Please, need help setting up a solar system with batteries and inverter, etc.

[magentawave]

Thank you everyone for your input!


And when you say "earthed to the high side of the shunt" you mean that I should connect a ground wire from the frame to one of the bolts on the top of the shunt instead of showing it like I did where it appears to come off the same ground wire that goes to the fuse block?

Its an old 1982 Toyota and alternators for Toyota trucks were very small back then. I'm pretty sure this alternator only puts out about 40 to 50 amps. I was thinking of replacing it with a high capacity 150 to 250 amp GM alternator but someone told me to not bother because it wouldn't make any difference when charging the house batteries.

Would the Blue Sea Automatic Charging Relay replace the existing solenoid and is it worth installing with such a small alternator?

-- For the shunt to work (that is, allow the TriMetric or other meter to give a valid reading) is is critical that none of your camper circuits be earthed directly to the frame; they must all be earthed to the high side of the shunt. The shunt must be the ONLY path to earth (or ground).

-- Junk the solenoid you have under the hood and all of the related wiring. The wires are much too small to ever allow you to get a good charge from your truck's alternator. There are tables that will allow you to size things properly, but a a gross rule of thumb you can expect a 1/0 cable to pass about 75A. How big is your truck's alternator? You need a cable big enough to carry the full output at least 15 feet.

I would recommend using the appropriate Blue Sea Automatic Charging Relay. http://www.bluesea.com/products/category/Automatic_Charging_Relays This will have the advantage of allowing your solar kit to charge your starter batteries at the same time.

OK, a third and fourth comment:

-- None of this will work unless your truck's alternator produces at least 14.2v at 70F. (That being the minimum voltage for most deep cycle AGM batteries.)

-- Your cabling, down from the roof, from your solar controller to your camper batteries, and between your starter and camper batteries is large enough. Voltage drop on 12v systems is fatal. You need to aim for no more than 0.5v drop; less would be even better.

Good luck!

Is there any particular brand of breaker I should buy?

It's a breaker.

View attachment 215629

Required. I like breakers, some others like fuses. It's recommended to use 175 Amp or better between batteries.

Copied from my post in Bbasso's thread about his isolator.

 

[magentawave]

Yes I remember you said that so thanks for the update. I will make a few changes to the wiring diagram and upload it again later.

 

[4RunAmok]

You can find much of, if not everything, you need from www.powerwerx.com They sell those breakers at the best prices I've ever seen.

 

[DiploStrat]

And when you say "earthed to the high side of the shunt" you mean that I should connect a ground wire from the frame to one of the bolts on the top of the shunt instead of showing it like I did where it appears to come off the same ground wire that goes to the fuse block?

From the "bottom" or "low" side, the order is: Frame>shunt>all earth leads. The shunt is where your battery meter (Trimetric, IPN Pro, etc.) measures. In order for it to have an accurate reading all of your loads must be earthed (grounded) to the high side of the shunt. This assures that all of your current flow is measured. If you ground something directly to the frame, then its load will not be counted.

... someone told me to not bother because it wouldn't make any difference when charging the house batteries.

I LOVE that quote! Looking at your original set up, they were probably right. But that is an issue of bad implementation, not a bad idea. My 2013 Chevrolet has a pair of 125A alternators and I assure you that every morning when I start the engine I have a charge rate of over 150A at the camper batteries.

Should you upgrade your alternator on your Toyota? Yes, if you can fit it and the engine has enough torque to spin it. Can you achieve the same charge rates I do? Certainly, but you have to use properly sized cables and switching.

 

[evldave]

There's an issue with that. I didn't want to bring it up in Evl's awesome cheap dual battery thread... buuuuttttt...

The only thing that worries me about using Jumper cables is the insulation. Most "value" jumper cables use a good amount of copper, and some are quite flexible like welding cable, but the insulation sometimes feels cheap and therefore dangerous. Should it be susceptible to temperatures (prolonged exposure to heat for example), it can harden, which leads to cracks, which leads to exposed copper, whic....well you know where this leads.

Other than that, they're a good way to get a lot of copper in place cheaply. I would do what I could to protect that wire from the elements, like split loom, and then cover that split loom with electrical tape end to end (or at least on the exterior sections).

This is definitely a possibility and something people should keep on eye on. On my Suburban, after 5 years I noticed some fading where the wiring was exposed to UV. The rest had no issues, but long-term it could be an issue. On my H3 I run the wiring along the frame and it's about 30 minutes to rerun if it starts to degrade. No issues after 6+ years but something I do check when crawling around under the truck...

Sent from my Nexus 5 using Tapatalk

 

[4RunAmok]

It's always a good idea to put some split loom on wires run outside the vehicle (and inside too, if you're inclined), just to protect against the elements and the occasional flung rock.

 

[magentawave]

Someone suggested that I run 14 gauge wire to my LED lights instead of 16 gauge if I have more than three lights on at a time. I doubt I'd have that many lights on at the same time, but just in case, is there any downside to running 14 gauge wire over 16?

 

[java]

No there is never a downside to larger wire. Except the cost and size.

 

[magentawave]

I have three more questions please...

1) What should I use to protect wire from chafe that I run through holes in wood? Wrap the part that passes through the holes with lots of electrical tape?

2) What are the best connectors for 14 gauge wires? Crimp style connectors?

3) Really dumb question but should I use white colored insulated wire for hot or red?

Thanks

 

[4RunAmok]

I have three more questions please...

1) What should I use to protect wire from chafe that I run through holes in wood? Wrap the part that passes through the holes with lots of electrical tape?

Split Loom: http://www.tiewraps.com/splitloom.html

2) What are the best connectors for 14 gauge wires? Crimp style connectors?

NYLON Butt connectors and terminals, make sure you get the NYLON ones http://www.tiewraps.com/connectorpage.html
and a good professional crimper.

3) Really dumb question but should I use white colored insulated wire for hot or red?

This really doesn't matter so much. You could run a different color power wire to each device from a fuse box, the only person it would matter to is you. But generally speaking, red for hot from the battery to your fuse box, black for ground everywhere.

 

[4x4junkie]

I would suggest sticking with red for your hot wires since it is the accepted standard in 12VDC systems (black being the standard for ground wires). If for any reason you should ever need someone else's help with anything electrical on your rig, they won't be so confused by a bunch of hot wires of an unknown color.

 

[100acrehuphalump]

In my trailer, I installed two AGM batteries, a solar charger with 2 100 watt panels, and a shore charger. There are pix on my trailer build...

 

[hitek79]

Bumping this thread. Lots of good information here, but I'm trying to understand exactly what the Shunt is for. Thanks!

 

[unseenone]

I believe it is what is required for a Battery Management System (BMS) to monitor / manage the battery bank. Maybe you would think of it like a pressure gauge or TPMS is to a tire.

 

[DiploStrat]

trying to understand exactly what the Shunt is for.

You can Google up a more precise definition, but, in simplest terms, a shunt is a device inserted on the negative leg of a battery system that allows a monitor (e.g. TriMetric) to measure the current flowing through the system.

Link: http://www.bogartengineering.com/sites/default/files/docs/SHUNTInfo2.pdf