Permanent Solar/CC for OEM Battery Question

Are any of you running permanent solar panels and a charge controller for the truck battery? If so, how did you spec fuses and did you use a diode?

As background, my old land cruiser sits around more than it’s driven. I bought a 10 watt solar panel with integrated charge controller from Amazon, and used the alligator clips to connect to the battery. Before I start the LC, I remove the alligator clips and the truck starts up. This setup is fine for that vehicle and works great if I don’t drive it for a few weeks.

For the 2020 Tundra with push button start, I’d like a more permanent setup that doesn’t require removing any solar component prior startup or while driving. I’ve looked around and asked on other platforms but advise is vague at best.

So, how would you build a diy permanent solar configuration for the truck battery?

Here’s my thinking so far:

- Solar panel, 10-25w, mounted with magnets on the hood scoop
- Fuse between solar panel and charge controller, 10a?
- Charge controller, 10-20a?
- Fuse between charge controller and battery, 10a?
- Diode of some type???
- Truck battery


That’s the logic... TIA for any help

 

I haven't done this for the Tundra, but have on another vehicle. It was permanent in the sense that it won't fall off, but modular and removable to leave no evidence it was installed.

- Solar panel, 10-25w, mounted with magnets on the hood scoop
Magnets will scratch up the paint. They do make paper-like flexible solar panels now that you can tape down. Or have it in the truck bed and run a cable to the battery.
- Fuse between solar panel and charge controller, 10a?
Fuse rating would be whatever max the solar panel can output. Using an example of a 100w solar panel at 12V it's 8.3A (100W/12V=8.3). If we change the volts to 14V to match alternator voltage, the amperage is 7.14A. I did not fuse this path for myself, as I could see all of my wiring from solar panel to charger. I don't think other people fuse this section either, as you want your fuse closet to the panel instead of down next to the charge controller and I see no easy way of doing this. 7.5A fuses exist. See FUS-ATO-7.5 https://powerwerx.com/75-amp-ato-blade-fuse
- Charge controller, 10-20a?
The charge controller states its amp range. Example this https://www.renogy.com/wanderer-li-30a-pwm-charge-controller/ states 30A, so put 30A fuse at the output of the charge controller. I did not fuse my output, as the solar panel would always be connected to the battery, wires were short and visible, and I was using a 40W panel providing 3A max. Renogy makes a 10A controller I could've used, but I could always repurpose the 30A controller for something else.
- Fuse between charge controller and battery, 10a?
See above. Choose the fuse of the max amps the panel/controller supports and put the fuse as close to the battery as possible. If the wires between the battery and charge controller break, you have both sides of the wires with 12V on them, so have a fuse at both the battery side and controller side.
- Diode of some type???
What's the purpose of this? To prevent the solar panel from draining the battery at night? The charge controller should handle that already.
- Truck battery

https://cdn11.bigcommerce.com/s-fhn...ucts/1494/18991/_07__69393.1584014244.jpg?c=2


Solar panels usually come with MC4 connectors (see photo between Solar Panel and Adaptor kit). They're waterproof connectors that have clips that lock in to each other, so they don't fall out. Positive cable is also shrouded, so it won't short or spark against anything if it falls out (get rid of those alligator clamps).

The charge controller terminals take bare wire. To make adding fuses easier though, terminate the adaptor kit and tray cables with Anderson Powerpole connectors, so you can add an inline fuse holder: https://powerwerx.com/powerpole-inline-atc-fuses-10-gauge . Add a short length of wire that is bare to go to the controller, and Anderson Powerpole to connect to the fuse holders.

I use this for my battery side: https://powerwerx.com/ring-terminal-powerpole-inline-fuses-10-gauge

Anderson PowerPole connectors have a single gender, so no dealing with male and female connectors. They're shrouded and won't short out against anything when disconnected. PowerWerx can also custom build any of the cabling you need, which I had them do at the beginning. I've found so many uses for PowerPole connectors though that I bought my own crimp tool, but also had a soldering iron before that.

 

Appreciate all of the great information.

When the truck starts, idles and is driving, will there be any issue with the alternator current back feeding the charge controller? I was thinking a diode would act like a check valve to prevent the alternator current from damaging the charge controller. Perhaps the CC has back feed protection built in, which would make sense for RV applications that use shore power.

