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ncampion
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Registered: 4-15-2006
Location: Loreto
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Mood: Retired and Loving it
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Quote: Originally posted by Bob and Susan  | larryC...if it works for you it works...but
you could wire the panels together and bring down the current at 48v
the fm80 will convert it to 12v to charge the batteries
i'm pretty sure you can bring down 5000w
you have about 2400w
as for the slave "going to sleep"...my stacked inverters never did
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It's not the current down from the panels, I imagine Larry has that running at high voltage/low current, it's the current out to the batteries which
has to be at 12 volts.
If the slave does not go to sleep, it is a programming problem.
Living Large in Loreto. Off-grid and happy.
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Bob and Susan
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i was using trace units when i stacked...they both failed...i repaired both now they are my 2 back ups
the fm80 is the controller...it takes current from the panels to charge the batteries...higher current down (72v) means a smaller wire and
cooler...less resistance
the charge controler (fm80) then charges the batteries at 12v
the voltage to the inverter is always the same 12v
using a welder with an inverter is incrediable ...
i don't have the guts
he probably bought more panels and his fm60 couldn't handle the extra current so he added another charge controller
now the 2 controllers fight each other about what condition the batteries are in voltage wise...one "fools" the other
i did that too...a mistake
but not a big one
i just split my system into 2 parts
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larryC
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| Quote: Originally posted by Bob and Susan | larryC...if it works for you it works...but
you could wire the panels together and bring down the current at 48v
the fm80 will convert it to 12v to charge the batteries
i'm pretty sure you can bring down 5000w
you have about 2400w
as for the slave "going to sleep"...my stacked inverters never did
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Bob
My panels are wired is series/parallel and run at about 65v into the charge controller. The hang up is out from the controller to the batteries. The
fm80 will only put out 80 amps, it doesn't care what the battery voltage is 12, 24, or 48v. So 80 amps at 12v is all I get. The mx 60 will put 70 amps
out to the batteries. Total I get 150 amps at 12v (on a good day) to charge the batteries. If I had a 24v system my panels could supply 75 amps at 24v
and the fm 80 could handle that by itself and I would have saved the cost of a second charge controller and the cost of some large wire from the
controller to the batteries. That's just the disadvantage of a 12v system.
As far as the welder, it has not been a problem. It is a 120v Hobart Handler mig welder. I tried to use my 220v volt 175 amp mig but it draws too much
power for the inverters and blows both 250 amp circuit breakers so I have to run the generator when I run the big welder.
I agree with ncampion if your slave inverter wouldn't go to sleep then either there was a software problem or your master inverter was putting out so
much all the time that the slave always thought it needed to be on. My slave wakes up when the master puts out more than 10 amps of AC. I imagine that
with your system and trying to run a hotel with guests that are not used to being off grid that a lot more power gets wasted at your place than mine.
It has got to be tough to run an off grid hotel. And the internet must drive you nuts trying to stay below your bandwidth limit. More power to you.
Larry
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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Alm
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| Quote: Originally posted by larryC | | The fm80 will only put out 80 amps, it doesn't care what the battery voltage is 12, 24, or 48v. So 80 amps at 12v is all I get.
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Yep. 12V bank limits the post-controller solar output from the Master to roughly 1000W, and current to battery is high. 24 or 48V bank would allow
larger solar wattage and/or lower current. A lot of people are stuck with 12V system - the rationale being "it works, don't fix it" - but new homes
are usually higher voltage.
[Edited on 5-13-2015 by Alm]
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BigWooo
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| Quote: Originally posted by Alm | | Quote: Originally posted by larryC | | The fm80 will only put out 80 amps, it doesn't care what the battery voltage is 12, 24, or 48v. So 80 amps at 12v is all I get.
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Yep. 12V bank limits the post-controller solar output from the Master to roughly 1000W, and current to battery is high. 24 or 48V bank would allow
larger solar wattage and/or lower current. A lot of people are stuck with 12V system - the rationale being "it works, don't fix it" - but new homes
are usually higher voltage.
