# Putting Solar Panels on my van

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Hello everyone
new to the forum and soloar energy. i have no clue what to use or really where to look. So any help will be greatly appreciated
I am setting up a van with seating in the rear for a tv and xbox 360 system. From what i understand the tv pulls about 350 watts and the xbox 360 about 75 watts.
The van will only be use for about 4 hours a night but only during the middle of the night. It will be open to charge during the day. If anyone can give me a few pointers or info on what i should use or need to get this project started.
Thanks

• Banned Posts: 17,615 ✭✭✭
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Re: Putting Solar Panels on my van

A little entertainment system in the van, eh?

First off, it would be a good idea to get a Kill-A-Watt meter and see what the loads really are. The spec plates on equipment is often wrong in one direction or another. With any luck the TV & DVD actually draw less.

Assuming your numbers are correct, you've got: 350W + 75W = 425W * 4 hours = 1700 Watt hours.
You'll need the equivalent in battery capacity: (12VDC system no doubt) 142 usable Amp hours capacity (@ the "20hr rate" as it's called in Deep Cycle terms) which is 184 Amp/hrs @ a maximum 50% Depth Of Discharge. So you should be looking for around a 200 Amp/hr Deep Cycle battery.

To recharge that from solar panels alone you'd need approximately 120 Watts of panels at the absolute minimum. This is to supply a minimum charge current of 5% of the battery capacity. They won't put out full capacity of course, especially not on a van where you won't be getting optimum sun angle. Better to go for the 'high end' of 15% to make up for the inevitable losses: 360 Watts of panels. That's a lot of panel; probably more than you can fit on the roof. You may have to go with some 'compromise' charging, such as drawing power from the vehicle's alternator to make sure the battery is full up (the alternator can do the "bulk" charging first thing, and then let the panels bring the battery the rest of the way up and through the absorb cycle).

Good news is there are some nice small pure sine wave inverters available these days for reasonable money. One like this would do: http://store.solar-electric.com/sa600wa12vos.html

But beware: once you've got 120 VAC available, you start adding loads!
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Re: Putting Solar Panels on my van

Marc/Cariboocoot has the issue nailed down.

Add the question about winter/summer and location where the van will be used... The amount of available sun you will have affects your choices too (you may have close to 6 hours of "full sun" in summer, but near 2 hours of "full" sun in the winter--that will affect by a factor of 3x the sizing of your solar panels too.

Normally, besides the Kill-A-Watt Meter to measure your loads--you really need to work on conservation with off-grid power. Realistically, Off-Grid and Generator power will cost you around \$1-\$2+ per kWHr--where your home power may cost you \$0.10 per kWhr...

If you can choose a different TV to reduce power use--that will be a huge help (projectors, perhaps a new oLED TV, or even an old picture tube set can use less power).

Otherwise, if this is for the occasional weekend uses--a Honda eu1000i or eu2000i inverter generator would probably be the more cost effective solution (and you may want one for backup power on cloudy days/forested campsites anyway).

To keep up with your power needs, you probably are looking at 200-400 watts minimum of solar panels (depending on season, location, and mounting angles). 400 watts of solar panels is not cheap, are big, and can be easy to break if not mounted well and/or falling objects (1/8" thick tempered glass in light weight aluminum frame).

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 246 ✭✭
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Re: Putting Solar Panels on my van

you may also be able to save yourself a few watts by having a look at the 360`s power supply, It outputs to the xbox @ 12v and 5v, the same as a standard pc power supply, you may be able to fudge that in some way ?
Tim

edited to add, or just buy one of these and depending on tv maybe also run it from dc, save a lot of money http://www.automonitor.co.uk/product.asp?c=40&c2=&p=234

(No recommendation given or implied, random web search)
• Solar Expert Posts: 264 ✭✭✭✭✭✭
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Re: Putting Solar Panels on my van

How about replace your van's battery with a 200AH marine one then just use a 12V 600W or more inverter using the cigarette plug. If your van is using much during the day, the alternator would recharge it.
GP
• Banned Posts: 17,615 ✭✭✭
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Re: Putting Solar Panels on my van
How about replace your van's battery with a 200AH marine one then just use a 12V 600W or more inverter using the cigarette plug. If your van is using much during the day, the alternator would recharge it.
GP

It would be 200 Amp/hr plus the capacity of the van's existing battery. Then you might have to replace the alternator as they are usually designed with the factory only battery in mind - i.e. as small as possible to keep costs down and profits up. And then you have the issue of the need for deep cycle for the inverter vs. the need for high starting current for the engine - so you look to the 'hybrid' battery of the RV/Marine type. There may not be room enough in the engine compartment for a really large capacity battery either - especially in a van. Running 600W inverter through the cig lighter isn't good - 50 Amps?

