Freightdawg
Expert Expediter
I have seen a few posts on people installing or considering solar panels on their Sprinters. How has that been working out? Have you been able to generate enough electricity to make it economically feasible?
Solar panels on Sprinters/vans.
- Thread starter Freightdawg
- Start date
ChrisGa23
Expert Expediter
Seen a person one time back around winter time that had what looked to be 4 attached to the window from the inside held up someway and ran to my guess was a battery bank. Then had his visor behind that for more privacy or sun blockage. Seemed like a cool set up. Never talked to him/her always seen the curtains up and didnt wanna bother no one.
Great story, but there are some significant problems there. Those batteries should last 7 or 8 years, but I'll be very surprised if he's still got the same a year from now, which will be a little less than three years on them.
Biggest problem with solar panels, IMHO, is that they are very expensive for what you get in return. About $1500 of solar panels will allow you to put back about 12-14 amp hours per day into the batteries, and that's if it's a bright, sunny Arizona type day. A really nice partly cloudy day, figure half that. Overcast, 1-3 amps, maybe.
Also, you can set the solar panel's charge controller to properly charge AGM batteries at 14.4 volts, but when driving the Sprinter's alternator won't charge them that high no matter what you do (except using an AGM cranking battery, as well), so they'll constantly be undercharging at too low a voltage, which will reduce the life of even really high AGM batteries by about a third. The predicted amp usage in the article is likely way short of actual usage. It always is, and his system is built on predicted usage, and he's very tight even at that.
Unless you live in Arizona or New Mexico, before you spend just a snotload of money on solar panels, make sure you know exactly what you are doing. Unless you're in a house with a roof of solar panels, they are to supplement other technologies, like wind, alternator or generator, and shore power, not to take the place of them.
A couple of lines from the story to be keenly aware of:
EN: What happens if you have a week of cloudy days?
Bill: You're not going to be using the air conditioner, most likely. So, that power will not be used.
That one trips up a lot of people (that, and the 12-volt AC running at half load, which doesn't happen as often as you think). A cloudy day and 88 degrees or higher and 95% humidity, naaa, no one would want to use the AC on a day like that, and the Midwest and south are just full of days like that.
Bill: Every time you move the truck, the alternator charges the batteries.
Yes, but in a Sprinter (and most other vehicles) it's always at the incorrect voltage for AGM batteries. A vehicle's alternator uses a variable voltage, while AGM batteries require rock-solid voltages, and at a very specific voltage. So no, the alternator doesn't charge the batteries. It under-charges them, decreasing their life. You can mitigate this somewhat by using an AGM battery for the starting battery, but even then, the vehicles charging system is still designed and optimized for the vehicle, not a house bank.
If you are sitting under clouds for days at a time and not moving the truck, the batteries will last, I'm thinking, two to three days.
Depends on how many amps you use and whether or not you go below 50% Depth of Discharge. Just from the raw, idealistic, predicted numbers to be found in the article, and knowing how many amps the cooler uses (5 amps per hour), plus the other things, he's drawing an average of about 8 amps per hour per day, which is far more than the 100 amp hour floor for a 50% DoD he'll use in a 24 hour period.
I don't know for sure if all or any of these things are happening with the driver in the article, as he may have taken steps to correct these problems, but they are definitely something to keep in mind before you lay out serious money for solar panels.
Freightdawg
Expert Expediter
Thanks Turtle! I know you seem to be the electrical/battery Guru here. I remembered reading in other posts that a few had put panels on their Sprinters. I know in theory it looks good, but reality is usually different. Maybe eventually the technology will improve so that it would work out economically.
comet_4298
Seasoned Expediter
I would think,by the time you add the battery bank,all wiring/controls,and enough panels,that your GVW would have taken a big bite.
Yes..that is the bigger problem..one guy can only handle about 1800 lbs max legally..in a Sprinter.
Solar panels while a great idea but are virtually useless at this point of development...
guido4475
Not a Member
Yes, while they sound like a great , queit, green idea, the solor panel user can be bound by the limits of power it will store,thus having to run the van to juice up the batteries anyway.And I would think cost of the solor panels and batteries would far be so much more than that of a generator to begin with.At least with a generator,the power is always there, except when one may run out of gas.Just my thought, anyway.
The solar panels are relatively light. What kills you is the weight of the batteries. The amount of amp hours a battery has is directly dependent on how much lead in in there, how much they weigh. A 100 amp hour battery is gonna weigh about 65 pounds, and two of those is really the minimum for a house bank (200 amps hours), and that's if you don't run a fridge or cooler (something with a constant drain of more than a couple of amps). With a 200 amp hour battery bank, you still only have a maximum of 100 amp hours between fully recharging the batteries before you go below 50% DoD. And as with all batteries, every time you discharge and recharge, you lose a little bit of capacity, so the 100 amp hours quickly drops. You may have 100 amp hours available when you first install the bank, but 6 months from now you're down to 85 or 90, a year later you're down to 70, and so on. In the meantime you're still trying to squeeze 100 amps a day from them, running the batteries below 50% Dod. And of course, once you electrify the place, you start finding other new and exciting ways to use even more amps per day.
