I have 4 6 volt batteries that I want to connect the Tiffen solar pre-wire cables from my controller to my battery.
First call to Tiffen, I was told there were posts included in the battery compartment to connect to and not to connect to the battery posts. When I couldn't find said posts, I did find a 250 amp/32 volt fuse screwed just above the batteries.
Second call to Tiffen he says sure, connect to the posts on the fuse, or just connect to the batteries.
So, Tiffen has been of little help. That 250 amp fuse does NOT look like something I should connect to. Can I just connect to the outboard batteries, positive to positive, and negative to negative. Also, should I put the 30 amp fuse to the battery in the battery compartment, or can I put it up in the cabinet over the driver, where I install the controller itself?
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Larry & Jane, retired aerospace engineer (Navy, Business, Air Trans)
2016 Tiffen Allegro 36la
2013 Honda CRV toad
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I have 4 6 volt batteries that I want to connect the Tiffen solar pre-wire cables from my controller to my battery.
First call to Tiffen, I was told there were posts included in the battery compartment to connect to and not to connect to the battery posts. When I couldn't find said posts, I did find a 250 amp/32 volt fuse screwed just above the batteries.
Second call to Tiffen he says sure, connect to the posts on the fuse, or just connect to the batteries.
So, Tiffen has been of little help. That 250 amp fuse does NOT look like something I should connect to. Can I just connect to the outboard batteries, positive to positive, and negative to negative. Also, should I put the 30 amp fuse to the battery in the battery compartment, or can I put it up in the cabinet over the driver, where I install the controller itself?
With consideration of what you said above, I suggest you pay to have a qualified electrician do the install.
You need the fuse near the battery. It's to protect the wire from melting, if it oveloads or shorts, to ground, on its way to the controller.
You can attach your positive, controller wire, to the batterys positive terminal OR to the terminal on the 250 amp fuse that goes directly back to the battery. Not the side that probably heads to the inverter.
In doing this, use a short wire of the same gauge, to go to the 30 amp fuse that you need to mount near the batteries.
A fuse near the controller would never blow because the panels shouldn't make more then 30 amps. If they can, you need heaver wire and a larger fuse.
The negative can go to ground near the battery or to the negative post.
I like to NOT use the battery posts for multiple connection points.
This limits the connection that can be affected by acid.
It also make changing the batteries simpler, with less wires.
Okay great, thanks TwinBoat ... very helpful. The other fuse I was going to install is on the red wire from the panel, right before the controller. Maybe that one is not necessary? The fuse/breakers I have selected would enable me to break power to either the controller (from the panel) or to the battery (from the controller), on those occasions where I might need to service the controller or batteries.
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Larry & Jane, retired aerospace engineer (Navy, Business, Air Trans)
2016 Tiffen Allegro 36la
2013 Honda CRV toad
Okay great, thanks TwinBoat ... very helpful. The other fuse I was going to install is on the red wire from the panel, right before the controller. Maybe that one is not necessary? The fuse/breakers I have selected would enable me to break power to either the controller (from the panel) or to the battery (from the controller), on those occasions where I might need to service the controller or batteries.
A breaker or fuse, on the panel to controller wire, is handy for switching it on or off for testing.
Since any fuse needs to be more then the max output of the panel, it shouldn't ever trip.
If the panels output is 8 amps max and the wire can handle 10 amps, it won't melt.
Fuses become important when multiple panels are combined.
An example;
Take 3, 8 amp panels, combined at a juntion box. If one panel shorts, the other 2 can send 16 amps back up thru the shorted panels wiring.
This is not your situation but others may be following.
Very good point, because I might add a second panel later this year. I've sized everything so that I can do this, and would just have to add branch MC4 connectors on the roof and install the second panel.
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Larry & Jane, retired aerospace engineer (Navy, Business, Air Trans)
2016 Tiffen Allegro 36la
2013 Honda CRV toad
You should have 2 sets of breakers. One breaker is for the current that comes down from the panels to the charge controller and the other is for the current that passes from the charge controller to the batteries. Both of these breakers are DC breakers not your typical AC breaker from Home Depot. DC breakers act differently than AC breakers. So be careful. The voltage coming down from the panel above could be 18v to 37v depending on the panel. I don't know what charge controller you have but with mine, I turn on the 12v circuit breaker first because the voltage on the batteries trains the controller to charge for 12v not 24v. Then I turn on the source current breaker from the panels. Doing it the other way around, might damage the batteries because the controller doesn't know what DC voltage to charge to. Here is a picture of mine. If you are going to add panels down the road you should size your wire bigger but not your breakers. A 10 guage wire at 48v should be able to handle 4 panels of 235 watts each. The breakers protect more than your wires. If there is a short in the panel or your batteries short, you don't want your charge controller burning up trying to charge your batteries. When you add additional panels, update your breakers. All of my connections are made in the inverter bay and not the battery compartment. This allows me to open the door easily and turn on and off the system and connections are easily available. As you can see, I have a 100 amp breaker for the batteries and a 30 amp breaker for the panels. Make sure your calculations are correct.
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Bill & Mary USN 69-73 ASW Technician, MBA.
2006 Tiffin Allegro Bus QDP 1060 watts solar
2012 Jeep Grand Cherokee '16 Polaris Razor 4
I am installing one GrapeSolar 180 watt panel (may add a second later), Morningstar Duo controller (25 amp) and 2 30 amp fuse/breakers (links below). One breaker upstream of the controller and the other downstream, close to the battery. Wiring is all 10 gauge as supplied by Tiffen in the solar pre-wire option. The GrapeSolar panels are available from HomeDepot for $219 with free shipping for anyone interested.
My tiffin coach has terminals in the battery bay going directly to the batteries, near the 300a fuse. I connected PV system there.
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Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.
I asked a dealer about the pre-wired option because of other threads. I was told that they only use 10 gauge wire for their "prewire".
With higher voltage panels and series, parallel wiring, you can get alot of solar down a 10 gauge wire.
I'm using 3, 225 watt, 36 volt panels in series. They send around 100 volts at 8 amps, down a 12 gauge wire to my MPPT controller. It converts it to high amp 12 volt power.
Of course you need BIG wire from the controller to the batteries.
I asked a dealer about the pre-wired option because of other threads. I was told that they only use 10 gauge wire for their "prewire".
#10 can be OK, depending on your system size and design and goals. I have three pair of #10. 500w on each string/pair. 15a DC breaker on each.
I am not a fan of manufacture prewire as it may not be what you want or need for your system.
__________________
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.