I'm not saying this isn't an option, but you have to look ahead to some of the other problems that might crop up if you go this route.

Putting a bigger alternator in may be necessary anyway, if you use it for a 'back up' power source to recharge your inverter battery.
• Solar Expert Posts: 264 ✭✭✭✭✭✭
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Re: Putting Solar Panels on my van
Running 600W inverter through the cig lighter isn't good - 50 Amps?
Good catch ! Maybe rig up something using these connector to connect to the inverter.
Putting a bigger alternator in may be necessary anyway, if you use it for a 'back up' power source to recharge your inverter battery.
Check the alternator's plate, most would give at least 100A if not more, especially for a van. It should be good enough to charge a 200AH RV/marine battery. If the battery is too big, it could be placed somewhere in the back of the van (probably inside a battery box ... in case some one drops a wrench and short across the terminals ! ) and connect to the front battery with heavy guage cables (leaving the original van's battery alone).
GP
• Solar Expert Posts: 1,341 ✭✭✭
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Re: Putting Solar Panels on my van
Check the alternator's plate, most would give at least 100A if not more, especially for a van.

Unlikely. Usually 40a - 60a is normal for US light trucks (and vans). 25a or 30a on a lot of cars.
• Solar Expert Posts: 82 ✭✭✭✭
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Re: Putting Solar Panels on my van

I have one 130 watt panel flat on the roof of my van. On a full day of sun, without tilting the panel it replaces about 50 amps back into the batteries, so I try to limit my energy consumption to less than 30 a/h overnight.

My 130 amp alternator, according to my monitor has never output more than 75 amps, and this number is only of short duration. Even with well depleted batteries, the alternator will be outputting 12 to 25 amps after 5 minutes, and 5 to 12 amps after 20 minutes. So Unless I'm driving a great distance, I have to say, in my case, the alternator is next to worthless in charging my batteries. Well not worthless, but a very inefficient way of charging if Idleing the engine.

I think the vehicles voltage regulator, located in the engine computer, has some sort of algorithm, designed to top off a starting battery, and doesn't let enough amperage flow from the alternator to dump some serious amps into some deep cycle/ hybrid batteries. This is on a '89 dodge van.

I am considering removing the chassis alternator from the house battery circuit, and adding a second alternator with it's own voltage regulator dedicated for the house batteries.
• Banned Posts: 17,615 ✭✭✭
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Re: Putting Solar Panels on my van

landyacht.318 -

You are correct about the vehicle's alternator: it is set up to recharge the battery that came with it, not a high-capacity deep cycle. But even a standard alternator can bring larger batteries up to that level and then allow the solar panel to 'finish" charging. As you said, it's pretty inefficient running a V-8 to charge batteries!

Adding a second alternator dedicated to charging deep cycles is an option if you've got the room. It can get pretty crowded under the hood - especially on a van. Carrying a small inverter gen is probably way more fuel efficient.

I hope your 318 is a fuel injected model - the older carburettor models were horribly inefficient. It was recommended that owners change the intake and exhaust manifolds as well as the carb because they 'breathed badly' and almost any after-market equipment was an improvement!
• Solar Expert Posts: 82 ✭✭✭✭
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Re: Putting Solar Panels on my van

I believe my '89 was the first or second year with throttle body fuel injection. MPFI came in '93 or 4 with the magnum engines. My alternator does charge my hybrid batteries, just slowly. My A/C compessor had been acting just as a pulley for many years now, and would be replaced with another alternator.

But for the most part, If I limit my computer useage, my 130watt panel has no problems bringing my batteries up to 15 volts where I've set my acceptance and float voltages. None of my appliances seem to be disturbed by this voltage either. Not the LEDs, stereo or compressor fridge or muffin Fans.

I know It is not recommended that I go this high, but the batteries use no water, and at this point in their lifespan are a writeoff anyway. They do hold more voltage overnight when treated thusly with the same amp/hours depleted.
• Solar Expert Posts: 1,341 ✭✭✭
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Re: Putting Solar Panels on my van
I think the vehicles voltage regulator, located in the engine computer, has some sort of algorithm, designed to top off a starting battery, and doesn't let enough amperage flow from the alternator to dump some serious amps into some deep cycle/ hybrid batteries. This is on a '89 dodge van.

How is your aux (house) battery connected to the alternator?

If you are using a diode type isolator, then your vehicle voltage regular doesn't even know about the aux battery and so when the engine battery gets charged up the regulator will back off even if the aux battery could use the extra. (No computer needed for that.)

My van has a "split-charge relay" setup, which just connects both batteries together into a single bank when the alternator is putting out voltage. I have noticed that when the aux battery is down, the instrument panel "alternator" gauge will show higher output for longer time - the voltage regulator sees both batteries as one and so puts out more.

