One Solar panel to seperate batteries

[mjac]

Here's hoping this is a short thread and way shorter than it will take me to explain what I am trying to do. I searched but I haven't quite found my answer. I learned a bunch of other stuff though. Thanks.

I am about to put a panel, probably a 100 watt on the stock roof rack of my T4R. I know I should be able to adjust (tilt) the panel but where I go/camp is mostly pretty heavy timber so it won't make much difference if its flat. So that's the way it will be mounted for now, but I digress.

I have an ARB fridge running on single oem (27 gp?) TV battery and hope a 100 watt panel will do the job keeping the battery charged for a few days. However there are days I will travel away from camp and return with a fully charged battery and wish to use the panel to charge a camping trailer that has a battery but without any means to charge it except with a generator and battery charger, which I carry but want to avoid.

I want to be able to connect the camper battery from time to time to the solar (and maybe while underway moving to another camp site) Will I need something like this:

https://www.amazon.com/gp/product/B007NNMEU6/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A1Z4QPXV0KM1LQ

mounted out of the weather on the TV. Or is there another less costly device available and how far can the panel/TV be from camping trailer before much charging loss?

Thanks

 

[1Louder]

1. Yes, you need a controller whether you are charging 1 or multiple batteries.

2. Do you have a 7 pin connector to your trailer? If so then you don't need to anything but leave the trailer connected to the truck. Your solar panel should be able to charge both batteries at the same time. I have a 100 watt Renogy panel and it can charge both of my batteries.

If not you would have to design a way to connect the two while parked. If you went through that effort I would setup a dual battery setup with a proper controller. That will charge you vehicle battery 1st and then when that is charged it will switch to trailer battery.

 

[mjac]

Yeah, I knew a controller was required. I was wondering the one I linked would be what I needed. It will service two batteries independent of each other. I think. Plus its pricey.

No, I do not have a 7 pin on the trailer. It never had a battery, I added one and tapped into the on board inverter wiring to run lights etc. Unfortunately the inverter does not have a charger function but that's another story. I was considering swapping the current trailer 4 pin over to 7 pin but then I found out I would only be maintaining a battery (barely). Plus I would have to leave the key on and that would be a problem. There is no accy position on my T4R ign switch.

The trailer is a old pop up, sorry for not making that clear, so hooking up each time with the bed out would be out. I was thinking I could make a jumper cable and and backing up as close and connecting the battery on the pop up tongue to what ever controller I was going to use.

Are you suggesting I could charge the pop up battery with the panel and one controller through the 7 pin? If so, I am all ears but have another question. Wouldn't that drag the TV's battery down if the trailer battery was flat?

I still would have to make a jumper to get to from the TV to the trailer but that's ok.

Thanks

 

[jonyjoe101]

for a 100 watt panel you can get away with using a 10 amp wincong pwm controller, they are less than 20 dollars. I use one for about 2 years on a 120 watt and even on a 240 watt panel. I think the 25 amp morningstar is too much controller for your needs. I dont see that kind of amps even on my 240 watt panel.

Your 100 watt panel will max out at 5 amps even on the best conditions. On my 120 watt panel it put out about 6 amps average in the midday sun.

The wincong is a cheap controller but it worked reliably nonstop for 2 years 24/7. I replaced it when I upgraded panels. But if you are going to spend 100 dollars instead get the ecoworthy 20 amp mppt controller (about 100 dollars) it will work with the 100 watt low voltage panel but it wont increase the amps you get. But if you upgrade later to a bigger high voltage panel thats when you see results, I get 12 amps from my 240 watt panel from the ecoworthy. It also has an lcd screen to see voltage amps etc. I had my ecoworthy for 3 years running 24/7. The ecoworthy is also programmable you can adjust the voltage going to your battery.

If you do get a cheaper pwm controller that has no lcd display, I recommend you get a dc wattmeter (about 15 dollars) and connect between the controller and the battery. This way you can tell how much voltage amps your battery is getting. Its better than using a voltmeter everytime you want to check if everything is working.

 

[SnoViking]

Here's the setup I used for my 4Runner. I have the solar going into the house battery and the house battery being charged by the 4Runner chassis battery when I'm driving.

With all my accessories and electronics: I try to build and wire them separate from the chassis battery. This way if I have an issue somewhere sometime with electronics, I can completely disconnect all the stuff I added on and I'm back to 100% stock 4Runner electronics. It's easier to diagnose any problems that way. I'd rather wake up to a warm fridge and dead house battery than dead chassis battery and be stuck some where. I do carry a portable jump pack as a plan B.

