installing panel on top of pickup fiberglass cover questions

[carl2591]

thinking about installing a 280 watt 24+ volt panel on top of shell on pickup. I was going to use this as additional power and something to move and put in sun if not able to have good exposure on trailer panels.

they have the MC4 connectors and trying to figure how to get the elec back to inverter/charger on trailer.

was guessing I could get length of cable with mc 4 connection and have a lead from inverter to a-frame with hook up. With 9 amps at 31 volts the 10 AWG wire should be good for some 30 ft from panel on truck to inventor.

was also looking at amsolars 35 mm rocker foot mount set mounted on short side of panel to allow for tilting of the panels in winter low sun times.

any hints etc

[idroba]

Be careful that your chosen charge controller is compatible with both the voltage (nominal) and peak of your proposed panel and can also feed your 12 volt batteries properly. The normal PWM charge controller using a 24 volt nominal rated panel will not properly interface with the 12 volt system. A MPPT controller may have issues with the open circuit voltage of the panel you suggest while trying to feed a 12 volt nominal system.

[TG Twinkie]

Here is one for the experts.
If you have a 24 volt panel and want to charge 12 volt batteries.
Could you wire two 12 volt controllers in series on the input side? In essence, using them as a voltage divider. They would be identical units.
Then wire the controller outputs in parallel for the 12 volt output.


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[lewster]

You need a solar charge controller that is rated for 24 VDC like this one: Solar Boost 3024iL MPPT | Charge Controllers

It can handle 24 VDC input with a rated 30 amp output or at 12VDC input, 40 amp output. A great controller!

[idroba]

Yes, lew, looks like what he would need. There are not many out there which will do the job. Thanks for posting this one.

[Silver Hawk]

Why not just use a 12 volt panel? I have one and it works great.

[TG Twinkie]

Voltage drop.


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[lewster]

Voltage drop is minimized with properly sized cables. We will tolerate no more than 2% drop, and less if we can do it.

[carl2591]

voltage drop was one reason for the higher voltage panels on camper top.

One thing i was thinking to make this a bit simpler was have a couple batteries in a box in pickup bed and have a bigish cable with connectors to extend to trailer batteries to add capacity to the system.

this way I could move the truck into sunny area to charge batteries and then move back to hook up batteries on trailer.

That way I could have one charge controller for the pickup batteries and a separate controller for the trailer panels better matched to there voltage needs.

or maybe if trailer panels not getting enough sun have way to disconnect line from trailer charge controller and use pickup system to recharge batteries on trailer. I know WOW..

I might be over-thinking this just a bit and just thinking out side the box for down the road adventure.

[cwf]

Carl, not trying to distract, but if concerned about voltage drop to the AS, why not install battery bank inside the truck bed? Short run for solar controller... and you could have additional capacity...

[slowmover]

Originally Posted by cwf

Carl, not trying to distract, but if concerned about voltage drop to the AS, why not install battery bank inside the truck bed? Short run for solar controller... and you could have additional capacity...

After seeing how a guy with a truck camper mounted a pair of BIG batteries under his truck bed outside of frame rails it got me to thinking the same. Now if I could only find a continuous duty diesel genset sufficient to easily run a 50A service twin A/C TT and magically raise TV GVWR all at the same time.

FORD offered a 2500 watt ONAN single cylinder that mounted under hood 1970-72. That, with solar as discussed, would sure cover extra batteries and those of the TT.

[carl2591]

Originally Posted by cwf

Carl, not trying to distract, but if concerned about voltage drop to the AS, why not install battery bank inside the truck bed? Short run for solar controller... and you could have additional capacity...

yes that is what i was trying to figure out. have one bank of 2 6v batteries in truck bed and the other in AS which could be hooked together making for more capacity.

just trying to get the plan in my head and any ideas other may have..

[HiHoAgRV]

Originally Posted by carl2591

yes that is what i was trying to figure out. have one bank of 2 6v batteries in truck bed and the other in AS which could be hooked together making for more capacity.

just trying to get the plan in my head and any ideas other may have..