I'm not recommending the split-charge relay setup...it's simply what is already there. I will be eventually changing that out for a diode type isolator.

Anyway, depending on how much battery capacity you have you can EASILY toast them with too much amperage.

I'm going to put 4 x 105ah @ 12v batteries in my rig. I was originally thinking about either a 45a or 55a Iota battery charger. But...there is the whole "C/*" thing...where "C = (battery capacity in amp*hours)".

As I understand it, "most" deep cycle batteries need to be charged at a max of C/8, which for a 410ah battery bank would be 52.5a. Technically, the 55a charger would be too much for my battery bank.

Many VRLAs can take more - some of them up to C/4 and a few even higher.

If you've got say...two 105ah RV/Marine batteries then you should almost certainly stick to the C/8 max - which would mean anything over 26.25a charging current would be too much for your battery bank.

Even if, as you say, the batteries are already a write-off...still, charging them at double the proper rate (C/4 or 52.5a for a 210ah bank) is going to do nothing but burn them out that much sooner - as well as doing the same thing to their replacements when you get them.

I am considering removing the chassis alternator from the house battery circuit, and adding a second alternator with it's own voltage regulator dedicated for the house batteries.

I think I would go the easy route and just buy a decent battery charger, and a MSW inverter to power it, and then power that off the engine side. When the engine is running, fire up the inverter and the charger to charge the aux battery bank.

The extra load on the engine side should keep your voltage regulator fooled into putting out the extra amperage you need - and even 75a is "way too much" for just battery charging.
• Solar Expert Posts: 82 ✭✭✭✭
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Re: Putting Solar Panels on my van

I have a Guest battery switch. 1/2/both/off. 1 being the stock location battery, which no longer exists due to one of the house batteries developing a bad cell.

I have the remaining 2 batteries paralleled together to the" 2" side of the guest switch. No isolation for over a year now. But I never let them go below 60% SOC and that is rare. The batteries are all the same make model and age.

I do have a 25 amp smart charger, and the highest number I've seen from that and my solar panel together is almost 28 amps( all loads removed), despite there being over 7 amps available of solar amperage to add to the mix. If the solar has my batteries up over 12.9 volts, the Smartcharger will not put out more than 5 additional amps if that. If I bring that number below 12.7 and then plug in the charger, it will put out 25 amps.

Ideally what I'd like to do is have the vehicles's stock wiring and charging system going to/from a starting battery completely separate from my house loads, solar and second dedicated alternator.

I doubt I'll ever get around to it because I really don't need to. The solar keeps up with a little laptop time rationing. I am aware of the inverter on the chassis battery powering a battery charger to the house batteries, but that's just another thing to remember when shutting off the engine. The 2nd alternator would automatically charge at the house batteries' maximum acceptance, for not much more money.

And when I do need to replace my current hybrid batteries, I am going to get some true 12 volt Crown deep cycle batteries, and change the float and acceptance voltages depending on what they seem to like, and the reading of a hydrometer when the controller goes into float mode.

And when My current batteries are being held at 15 volts by the solar, they are only getting under 3 amps if that, so it's not like the things are getting royally boiled each afternoon. They use no water, and if I set the float down to 13.3, in the morning they are at least .2 volts less than the higher float setting all other things being equal.
• Solar Expert Posts: 1,341 ✭✭✭
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Re: Putting Solar Panels on my van
I am aware of the inverter on the chassis battery powering a battery charger to the house batteries, but that's just another thing to remember when shutting off the engine.

Nah. Just wire it like the split-charge relay in my truck - it only works when the alternator is putting out.

In fact, when I do install a diode isolator, I'll be keeping the split-charge relay to use for another purpose. I'll be installing a "Battery MINDer" to keep the engine battery topped off and desulfated whenever there is gen or shore power - but I don't want that charger sending current through the diode isolator to the house batteries.

So I'll keep the split-charge relay just as it is, only instead of feeding from it directly to the aux battery I'll feed from the relay to the isolator and then to the aux.

When the engine is running, then current from the alternator will flow to the aux, and when the engine is off and there is gen/shore power, the Battery MINDer can take care of the engine battery while the Iota takes care of the aux bank, "and never the twain shall meet".
• Solar Expert Posts: 82 ✭✭✭✭
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Re: Putting Solar Panels on my van

I have to confess ignorance of the function of a split charge relay.
And question the desirability of a Diode which reduces the charge voltage to the batteries that need it the most.

One reason I want to go with a second alternator, is for the next time my "Lifetime" warranty reman alternator fails, I have a backup at the turn of my battery switch. I have returned many of these poorly rebuilt alternators. Once, I was stranded in Mexico, where the warranty of course did me no good.