If you start out with the amount of amp hours you really need, you're looking at 300 or 400 amps, which is upwards of 200-250 pounds. High end AGM's will push 400 pounds. Then, if you cable it properly, with all the correct fuses and wire, you're adding another 50 pounds minimum.
Best way to size a battery bank is to figure out your predicted amp hour usage between rechargings (always fully recharge the batteries once you start charging them), double that, and then at 20% on top of that. Then, double that figure for the number of amp hours in the bank. That way, you are very unlikely to go beyond 50% DoD, even with the added 12-volt and inverter toys you add along the way. Do that, and making sure they are properly charged, and good batteries will last 7-10 years instead of 2 or 3.
Solar panel technology is changing and improving, but it has a long way to go. There are basically three kinds of solar panels. The cheap kind that put out almost no watts, where you need a bazillion of them to be effective, the higher priced ones that put out enough to keep a house bank trickle charged but not enough to be the sole charging source (the kind we're talking about here), and then there's the "OMG That's Expensive" kind where two panels on the van roof will cost you 30 or 40 grand, but will put out way more than enough to keep up with whatever discharge requirements you may have out here.
The biggest problems with solar panels in expediting is that you need a lot of bright sunny days to make them semi-effective, which means spending most of your time in places where clouds are few and far between (desert southwest, places like that), and even at that they don't put out enough watts to replace other charging sources.
Basically, if your amp hour requirements are so low that solar panels will suffice, then you don't need anything other than the vehicle's alternator in the first place.
If you start out with the amount of amp hours you really need, you're looking at 300 or 400 amps, which is upwards of 200-250 pounds. High end AGM's will push 400 pounds. Then, if you cable it properly, with all the correct fuses and wire, you're adding another 50 pounds minimum.
Best way to size a battery bank is to figure out your predicted amp hour usage between rechargings (always fully recharge the batteries once you start charging them), double that, and then at 20% on top of that. Then, double that figure for the number of amp hours in the bank. That way, you are very unlikely to go beyond 50% DoD, even with the added 12-volt and inverter toys you add along the way. Do that, and making sure they are properly charged, and good batteries will last 7-10 years instead of 2 or 3.
Solar panel technology is changing and improving, but it has a long way to go. There are basically three kinds of solar panels. The cheap kind that put out almost no watts, where you need a bazillion of them to be effective, the higher priced ones that put out enough to keep a house bank trickle charged but not enough to be the sole charging source (the kind we're talking about here), and then there's the "OMG That's Expensive" kind where two panels on the van roof will cost you 30 or 40 grand, but will put out way more than enough to keep up with whatever discharge requirements you may have out here.
The biggest problems with solar panels in expediting is that you need a lot of bright sunny days to make them semi-effective, which means spending most of your time in places where clouds are few and far between (desert southwest, places like that), and even at that they don't put out enough watts to replace other charging sources.
Basically, if your amp hour requirements are so low that solar panels will suffice, then you don't need anything other than the vehicle's alternator in the first place.
Jack_Berry
Moderator Emeritus
seems like someone at eo should do a follow up story.
ebsprintin
Veteran Expediter
http://www.expeditersonline.com/forum/garage-beta-test-forum/39798-solar-panels.html
link to a related thread to avoid having to repeat a lot of what I already said.
I'm approaching a year with the system I set up. It is doing everything I ask of it perfectly. The two critical tasks are to power the Espar heater, and Engel refrigerator. During the heat of the day, I can also run the roof vent all day and still get a full charge. I can run my laptop as much as I want, but most of my computer time is outside the truck (usually in the library). I set my power cut off at a level that keeps me from ever coming close to the 50% DoD that Turtle talked about, and even with the high cutoff level, I only activated it twice back when I was first figuring out the system.
I never lied to myself about what I could get out of the system. My life is very much driven by the capabilities of the system. Many people wouldn't want to put up with that, as much as I don't want to put up with dragging around a portable generator. Air conditioning is only a dream for me. When I get ac it will be in a different vehicle that can haul a permanently mounted generator. As for the current set up I just scaled a couple weeks back. I can carry 2200 lbs with the volume of three tall skids. As for aerodynamics I've been regularly running at monthly averages of 22.6 mpg. My last 10,000 mile average was 24.5 mpg. When I had the generator/air conditioner on the roof, I never touched 20 mpg.
eb
link to a related thread to avoid having to repeat a lot of what I already said.
I'm approaching a year with the system I set up. It is doing everything I ask of it perfectly. The two critical tasks are to power the Espar heater, and Engel refrigerator. During the heat of the day, I can also run the roof vent all day and still get a full charge. I can run my laptop as much as I want, but most of my computer time is outside the truck (usually in the library). I set my power cut off at a level that keeps me from ever coming close to the 50% DoD that Turtle talked about, and even with the high cutoff level, I only activated it twice back when I was first figuring out the system.
