Doug/Vamonos
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Registered: 6-19-2006
Location: Bahia de los Angeles
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Best way to disconnect solar from batteries?
Hi. I'm away from Baja for several months at a time. And the electrolyte in my batteries gets low. I have 6 6-volt GC batteries set up for 12-volts. I
have two sets of panels that charge through 2 charge controllers. My idea is to disconnect the more powerful set and only leave the lesser panels
connected to the smaller charge controller to limit the charge to the batteries. Hope that made sense. My question is can I simply disconnect the +
and - cables that come out of the charge controller? Or is there a better way to separate the panels/charge controller from the batteries? I don't
want to do this via programming the charge controllers. Keep it simple. Somewhere I heard not to leave the panels in the sun and connected to nothing.
Thanks.
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willardguy
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I get what you're after but even with two charge controllers stacked a day after you leave they'll be at float, remove one and it'll still be a the
same float voltage.
for disconnects or combiners use quality marine battery switches (off-1-2-both)
[Edited on 12-15-2015 by willardguy]
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captkw
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small tip
car,truck,boat, RV, solar always disconnect the neg side first and hook up last at the battery 
[Edited on 12-15-2015 by captkw]
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rts551
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Willard has it. the voltage will be the same. You can disconnect the panels without damage to them. Just make sure they (the wires) do not short
out. (Nothing will be going into your batteries then).
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Bob and Susan
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actually you should have a 250A breaker from you solar panels to each charge controller...
just flip the breaker on one
you should have another 250a breaker from the inverter to the batteries too...flip that also
don't disconnect the batteries and don't use marine battery switches...your house is not a boat
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larryC
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Quote: Originally posted by Bob and Susan  | actually you should have a 250A breaker from you solar panels to each charge controller...
just flip the breaker on one
you should have another 250a breaker from the inverter to the batteries too...flip that also
don't disconnect the batteries and don't use marine battery switches...your house is not a boat |
A 250 amp breaker between the solar panels and the controller is a little large. Circuit breakers are designed to protect the wiring so if he had 12
gage wire from the panels to the controller then a 25 amp breaker should do it. That is for each panel to the controller. Between the controller and
batteries he should have a breaker large enough to allow all the current from the controller to pass into the batteries but not so large to allow the
wire to burn up in case of a malfunction. So wire size is also important.
To answer the OP question, he could either install a switch, circuit breaker or do it the old fashioned way and disconnect one or both of the wires.
The end result will be the same.
Larry
[Edited on 12-15-2015 by larryC]
Off grid, 12-190 watt evergreen solar panels on solar trackers, 2-3648 stacked Outback inverters, 610ah LiFePo4 48v battery bank, FM 60 and MX60
Outback charge controllers, X-240 Outback transformer for 240v from inverters, 6500 watt Kubota diesel generator.
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Bob and Susan
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that is actually true...the "snap" when removing the positive first can fry electronics
it is weird but true
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Bob and Susan
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| Quote: Originally posted by larryC | | Quote: Originally posted by Bob and Susan | actually you should have a 250A breaker from you solar panels to each charge controller...
just flip the breaker on one
you should have another 250a breaker from the inverter to the batteries too...flip that also
don't disconnect the batteries and don't use marine battery switches...your house is not a boat |
A 250 amp breaker between the solar panels and the controller is a little large. Circuit breakers are designed to protect the wiring so if he had 12
gage wire from the panels to the controller then a 25 amp breaker should do it. That is for each panel to the controller. Between the controller and
batteries he should have a breaker large enough to allow all the current from the controller to pass into the batteries but not so large to allow the
wire to burn up in case of a malfunction. So wire size is also important.
To answer the OP question, he could either install a switch, circuit breaker or do it the old fashioned way and disconnect one or both of the wires.
The end result will be the same.
Larry
[Edited on 12-15-2015 by larryC] |
25A too small...
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monoloco
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| Quote: Originally posted by Bob and Susan | | Quote: Originally posted by larryC | | Quote: Originally posted by Bob and Susan | actually you should have a 250A breaker from you solar panels to each charge controller...
just flip the breaker on one
you should have another 250a breaker from the inverter to the batteries too...flip that also
don't disconnect the batteries and don't use marine battery switches...your house is not a boat |
A 250 amp breaker between the solar panels and the controller is a little large. Circuit breakers are designed to protect the wiring so if he had 12
gage wire from the panels to the controller then a 25 amp breaker should do it. That is for each panel to the controller. Between the controller and
batteries he should have a breaker large enough to allow all the current from the controller to pass into the batteries but not so large to allow the
wire to burn up in case of a malfunction. So wire size is also important.
To answer the OP question, he could either install a switch, circuit breaker or do it the old fashioned way and disconnect one or both of the wires.
