Solar for Hybrid Battery?

[Davexxxx]

If there was plug n play infrastructure already on the truck, adding solar panels for the HV batt would be easy and cheap. Premium brand monocrystalline glass solar panels are down to just over a buck a watt and apparently there is a mkt. for used panels, where you can cut that cost in half, or less.

But there isn't.

Not saying it can't be done. With enough money and desire, almost anything can be but the kind of charge controller you'd need, wiring and computer integration, would be extensive, compared to letting the truck run for a minute or 2. Not to mention, very little of that stuff would be off the shelf.

And by the way, they need at least some way to dissipate heat, so putting them on the hood is a no go and flexible panels already have heat build up problems, resulting in either short life spans, or even catastrophic failure.

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[amschind]

It's a great idea, and it IS workable, but not for these trucks. Going by the data from the Lightning, you need 0.4-0.5 kWh/mile. So let's say you have the 157" wheel base, which is 80" wide, and built a frame over the top of it so you can mount the max number of panels. If we use ZAMP 100W mobile panels, then we can fit 4 rows of 3, for 1.2 kW of power in full sun. That will provide you with enough energy each hour to travel 2-3 miles, but only during peak sunlight, so maybe 1000-1400. You'll still generate as long as you aren't in the shade in off peak hours, but maybe only 1 mile per hour. These calculations assume that the giant rack on top of your truck generates zero net drag (which is obviously not the case). For a 99% city driven truck in the Southwest that lasted for 20 years, you MIGHT break even some time in the 2040s.

The Aptera, which is designed to run almost completely off of solar, is HEAVILY optimized for low energy use per mile, and uses 0.13 kWh per mile, or about 40 miles per day in a very sunny place when charging all day.

If I had a Lightning, I'd probably keep a foldable 500W array behind the rear seat for emergencies. If I put a camper shell on it, I'd really look at integrating solar into that (though it's usually easier to wait on a company to do it for you and then buy that).

 

[Samson16]

It's a great idea, and it IS workable, but not for these trucks. Going by the data from the Lightning, you need 0.4-0.5 kWh/mile. So let's say you have the 157" wheel base, which is 80" wide, and built a frame over the top of it so you can mount the max number of panels. If we use ZAMP 100W mobile panels, then we can fit 4 rows of 3, for 1.2 kW of power in full sun. That will provide you with enough energy each hour to travel 2-3 miles, but only during peak sunlight, so maybe 1000-1400. You'll still generate as long as you aren't in the shade in off peak hours, but maybe only 1 mile per hour. These calculations assume that the giant rack on top of your truck generates zero net drag (which is obviously not the case). For a 99% city driven truck in the Southwest that lasted for 20 years, you MIGHT break even some time in the 2040s.

The Aptera, which is designed to run almost completely off of solar, is HEAVILY optimized for low energy use per mile, and uses 0.13 kWh per mile, or about 40 miles per day in a very sunny place when charging all day.

If I had a Lightning, I'd probably keep a foldable 500W array behind the rear seat for emergencies. If I put a camper shell on it, I'd really look at integrating solar into that (though it's usually easier to wait on a company to do it for you and then buy that).

Did you guys solve the voltage level hurdle with using solar panels? I understand them to be 12V-24V typically. Using 24V panels you need 12 of them in series! Towing a giant solar panel trailer behind you will rob efficiency I fear.

It seems like we're inventing a solution to a problem that's already been solved. Fill up your PB with 30.6 gallons. If the neighbors you encounter in the middle of nowhere somehow complain about the quiet occasional purring of the ICE, then bring along a 12V/200Ah LiFePO4 battery and AC/DC charger so you can run the fridge on it during the night all quiet like. Hopefully they won't complain about your fridge compressor kicking on or your LED nightlight. Good Lord.

 

[amschind]

Did you guys solve the voltage level hurdle with using solar panels? I understand them to be 12V-24V typically. Using 24V panels you need 12 of them in series! Towing a giant solar panel trailer behind you will rob efficiency I fear.

It seems like we're inventing a solution to a problem that's already been solved. Fill up your PB with 30.6 gallons. If the neighbors you encounter in the middle of nowhere somehow complain about the quiet occasional purring of the ICE, then bring along a 12V/200Ah LiFePO4 battery and AC/DC charger so you can run the fridge on it during the night all quiet like. Hopefully they won't complain about your fridge compressor kicking on or your LED nightlight. Good Lord.

My reply would be yes to all of that, but if the cost is low, then I'm happy to pay to have options. I'm using a minisplit with the condenser coil on the trailer tongue, and while that's not an aerodynamic gain over what trailer makers COULD be doing, it's a dramatic gain over what they ARE doing (namely the giant air conditioning drag chutes mounted on the roof). For me, the other huge gain is that I live in the south, where solar heat gain is a giant load that you have to air condition out of your space. Even if my solar panels were never wired up, they would still provide a huge benefit in the summer due to shading the roof and keeping heat out.

As for using them to charge a Lightning, I agree that it's impractical. I only brought up the 500W panel idea because it's a kind of failsafe in that you're never "REALLY" stranded.

 

[Samson16]

I like your thought process. Finding a way to stretch our time spent off grid and build in backup options for "just in case" is wired into our primordial DNA.

It got a little windy here today and the power flickered for a while then went out for 5-10 min. Strategically employed UPS equipment kept the wifi etc. going and just as I was about to run the generator the power came back on. Survival skills lol

edit: I think that's part of why I love my PB. The ancient DNA part of me says Oh Yeah.

 

[Lefty665]

Old thread I know, but has anyone tried just back feeding solar through a 120v outlet? Number of panels required to get to 120v is a lot less than getting to HV battery voltage and could use the truck's AC inverter and DC/DC components in reverse to rectify and step up voltage.

 

[HammaMan]

Old thread I know, but has anyone tried just back feeding solar through a 120v outlet? Number of panels required to get to 120v is a lot less than getting to HV battery voltage and could use the truck's AC inverter and DC/DC components in reverse to rectify and step up voltage.

That's not how it works. Don't try to do that.

 

[tsigwing]

That's not how it works. Don't try to do that.

or if he does try it, record it.

 

[HammaMan]

or if he does try it, record it.

It won't do anything based on paralleling tests. Not so much of an issue for inverters, but on DC power supplies fed by AC, backfeeding DC can start a fire.

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