Hood mounted solar panel

[OregonLC]

Stupid solar question of the day: does solar charging the primary rig battery while driving interfere/confuse our "smart alternators"?

I'm about to mount one of these to feed my house LiFePO4 bank, but i'm also considering branching off to the primary battery. If i do this, the alternator will see the additional voltage.

The bigger issue is the charging profiles. Starting / winching want a lead acid battery for the short duration high current needs. This is a different charging profile than the Li batts.

For system reliability, I would recommend just leaving the vehicle system alone. The starting battery will last weeks without need for input as long as the house batt is taking all camping loads. Just let the alternator do its job. I definitely would NOT have a charge leg from the DC|DC connect back upstream to the source powering it. This could be the case if you had a BCDC with solar input also charging your starting battery. The charge leg would be connected to the feed leg, a potentially harmful situation.

Reading other posts in the above, I wouldn't worry too much about engine heat on a hood-mounted solar array. We're not asking for max solar performance while the engine is running. Driving down the trail the alternator will supply required current. Once camped, the engine bay will cool and hood surface temps will align with roof temp.

As far as the air gap, again I think this can be over thought too. A rigid panel elevated above the roof surface induces other problems. Wind noise, debris accumulation, risk of a branch getting under it, etc. I've ran a Sunflare adhered directly to the roof of my AT Summit without issue. If installed correctly there is no risk of the adhesive tape coming free. Our goal is low-maintenance reliability, not ringing every last watt out.

The way I would value a hood-mounted solar solution is one of incremental gain, not an all-encompassing solution. Getting some addition of charge while parked may be beneficial to some. For example, if you run a fridge 24/7 having your house battery charged while at work may be a benefit even though it isn't sized to allow limitless off-grid power. Or perhaps it stretches your power reserve from 2 days to 3 days while camping.

 

[radman]

The alternator will charge the starting battery just fine, there’s no need to apply a float to the battery unless the vehicle is sitting for weeks at a time unused. If it is then yes you can do this and so long as the LFP is fully charged to start with then no it won’t hurt the starting battery.

this. Primary use is for the LFP; however, the rig will sometimes sit 3-4 days with WFH, and for those days, a little trickle would be nice since she lives outside.

I am pretty interested in these, has anyone used one of the ones from Lenssunsolar? they make versions for both of the 200 series hoods..

this is the 4Runner model, fits nicely in the LX

 

[TeCKis300]

Stupid solar question of the day: does solar charging the primary rig battery while driving interfere/confuse our "smart alternators"?

I'm about to mount one of these to feed my house LiFePO4 bank, but i'm also considering branching off to the primary battery. If i do this, the alternator will see the additional voltage.

Short answer, no issue here and it'll work seamlessly. So long as you set the solar charge controller to the right battery profile of which it is charging.

That's the beauty of DC, you can have as many charge sources and draws in parallel as you'd like. They will all sort themselves out by referencing the battery voltage/state of charge. Alternator and solar will work together to pump charge into the battery. They will float when they detect that the battery is no longer taking charge as referenced by the battery voltage. Sure, one may cut-off earlier than that other, but that detail doesn't really matter, as both are respecting the charge profile requirements of the battery.

If the setup were tailored enough, could even have the house DC-DC charger detect excess solar charge. There'd be some low level cycling of the starter battery as the house charger draws things down slightly, cuts off, allowing the solar to re-top off the starter battery, and repeat.

 

[OregonLC]

If we’re talking about doing what’s shown below, it’s a bad idea. Maybe I’m misunderstanding the plan. But you do not want the input to the charger connected to the output from the charger. You also want the DC|DC to properly sense the charge state of the Li House batt. This would be corrupted with the diagram below.

 

[TeCKis300]

If we’re talking about doing what’s shown below, it’s a bad idea. Maybe I’m misunderstanding the plan. But you do not want the input to the charger connected to the output from the charger.

View attachment 3150340

Thanks for clarifying and maybe I'm mis-reading @radman intentions.

Radman, can't branch a solar charger to support multiple batteries. I needs to be one or the other.

 

[UPR LC]

I wonder if this 100 Series panel will fit on a 200 Series hood. I sent Cascadia 4X4 an email for the measurements .

Land Cruiser 80 & 100 Series/Lexus LX450 & 470 VSS System™ 90 Watt Hood Solar Panel

The Cascadia 4x4 VSS System is the world's first vehicle specific hood solar panel system. This particular model is designed to fit the 80 & 100 Series Land Cruisers & LX450/470. Generating 90W of clean solar energy to keep your truck's battery topped up when the engine isn't running. Perfect...

www.cascadia4x4.com

View attachment 2455441

Quick answer for the 2016+ crowd (at least for my 2021) the LC 200 hood is not "flat". There are two high sections with a valley in the middle. So if a hood solar panel were to be used, it would need to be two separate small panels, one on each "ridge".

 

[WCDAVE]

I can report I have used this solar panel mentioned above and it is as advertised. Portable Solar - https://4thdsolar.com/collections/portables Spendy, but delivers and is seriously robust. All of the guys reporting on the effects of heat are correct. A hood mounted unit will be less efficient, but.... always deployed. A portable unit, like the one in the link, while in the sun working does get hot up front but also has the other half in the shade by default and vented making it way more efficient. Also most hood units have way fewer watts than portable, deployable panels.

