Pretty much like the title says… What size solar setup do you have, and what do you run on it?
Greetings!
The solar salespeople have obviously been working overtime…
Solar is the most expensive and least reliable battery charger on earth. Every other option is cheaper and better.
The best place to start is figuring out just how low you can make your power consumption. The lower the better. Heating, cooking, refrigeration, water heating, and more are best accomplished with fuel, not electricity. Avoid an inverter if at all possible. Power as much as possible with USB first, then 12vdc when you can’t power it via USB. There’s USB & car adapters available for almost everything.
If you need something bigger than a laptop screen, then get a usb projector instead of a big TV or monitor. Hopefully you get where we’re going with this. Use rechargeable batteries in whatever is possible rather than your house battery. They have small solar battery chargers you can place on your dash or inside a window, so you’ll always have freshly recharged batteries when you need them. Many things come with their own solar panels, lights, lanterns, bug zappers, and much more. The individual solar powered stuff is great. Solar hot water can work well too.
Once you get your power needs adjusted to an absolute bare minimum, now it’s time to figure out the amount of battery power you actually need. My 100ah deep cycle battery will last me a little over a week as an example. Keep in mind, that a 100ah battery shouldn’t be discharged below half, so that’s 50ah usable. It’s really rare for me to use 10 amps per day, and it’s usually much less.
Now let’s look at the best ways to charge your house battery. The best choices are isolator/solenoid/relay, generator, or shore power. Solar comes in dead last. An isolator to charge while driving should always be your first choice. If you have places where you can plug in a battery charger, an extension cord is always a good investment. If you need to generate more power than your driving can provide, and there’s no shore power available, then a generator is a wise choice. You don’t need an expensive one either, my $99 (on sale) generator serves all my needs perfectly well.
Now if you’re a tinkerer, and want an expensive, never ending project, let’s talk solar. For every 100ah of battery capacity, you want at least 200 watts of solar, and 300+ watts of solar is preferable. Now keep in mind that surveys show that less than 1% of the people who try solar ever get it working satisfactorily, and 99% of the people who have tried it, hate it, and regret ever having tried it. Almost everybody that is happy with their solar are also using other methods of charging too, and it’s actually those other methods that are keeping them happy.
Once I added an isolator to my solar, it was like magic, my solar was great. But when the solar got stolen, guess what? There was NO noticeable change. It was the isolator doing all the work all along.
Don’t get suckered into expensive batteries either… For over 20 years now, I’ve been buying cheap deep cycle RV batteries from junkyards, for usually under $20. They’ll typically last me 5-7 years. When I had solar alone, I was burning through two $350+ batteries every 9-12 months.
On my house battery I charge my laptop, run a fan, a swamp cooler in the summer, heating/cooling blankets & seat cushions as needed, and that’s really just about it. Everything else is either fuel powered, solar powered, or has rechargeable batteries that get recharged by a solar battery charger. (AA/AAA/C/D/9v type batteries) [I didn’t list the stuff that I run off my laptop’s USB, like the projector, my razor, another fan, a light for my keyboard, etc. I think all of my solar goodies can be charged via USB too.]
Cheers!
"Solar is the most expensive & inefficient battery charger on Earth." ~ Truth_Matters
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Wow! That was a wealth of information. Thank you. Did you have all that on a flash drive ready to school folks? 
Where and what kind of generator did you get for $99! Me myself…just want to run my 12v alpicool45 24/7…an exhaust fan when I sleep and some light electronics…laptop, phone, toothbrush etc. I also plan on being off grid more than anything…so I think SOME solar will be useful. Especially if I don’t want a loud gas generator going. But most my charging will be from drives and the isolater. All my lighting will be battery operated
I don’t think that solar is as unreliable as stated. I think it’s one of the most reliable ways to charge your batteries as long as you don’t consistently use more power than your panels supply. There will be cloudy days, shorter days in the winter, and you might park the van in the shade to avoid the heat - these things do affect solar charging, but it doesn’t mean that it’s unreliable. It just means that you have to think about how your batteries are being charged, and if you need to augment solar charging on those less than ideal conditions. It’s good to have two or more ways to charge, such as solar, augmented with alternator charging, and maybe a battery charger that plugs into shore power. The more options the better, but to say that solar is unreliable is just not correct.
And to add… solar is cheaper now than it ever was before. New panels are less than $1 per watt. If you’re paying more than that, you’re paying too much. I just bought a 150 watt panel for my van and paid $137. The only other thing that you need to add is a charge controller to properly maintain your batteries - I found a good quality used Morningstar controller on eBay for $40. Make sure you get a good quality controller, and that all your connections are tight with properly sized wire that’s protected from chafing etc.
This is the electrical panel that I assembled a few days ago that will go into my van. For right now I’m only going to connect one 150 watt panel, but it’s sized to accept two 150 watt panels if I feel that 300 watts is needed. My plans for this van is trips of a week or two, sometimes more, and the only thing I envision using the battery for is to run lights, fans, device/laptop charging, a small 300 watt inverter if needed, and an evaporative cooler on occasion. It’s probably enough to run a small fridge as well, but I’ll probably stick with the old ice chest. The battery is a new Interstate 110 amp AGM type (so it can be used inside the van without venting).
Greetings!
Keeping many of the frequently asked questions and answers saved seems like a good idea, but stuff changes so frequently that I just take the time to type it out, often after a little research to see if anything has changed either for the better or the worse.
