Fuse Size, Wiring Plan Review

[A.Smith]

I am wiring a Dc to Dc Charger and Solar Panel and controller
into my 2006 Hawk.

# 4 welding cable from the truck battery to a 100A 285 series circuit breaker ( next to the battery) to 100A circuit breaker in the camper area ( next to the battery /component area) , The wiring will be split at the circuit breaker, because #4 will not feed into the charger without an extreme loss of wires, therefore #6 wire. If this is not advised,suggestions, a buss bar ?

#6 wire out of the series 285 circuit breaker to the Victron DC to DC Smart Charger 12/12-30m to

? fuse to the 100A BB Lithium Battery.

Solar; 100 watt Renogy pane. Victron MPPT 100/30 charge controller.

#8 wire from the solar panel to the controller to

? fuse, to the Lithium battery.


A Victron BMV 712 battery monitor will be wired into the system.

As the component area is small, service loops will be installed behind each component panel for maintenance.

So as you can see I need Help.

Thanks
Fred
A.Smith

Pictures did not show, will try again.

+ In writing this piece I had many re-do's as trying to load pictures caused everything to cancel so I had to start again, and again.

As the pictures show I can mechanically complete connections, but I admit I am weak on theory. I have been posting questions and reading everything I could find on this forum. The wiring fuse charts from Blue Sea Systems have confused me therefore this recent asking for help.
Some aspects are redundant, like the switches. I am overly cautious until I thoroughly understand. And this project is a bit overwhelming at times.
One or more of the previous owners had electrical fires unbeknownst to me. therefore I have had to tear apart the interior far more than planed. But by pulling the water holding tank and numerous charred boards and wiring, I have created a larger batter/component area.

Thanks to all for this and previous help.

 

[A.Smith]

I am wiring a Dc to Dc Charger and Solar Panel and controller
into my 2006 Hawk.

# 4 welding cable from the truck battery to a 100A 285 series circuit breaker ( next to the battery) to 100A circuit breaker in the camper area ( next to the battery /component area) , The wiring will be split at the circuit breaker, because #4 will not feed into the charger without an extreme loss of wires, therefore #6 wire. If this is not advised,suggestions, a buss bar ?

#6 wire out of the series 285 circuit breaker to the Victron DC to DC Smart Charger 12/12-30m to

? fuse to the 100A BB Lithium Battery.

Solar; 100 watt Renogy pane. Victron MPPT 100/30 charge controller.

#8 wire from the solar panel to the controller to

? fuse, to the Lithium battery.

A Victron BMV 712 battery monitor will be wired into the system.

As the component area is small, service loops will be installed behind each component panel for maintenance.

So as you can see I need Help.

Thanks
Fred
A.Smith

Pictures did not show, will try again.

 

[Jon R]

Hi Fred,

I am installing the same Victron 12/12-30 DC to DC charger. There is nothing absolutely wrong with your proposed configuration, but it could be improved while at the same time maybe simplify your connections. The short run of 4awg wire seems unnecessary especially if it is complicating the connections (just use the same 6AWG as the rest of the run). The 100 amp circuit breaker, while it is adequate to protect the 6AWG wire, is unnecessarily large for the rough maximum of 35 amps the charger will draw from the truck. A 50 amp CB should avoid any nuisance fuse opening from the operation of the charger, and would reduce the damage that occurs if you get a short to ground.

I'm also using the same solar charger, two 200 watt panels, and a 200Ah 12V Lithium battery.

Most people wouldn't bother fusing a cleanly installed 2 foot run from the charger to the battery in a battery compartment because a short to ground is unlikely in that short run if it doesn't pass through a wall and has no other specific threats. However, you do need to put a main battery fuse at or very near the battery positive terminal because of all the other wiring you will have connected to it, particularly hidden wiring to your main fuse block. The sizing of that fuse should be set by the smallest otherwise unfused wire connected to that part of the system due to its potential to pass a large fault current from the battery in the event of a short. If that would make the main fuse too small for other things connected to the battery (my maximum theoretical current is driving on a sunny day with a depleted battery so both chargers are charging the battery at a total of 60 amps), you will need to use an additional fuse to protect the smallest wiring or upsize that wiring so that you can make the main fuse larger. If you run 6AWG wiring from the DC to DC charger to the battery and from the MPPT charger to the battery, you don't need any fuse protection for that wiring other than the main battery fuse. I'm using an 80 amp main battery fuse, and I don't ever expect to actually see that theoretical 60 amp charge rate.

I haven't looked at the camper load wiring yet, but I suspect I'll end up with a 30 amp fuse protecting that wiring at the point of wire size reduction. I may later run 6AWG all the way to the fuse block.

I know some people put fuses in their solar panel circuits, but that doesn't make sense to me. The controller is not a threat current source if a short to ground occurs in the PV circuit, but the panel is. However, the panel network is self limiting at the short circuit current level, and you need to be able to continuously pass nearly that current level for normal charging purposes. So any fuse small enough to blow in a wire short would blow during charging, and the wire is sized to handle the short circuit current continuously. You would eventually figure out you aren't charging and sort it out. Maybe someone can explain if they think I'm incorrect.