So if I were to power another battery charger through an inverter running off the chassis reman alternator, there is a higher likelyhood of the alternator failing, most likely at the most inconvenient time, again.

Like I indicated, my A/C compressor has been only a pulley for years. I could buy an 80\$ 90 amp alternator and a 30 dollar voltage regulator, Fab up an alternator bracket, and have dual alternators and solar.

My A/C compressor is also slightly out of line with the other pulleys, so I want it gone.
• Solar Expert Posts: 10,300 ✭✭✭✭
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Re: Putting Solar Panels on my van

your alternative might be to buy a new one even though high priced.
• Solar Expert Posts: 9,583 ✭✭✭✭✭
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Re: Putting Solar Panels on my van

If you have money to spend, or just want to drool over rugged, high output alternators, look at the Balmer offerings. 3 stage charge regulators, switches, relays, isolators, dual chargers. Too rich for me, but nice stuff. http://www.balmar.net/
Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,

• Solar Expert Posts: 82 ✭✭✭✭
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Re: Putting Solar Panels on my van
niel wrote: »
your alternative might be to buy a new one even though high priced.

A new alternator, or an A/c compressor?

If I have 2 functioning alternators, I'm using 2. My current one has a lifetime warranty and has been replaced only once since I've had solar. (Bad bearing) I can swap out an alternator in that location under 15 minutes after so much practice.

The a/c system has been removed. To get it functioning again would cost twice as much as the bluebook value of the van. Not gonna happen.

There has been marked resistance of my dual alternator Idea, over on RV net, and I don't really understand why. I know it is not necessary, but if one wants maximum current from an alternator, having it controlled by the (my)vehicles stock voltage regulation seems a poor way to charge some house batteries via the engine. If I were to bypass the stock voltage regulator inside the ECM, the Check engine light goes on and I can't pass a smog test.

I really like the Idea of having the chassis charging system completely removed from the house loads and solar charging. Sure I could isolate a battery now(by moving one battery), but the isolated battery gets no charge either.

I guess the Split charge relay, that when it is sees a switched(ignition) 12 volts combines the batteries? I was just used to this being called an isolation solenoid capable of passing some serious current. Continuous duty solenoid or some such. I explored this option back when I added a second battery. I liked the automatic part, but I didn't like that once it sees 12 volts from the ignition, the vehicle is being started with one depleted battery, and one good battery. I guess it makes no difference, but just doesn't seem right.

I like the Manual switch. When the house batteries are low, I start it with the starting battery, and after a minute I switch it to both, and instantly the engine note changes as the alternator causes some drag.

It's been over a year since I've done that since my house batteries are currently also my starting batteries.

I know were getting off topic to the original post, but this info could help the OP decide what he wants and how to proceed.
• Solar Expert Posts: 1,341 ✭✭✭
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Re: Putting Solar Panels on my van
I guess the Split charge relay, that when it is sees a switched(ignition) 12 volts combines the batteries? I was just used to this being called an isolation solenoid capable of passing some serious current. Continuous duty solenoid or some such. I explored this option back when I added a second battery. I liked the automatic part, but I didn't like that once it sees 12 volts from the ignition, the vehicle is being started with one depleted battery, and one good battery. I guess it makes no difference, but just doesn't seem right.

That's one way to do it...maybe even a common way - I wouldn't know.

Mine does not work that way - I know because I ran the engine battery down once by accidentally leaving the lights on. Turning on the ignition did not tie the batteries together and the truck would not start.

However, I was able to jump start the truck off the aux battery (both are under the hood).

I haven't mapped out the wiring yet, but I'm pretty sure that the relay (solenoid) is energized by voltage *from the alternator*, not from the battery. If so, then the batteries are not tied together unless the engine is running and the alternator putting out voltage.

There is also a bright blue LED on the lower left of the instrument panel, down near the floor. At first I wondered what this thing did, but now I'm pretty sure that it indicates the solenoid is engaged. That indicator does not go on with the ignition switch - it only goes on when the engine is running.

(And admittedly, I could have this all wrong because, as I said, I haven't bothered yet to map out the existing wiring. One reason for that is because I intend to completely re-wire it anyway and so I'm not all that interested in what is there now.)
• Solar Expert Posts: 1,341 ✭✭✭
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Re: Putting Solar Panels on my van
mike90045 wrote: »
If you have money to spend, or just want to drool over rugged, high output alternators, look at the Balmer offerings. 3 stage charge regulators, switches, relays, isolators, dual chargers. Too rich for me, but nice stuff. http://www.balmar.net/

Wrangler too:

http://www.wranglernw.com/