Solar Power-interesting read

[Pug Loaf]

My power needs are simple: Charge a phone, run a fan and some LEDs. I've been looking this battery and this solar panel, which I think should do the trick. Any thoughts? It has an inverter in case I want to do something wild like bring a laptop or run a power tool, but the idea is that the battery is big enough for my needs alone and then some, and the panel should be enough to charge it with my limited use. There may be a fridge in the future, but I'm iffy on that and I'm not building out for that.

I'm have basically the same idea. Here is what I was thinking: 100 watt solar panel on roof outputs charge to the vehicle battery (going though a solar charge controller, of course). The output load on the solar charge controller goes to a lithium battery pack in the back of the vehicle (aka a "solar generator" pack - ex. goal zero, the one in the link you provided, etc).

So since the solar generator is connected to the load output on the solar charger, it is charged by the vehicle battery, but the vehicle battery is getting power from both the alternator and the solar panel. At night, car is off, and the solar generator is presumably fully charged at end of day (from sun light and/or driving around). Then, solar generator powers your devices (my goal is a fridge, phones, maybe tablet). Since the solar generator is on the load output of the solar controller, and the solar controller has load protection, the solar controller will automatically stop charging up the solar generator from the vehicle battery when/if the vehicle battery dips below your load protection threshold. At this point, your devices are pulling power from the solar generator which is no longer getting charged up by anything else, until the next morning.

Next day, sun comes up//you drive around, and the alternator/solar controller recharges the vehicle battery (which should not have been fully depleted due to the load protection on solar controller), which replenishes the solar generator through the load output on the solar controller (the solar generator may or may not be out of power but this does not matter, unlike draining your vehicle battery).

Someone please tell me if this makes sense!

 

[billiardspintail]

I'm have basically the same idea. Here is what I was thinking: 100 watt solar panel on roof outputs charge to the vehicle battery (going though a solar charge controller, of course). The output load on the solar charge controller goes to a lithium battery pack in the back of the vehicle (aka a "solar generator" pack - ex. goal zero, the one in the link you provided, etc).

So since the solar generator is connected to the load output on the solar charger, it is charged by the vehicle battery, but the vehicle battery is getting power from both the alternator and the solar panel. At night, car is off, and the solar generator is presumably fully charged at end of day (from sun light and/or driving around). Then, solar generator powers your devices (my goal is a fridge, phones, maybe tablet). Since the solar generator is on the load output of the solar controller, and the solar controller has load protection, the solar controller will automatically stop charging up the solar generator from the vehicle battery when/if the vehicle battery dips below your load protection threshold. At this point, your devices are pulling power from the solar generator which is no longer getting charged up by anything else, until the next morning.

Next day, sun comes up//you drive around, and the alternator/solar controller recharges the vehicle battery (which should not have been fully depleted due to the load protection on solar controller), which replenishes the solar generator through the load output on the solar controller (the solar generator may or may not be out of power but this does not matter, unlike draining your vehicle battery).

Someone please tell me if this makes sense!

Are you saying the starter battery is always charging the solar generator, or only when the car is on? It seems like it could be a way to drain the starter battery. Instead, maybe have a system where the solar panel charges the solar generator only, and the starter battery charges the generator only when the car is running. Most of my time won't be spent on the trail, but at base camp, so I want to make sure my own starter battery doesn't get drained if the day is cloudy or there is too heavy use on the generator.

 

[Pug Loaf]

The vehicle battery would always be charging the solar generator, but the output is limited by the load protection feature on the solar controller. So if the starter battery dips below whatever you set the load protection at, the solar controller is going to shut off the load output (ie., the power going from the vehicle battery to the solar generator). Most solar controllers seem to have a load protection feature.

Other advantages: If you run a winch, air compressor, etc, it is going to pull some power from your starter battery. By having the solar charger on the starter battery, you are helping replenish this power, along with the alternator. If your solar generator is hooked up to the load output on solar controller, you are effectively recharging the solar generator with the alternator AND the solar panel.