You can just move the solar charge controller (and panel) in my picture so it feeds into the chassis battery first. I got my charge controller off of amazon for $20. Its a 20 amp unit and works great with my 100w solar panel. I have one of the thin flexible 100w panels. It's absolutely awesome. It weighs 4lbs. (Looking back though, I should have picked up 2 50w flexible panels instead of 1 100w panel. It would have made for storage even easier.)

I use a "Dinghy" charger to keep the house battery topped off when the solar isn't cutting it or when I'm driving. It's not a true dual battery setup but it does what I need (plus I don't have room for a second battery under the hood unless I invest some serious money for a new tray and start cutting things up). My setup is more like a battery pack. The dinghy charger is made by Toad and puts out 10amps. It had built in reverse polarity protection and a few other smart features. They go for about $50.

 

[mjac]

Verkstad,

Thanks so much for your reply. I have looked at few intelligent charging relays since your reply and think I have a handle on using one while the car is on. But I have the following question, specifically for use when the car is switched off.

Charging the trailer battery with my car via the 7 pin trailer connection (which I will have to make on the trailer side), when the car is turned off an OEM isolater prevents the trailer from drawing down the car's battery. How will a intelligent charging relay know the trailer battery is connected when the car is switched off? Or will I have to run a separate set of wires from the intelligent charging relay to the trailer, instead of using the car's 7 pin connector? Plus an extender to the trailer when the car is parked nearby.

Thanks

 

[mjac]

Thanks, Jonyjoe101

I was considering, the Morningstar Duo, because it was what I thought I needed to charge two isolated batteries. I am learning that there are other other ways to do what I need.

I'll keep your suggestions in mind.

 

[mjac]

SnoViking,

I have one (starting) battery in my T4R. I have a ARB fridge and one or two non essential devices hard wired to the starting battery. The non essential devices are manually turned off when parked and the fridge becomes the only draw on the battery. I plan to roof mount a solar panel to the T4R for the purpose of off setting the fridge draw on the starting battery. I don't have room for a second battery under the hood and I am not wanting to move things around to accommodate a second battery either at this time.

I have small, old, no frills pop up I hunt out of. It did not have any provision for a battery but I have added one. This is my second battery. While the load will remain low on this battery it will nevertheless require some charging and is the battery that I was/am hoping to funnel, siphon or otherwise get some charging from the solar panel that is on top of the T4R.

I have found that I can maintain (barely) the TR battery with the TV while traveling by using the TV's 7 pin connector. The solar may or not help while traveling but I don't really care. The 7 pin arrangement appears useless when parked as the 12v is no longer available as per the design of the T4R. Its when the TR is parked and the TV's battery is full, how can I use the TV's solar on the TR's battery. Compounding the issue is the TR will most likely be unhitched from the TV and some sort of extender will be needed.

Sorry to have repeated myself but I am trying to clearly present what I am trying to archive.

Thanks

 

[mjac]

This would need minor modification of the OEM wiring.
The OEM isolator relay could be replaced with the automatic relay.
Or, and probably better for charging capacity and less mods on the OEM system, Just run a new large conductor from the ACR back to replace the charge circuit of the 7pin or better yet, install another connector just for the battery.

[/QUOTE]

Ok, great. I think I got it now.

I'll leave the 7 pin set up on the TV alone. It works ok as designed with or without solar when going down the road. I'll still have to fit the TR with a mating 7 pin but that's not a big deal.
Install a solar panel and controller and connect to the TV battery.
I'll install a intelligent charging relay or solenoid, one side connected to the TV battery.
(For a number of reasons it will much easier to drive up to my parked TR rather than back up to it)
I'll put a short as possible pig tail size/wire under the hood of the TV, connected to other side of the charging relay/solenoid and put connectors on the other end.
I'll put a another yet to be determined size/length wire on the TR, one end connected to the TR battery and the other with mating connectors to connect to the TV's pig tail.
Drive up, open the hood, plug up, done.
Ok?
It is ok to leave the pig tail from the charging relay/solenoid on the TV unconnected when not using it to pass a charge to the TR?

 

[dwh]

Have a look at Samlex ACR-160.

 

[mjac]

Have a look at Samlex ACR-160.

