Wiring Diagram Review

[dgshelto]

Hi,

I'm in the process of planning my solar build and I'd like some input based on my attached wiring diagram. If anything is out of wack please let me know!

 

[highdesertranger]

please note I am leaving the link up because it does not take you off the CRVL website. welcome, please go to the "Newcomers corner" and give use an intro, you will be given an official welcome and a link to the rules. thanks highdesertranger

 

[abnorm]

I'm not sure the CC "switch" is in the right place..........I thought we switch the Input to the CC ?????

 

[highdesertranger]

yes that's a good point. I think the switch should be on the panel side. highdesertranger

 

[Canine]

As long as the inverter has its own on/off switch, you don't need to add another switch. I'm not sure it is a good idea to ground the inverter to the frame; does the manual say that? You don't need to add a ground to the chassis with your battery; I ground only to the batteries themselves. My batteries are not grounded to the frame. I like how you have a switch to the charge controller. With the solar panels, I have an easily accessible switch connected. You don't need a switch, but make sure the fuse for the solar panels or however you will disconnect them is easily accessible for when you need to turn the solar off. Whenever you do add a switch, place the fuse closer to the battery. Use deoxit to help keep a good contact. Make good crimps. Don't cheap out on wire.

It looks great overall!! I tried to be as picky as possible to try to give some feedback.

 

[dgshelto]

As long as the inverter has its own on/off switch, you don't need to add another switch.
It does indeed, I'll remove my switch.

I'm not sure it is a good idea to ground the inverter to the frame; does the manual say that?
The manual does say to ground the inverter chassis screw to the vehicle chassis.

You don't need to add a ground to the chassis with your battery; I ground only to the batteries themselves. My batteries are not grounded to the frame.
Interesting...I always thought the house battery needed to be grounded to the frame, but if that's the case I'll remove it!

I like how you have a switch to the charge controller. With the solar panels, I have an easily accessible switch connected. You don't need a switch, but make sure the fuse for the solar panels or however you will disconnect them is easily accessible for when you need to turn the solar off. Whenever you do add a switch, place the fuse closer to the battery. Use deoxit to help keep a good contact. Make good crimps. Don't cheap out on wire.
Does it matter where the switch is located (i.e. panel side positive or battery side positive?)

It looks great overall!! I tried to be as picky as possible to try to give some feedback.
Thank you!!!

 

[Canine]

With the charge controller, have the switch between the charge controller and the battery. The reason is this: When disconnecting power (to add/remove connections or to work on it) the solar needs to be disconnected first. When the solar panels are disconnected, the charge controller will still be on because it has power from the battery. (If the switch was between the solar panels and the charge controller, power from the battery would still power the charge controller. Having the switch between the charge controller and the solar panel only disconnects the solar panels.) Then turn off the switch for the charge controller to disconnect it from the battery. It will now be off. Now you can disconnect the batteries or add stuff without worry of damaging the charge controller. When you get the batteries and connections the way you want them, turn on the switch to the charge controller. Lastly, reconnect the solar panels. Solar panels are first to be disconnected and last to be connected. You just do the reverse when hooking all the stuff back up.

Get a second opinion on grounding the battery to the frame. It may not hurt and may help, although, I could see that being a problem. I see nothing but advantages for having no ground to the frame, but then I was wrong about the inverter being grounded.

 

[Canine]

I like these fuses. Great space saver.

https://www.amazon.com/Blue-Sea-Sys...D=41U7coK3abL&preST=_SX300_QL70_&dpSrc=detail

 

[John61CT]

I ground to chassis and engine, but from negative buss(es) not directly to the bank post.

Talking about DC only

 

[John61CT]

The bank should have a single master isolation switch close to the bank, just after the master fuse, sized just under the max wire capacity.

From there, rather than a single positive buss, I prefer a charging buss separate from a "to loads" one.

Any long runs to loads fused on the bank end, rated either for the wire or lower based on max currents expected.

 

[John61CT]

Wire gauges according to distance to minimize voltage drop. make sure to double distances for the round trip.

Blue Sea Circuit Wizard app is great

 

[Trebor English]

You don't have a connection to the vehicle alternator for additional charging.  Since the alternator uses the chassis for the minus side connection you need to connect your battery minus to the chassis only if you add an alternator connection.  

Solar charge controllers come with installation instructions that say that the battery must be connected first and the solar panel last.  The battery provides stability for the system.  Having solar panel input with no battery causes some solar charge controllers to fry themselves.  Some will self destruct if the battery becomes disconnected while the battery is being charged.  Some survive ok.  A switch to deliberately cause that situation is an invitation for trouble.  A switch between the solar panel and the solar charge controller won't fry the controller.