When the truck is off this diagram is spot on. I’m not 100% sure if all the back feed protection is there when the truck starts/drives.

 

The diode would act as a valve, but the charge controller already handles it.
https://www.etrailer.com/question-393774.html
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27633424/print/true.cfm

I've used both alternator and solar panel to charge my batteries, with all 3 being in parallel to each other permanently. Did it from March 2017 till July 2020 without any problems. Panel, controller, and battery still work fine.

Below is the information as to how my minivan was setup

My parts are:
40W Renogy Panel
30A Renogy charge controller
2016 Honda Odyssey. Factory stock
Factory battery in engine bay
12V 79AH AGM (East-Penn 8A24M) as auxiliary battery

Solar panel was placed on the dash. Added some foam around the corners just in case so the corners of the panel wouldn't hit the windshield. ?silicone? friction pad below to keep the panel from sliding. Solar panel cables go to the floor on the front passenger side to a charge controller. Tray cables from the charge controller go to a Powerpole splitter (https://powerwerx.com/8-position-powerpole-distribution-block) right next to it. From the splitter, another powerpole cable runs to the back of the van to another powerpole splitter. The auxillary battery in the trunk connects to the rear splitter, as well as some powerpole to 12V outlets and an inverter. (https://powerwerx.com/automotive-cigarette-lighter-socket-fused-powerpole-connector) to power a dashcam.

Back at the front, the front powerpole splitter also has a powerpole to 12v adapter to run the front dashcam, cb radio, and phone chargers.

For the alternator path, I had tried 2 types. First was running a cable from my engine bay battery, through the firewall, and to the front powerpole splitter. So when engine is running, the alternator recharges the rear battery and powers everything. When the engine is off the rear battery and solar panel take over and power everything. This was used for several months until I had to bring it in for a safety recall of idiots not making sure the removable seats are locked in place correctly. Pulled everything.

After getting the vehicle back, I didn't want to fishtape the cables back through the firewall. So instead I used a 12V outlet to powerpole adapter (https://powerwerx.com/cigarette-lighter-powerpole-adapter-6ft). The outlets have a 15A fuse, but I never drawed more than 2A (https://powerwerx.com/watt-meter-analyzer-inline-dc-powerpole) anyway to power everything and recharge the rear battery, so I knew it was safe to do this.

Any reputable solar panel brand should be able to do this. I went with Renogy because it was budget priced but decent quality, and the Reddit Vandwelling people liked it. Powerwerx and Powerpole were recommendations from the HAM radio crowd, I use it for alot of things even around the house. Saves me from truely hardwiring things and dealing with screw terminals constantly if I want to swap things around.

 

Won't even notice this setup on a BLAAAAACK tundra....



Toyota Tundra 1st/2nd Gen | 90 Watt Hood Solar Panel | Cascadia 4x4

 

Great advice here. Thank you

 

I have extra charge controllers laying around, one is 10a I believe. I’ll give it a shot on the old Land Cruiser first and report back. Your logic makes sense to me. Crossing my fingers the CC and/or solar panel don’t explode once the truck is running.

 

here's my setup with the cascadia product you mentioned.
https://www.tundras.com/threads/cascadia-4x4-vss-tundra-specific-solar-system-just-installed.84553/

 

The tundra system is out of stock, is there any difference with the taco package other than it being 70w?

 

Have no idea. I'd contact Cascadia directly.

 

@FrenchToasty what did you ultimately go with

 

Nothing let, I’m powerless

 

got ya. going with a Jackery and a solar panel for now to power the fridge

 

That should be plenty.

 

I think that Cascadia kit is back in stock.

there's another brand (Lensun) that looks the same
https://www.lensunsolar.com/index.php?route=product/product&path=88&product_id=562

if the goal is to keep the battery full inbetween infrequent uses, why not the $15 1.5W charger from Harbor Freight?

 

100w Renogy panel mounted on my roof platform. Inline fuse between the panel and cc, inline fuse between the cc and battery. No issues.
Same type of setup that I have on my trailer, just 500w less. Charge controllers recognize battery voltage along with panel and adjust as needed, so don't use a diode.
If there were an issue of charging from another source, there would be a lot of dead panels from people hooking up to generators or shore power without disconnect their cc. There isn't...