I never lied to myself about what I could get out of the system. My life is very much driven by the capabilities of the system. Many people wouldn't want to put up with that, as much as I don't want to put up with dragging around a portable generator. Air conditioning is only a dream for me. When I get ac it will be in a different vehicle that can haul a permanently mounted generator. As for the current set up I just scaled a couple weeks back. I can carry 2200 lbs with the volume of three tall skids. As for aerodynamics I've been regularly running at monthly averages of 22.6 mpg. My last 10,000 mile average was 24.5 mpg. When I had the generator/air conditioner on the roof, I never touched 20 mpg.
eb
Freightdawg
Expert Expediter
Thanks, EB! I had read the solar panel thread and was looking for an update since you have had the system operational for some time.
This is Bill the one the story's on. The panels are still working great I don't have to lug a round a generator or have to worry about it getting stolen like when the cut the cable on the one next to me at the flying hook in NC.
I have changed from a dumb solenoid to a smart one from sure power and got rid of the Coleman cooler to go with one from Engel
The only time I was worried was in Lafayette IN was sitting and on the 4 day was down to 20% LEFT was using TV, Internet,frig,oh yes Espar heater because it was snowing and snowing so no charging to speak of
Wile the truck alt wont bring to full charge if they get close the Blue Sky controller will bring them up to 14 volts and I get a full charge states If you want Adverc Battery Management ( about 500.00) makes a 14 volt module that goes on the Alt to charge AGM at 14 volts that is used on the Sprinter Ambulances but I have found it not necessary at lest not yet. May be when I get the 12 air
I am using a Power Pulse 12 Volt # PP12L to prevent sulfation buildup
Going to try to make Expo and I want to make Sprinter Conference the fowlling week in Mechanicsville pa the following week end
Bill
I have changed from a dumb solenoid to a smart one from sure power and got rid of the Coleman cooler to go with one from Engel
The only time I was worried was in Lafayette IN was sitting and on the 4 day was down to 20% LEFT was using TV, Internet,frig,oh yes Espar heater because it was snowing and snowing so no charging to speak of
Wile the truck alt wont bring to full charge if they get close the Blue Sky controller will bring them up to 14 volts and I get a full charge states If you want Adverc Battery Management ( about 500.00) makes a 14 volt module that goes on the Alt to charge AGM at 14 volts that is used on the Sprinter Ambulances but I have found it not necessary at lest not yet. May be when I get the 12 air
I am using a Power Pulse 12 Volt # PP12L to prevent sulfation buildup
Going to try to make Expo and I want to make Sprinter Conference the fowlling week in Mechanicsville pa the following week end
Bill
Freightdawg
Expert Expediter
Thanks for the update, Bill, I'll look for you at the Expo!
Yeah, thanks for the update. A couple of questions... When you say after the 4 days you were down to 20% LEFT.... 20% of what? Does that mean you had discharged 80% of the fully charged battery? Also, are you using a battery monitor, like a Xantrex?
Tutle
Yes I use a xantrex link 1000 set for 280 amp hr have 2 100 ah and a 80 ah AGM so out of 280 amps had only 56 amps left in bank
The red light was on when I woke up so was down 80% was a little worried but have not had any problems
Sitting all day in truck Roanoke VA 2 fans going frig running and on Internet
Voltage at 13.11
panel current 6.7
output charge current 7.4
only putting in 1.8 amps because of all I'm running right now so still down 22.8 from fully charged
Never said this was the cheap way to go gen MUCH cheaper
Yes I use a xantrex link 1000 set for 280 amp hr have 2 100 ah and a 80 ah AGM so out of 280 amps had only 56 amps left in bank
The red light was on when I woke up so was down 80% was a little worried but have not had any problems
Sitting all day in truck Roanoke VA 2 fans going frig running and on Internet
Voltage at 13.11
panel current 6.7
output charge current 7.4
only putting in 1.8 amps because of all I'm running right now so still down 22.8 from fully charged
Never said this was the cheap way to go gen MUCH cheaper
Ah, OK. Yeah, 56 amp hours is a long way down. But as I'm sure you know, the occasional deep discharge on an AGM battery won't kill it too soon like it will with a cranking or hybrid battery.
Are you concerned much about having different amp hour capacity batteries? I think if I did that I'd want the 80 amp in the middle, so that it gets the least amount of draw and charge, to at least help balance out the workload that would otherwise cause it, or the other two, to be working harder and thus have a shortened lifespan.
I'm right there with ya on not having to deal with generator maintenance, plus they use fuel, too.
Are you concerned much about having different amp hour capacity batteries? I think if I did that I'd want the 80 amp in the middle, so that it gets the least amount of draw and charge, to at least help balance out the workload that would otherwise cause it, or the other two, to be working harder and thus have a shortened lifespan.
I'm right there with ya on not having to deal with generator maintenance, plus they use fuel, too.
Van came with the 80 could be 75 its the yellow optima under the hood as extra could not see getting rid of it the 2 100 I bought @ 250.00 a piece ouch they are on a rack under the van camping world built and wired 00 welding cable I believe so the cable Resistance should be minimal