The end result will be the same.
Larry
[Edited on 12-15-2015 by larryC] |
25A too small...
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It all depends on the size of the array. To protect your equipment, the breaker should be sized just
slightly higher than the maximum output amperage of the panels. With a modern MPPT controller and panels wired in series, the amperage can be quite
low due to the higher output voltage, which also allows for the use of smaller gauge cabling to the charge controller.
"The future ain't what it used to be"
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weebray
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Negative terminal off first and on last - cuz - if your wrench happens to touch ground (a very real possibility) and you're working on the positive
terminal with the ground still attached the system goes in to "weld" mode.
Every beautiful beach in the world needs a few condo towers - NOT.
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willardguy
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look, dougs original question was simply "can I disconnect one of my solar arrays to lessen the current to my battery bank to slow the need for
watering". the answer is no.
now we have susan telling him to install 250amp breakers between panels and controller. really? 
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captkw
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OMG !!
Being I do this for a living and a specialist in electrical systems,,I am staying out of this...BUT,, did BOB just agree with me ??? raise the flags
and get the trumpets blarring !! LOL Since I had to edit the word "and" I will
throw this in; a 250 Amp fuse/circuit breaker ??????????? WTF ???
[Edited on 12-16-2015 by captkw]
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mtgoat666
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Posts: 18385
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Location: San Diego
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| Quote: Originally posted by Bob and Susan | | Quote: Originally posted by larryC | | Quote: Originally posted by Bob and Susan | actually you should have a 250A breaker from you solar panels to each charge controller...
just flip the breaker on one
you should have another 250a breaker from the inverter to the batteries too...flip that also
don't disconnect the batteries and don't use marine battery switches...your house is not a boat |
A 250 amp breaker between the solar panels and the controller is a little large. Circuit breakers are designed to protect the wiring so if he had 12
gage wire from the panels to the controller then a 25 amp breaker should do it. That is for each panel to the controller. Between the controller and
batteries he should have a breaker large enough to allow all the current from the controller to pass into the batteries but not so large to allow the
wire to burn up in case of a malfunction. So wire size is also important.
To answer the OP question, he could either install a switch, circuit breaker or do it the old fashioned way and disconnect one or both of the wires.
The end result will be the same.
Larry
[Edited on 12-15-2015 by larryC] |
25A too small...
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you guys dont know how many panels and the panel rating. you dont know if he has string inverters or a single inverter. you guys got no flocking
idea if he needs a 10, 20, 40 or 80 amp breaker!
the way he asked his question, i suspect he doesn't have any breakers
all he needs do is clip the wire, then rewire and wrap with duct tape when he comes back
if he's gone 6 months of the year, the panels would last longer if he took them out of the sun
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willardguy
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few are designed for DC use, and are clearly marked as such. the issue is arcing,DC switches and breakers use a Knife type switch to prevent this.
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healthdetective
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You can use Square D breakers but ONLY QO series as they are DC rated (not their Homeline series)
Here is a video (not mine) that goes into it:
https://www.youtube.com/watch?v=ZkSk4Go2ACo
I recently hooked up a wind generator this way with great success
�The average man does not want to be free. He simply wants to be safe.� � Mencken
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captkw
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GRrr
switchs are always on the positive side and if you want to be ahead of the game use:" Blue sea marine" parts..no its not a boat but we have been using
solar stuff in/on boats long before houses...FACT and marine grade is the way to go if your any where near the coast (DUH)...Hey Billy bob,, just
twist those wires together......NOT !!
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mtgoat666
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| Quote: Originally posted by captkw | | switchs are always on the positive side and if you want to be ahead of the game use:" Blue sea marine" parts..no its not a boat but we have been using
solar stuff in/on boats long before houses...FACT and marine grade is the way to go if your any where near the coast (DUH)...Hey Billy bob,, just
twist those wires together......NOT !! |
Cappy, this is Mexico, anything that works is fine! Twisting wire accomplishes same thing as a switch!
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captkw
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Yo Goat
Ya,, your right,,BUT. in a normal little room with controller and batts that are "gassing" while being charged// I would use marine parts as they will
hold up in the long run with almost no failures and are ignition protected,, aka no spark to go Boom,Boom...Cant tell how many propane tanks that I
have seen hooked up with car fuel line and hose clamps...just not the way I roll
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Doug/Vamonos
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Location: Bahia de los Angeles
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You guys kill me! Too funny. Didn't mean to start all this! :-)
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Pescador
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Yeah, I read through the whole thing and figure if I ever need some solar help, I will use Bob Frambes cause he runs his whole place on Solar. Now
as far as the Cappy is concerned, I suspect he was filtering a little too much Sterno through bread slices in his younger days.
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