Thanks for checking in Mr dwh. I noticed the Samlex product over in the "How to make a cheap isolated dual-battery setup for $50" thread". A very long, very informative and sometimes entertaining thread indeed. Thanks for your many and sometimes over my head contributions.

In spite all I read advocating the use of a solenoid over an intelligent charging relay, I am undecided about which I should use.

If you don't mind, in your valued opinion which would be best suited for my application and why?

Thank you.

 

[dwh]

Lucky for you I fired up my netbooks to update their Kali linux. So I'm on a real keyboard. The phone makes me wanna lurk since posting is such a PITA.

Intelligent relay is a solenoid with a brain. Plain ol' solenoid without the brain is dirt cheap. Which would be fine for you, except that you need to be able to charge the trailer from the truck mounted solar when the engine is off. The dumb solenoid is ignition controlled, like what is in your truck from the factory, and won't work for what you want to do. So you need a solenoid with a brain, or "Automatic Charge Relay" (ACR).

The Samlex ACR-160 is bloody good unit for the price. Dual sensing - that means that whenever it sees a charge voltage on either side, it will tie the batteries so both get charged. Easy option to add your own switch to force on/force off if you want, and also easy option to add an LED so you know when it's engaged. Rated high enough to handle the output of just about any factory alternator. And...IIRC...waterproof.

Your problem is getting power back to the trailer. The Morningstar Duo isn't really the right unit for that, since it really should be connected to both batteries all the time. Oh, you could make it work, but I wouldn't bother. I'd say you're better off with a relay/solenoid setup since that also gets you the alternator charging when the engine is running, which the Duo setup doesn't.


So...

Get the ACR-160 (best price I've seen was DonRowe.com, about a hundred bucks, but I haven't really looked, you might find it for less).
Feed from the engine battery to one side of the ACR.
Find the wire that runs from the truck 7-pin to the factory isolator (ignition controlled), and unhook that wire from the factory isolator and hook it to the other side of the ACR.*
Put a 7 pin on your trailer and hook the trailer to the truck.
Hook the solar up to the engine battery.


When either the solar or the engine is supplying charge voltage, the ACR will engage and tie in the trailer battery and both batteries get charged.
When neither the engine nor the solar is supplying charge voltage, the ACR will disengage to keep the trailer from pulling down the engine battery.
If the solar is supplying charge voltage, but you load up the battery on the trailer, and pull down the trailer battery voltage to where the solar can't keep up, and then start pulling down the truck battery, the ACR will disengage and keep the engine battery from being pulled down. Until the solar brings the truck battery back up, then the ACR will re-engage. Rinse and repeat ad nauseum.


It's all good. Except...

The solar will (hopefully) keep up with the fridge demand so you don't end up killing your engine battery. That's a roll of the dice if you ask me. 100w solar, fixed mount...might be enough.


Also buy a decent battery charger if you don't already have one, so you can charge up the trailer at home, and if the truck is connected, top it off as well. Won't matter whether you hook the charger to the trailer battery or the truck battery, since the ACR will tie them when it sees charge voltage.

And then, to be fully ExPo approved, carry a jump pack, a small generator, a sat phone, a SPOT, air medevac insurance and you're good to go.

Cheers.



*(Actually, you need a fuse or a breaker to protect that wire in case it shorts out along the frame somewhere. I like the Bussman ShortStop breakers. They are cheap, and last forever if you don't let them get rusty. It's probably a #10 wire, so you'd need a 30a ShortStop.

10 bucks for the fancy one at Amazon:

https://www.amazon.com/Vulcan-Short...-fkmr1&keywords=bussman+shortstop+breaker+30a


So run the factory 7 pin battery wire to the breaker, then the ACR.)

 

[dwh]

Whoops, just noticed that one I linked at Amazon is made by Vulcan, not Cooper-Bussman. Ah well, you can probably find a Bussman at the local auto parts for less than 10 bucks anyway.

 

[mjac]

Whew. Thanks. That's going to take a while to digest.

I am kinda worried about the ExPo approval tho........I only have 4 of the 5. Can I get an ExPo in-training badge? :drool:

 

[dwh]

Whew. Thanks. That's going to take a while to digest.

I am kinda worried about the ExPo approval tho........I only have 4 of the 5. Can I get an ExPo in-training badge? :drool:

Four out of five is fine, as long as you can make a claim of "saving weight" and make it stick.