Need help validating my simple 12v trailer power setup?

[DaveM]

Need a little help vetting my very simple 12v power set up for my little Venter trailer:
I've installed a small battery box with 12v deep cycle battery (Interstate SRM-24). The batt is connected to a Renology Wanderer solar charge controller which feeds power (when connected) from a portable Rockpals 100w panel.

The battery is connected out to a Blue Sea fuse box that runs two circuits into the main trailer compartment. 1) for a 12v power outlet for running the Dometic fridge and 2) for the 2 low amp LED light bars (in in the trailer hood and one under the trailer for exterior light). The LED bars are run in series, with a common ground back to the fuse box.

This is a very simple system that won't ever be asked to do anymore than it is right now. My questions are:

1) do I need to ground this system to the trailer frame? Or is having the batter neg act as ground ok? I've read both.

2) I've noticed that when charging the batt at home on a 3.5 amp charger, if the accessories are left attached to the batt the charger never reads full. If I disconnect all the lines, it charges quickly. It also seems to drain slowly when hooked up with nothing running. Assuming I need to add a batt isolator switch, but not sure to which line(s)?

Any help is appreciated.

View attachment annotated 12v-01.jpg

 

[DaveM]

at this point you dont need to, but I normally suggest negative grounding as best practice unless there is strong reason not to. Using positive grounded solar for example.
That stands to reason, but only if your accessories are switched on. If switched off, it should be no different than your disconnecting them.
As you say, if disconnected it charges quickly. You should find out which of your four circuits is drawing current when you dont want it to.
Three of which are easy to isolate pulling their fuse. Fourth being solarcontroller.
But ! Thats not all, you may have five...
In your picture is 3 connections to the battery, smaller wires what lead upward out of frame. What does that connect to? Thats a possible cause of unwanted current draw also.
A battery isolator switch maybe handy, but your tiny system wont really need it. Further, if using one to eliminate your slow drain problem, is only hiding that problem not identifying or fixing it.

Thanks! So there is no load from any of the accessories, LEDs are off and the fridge is not attached, plus everything runs to a switch panel in the trailer box that is off anyway (see pics from instagram link in the OP).

The solar controller does have an active LCD panel that is always on so that's a small draw. The smaller wires you mentioned go to a little battery charge indicator I've added to the batt box lid. It's designed to always be on, but I've added a momentary switch so it only draws when depressed.

It may just be the solar charger, but it seems like a fast draw for that little thing. I was concerned that maybe my closed circuit was a problem somehow.

The other thing I've noticed is my little batt charge indicator fluctuates wildly when everything is hooked up. It will read 68% one minute then later 89% etc. I'm assuming that's because there is an alternating load coming from the fridge and it can't tell the correct state of batt when in use, which makes it mostly useless. Is there another way to hook that system up as well?

 

[RLM975]

Draw yourself a schematic of your system. It will help with future troubleshooting and may reveal your parasitic load. It will also help you decide where to put your disconnect.

 

[calicamper]

My 9yr old setup is like your only far cheaper stuff. The solar controllers do have a small draw, my trailer is outside so the 2 10watt panels are just left laying on the trailer yr around. Its s closed system due to the solar controller. I used a cheap no name fuse box and used a ground bar to run all the neg leads to one neg lead back to battery etc. Battery is a deep cycle 18 amp hr that fits in the 50cal ammo box. Controller and fuse box also in 50cal box. Solar panels are plugged in via the Anderson connectors with lid popped loose on the 50cal box. Box only has bolts through it for the mounting to the trailer front plate. I get 5-6 yrs out of a battery solar controller is just a cheap no name 20amp its been fine for 9yrs.

We power LED lights and charge small devices with it. Zero issues.
No cut off switch. I actually used the power side of the controller so I can turn it off via controller or see our power numbers on the controller. Again super basic but has been perfect for 9 yrs lol. Heaviest load I’ve had was about 8-9amps with several lights on and a few devices being charged

 

[DaveM]

My 9yr old setup is like your only far cheaper stuff. The solar controllers do have a small draw, my trailer is outside so the 2 10watt panels are just left laying on the trailer yr around. Its s closed system due to the solar controller. I used a cheap no name fuse box and used a ground bar to run all the neg leads to one neg lead back to battery etc. Battery is a deep cycle 18 amp hr that fits in the 50cal ammo box. Controller and fuse box also in 50cal box. Solar panels are plugged in via the Anderson connectors with lid popped loose on the 50cal box. Box only has bolts through it for the mounting to the trailer front plate. I get 5-6 yrs out of a battery solar controller is just a cheap no name 20amp its been fine for 9yrs.