 

[billiardspintail]

The vehicle battery would always be charging the solar generator, but the output is limited by the load protection feature on the solar controller. So if the starter battery dips below whatever you set the load protection at, the solar controller is going to shut off the load output (ie., the power going from the vehicle battery to the solar generator). Most solar controllers seem to have a load protection feature.

Other advantages: If you run a winch, air compressor, etc, it is going to pull some power from your starter battery. By having the solar charger on the starter battery, you are helping replenish this power, along with the alternator. If your solar generator is hooked up to the load output on solar controller, you are effectively recharging the solar generator with the alternator AND the solar panel.

Okay, yeah that would work. Though just so you know, even a 100W panel won't do anything appreciable in replenishing power after winch usage. They just don't produce enough power, even in direct sunlight. The main article goes into that here. It's a nice little side benefit, but don't expect it to recharge at anywhere near the rate your alternator can.

 

[Pug Loaf]

Yeah, agreed. With a setup like this, do you think a 4-5 camping trip with a overland style fridge sounds feasible? From what I understand, most people do ok running them off vehicle power alone since us overland types are usually driving some. Add in solar and some power in the solar generator and it seems feasible to me. The whole thought of powering a fridge in a vehicle still seems too good to be true but I'm starting to come around to it.

 

[billiardspintail]

Yeah, agreed. With a setup like this, do you think a 4-5 camping trip with a overland style fridge sounds feasible? From what I understand, most people do ok running them off vehicle power alone since us overland types are usually driving some. Add in solar and some power in the solar generator and it seems feasible to me. The whole thought of powering a fridge in a vehicle still seems too good to be true but I'm starting to come around to it.

I have no idea, I've never run a fridge that long in a car (nor do I own one), and my rig isn't ready to run yet :(.

Try posting that question in the general discussion forum, I know there are a lot of people here who are experienced with running a fridge with batteries that can give you a general idea of usage limits.

 

[Mark D]

I have no idea, I've never run a fridge that long in a car (nor do I own one), and my rig isn't ready to run yet :(.

Try posting that question in the general discussion forum, I know there are a lot of people here who are experienced with running a fridge with batteries that can give you a general idea of usage limits.

Just to add some experience here, I have a Wynter 90quart. My auxiliary battery is a group 31 and is completely isolated from the vehicle battery. My fridge does fine for 3 or 4 days (depending on ambient temps).

 

[CSG]

I love the idea of solar but there is so much hype and misinformation out there, I'm left more confused about it than ever. However, as my needs are so simple and I spend more time driving in that I only camp in a spot overnight that I've been able to make due just fine with my two Group 27 house batteries in the van to run the built in fridge. I can charge my computer through a simple inverter when I'm driving but more and more, I just have my phone and an iPad. I rarely use house lights favoring the low light of a small Streamlight LED lantern or a candle lantern. And for times when I'll want to run the built in microwave off grid, I've got a handy dandy Honda 2000 which also can run the 5k BTU a/c built in the back door.

 

[billiardspintail]

I love the idea of solar but there is so much hype and misinformation out there, I'm left more confused about it than ever. However, as my needs are so simple and I spend more time driving in that I only camp in a spot overnight that I've been able to make due just fine with my two Group 27 house batteries in the van to run the built in fridge. I can charge my computer through a simple inverter when I'm driving but more and more, I just have my phone and an iPad. I rarely use house lights favoring the low light of a small Streamlight LED lantern or a candle lantern. And for times when I'll want to run the built in microwave off grid, I've got a handy dandy Honda 2000 which also can run the 5k BTU a/c built in the back door.

I've gone the "math" route, which vastly over-inflates the usable charging solar gives you. So, I'm banking mostly on the fact that I use very little power to charge/run things (big battery) and the fact that when I'm out, I don't usually leave camp until the end of the trip, so I get the bigger solar panel.