Also correct - 2016+ will not have a very powerful single panel solution given the valley in the middle of the hood. There are "strip" type 35W panels that can be combined if you absolutely need a hood mounted solution though.

For guys wanting to ensure reliability of the starter battery through solar charging, another option might be to have your solar array charging a Li jump pack like a NocoBoost in addition to the house battery. This avoids potentially making a charging error involving disparate charging profiles between house (Li) and starter (pba) batteries. The jump pack has the added benefit of being able to be employed elsewhere. (Also, if you have all of this other kit, you probably have a good set of jumper cables too......)

All of these problems - hood mounting, heat abatement, sun orientation, wiring concerns, etc. - have solutions that can be engineered, but in the realm of mistakes that can result in fire or shorten battery life, I think it's best for me (someone who is not an electrical engineer) to keep it simple. I look at some of these Redarc systems at trade shows and wonder why people need all of that to charge their camera batteries and make coffee in the back of their pick up truck - which is what they all seem to be doing. To each his own, I guess.

 

[linuxgod]

this. Primary use is for the LFP; however, the rig will sometimes sit 3-4 days with WFH, and for those days, a little trickle would be nice since she lives outside.

this is the 4Runner model, fits nicely in the LX

View attachment 3150315

My truck is garaged though it’s a detached garage so pretty much the same temp as outside. I often went for a week during quarantine (Or more) and the battery was fine. My battery is just a Sam’s Club $99 special. I wouldn’t worry about 3-4 days. If it struggles to start then the battery is likely reaching its life anyway

 

[radman]

Radman, can't branch a solar charger to support multiple batteries. I needs to be one or the other.

Poor choice of words with “branch”. I was thinking more of a toggle switch to flip between the starting and LFP batteries.

If set to the starting, the alternator would see additional voltage coming in from the panel, and I’m not sure how it would react to that.

If it struggles to start then the battery is likely reaching its life anyway

I have a relatively new “Lexus” battery, but I also have dash cams that sometimes get left on for multiple days. I have since noticed that the battery struggles over a weekend, but as you said, it probably needs to go in for a warranty replacement.

Back to this mod:

I gave the hood a good Dawn wash and then clay bar’d it. Then, i used a wet method to lay this puppy down. Will wait a few days before mounting the panel…

 

[NicksFJ40]

Any thoughts on removing 3M double sided tape? I installed my Lensun solar panel and it delaminated along the edges. Lensun is sending out a replacement so I now need to remove the defective panel.

I’ve seen videos on using dental floss and heat gun but those were on small objects.

Thank you
Nick

 

[mep1811]

A breakaway razor knife works well. You can extend the blade a couple of inches and is flexible enough to get under and cut the tape.

 

[Fisher23]

I would go the heat gun and either dental floss or braided fishing line. I think that casing around the exacto blade would be too thick and cause too much angle.

 

[mep1811]

I would go the heat gun and either dental floss or braided fishing line. I think that casing around the exacto blade would be too thick and cause too much angle.

The breakaway razor knife is not an exacto knife. Although the segments can be broken off the blade can be extended a few inches and is very flexible. I used this to remove my panel. As the panel is cut away you can lift and slicing the tape becomes very easy.
I've never had luck with dental floss.

 

[82SC]

Hmmm. I was thinking of putting matte vinyl to cut down on glare but this seems to be a way to kill 2 birds with one stone.

Heat will make it much easier to peel up the 3M tape. A lot of times you don’t need floss or razor. But good to have on hand. A little “goo off” to get the residue.

I’d start with a regular hair dryer. Heat guns get a lot hotter and can damage and melt stuff. Also could melt the stuff on the underside of your hood.

 

[RET2]

To OP please document your efforts as I'm sure others can benefit.

 

[customcruiser]

I'd use braided fishing line or old dental floss - new floss is flat and not nearly as strong as the old stuff.

 

[NicksFJ40]

All great ideas, I do have one of those break away razors, heat gun with temp control and fishing line. Im all set! I stopped by the shop that installed the vinyl, he said I will have to remove the panel, I was hoping they could easily remove the vinyl with the panel.

I will definitely report back.

 

[customcruiser]

I would try and remove vinyl and with it should come the panel.

 

[NicksFJ40]

That’s what I ask from the vinyl guys, they said no, they can steam it off but not with the panel.

So I’m back to square one.

 

[UPR LC]

Quick answer for the 2016+ crowd (at least for my 2021) the LC 200 hood is not "flat". There are two high sections with a valley in the middle. So if a hood solar panel were to be used, it would need to be two separate small panels, one on each "ridge".

Toyota LandCruiser 200 Lensun 90W Hood Flexible Solar Panel

Lensun hood flexible solar panel mounts to the hood/bonnet of your vehicles. Charge the vehicle battery, leisure battery, or power station. Keep your fridges, dash cam, starlink, lighting, phones, etc., charged. Do not worry again about a dead battery while camping/off the grid.

www.lensunsolar.com

Looks like lensun now makes a 2016+ dual panel product.