GZ 100W > Victron 75/10 > Battery: Final wiring questions

JB30

Member
Trying to wrap up all these loose ends (pun intended I guess) on solar install.

Have a Goal Zero 100W panel and Victron 75/10 Smart Controller in my possession, and a handful of things in my amazon cart.

Goal Zero 8mm Female to SAE Connector:

SAE plug to mount in grill or side of Jeep:

The plan is to mount the panel to the roof, but be portable- so I can run the panel to a sunny spot if I’m parked in shade. Thus the SAE plug.

Going to try to find a home for the controller somewhere in the engine bay close to battery. Planned on 10 gauge wire to finish connection.

Does this all seem like a decent plan? Missing anything? Any fuses needed inline anywhere?
 

dreadlocks

Well-known member
you should fuse the charge controller between the battery, panels themselves don't need fused.. especially if you have a quick disconnect for portable usage and can wire up the solar side of the controller w/out it being hot.. just ensure you exceed any cable ratings on solar side for the panels short current rating, which is not that high for a single 100W, basically even the worst cable will exceed your needs.. the battery side of the SC has potentially hundreds of amps (thousands of watts) at its disposal and will easily burn up the wiring.. so it must have a fuse.

Pay attention to polarity w/SAE connectors, one end of the cable the positive will be male, and the other end it will be female, real easy to wire things up wrong and reverse polarity, tho the victron unit will survive it, dont ask me how I know.. 10AWG seems a bit overkill for a 100W panel, how much portable cabling are you planning on carrying? 12awg is likely more than enough unless your bringing over like 50ft.. otherwise the difference in power saved is going to just be a couple watts max at peak input, vs cost and weight.. at 50ft, with 9A power the loss difference of 12AWG vs 10AWG is 3%, or 3W extra you get from the 10awg. assuming full 100W output.. (7% v 10% losses).. at that point your just better off with shorter cables you can chain to desired length without too much extra.. you'll see better gains when you only use what you need.
 
Last edited:

JB30

Member
you should fuse the charge controller between the battery, panels themselves don't need fused.

Pay attention to polarity w/SAE connectors, one end of the cable the positive will be male, and the other end it will be female, real easy to wire things up wrong and reverse polarity, tho the victron unit will survive it, dont ask me how I know.. 10AWG seems a bit overkill for a 100W panel, how much portable cabling are you planning on carrying? 12awg is likely more than enough unless your bringing over like 50ft.. otherwise the difference in power saved is going to just be a couple watts max at peak input, vs cost and weight.. at 50ft, with 9A power the loss difference of 12AWG vs 10AWG is 3%, or 3W extra you get from the 10awg. assuming full 100W output.. (7% v 10% losses).. at that point your just better off with shorter cables you can chain to desired length without too much extra.. you'll see better gains.
Ah sorry, yeah I meant 10AWG just from the controller to the battery. The SAE plug is already wired with 10AWG, so I was just continuing the trend.

For extension to the panel (when it’s not on the roof), I’ll just be using that GZ 8mm to SAE lead (And 8mm extension cable if needed).

Re: fuse between controller and battery, any size recommendation? I’m useless when it comes to electrical calculation.
 

dreadlocks

Well-known member
a 75/10 is 75V input max, and 10A output max, it limits its self hard at 10A output regardless of how much you input.. so wire up a ~15A fuse, thats 50% more than you need.. it should never trip in normal usage, and 15A is more than enough to protect a couple feet of 10AWG from any damage if a short were to occur.. mount your SC next to your battery as close as possible, so it can get the most accurate voltage/temp readings from the battery that you can provide it.. oversizing the battery side of the wiring is worth it, any extra expense is negligible with such short distance.
 

JB30

Member
a 75/10 is 75V input max, and 10A output max, it limits its self hard at 10A output regardless of how much you input.. so wire up a ~15A fuse, thats 50% more than you need.. it should never trip in normal usage, and 15A is more than enough to protect a couple feet of 10AWG from any damage if a short were to occur.. mount your SC next to your battery as close as possible, so it can get the most accurate voltage/temp readings from the battery that you can provide it.. oversizing the battery side of the wiring is worth it, any extra expense is negligible with such short distance.
Awesome, thanks @dreadlocks. Appreciate the help!

EDIT: I did find some already pre-fused 12AWG wire with connectors and matching SAE plug. Would save me a couple bucks. Still do the trick?
 

highwest

Active member
I wish I would’ve had this thread available about a week ago...

I believe the Victron manual recommends a 20A fuse for the 75/10.
 

JB30

Member
I wish I would’ve had this thread available about a week ago...

I believe the Victron manual recommends a 20A fuse for the 75/10.
Ah okay cool. Thanks for the heads up! Anything else learned from (I assume) a similar setup?
 

dreadlocks

Well-known member
EDIT: I did find some already pre-fused 12AWG wire with connectors and matching SAE plug. Would save me a couple bucks. Still do the trick?
go for clean as possible so it dont give you any grief out in field where tools are scarce, support the cable bundle with zip ties or anchors of some sort so the inline fuse is not a floating weight just shaking down the trail and weakening the wires.

however from battery to SC dont need SAE plugs since they should be nearby, the charging side is going to be battery or battery disconnect -> ring terminals -> fuse block -> SC.. its from the SC to the panel you should be using those type of connectors.. and you dont need an inline fuse there.
 
