND amps) in an instant. This means that that dropped wrench is going to weld itself inplace, turn red in about as much time as it takes to snap your fingers, and melt... Or it may skip a few of these steps and go right to spraying molten metal...

Here is a basic theory link. The diagrams and description you should be interested in are down about the middle of the page... There just happens to be a 4 battery parallel circuit with load diagram that is probably similar to what you have with your four 12V pairs and inverter. Note the 5 fuses used. The main load fuse is the largest as it should be the one that sees the most current in normal use and should be sized to carry the normal load current. It protects from a short in the load(inverter). The fuse on each battery should be approx 1/4 the size of the main load fuse as each 12V pair should only see 1/4 of the electrical load of the 12V buss during normal use.
Practical considerations : BATTERIES AND POWER SYSTEMS

I know my buildings and safety are certainly worth a couple of fuses.

Good Luck.

 

[tommu56]

Ron
I have been an electrician for over 30 years in that case you propose then any large parallel wire runs would have to have each wire protected individually!
It is common practice to parallel wires and have them on one large over current device as we wouldn't be able to work with the wires that large the NEC has provisions to cover that type of insulation.

I will take the fuse idea in to consideration.


tom

 

[Buckeye_Jim]

Tom,

I take it that your home is in Limerick, while your getaway place is in Lycoming County. What a beautiful place. My company installed a flood warning system all over the county in 2003. I spent a very nice couple of months there. While the mountains of Northern California is my home, an easy second choice would be Lycoming County. Here is a link the system there:
DataWise River and Stream Levels

Regards

Jim

 

[tommu56]

Jim
I am just above a flood control dam in the county

Here is a picture while I was up on the roof looking east


tom

 

[3RRL]

Oh man,
That's like a scene out of a movie. How beautiful Tom.