[Edited on 5-13-2015 by Alm] |
I'm in the same boat. Started off when 12v was the only thing available and kept expanding. Someday I'm going to replace my 12 volt inverters with 48
volt and get rid of a few charge controllers. 48 volts would make charging the batteries much more efficient. A ton of 12volt batteries in parallel
isn't a very efficient charging scenario, but it works. Every time I expanded it was cheaper to buy an additional charge controller than replace two
inverters.
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BigWooo
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When we were building I had to go to Constitucion for the day. While I was gone, the guy showed up to put in our decorative metal hand rails. When I
returned, the guy was plugged in with his huge welder just arc-ing away. Needless to say I was a bit freaked when I saw what was going on! He'd been
welding for hours using my solar rather than his generator. My batteries were low, but my parallel 12v 2000w outback inverters did just fine.
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Bob and Susan
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wow...woo : )
i think outback is still the best on themarke for now...but...things change
i still want to correct my system someday to 12v
i think we were told incorrect info in the past about systems
the loss of one 12v battery is nothing but
or 2- 6v
if you have a 6v system and lose one on a 48v system you loose
7 more batteries..$$$and POWER
inside the inverters 12v and 48v are simular...if you are stacking for wattage power then you are the same
the welder proved that
i corrected power from the panels to the charge controller by using a bigger wire and eliminating the combiner box and increasing voltage coming down
the batteries are much "happier"
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Bob and Susan
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| Quote: Originally posted by Alm | ...
12V bank limits the post-controller solar output from the Master to roughly 1000W, and current to battery is high.
... but new homes are usually higher voltage. |
what does this mean...i dont understand
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Bob and Susan
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here is what happened to me when i ran
2 separate charge controllers with
2 separate solar panel sets on
one bank of batteries....
the first controller would add voltage to the batteries "faking out" the second
remember controlers can ONLY read voltage not condition of the batteries
so as the voltage would go up the controllers would reduce the panel wattage thinking the batteries were charged when they weren't
they were fighting against each other and not charging the batteries
i would check the hydrometer and only get 3 balls out of 4
(3/4 full) when they should have been full (voltage indicated full)
the soulution was to only use one controller at a higher voltage and then let it reduce the voltage and charge the batteries
if im wrong or missing something please correct me
what did you do to avoid this
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Alm
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It means running higher voltage battery bank in order to get same charging watts with lower charging current. Or - more watts with the same current.
What Larry said. Controller outputs max 80A. With 12V bank it will output max 80*12=960W (make it 1000W because charging voltage is 13-14V).
5000W array on a good summer day could generate close to 4000W, so a single 80A controller with 12V bank won't be able to handle all the energy from
panels. Which means - some energy will be lost. That's why with 12V bank he needs a second controller.
With 24V bank a single 80A controller would still output max 80A, but in watts this would be 2000W. It would (probably) still cut some power off
during peak times, hard to tell how much - depends on time of the year, temperature, losses in the system and other things.
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larryC
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| Quote: Originally posted by Bob and Susan | here is what happened to me when i ran
2 separate charge controllers with
2 separate solar panel sets on
one bank of batteries....
the first controller would add voltage to the batteries "faking out" the second
remember controlers can ONLY read voltage not condition of the batteries
so as the voltage would go up the controllers would reduce the panel wattage thinking the batteries were charged when they weren't
they were fighting against each other and not charging the batteries
i would check the hydrometer and only get 3 balls out of 4
(3/4 full) when they should have been full (voltage indicated full)
the soulution was to only use one controller at a higher voltage and then let it reduce the voltage and charge the batteries
if im wrong or missing something please correct me
what did you do to avoid this |
This is only a guess but I would suspect a loose connection or a corroded connection somewhere between one of your controllers and the battery bank,
causing one of the controllers to get an erroneous hi voltage reading. My controllers each put out about the same amps until the batteries are in
absorb mode then one controller will start tapering off and the other picks up the slack. At that stage the amps have dropped off enough that one
controller can put out enough to keep the bank in absorb.