 

[[DO]Ron]

Nice article, been reading up on solar power and what not the last few days.
If in the future I get a camper trailer I am thinking about adding solar. Should at least run a screen / power 2 laptops and charge phones. Was looking at 2x 160 watt panels as they aren't that expensive imho.. but after reading the article that might be somewhat to much.
Lithium vs AGM is also a nice discussion.. a Lithium 100ah is around 1800 to 2000 euro's.. While a 100ah AGM is around 200. so even if you need 2 (because you can't drain them) you are still 'just' on 400. Even if they break more often and need to be replaced.. I can replace 5 sets of AGM for the price of one Lithium..

 

[Mark D]

I love the idea of solar but there is so much hype and misinformation out there, I'm left more confused about it than ever. However, as my needs are so simple and I spend more time driving in that I only camp in a spot overnight that I've been able to make due just fine with my two Group 27 house batteries in the van to run the built in fridge. I can charge my computer through a simple inverter when I'm driving but more and more, I just have my phone and an iPad. I rarely use house lights favoring the low light of a small Streamlight LED lantern or a candle lantern. And for times when I'll want to run the built in microwave off grid, I've got a handy dandy Honda 2000 which also can run the 5k BTU a/c built in the back door.

The hype and misinformation is what I was trying to point out to people. I am going to add solar to my houseboat but I think solar on my Overland rig would be a waste for what I do. As I said in my intro, I see so many overlanders set out their 60w panel after a day of travel and then get up and hit the trail the next day not realizing the solar panel is really not doing anything.

 

[CSG]

How much is a little Honda 1000? Makes more sense to me than solar for 1-2 night stays. Longer too if you carry your own gas.

 

[THorner]

New member here, joined at Overland West 2019. First post and I'll start off by saying that I'm not an expert on solar nor am I an Electrical Engineer. I thought I'd offer what has worked for me for the past couple of years. I have an ARB 50 qt. fridge and leave it in my rig running all the time. ARB says it draws an average of 0.87 amps. I have a Zamp Solar 170 watt panel on top of the rooftop tent. I use two 35AH sealed batteries connected in parallel, I chose this to be able to place them in the tub under the rear deck of the Jeep. I use some power for charging cameras, computers, phones etc. and running some LED lights. The heart of my system is a CTEK D250SA MPPT charge controller. It can charge from solar or from the Jeep alternator or both. This set-up has worked for me for nearly 2 years and I have never run out of power. Just thought I'd offer what has worked for me. Happy to be a part of this community.

 

[Brewbud]

Yeah, agreed. With a setup like this, do you think a 4-5 camping trip with a overland style fridge sounds feasible? From what I understand, most people do ok running them off vehicle power alone since us overland types are usually driving some. Add in solar and some power in the solar generator and it seems feasible to me. The whole thought of powering a fridge in a vehicle still seems too good to be true but I'm starting to come around to it.

My Renogy 100W panel and my Goal Zero 1000 with added MPPT charge controller has powered my ARB 63 qt fridge for 5 days at a stationary campsite. The fridge was set just above freezing and the air temp was in the 80s. At the end of 5 days the battery was still at 100%. The panel would replace the charge lost overnight by about 1:30 the next day. We had sunny weather and I did need to be conscious about aiming the panel every hour or so.

 

[RoarinRow]

Are you saying the starter battery is always charging the solar generator, or only when the car is on? It seems like it could be a way to drain the starter battery. Instead, maybe have a system where the solar panel charges the solar generator only, and the starter battery charges the generator only when the car is running. Most of my time won't be spent on the trail, but at base camp, so I want to make sure my own starter battery doesn't get drained if the day is cloudy or there is too heavy use on the generator.

Something like this I believe would work. It charges the second solar battery via the main starter battery - Renogy 12V DC to DC On-Board Battery Charger

 

[Vantams]

That was a great article. I've considered solar on an RV renovation I'm doing and this just sealed the deal. Thanks for sharing!