I got my generator at a Builders Square years ago, they had a mountain full of them. They’re el cheapo, no name ones, but mine has lasted well. It was a little louder than I liked, so I added an $18 scooter muffler to it, which REALLY quieted it down, actually less than half as loud as most of the quiet generators. I don’t get hung up on name brands, I knew if I had trouble Builders Square would make it right.
Just doing a quickie google search turned up three cheapies for under $130. You don’t need much to run a battery charger.
When I converted a shuttle bus, the wiring was so complicated that I opted to just use a generator rather than install an isolator. Charging my house batteries weekly, I used under 5 gallons of gas total for the year I owned it. Gas was nearly $5/gal at that time, and it still cost me under $25 for that years worth of power. Even doing it that way, just imagine how many years it would take for a solar system to pay for itself…
Back when I was using 12v compressor fridges, they would use 50-100ah per day in the summer. That’s more than I typically use in a week now, and it was like running a heater inside during the hottest parts of the summer. If I was ever to go back to a powered fridge, it would be a 3 way, vented to the outside, that would fuel rather than electrical power except while driving. If you mount them with a gimbal like they do on boats, your rig doesn’t need to be leveled.
With my ice chest, I spend $1-$2 a week for a big block of ice. I keep the ice in a separate container, so my food never gets wet. Simple, cheap, and easy, and I usually go shopping once a week anyway. During heat waves I’ll wrap my ice chest in a moving blanket, and the ice still lasts a week+. If I need a freezer, I use dry ice. For a 6 month boat trip, not knowing what would be available or where, we rented a couple of $20 tanks to make our own dry ice as needed. That gave us 120qt of freezer space, and then we just made the ice for the cooler in that. Worked out well.
Even though I have lots of LED lights & lanterns, I usually find myself using my kerosene lantern for ambient lighting, and my headlamp if I’m really working on something. Something about the nice soft warm glow of that kerosene lamp that I just really enjoy. Makes it feel more like camping too, and lessens my feeling of missing out on a campfire.
Cheers!
"They told me I'd save money with solar, and have free electricity.
Neither was true." ~ Disgusted in Dallas
Neither was true." ~ Disgusted in Dallas
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Greetings!
Look up the statistics my friend, they’re not encouraging…
Cheers!
"They told me I'd save money with solar, and have free electricity.
Neither was true." ~ Disgusted in Dallas
Neither was true." ~ Disgusted in Dallas
I’d like to see those statistics. Can you point me toward some documented examples?
I’m willing to bet that people who had trouble either didn’t install it correctly, or did not have realistic expectations - such as running an electric heater through an inverter all night. Do the math, have realistic expectations, and don’t be a dummy when it comes to charging and using your batteries.
Solar is a great way to charge batteries - one of many, and my preferred way because it’s quiet, it’s automatic, and it uses no fossil fuels.
Another thing to keep in mind when using an AGM or gel battery is that alternator charging is a last resort, and will drastically reduce the life of these batteries due to over-charging. Don’t get in the habit of charging while you’re driving because you’ll be replacing the batteries sooner rather than later. Better to charge them with a good quality solar charge controller, or a smart charger from shore power.
@Axel - Are you certain that alternator charging lessons the life of an AGM battery. This is the only way I charge them and have had no issues doing so. I would think this is no longer the case as I believe the battery in my Promaster is an AGM. Either way it is sealed - “95-Amp/Hr 800CCA Maintenance-Free Battery w/Run Down Protection”. I can’t find exact details on what type it is. I am also under the impression that alternators have built in regulators that essentially disconnect the alternator when the voltage reaches a certain level to prevent overcharging batteries.
Bret, not in all cases if your alternator doesn’t put out too much voltage, but a lot of alternators put out more than 15 volts, especially in older vehicles, and that will cause sealed batteries to start venting due to over-charging. When a sealed battery vents, it can’t be recovered or refilled, causing it to lose performance until it’s no longer useable.
Another issue can be under-charging, especially with diode type isolators and long runs of wire from the starting battery to the house battery that can drop the voltage to where the battery never really gets a full charge. AGM and gel batteries do best if charged at a very specific voltage, and when they reach that voltage they benefit from the charge being stopped or “floated.” When batteries like this are either over or under charged they just won’t last as long.
Interesting, mine does not appear to do either, typically i’m around 14.4v which from my understanding is perfect. My old van ran at like 15v but it was a 1983. I guess that is a win for technology. However ,I don’t see how my batteries ever could get a full charge, being that I am constantly using them. Something is always running or plugged in. I think I am going to take them in and get them tested (including my starting battery). I wonder how much their capacity has depleted up to this point.
14.4 volts at the house battery is just about ideal for charging, so you’re doing well. Bretly, how long have those batteries been in your van?
The starter battery since it was built so not clue on that one, but it has been run about 10 months pretty hard so far.
2nd AGM is 92 amp hour duracell from batteries and bulbs that has been in there for -~8 months
3rd AGM is 92 amp hour west marine battery (clerk tested it at 95% capacity when I bought it) ~ 6months
I expect some natural loss in capacity and we rarely drop below 12.2-12.3v on the house side. Might not be the best indication as it is not a resting voltage, but I don’t believe we’ve dropped below 50% capacity ever. Regardless I expect these things will certainly last much longer than a year.
Bretly, I think you’ll be fine as long as you’re seeing the proper voltage while charging (measured at the house battery terminals, not at the starting battery) and you’re not running them down too far. Sounds like you’ve been pretty good not over-discharging, so they’ll probably last.