Overall Electrical System Guidance Please

[jamorgan3777]

Okay, I am starting to think about the electrical system. Anyone have a good source for overview of a Solar+shore power+battery system set up? I am looking for the standard. I was thinking I want a single box to do everything (take in the solar panel output, the battery output, and the AC shore power and route it to two systems (a 12V and a 110V). I understand that the combination "charger/inverter" systems are used for this, but I dont understand how they handle the AC shore power. Is there a box smart enough to do what I am looking for?

[saltydawg]

First you need to list your loads both 12 and 120 volt.

You 120 v can be simple or hard, most teardrop trailers dont need anything beyond very simple.

12 volt loads can also be very simple. Mine is but I went stupid on a few things. Read my over complicated electrical system a few threads down.

12 and 120 are seperate, unless you buy a very expensive panel. For 12 volt just buy a simple blue sea fuse box, they are cheap.

You said inverter, are you going to have a shore power plug as well or just the inverter? If doing both you need a transfer switch. What you need to watch is to make sure your shore power charger is not connected to the output of the inverter, other wise power just goes in a circle. So for 120 bring in power, hit the shore charger, then the transfer switch, then the plugs inside/outside the trailer.Other side of the transfer switch goes to the inverter, so when its on shore power the plugs are feed from shore power, when its on inverter plugs are fed from the inverter.

Here is a simple switch to use for the transfer switch. It can handle 20 amps at 120 volts

https://www.amazon.com/gp/product/B001P ... UTF8&psc=1

now 12 volt, you go from the battery to the main fuse block with some sort of disconnect, I used anderson plugs. From the main fuse block you go to the inverter, then preferably another fuse to the 12 volt fuse block. Then your loads come from there to what ever you need, be it switches for water pumps, fans light etc. I put in a master light switch, that then runs to switches for interior, ext, litcken light etc. I did that so I have one switch that kills all the lights when its not being used, I did that so I am less likely to leave a light on accidently. I did the same thing for my fans.

[saltydawg]

Solar is easy, panel to charge controller, to the fuse box. This allows the charger to directly feed any loads being used, I have a number 8 wire from the fuse to the main fuse. This also allows you to have a fuse in the fuse box for the charge controller for if anything goes wrong.

Dont over think it like I did. 12 volt is separate from 120v but they link via inverter and charger.

Install them as 2 separate systems, and treat them that way.

You dont really need a "panel" for the 120 volt. If you really insist on one square d makes a nice little box that in meant to be used as a disconnect switch, take the switch it comes with out and put in two breakers, one that is the "main" then that loops to the other one which has a tandem breaker, this give you 2 outs, one is normally the charger, the other is your plugs.

[jgizzi]

We just completed that step and had the same set of questions. We went with the Power Dynamics 4045 power converter from Vintage Technologies but the instructions were a bit thin. I asked some questions on the FB page and had a photo showing my wiring. You can see that here https://www.facebook.com/jim.gizzi.9/po ... 9212704079

A lot of folks also use the WFCO unit which does the same thing. They basically take your battery inputs and your shorepower inputs and give you output control for AC, DC and battery charging.

We had some thoughts about going with the 4135 as it is quite a bit smaller but had heard that some folks complained about that unit humming.

[saltydawg]

The all in ones work, but there is a problem. The chargers, if they have a built in one are simple chargers with very few if any settings. Ie no lithium or agm setting.

For a 24 foot travel trailer they are fine, but way over kill for a teardrop.

[jgizzi]

The PC4045 now has a DIP switch to change battery charging profile from LA to Li.

[Tom&Shelly]

The PC4045 now has a DIP switch to change battery charging profile from LA to Li.

Nuts! My Winter project after Christmas will be installing the one we bought 3 years ago (finishing our 3 year long build). Should have waited!

First thing we did was mock up the entire electrical system



to make sure I understood how it worked. Didn't realize at the time how much progress Li batteries would make. We'll start with a LA or AGM battery and see if we want to upgrade later.

Tom

[saltydawg]

I would like to see thier lifepo4 charge profile. My victron charger, will go in to a storage setting an allow the battery to discharge to 13.5 and will kick the charging cycle on once a month if the voltage does not drop below iirc 13 volts.

I have looked at the charging profile of a few so called lifepo4 chargers, they are not ideal and a few are actually bad. I bought a very expensive charger labeled for lifepo4, it tried to charge to 14.6 then run a trickle charge. At 14.6 a lifepo4 is at 100%, a trickle charge will over charge it, it needs to shut off between 13.6 and 13.8 which is 98% charged.