We power LED lights and charge small devices with it. Zero issues.
No cut off switch. I actually used the power side of the controller so I can turn it off via controller or see our power numbers on the controller. Again super basic but has been perfect for 9 yrs lol. Heaviest load I’ve had was about 8-9amps with several lights on and a few devices being charged

Thanks, this is really helpful info. Sounds like a very similar setup to mine. I plan to add a smaller solar 'trickle' charger to plug in at home and I guess that will handle batt maintenance and countering the draw from (I'm guessing) the solar charger. I may add one of those small batt isolator things that attaches to the batt post so I can disconnect quickly for faster 110 charging. Still getting used to how all this works, seems like I get some variable feedback from all my inputs and readouts depending on what's connected and what's running.

 

[DaveM]

Something is wrong with my system. I'm getting a battery over discharged error on my Reneology solar controller after only about a day or two on a full battery.

I ran a test this week to see how long I can expect my batt and solar panel to run my fridge while camping and see if the system is over drawing. Based on past experience with this fridge and a similar marine batt I should get at least 3-4 days without solar helping out. Probably die on the 5th day depending on temps.

This test: full charge on marine batt, batt meter read 99% at 12.83 volts. Fridge was already cold (37*) and 100w solar panel plugged in (though mostly in shade).

@24 hours later: batt meter read 66% at 12.28 volts. Solar panel was producing a little charge but not much.

@48 hours later: batt meter reads 41% at 11.93 volts.

I stopped the test here (2nd round, same results). I'm recharging the battery now. Will test one last time, but this time disconnecting the trailer LED light bars. They weren't on, but worried there may be something wrong with how I wired it. After that I'll take the battery in to Interstate to have it checked (it's brand new).

Any tips on how to troubleshoot this greatly appreciated.

 

[calicamper]

Buy an el cheapo solar controller and swap it in. See if anything changes. It does sound like the controller is screwy.
My load side is all through the 20amp output on the solar controller. Neg goes to a bar with all the negatives from lights etc. pos has a 15amp
In-line fuse then a fuse box which is then tied to my various stuff. Any load shows up on the controller output display. The controller does have its own parisitic draw but with the panels on it 24/7 doesn’t matter

 

[67cj5]

Something is wrong with my system. I'm getting a battery over discharged error on my Reneology solar controller after only about a day or two on a full battery.

I ran a test this week to see how long I can expect my batt and solar panel to run my fridge while camping and see if the system is over drawing. Based on past experience with this fridge and a similar marine batt I should get at least 3-4 days without solar helping out. Probably die on the 5th day depending on temps.

This test: full charge on marine batt, batt meter read 99% at 12.83 volts. Fridge was already cold (37*) and 100w solar panel plugged in (though mostly in shade).

@24 hours later: batt meter read 66% at 12.28 volts. Solar panel was producing a little charge but not much.

@48 hours later: batt meter reads 41% at 11.93 volts.

I stopped the test here (2nd round, same results). I'm recharging the battery now. Will test one last time, but this time disconnecting the trailer LED light bars. They weren't on, but worried there may be something wrong with how I wired it. After that I'll take the battery in to Interstate to have it checked (it's brand new).

Any tips on how to troubleshoot this greatly appreciated.

Yeah take the battery out of the system and fully Charge the battery from an AC outlet and then run the fridge directly from the battery,

Depending on the size and make of the fridge it should run for 2 or 3 days before it gets down to 12.5v depending on the battery, without any of this info it is impossible to give you exact figures.

 

[DaveM]

Yeah take the battery out of the system and fully Charge the battery from an AC outlet and then run the fridge directly from the battery,

Depending on the size and make of the fridge it should run for 2 or 3 days before it gets down to 12.5v depending on the battery, without any of this info it is impossible to give you exact figures.

The dometic draws around 4 amps I think when running and I've seen some calcs that suggest a good average is about 1-2 amps per hour (cycling on/off in moderate temps). The battery is an Interstate SRM24 81 amp hours. Which may be too small for what I need.