I don't have much experience with hydrometers because I use AGM batteries, but hydrometers with balls are pretty low end, if it was me I would invest
in a temp compensated hydrometer with the graduated float, much more accurate than the balls.
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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BigWooo
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Bob, do you have outback controllers? I have 5- FM80 controllers hooked up to a Mate to regulate them. They work exactly as Larry described. No
conflicts at all...however, I'm not sure how they would work if there was nothing like the Mate to coordinate the charging. If you put a couple
FM80's together without any coordination from the Mate, they might act just like yours did.
[Edited on 5-13-2015 by BigWooo]
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Bob and Susan
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i've been reading...they need a mate to coordinate the charge controlers...its like a little computer
the controlers share the charging wattage load
as the batteries get higher in charge
the wattage goes down on both controllers
the reason they need 2 or more is because the controller has a limit it can release to the batteries
80x12= 960watts for a 12v battery bank
if they were using 24v system the controlers could use more power
from the solar panels
80x24= 1920watts for a 24v battery bank
if they exceed 960 watts to the battery a breaker will trip
so in reality a 24v system may be better than a 12v system if you use alot of energy
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Bob and Susan
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| Quote: Originally posted by Alm | | It means running higher voltage battery bank in order to get same charging watts with lower charging current. Or - more watts with the same current.
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i still dont understand this statment...i really am a simpleton
was i right explaining it in the post above
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wessongroup
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Posts: 21152
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You guys are scaring me ...
Except the "Hobart" ... that's cool 
[Edited on 5-14-2015 by wessongroup]
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monoloco
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Location: Pescadero BCS
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| Quote: Originally posted by Bob and Susan | here is what happened to me when i ran
2 separate charge controllers with
2 separate solar panel sets on
one bank of batteries....
the first controller would add voltage to the batteries "faking out" the second
remember controlers can ONLY read voltage not condition of the batteries
so as the voltage would go up the controllers would reduce the panel wattage thinking the batteries were charged when they weren't
they were fighting against each other and not charging the batteries
i would check the hydrometer and only get 3 balls out of 4
(3/4 full) when they should have been full (voltage indicated full)
the soulution was to only use one controller at a higher voltage and then let it reduce the voltage and charge the batteries
if im wrong or missing something please correct me
what did you do to avoid this |
You also need to make sure that ALL the set points on BOTH charge controllers
are set exactly the same or they will do what you are describing.
"The future ain't what it used to be"
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larryC
Super Nomad
Posts: 1495
Registered: 8-11-2008
Location: BoLA
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| Quote: Originally posted by Bob and Susan | i've been reading...they need a mate to coordinate the charge controlers...its like a little computer
the controlers share the charging wattage load
as the batteries get higher in charge
the wattage goes down on both controllers
the reason they need 2 or more is because the controller has a limit it can release to the batteries
80x12= 960watts for a 12v battery bank
if they were using 24v system the controlers could use more power
from the solar panels
80x24= 1920watts for a 24v battery bank
if they exceed 960 watts to the battery a breaker will trip
so in reality a 24v system may be better than a 12v system if you use alot of energy
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You're getting the hang of it Bob.
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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Alm
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Posts: 2729
Registered: 5-10-2011
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| Quote: Originally posted by Bob and Susan | | Quote: Originally posted by Alm | | It means running higher voltage battery bank in order to get same charging watts with lower charging current. Or - more watts with the same current.
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i still dont understand this statment...i really am a simpleton
was i right explaining it in the post above |
Mostly - yes.
If breaker between panel and controller is rated to maximum ARRAY current (not controller current), - it will not trip when panels are pushing more
watts than controller can handle.
The excess energy will just not get through. This type of controller will be "clipping" the excess watts off.
"Normally", the controller will not go up in smoke when doing this, though it will get hotter when running full 80A all the time. It's not good for
electronics to run hot.
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