Solar Charging While Driving?

[seprintz]

Possibly a stupid question, but my wife asked and I couldn't say for certain.

We're planning a long cross country trip this summer, I'm planning on 1,365 watts of solar for our travel trailer's roof. Will those panels charge our batteries while we drive? It seems like they obviously would, but I thought I'd ask.

Reason for asking: If we're driving for 8 hours a day, it'd be nice to arrive at the next camping spot with fully charged batteries.

TIA!

 

[Bob B]

Probably better since the panels will be cooler.

If you don't get enough charge you could consider one of the DC to DC solutions.

 

[Lt.Dan]

Yes they will charge while in motion

 

[richard cabesa]

As Bob B said, the panels will stay cooler with the air flow and there is rarely shade on the interstate

 

[TacomaJoe]

A 100W panel will charge a battery. To answer OP's question, need to fill in a couple of blanks. Size and charge profile of the battery, and how much is used during travel. I'm using next to nothing on the road (LP refrigerator) but I can shut off the propane and run the refrigerator with the inverter using more of my energy. I find usually better solar on the road than when stopped (a lot of trees around here).

 

[seprintz]

@TacomaJoe I appreciate your concern, at this point, I wasn't too concerned with details, but just wondering if it was possible, if so, then it's just free SoC for driving I'll be doing anyhow.

I've got 8.64 kWh of LiFePO4 in 8s2p, 16 CALB SE200 cells. I'm planning on 1,365 watts of solar 3x455 watt mono panels. I haven't picked a charge controller yet, but back in the day I used the EPEVER 30 amp controller that Will Prowse used to recommend. That charge controller is now permanently installed in my father in-law's milking barn, so I need something else. In theory, next to nothing will be used during travel, I'll have the inverter turned off, and only our 12v electric cooler running.

Let me know if any other details are relevant. I was trying to determine how much I might have to use the generator after a day of driving, and IF a DC to DC option is needed. Based on the replies I've gotten so far, I think DC to DC won't be necessary.

 

[dcg9381]

Possibly a stupid question, but my wife asked and I couldn't say for certain.

We're planning a long cross country trip this summer, I'm planning on 1,365 watts of solar for our travel trailer's roof. Will those panels charge our batteries while we drive? It seems like they obviously would, but I thought I'd ask.

Reason for asking: If we're driving for 8 hours a day, it'd be nice to arrive at the next camping spot with fully charged batteries.

TIA!

RV'er here. Your 7-pin trailer connection will likely charge your batteries (also). At least it does on my RV.

 

[Lt.Dan]

RV'er here. Your 7-pin trailer connection will likely charge your batteries (also). At least it does on my RV.

Lots of voltage drop and very little current though. I wouldn't "rely" on it.

 

[seprintz]

RV'er here. Your 7-pin trailer connection will likely charge your batteries (also). At least it does on my RV.

I'm building this trailer myself from an enclosed cargo trailer. I currently have no intention of connecting my house wiring to the 12v of the trailer. The trailer wiring will be it's own system that is just used for the trailer lights and trailer brakes.

Does my system sizing look OK? Or am I way off somewhere? Thanks.

 

[OffGridInTheCity]

I have panels on top of my 7 x 14 cargo trailer wired into the trailer's AIO MPP Solar 3048LV which we leave running while driving and they charge the batteries just fine.

The problem occurs when we reach the destination / camping spot - it's usually among or under the trees which blocks the sun.

 

[HarryN]

So it depends.

If you have one of the import dual input combo solar / vehicle power units - the answer is no, because they will turn off the solar if their is a vehicle 12 volt power source available to charge from. (example kisae type and many packaged solar generators )

If your system has dedicated solar chargers and DC - DC chargers and they are designed / tested to work together, the answer is yes.

BTW - the vibrations are a lot worse in a trailer than in most vehicles so just keep that in mind when building electrical stuff.

edit - just saw that you won't be using DC charging, so no problem.

 

[OffGridInTheCity]

BTW - the vibrations are a lot worse in a trailer than in most vehicles so just keep that in mind when building electrical stuff.

Ours is a dual axle with tires balanced and it's similar to the inside of a car. Single axle is different / prone to bouncing much easier I understand. The MPP Solar 3048LV AIO has traveled over 1000 miles and 2 years with no problem. It's good to stay on first class roads and avoid bouncing too much over speed bumps at a camp ground and to limit 'off-grid county roads' of course

When I was building things, one person suggested using hot glue to help secure electronics if you have things like 'large capacitors' (or something electrical) that sticks up off the PCB and can wiggle on bounces - but we've not needed to do anything like this.

 

[dcg9381]

I'm building this trailer myself from an enclosed cargo trailer. I currently have no intention of connecting my house wiring to the 12v of the trailer. The trailer wiring will be it's own system that is just used for the trailer lights and trailer brakes.

Does my system sizing look OK? Or am I way off somewhere? Thanks.

You're missing my point. If your trailer is large enough to have trailer brakes (electric) then your batteries are usually inherently connected through the trailer 7-pin to the DC voltage of your vehicle.

As your trailer is smaller (and likely not a 7-pin) there are ways to get power from the vehicle that might be worth exploring by using the 7-pin.

Lots of voltage drop and very little current though. I wouldn't "rely" on it.

~15A give or take. Depending..


We don't know what the "traveling" loads are on your trailer. In general, if the batteries are just sitting there, a 25W panel is enough to keep them topped up. I run 175 watts on a truck camper and that way more than enough between stops with shore power. It's actually more than enough for most cases boon-docking as we don't use the 12V furnace much - it's simply running LED lighting and the propane fridge controls. The rigs I see with 1000W or more of power usually have inverters and big battery banks - they're usually running something like a residential refrigerator.