Your 20 amp fuse size is sufficient so that the solar system cannot blow the fuse.  That is good.  A 10 amp fuse with panels that can produce 10 amps would also be an invitation for the same controller frying  trouble.  

If your solar wiring is more than a few feet you might want bigger wire than AWG 10 for less voltage drop.  

The #10 solar wire needs to be protected by a fuse from being fried by the battery.  The solar stuff can't overheat a #10 wire so there is no need for a fuse anywhere but at the battery.  The 20 amp fuse in your drawing is shown at the charge controller.  If that wire chafes and shorts the battery will ignite it and the fuse at the charge controller won't protect the wire.  If you put the fuse at the battery then that wire will be protected.  The fuse between the solar panel and the charge controller is similarly unnecessary and ineffective as the battery is the source of enough current to cause a problem.  

Extra fuses add resistance to circuits causing more voltage drop.  Only put in fuses where necessary to protect wires from power sources that can overheat the wire.

 

[Weight]

i have studied much. But the other experts will disagree with my system. With two 100 watt solar panels there is no need for a fuse between the panels and controller unless the wires are very much undersized. There is just not enough amps even when dead shorted. But a fuse could be used to disconnect the panels from the controller or a switch. After the controller, you need a heavier fuse. It is a 30 amp controller. Use wire heavy enough to carry the current and a fuse at the battery terminal of 40 amps. Use a wire size chart to determine the awg with the objective to have less than 1% voltage drop on your solar charging circuits. With 10 awg marine type wire, I would fuse at 50 amps. You must have a fuse on every wire that connects to the battery positive. I use these. ;; https://shop.marinehowto.com/products/blue-sea-marine-rated-battery-fuse
You are correct with the inverter case ground to the chassis. As well as the battery negative to the chassis. If you are going to have a switch to disconnect the inverter, put the fuse at the battery then to the switch. I have a heavy duty battery switch and disconnect the battery negative when i need to work on the circuits.
The Rule. Fuses protect the wire. there are charts that list the maximum amperage for different wire gauges and insulation. Fuse near that amperage. The object is to reduce voltage drop. Each fuse is another resistance in the circuit and contributes to voltage loss. Larger amp fuses have less resistance. Protect the wire.

 

[highdesertranger]

some controllers will fry if the batteries are disconnected and the panels are still inputting power. to be safe always disconnect the panels first. highdesertranger

 

[wayne49]

A Renogy 20A MPPT won't fry. The display goes into a holding pattern until the battery is connected.

It is convenient to have both battery and solar to the CC separately switched.

My Tristar 45A MPPT started displaying alien runic text and needed a power down to break the connection to the mother ship. I had to disconnect at the MRBF fuse.

The Blue Sea MRBF fuse has a small footprint, but the Blue Sea MRBF fuse holder does not have a small footprint. Requires a powered stud to mount. Also has height off the surface.

https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A

ANL has its uses.

 

[Weight]

Except for maybe some very cheap off brand solar controllers that I have not studied. The warning about battery first solar last is for safety reasons. Sparks and shocks. Not to protect the controller.

 

[John61CT]

No even some well respected expensive brands can fry.

RTM before playing around.

 

[dgshelto]

To touch on some points that were made:

1. All pos wires will be fused as close to the battery as possible (except for the Renogy in-line fuse between the panels/CC. This will act as my switch to disconnect the two if need be and connects at a specific point in the circuit as defined by Renogy).

2. I do intend on adding an alternator isolator kit for additional charging while driving. Does this require I ground my house battery to the chassis? If so, why?

3. The wire and fuse sizes in relation to the solar panels / C.C / inverter were all recommended by Renogy and Xantrex. I will update the 20A fuse between the CC and the battery to a 30A to match the controller (the 20A was recommended for their 20A MPPT controller, which I've switched to the 30A PWM instead). Everything else was sized using the Blue Seas charts/calculator.

New question!! And maybe there's another thread for this...but how do I go about connecting large wires (such as 6AWG) to small connection posts (such as #10 pos/neg posts on my fuse box)?

 

[John61CT]

Easiest and best is a ferrule terminator if you can find the right sizing.

Next best is crimped heat shrink "step down" butt connectors.

Next easy is ring terminals to a terminal strip.

Many feel spiral twisting together of both wires over a long length along with soldering and heat shrink is "good enough", but make sure extra slack and well supported, so no movement.

Circuit protection needs to be sized for the smallest wire.

 

[John61CT]

I do intend on adding an alternator isolator kit for additional charging while driving. Does this require I ground my house battery to the chassis? If so, why?

Use a proper ACR/VSR or combiner with plenty of ampacity overhead, Blue Sea's are excellent.

And yes, all DC circuits should have a common negative return (no real ground with a wheeled vehicle).

Only applies to DC circuits.