 

[Mike Dubya]

New member here, joined at Overland West 2019. First post and I'll start off by saying that I'm not an expert on solar nor am I an Electrical Engineer. I thought I'd offer what has worked for me for the past couple of years. I have an ARB 50 qt. fridge and leave it in my rig running all the time. ARB says it draws an average of 0.87 amps. I have a Zamp Solar 170 watt panel on top of the rooftop tent. I use two 35AH sealed batteries connected in parallel, I chose this to be able to place them in the tub under the rear deck of the Jeep. I use some power for charging cameras, computers, phones etc. and running some LED lights. The heart of my system is a CTEK D250SA MPPT charge controller. It can charge from solar or from the Jeep alternator or both. This set-up has worked for me for nearly 2 years and I have never run out of power. Just thought I'd offer what has worked for me. Happy to be a part of this community.

I have a similar setup to yours THorner, I like the D250SA, but I thought they required solar input to the MTTP to be limited to 22 volts? Does your Zamp 170 exceed this? I'm looking for solar options without a solid roof mount panel. I would like a Flexopower flexible unit, but the service and availability have seemed sketchy in the US. I had even considered a Harbor Freight folding panel setup. I just don't want to pay more than $250 for the limited benefit of a solar battery boost when I drive my vehicle most days.

 

[THorner]

I have a similar setup to yours THorner, I like the D250SA, but I thought they required solar input to the MTTP to be limited to 22 volts? Does your Zamp 170 exceed this? I'm looking for solar options without a solid roof mount panel. I would like a Flexopower flexible unit, but the service and availability have seemed sketchy in the US. I had even considered a Harbor Freight folding panel setup. I just don't want to pay more than $250 for the limited benefit of a solar battery boost when I drive my vehicle most days.

Hi Mike, Great questions. The specs on the Zamp panel are 9.4 amps and 170 watts. By calculation that would give a nominal 18.08 volts. I'm sure the open circuit voltage is much higher, I haven't put a meter on it. The D250SA spec. sheet says Input 11.5 to 23 volts and 25 amps. I haven't noticed any issues with the set-up and the CTEK runs nice and cool. My rig was parked for 4 days at EXPO West and my voltage never dropped below 12.5. That said it was cool and windy so there wasn't a big refrigeration load on the batteries. When I take my RTT off of the Jeep (the Zamp is mounted to the top of the RTT), I replace the Zamp with a Renogy 100 watt panel and that has also worked well for me. I use Anderson plugs so my set-up is easily changed.

 

[Mark D]

I have a similar setup to yours THorner, I like the D250SA, but I thought they required solar input to the MTTP to be limited to 22 volts? Does your Zamp 170 exceed this? I'm looking for solar options without a solid roof mount panel. I would like a Flexopower flexible unit, but the service and availability have seemed sketchy in the US. I had even considered a Harbor Freight folding panel setup. I just don't want to pay more than $250 for the limited benefit of a solar battery boost when I drive my vehicle most days.

I did not have good luck with the Harbor freight controller. My experience with them goes back about ten years with two systems, one installed on my houseboat another on my travel trailer. They seemed very weak and both systems are dead now. I just installed two 100 watt panels on the houseboat from a great company here in the Los Angeles area and it provides all the power I need to keep the lights on and a 92 quart Wynter fridge running.

 

[Mike Dubya]

I did not have good luck with the Harbor freight controller. My experience with them goes back about ten years with two systems, one installed on my houseboat another on my travel trailer. They seemed very weak and both systems are dead now. I just installed two 100 watt panels on the houseboat from a great company here in the Los Angeles area and it provides all the power I need to keep the lights on and a 92 quart Wynter fridge running.

With the D250SA it has a MTTP controller integrated, so I wouldn't use the Harbor freight regulator. Any issues with the panel?