I hope this helps,

Jon

 

[A.Smith]

Hi Fred,

I am installing the same Victron 12/12-30 DC to DC charger. There is nothing absolutely wrong with your proposed configuration, but it could be improved while at the same time maybe simplify your connections. The short run of 4awg wire seems unnecessary especially if it is complicating the connections (just use the same 6AWG as the rest of the run). The 100 amp circuit breaker, while it is adequate to protect the 6AWG wire, is unnecessarily large for the rough maximum of 35 amps the charger will draw from the truck. A 50 amp CB should avoid any nuisance fuse opening from the operation of the charger, and would reduce the damage that occurs if you get a short to ground.

I'm also using the same solar charger, two 200 watt panels, and a 200Ah 12V Lithium battery.

Most people wouldn't bother fusing a cleanly installed 2 foot run from the charger to the battery in a battery compartment because a short to ground is unlikely in that short run if it doesn't pass through a wall and has no other specific threats. However, you do need to put a main battery fuse at or very near the battery positive terminal because of all the other wiring you will have connected to it, particularly hidden wiring to your main fuse block. The sizing of that fuse should be set by the smallest otherwise unfused wire connected to that part of the system due to its potential to pass a large fault current from the battery in the event of a short. If that would make the main fuse too small for other things connected to the battery (my maximum theoretical current is driving on a sunny day with a depleted battery so both chargers are charging the battery at a total of 60 amps), you will need to use an additional fuse to protect the smallest wiring or upsize that wiring so that you can make the main fuse larger. If you run 6AWG wiring to from the DC to DC charger to the battery and from the MPPT charger to the battery, you don't need any fuse protection for that wiring other than the main battery fuse. I'm using an 80 amp main battery fuse, and I don't ever expect to actually see that theoretical 60 amp charge rate.

I haven't looked at the camper load wiring yet, but I suspect I'll end up with a 30 amp fuse protecting that wiring at the point or wire size reduction. I may later run 6AWG all the way to the fuse block.

I know some people put fuses in their solar panel circuits, but that doesn't make sense to me. The controller is not a threat current source if a short to ground occurs in the PV circuit, but the panel is. However, the panel network is self limiting at the short circuit current level, and you need to be able to continuously pass nearly that current level for normal charging purposes. So any fuse small enough to blow in a wire short would blow during charging, and the wire is sized to handle the short circuit current continuously. You would eventually figure out you aren't charging and sort it out. Maybe someone can explain if they think I'm incorrect.

I hope this helps,

Jon

Thanks Jon,
The # 4 wire runs from the truck battery to the camper, so it is the longest run, therefore the double fuses.
As I am apt the go off road a bit, I double fuse often. But you are spot on with thoughts about short runs.
On the adventure
Fred

 

[rando]

What is the large switch in the photos for?

 

[A.Smith]

What is the large switch in the photos for?

The switches are so I can isolate the separate components in case of emergency.
I realize they maybe over kill,so to speak, just a redundant safety.

Fred

 

[ri-f]

The switches are so I can isolate the separate components in case of emergency.
I realize they maybe over kill,so to speak, just a redundant safety.

Fred

I think what you are proposing is correct and appropriate. I like fusing all components in order to isolate in case of troubleshooting without shutting down the entire system. Also, I used 4 AWG marine cable on the long run between the starter battery and the DC-DC charger. It's not overkill by any means. I ran it to a short bus bar, and then connected 6 AWG from that short bus to the DC-DC, which requires a smaller guage wire (at least it did on mine - a Sterling 1230 DC-DC charger). I then ran 6 AWG from the DC-DC to the Lithium battery. These wires were protected on both ends with a 60 amp Blue Seas circuit breaker. My solar is also fused before and after the MPPT controller and uses 6 AWG between the MPPT output and the Lithium battery. I didn't use a big red switch like you did, I assume it is a system wide kill switch. I simply used the individual circuit breaker switch(es) to flip on or off the solar or DC-DC charger as needed. Don't see any problems with what you are trying to do.

Rich

 

[A.Smith]

I think what you are proposing is correct and appropriate. I like fusing all components in order to isolate in case of troubleshooting without shutting down the entire system. Also, I used 4 AWG marine cable on the long run between the starter battery and the DC-DC charger. It's not overkill by any means. I ran it to a short bus bar, and then connected 6 AWG from that short bus to the DC-DC, which requires a smaller guage wire (at least it did on mine - a Sterling 1230 DC-DC charger). I then ran 6 AWG from the DC-DC to the Lithium battery. These wires were protected on both ends with a 60 amp Blue Seas circuit breaker. My solar is also fused before and after the MPPT controller and uses 6 AWG between the MPPT output and the Lithium battery. I didn't use a big red switch like you did, I assume it is a system wide kill switch. I simply used the individual circuit breaker switch(es) to flip on or off the solar or DC-DC charger as needed. Don't see any problems with what you are trying to do.

Rich

Thanks Rich,
I have learned so much due to all the generous folks on this site.
One of the interesting things is knowing which question to ask and utilizing the search area to further research.
On the Adventures
Fred