Last edited:

highwest

Active member
Ah okay cool. Thanks for the heads up! Anything else learned from (I assume) a similar setup?
I did 2 x 70W panels in series, connected to a 75/10, connected to a 100aH Renogy Hybrid Gel. The charge controller and battery are in a toolbox (it's heavy, but I can't afford lithium). The wiring is a mix of 10, 12, & 16 AWG, depending on what was pigtailed on the adapters, SAE connectors, and inline fuses. The 75/10 specifies 10AWG max, I figured bigger is better, but it's a pain to get 10AWG into the terminals - 12AWG was easier. I placed 20A fuses between the panels and the charge controler and the charge controller and the battery. If you're interested in preventing the solar charger from draining the battery, don't forget a switch (I now have one on order).

My primary goal is to power a 12V diesel heater, but I also included a USB charge port. This is my first real foray into this, so I appreciate any critique from those wiser than I.
 

jonyjoe101

Adventurer
i wouldn't put the controller in the engine compartment. Its too hot for it, it needs to have air to cool down. At 104 degrees farenheit is the max where it produces the best power, at 158 degrees it shutsdown to protect itself. Engine compartments gets into the 150's. I would put it in the shade somewhere with a small fan blowing on it, even inside a car with the windows up it gets into the 140's.

I checked the manual it didnt say not to put in the engine compartment but it did say it needs plenty of ventilation and install in a heatproof environment. I suspect victron thinks the controllers will be mainly use in a comfortable home environment.

I would also stay away from the SAE plugs, too easy to hook up in reverse, I was careful and still hooked them up in reverse. I would seriously consider the xt60, its all I use, handles up to 60 amps and no way to hookup in reverse. You can get 10 sets for 6 dollars.
 

rayra

Expedition Leader
i wouldn't put the controller in the engine compartment. Its too hot for it, it needs to have air to cool down. At 104 degrees farenheit is the max where it produces the best power, at 158 degrees it shutsdown to protect itself. Engine compartments gets into the 150's. I would put it in the shade somewhere with a small fan blowing on it, even inside a car with the windows up it gets into the 140's.

I checked the manual it didnt say not to put in the engine compartment but it did say it needs plenty of ventilation and install in a heatproof environment. I suspect victron thinks the controllers will be mainly use in a comfortable home environment.

I would also stay away from the SAE plugs, too easy to hook up in reverse, I was careful and still hooked them up in reverse. I would seriously consider the xt60, its all I use, handles up to 60 amps and no way to hookup in reverse. You can get 10 sets for 6 dollars.
How on Earth did you hook up a SAE connector in reverse. They're basically designed to prevent that. Or are you saying you wired them incorrectly?

--

Seconding the 'dont put it in the engine compartment'. Don't worry about all the 'efficiency' guys talking about voltage drop over a run (thus having to crowd the charge controller up on the battery). It's not enough to matter. You'd lose / gain more juice from re-aligning your panel every couple hours.

If your overall wiring setup will allow, put your controller somewhere in the passenger compartment. Not under the panel on the roof, or in the engine compartment. Mine is at the other end of about 19' of 1/0 cable from my under-hood Aux battery and I get about 4/100th of a volt difference, measured at the terminals by the controller in the rear of the vehicle, cs at the battery. That's about a 3/10 of 1% drop. whooptifndo.

 

dreadlocks

Well-known member
lots of people have installed it into the engine bay fine, obviously away from exhaust components and whatnot.. but when your engine bay is that hot that means it was running or was very recently so the solar is not even needed.. its built in protection is adequate, the key is installing it so it maintains its IP rating, but bringing it to the other side of the firewall is fine, as long as it dont require an absurdly long cable run.. depending on how much money you spent on the batteries you may look at the victron temp probe so the controller can compensate for any harsh under hood temps.. otherwise its designed to operate in the same environment as the battery bank for the most part.
 

highwest

Active member
I wish I would’ve had this thread available about a week ago...

I believe the Victron manual recommends a 20A fuse for the 75/10.
Upon further inspection, I think the 20A fuse the manual is referring to is the internal one in the 75/10. Seems like conventional wisdom is to size the other fuses in the circuit for max current + 25%. Dread’s suggestion of a 15A fuse is probably more in line with that.
 

moose545

Active member
lots of people have installed it into the engine bay fine, obviously away from exhaust components and whatnot.. but when your engine bay is that hot that means it was running or was very recently so the solar is not even needed.. its built in protection is adequate, the key is installing it so it maintains its IP rating, but bringing it to the other side of the firewall is fine, as long as it dont require an absurdly long cable run.. depending on how much money you spent on the batteries you may look at the victron temp probe so the controller can compensate for any harsh under hood temps.. otherwise its designed to operate in the same environment as the battery bank for the most part.
Good info in this post, mind taking a look at mine, much appreciated to get some more experienced insight 😬
 

rayra

Expedition Leader
Upon further inspection, I think the 20A fuse the manual is referring to is the internal one in the 75/10. Seems like conventional wisdom is to size the other fuses in the circuit for max current + 25%. Dread’s suggestion of a 15A fuse is probably more in line with that.
Size your WIRE GAUGE that way, fuse lower. Primary goal is to not slag your wire and burn things down, not just prevent fuses from blowing.
 
Top