Going Solar!

WRONG

Fishinghat wrote:
First off, almost all solar panels will only produce enough electricity to keep a charged battery charged up, but not to re-charge a run down battery.

Man! I got tons of info here! OK, got my amps and watts mixed up. That's what I meant...10w is maintenance, like when it's parked at home. Having said that this unit comes prepared for a 150w panel. Yes I said 150w. They stick a 10w on there and call it "Solar Ready". I explained to the dealer what my needs are:
1. We don't watch TV when RV-ing
2. We don't use a micro wave when RV-ing
3. We boil water on the stove to make French press coffee
4. The main reason I want Solar is to replenish the batteries after a night of running the heater.
5. Before you suggest a catalytic heater, they worry my wife to much.
6. This trailer has all LED lighting inside and out.
7. I plan to buy a back up generator to use if there is too much cloud cover.
8. Not really even thinking of an inverter except maybe to run my C-pap at night. If you want the humidifier to work it need 110v. Don't eve know if that is plausible, but as it stands that would be the only reason now.

Talking to the dealer who apparently is a real solar geek, said he would add another 85w panel, 2 6v deep cycle golf cart batteries and the fancy, convert to amp from watt controller. He commented that since this unit comes pre-wired with the quick connects, adding the 85w would be a snap. I think he knows the business pretty well. The other sales man with him said he can power other trailers off his! Both the owner and the sales person at this dealer are avid hunters, fishermen and know their way around a tool box and a test light. I think they sell these rigs to support their habit!

Thanks
V-465

Vintage465 - first off, find out what kind of OEM "quick connect" they will provide. Majority of panels have MC4 connectors, so this is what you want. Also, find out what wire gauge will be in there. Then we'll be able to tell the maximum number of panels and watts and volts you'll be able to install.

You're right on numbers, but mixed up with units.
10W is for maintenance in storage (it's Watts, not Amps).
80-150W is for topping up after you've used them, though 150W may take more than a day to top it up, depends on battery bank size.

Yes, panels up to 180W put out 17V, so regulator is necessary. It's called PWM controller. Such a panel is called "nominal 12V".

Big panels from 200W and up put out 30V, and are called "nominal 24V". They require MPPT controller - this is the one that converts excess volts to amps. It's more expensive than PWM, and you don't need it with a 12V panel.

Check solarblvd.com for controllers and panels, their inventory is well categorized, easy to understand. Solar is mostly DIY thing, though I have a feeling that learning curve in your case might be too steep, so you will need to hire some solar installer.

Normally, people with arrays up to total 300W use 12V panels and PWM controller, and with larger arrays - 24V panels and MPPT controller. Though there are exceptions - rigs with mere 200W single 24V panel and MPPT controller, or rigs with many 100-150W 12V panels (total 400W or more), and PWM controller. I would suggest following the crowd - decide how many watts you want, and then you'll know whether you need 12V+PWM or 24V+MPPT.

Fishinghut doesn't know much about solar or doesn't have the right experience. There are people here who live off solar and leave their generators home. Others still carry generator, just in case. "Normally", in Ca you should be able to leave your genny home if you install around 500W or more. Though some people can't live off 900W solar in Ca or Az - it depends on your energy habits. Keep in mind that in order to harvest enough energy from sun, you will have to avoid camping in deep shade.

The only thing that you can't expect from solar is running A/C (and I wouldn't be surprised to hear objections, because with a lot of solar you can still run a small A/C for a few hours).

Fishinghat

You should research solar again. I think a lot has changed since you last did. Prices have come down considerably. I am putting together my 750w system for less than you pay for Honda 3000 inverter generator. It will push up to 50a just like my converter plugged into a generator would. The difference is my solar does it all day long, not just a few hours. A few hours may get the battery back up to 90% but never full. Over time that will cause you to lose battery capacity.

Vintage465 wrote:
So, this is what I know, or think I know about Solar. A ten amp panel is for maintaining. Something like a 85, 100, 150 is for charging after pulling the batteries down. Big panels put out like 19volts so a regulator of sorts is necessary.

Those are WATTs not amps.

Large 24v nominal panels are closer to 30 volts and need an MPPT controller that does cost a bit more.

The 12volt Side of Life

> Forum Members Solar Installations With Pics

Welcome to the forum

Solar is a balance of your needs, conservation, enough battery to cover your needs while the sun doesn't play nice, enough solar to recharge those batteries back up when the sun does shine again, and a back up for when the sun hides too long.

Your needs can be calculated or if you know the size of the battery bank and how long it last, you have a rough guess to start with.

Conserve with LED lighting, lower power TVs. etc.

2 or 3 days of battery depending on your appetite, space and budget.

A 1-1 ratio of solar to Ah of battery or better so that you can recharge in a day. Dependent on roof space and budget.

A MPPT controller converts excess voltage to amps but they are more expensive. You have to look at what it offers to decide if it is worth the expense. sometimes another 12v panel will do better for you. Then again the big panels are even higher volatges and require the MPPT controller to be used at all. Those panels are cheaper per watt and offsets the extra cost some.

A 10 watt panel may keep a fully charged battery from self discharging if it is disconnected from any loads.

There are plenty people on this forum, that live off solar panels
Enough solar with correct power management,
And you can easily recharge batteries

Like with all things "rv electrical", you must first determine your needs/usage, then size your entire system accordingly... that means battery bank, converter, charger, inverter, solar, generator, wiring, etc. It may seem a little overwhelming at first, but it's not that difficult... and you have experience rv'ing, so that will help lots.

Best thing to do is list what you have in the way of batteries, chargers, etc., and your daily usage, and many here can point you in the right direction. There is a lot to learn about solar, but you don't need a phd in solar energy to get started. And the good news is, solar is coming way down in price. About $2/watt will get you a modest system.

We can't get enough of this.

There are PWM and MPPT controllers. You want MPPT. For serious solar you need to google Morning Star, Blue Sky and some others. Many RV solar dealers will do a better installation. The solar prep, especially if it is only 10 amps is just going to keep your battery from running down in storage. When people hear 10 amps they are wowed but do the numbers. A 10 amp solar on 12 volts is only 120 watts. Equivalent to one light bulb in a stick & brick house. Current times voltage equals watts. I have a 120 watt portable unit because I dry camp 2 weeks a year. My RV is plugged in or moving the rest of the year. Plus I kick my generator on in the mornings while dry camping. You may want to be thinking 60 to 80 amp mppt controller. An 80 amp controller will give you 960 watts. If you buy a large controller you can add more panels as needed. Don't know where you live but talk to some Solar dealers first. I think you would be wasting money on a manufacturer prep unless it was an 80 amp. Think you would be looking at #4 wire. JMHO