The biggest problem is making a decision...
A big battery bank in the trailer OR one in the truck. One in each isn't a good solution, unequal charging will not work out, one set will boil while the others will be short charged.

It sounds like you are leaning toward a high voltage, low current MPPT system with the panels on the truck, fairly good sized cables and a big battery bank in the trailer.

Me too.

Down side? When I'm out driving the Wife to shop, the trailer ain't getting a charge. Up side? Trailer in the shade, truck in the sun.
Other options? Solar, inverter and battery bank in the truck. Kick in the inverter to charger the wimpy trailer battery and run 110 stuff.

Too many options.

[Griff]

If the truck is going to be parked 80% of the time at the trailer just run the power to the trailers charging system.

Truck away from the trailer, just put a small panel outside connected to the trailers charging system to trickle charge.

It all depends on truck time in the sun and when the truck is back. If truck is back at dusk your going to need the extra batteries in the truck to supply power. Truck back in time to charge trailers batteries no need for extra batteries in the truck. If you will need more power just put the extra batteries in the truck then everything will be covered.

Tom

[carl2591]

know it been a while but was wondering if this unit can be hooked up to the bogart TM 2025 RV display system or do you want to stick with the blue sky.

The SC2030 work on 24 v panels to 24 volt batteries or 12 and 12.

thanks

Originally Posted by lewster

You need a solar charge controller that is rated for 24 VDC like this one: Solar Boost 3024iL MPPT | Charge Controllers

It can handle 24 VDC input with a rated 30 amp output or at 12VDC input, 40 amp output. A great controller!

[gandttimes]

Originally Posted by TG Twinkie

Voltage drop.


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I have 3 100w. Mc4 connectors join up with # 6 welding cable that plugs into a lead coming from the charge controller near the batteries. Works fine.


George

[slowmover]

TORKLIFT Hiddenpower. Locate one or more batteries under truck bed with frame mount kit. Slick!!

[carl2591]

man you must be psychic or psycho as I was just looking at that same thing last night. I keep a catalog of RV parts the "RV 2013 Accessories" by the bed and every so often just grab it and let it flip on to what ever..

as luck would have it last night the page with tork industries showed up.. and there it was the under frame battery holder.

I do wonder how hard it is to check water etc.. looks good on paper and on the 4 post car lift as well but real world might be a different deal.

do you know of any one that is using one or two??

thanks a million for the head ups..

Originally Posted by slowmover

TORKLIFT Hiddenpower. Locate one or more batteries under truck bed with frame mount kit. Slick!!

[carl2591]

george..
thats sound cool for sure.. how far are you going with the MC4 lines and the #6 cable to charge controller.. i guess your panels are 12 v vs 24 v.

I was thinking of one 285ish watt panel in the 24v (actually 32+v) going from truck using #8 wire of some 30-40ish feet. I like the plug deal sorta like the anderson power plugs like they use on elec fork lifts.

good idea for sure.. thanks

Originally Posted by gandttimes

I have 3 100w. Mc4 connectors join up with # 6 welding cable that plugs into a lead coming from the charge controller near the batteries. Works fine.


George

[gandttimes]

Originally Posted by carl2591

george..
thats sound cool for sure.. how far are you going with the MC4 lines and the #6 cable to charge controller.. i guess your panels are 12 v vs 24 v.

good idea for sure.. thanks

The Renogy panels came with the mc4 connectors on them. I joined them to a connector down through the cap to a "Pollack" female two prong connector (attached to my bumper) that is used in trucking applications that can handle up to #4 welding cable.
The Bogart Engineering SC2030 controller is about 2 feet from the batteries,and the #6 PV lines run out to beside the battery box where I have one end of the Anderson connector. Then I have 25 ft of #6 cable with the Anderson on one end and the Pollak male end on the other so I can take it off the trailer as it would be too tempting for someone else to remove it for me.

George