How Much Solar Power is "Enough"

[Eriik]

I have four 130 watt, 7.5 amp solar panels on the roof of my RV (with a 30 amp controller), three 12 volt house batteries, and a 2500 watt inverter. The solar panels do a great job keeping my batteries topped off, but don't seem to generate enough power to watch the TV for more than 30 minutes or so. What do I need to do to boost this system, and how much is "enough"? Eriik

[autofish]

Eriik== that should be plenty of solar I have 500 watts and 4 six volt batteries that will power tv all night and charge back up next day. I would look at the batteries if they will only run tv for 30 min.

[Baddad53]

Originally Posted by Eriik

I have four 130 watt, 7.5 amp solar panels on the roof of my RV (with a 30 amp controller), three 12 volt house batteries, and a 2500 watt inverter. The solar panels do a great job keeping my batteries topped off, but don't seem to generate enough power to watch the TV for more than 30 minutes or so. What do I need to do to boost this system, and how much is "enough"? Eriik

Change your TV from an IMAX 100ft x 80ft to normal a 50inch and it should be ok JK You should check your batteries somethings not right there.

[TexasTwoStep]

You definitely have a problem there. You should have an ass kicking system. My first reaction is that your controller is undersized, but I think there are other issues as well. Tell us everything you can about the system. How are the panels wired? What size wire? How far from roof entry point to controller? What size wire from roof to controller? How far from controller to battery bank? wire size from controller to batteries? How far from inverter to battery bank? What size wire from inverter to batteries? What size wire between batteries? What type of controller and at what voltage is it set to charge the batteries? What type of inverter?

I have 3 130 watt panels and 4 6v Trojans and can run the tv all I want and still have juice to make coffee and wife hair dryer, etc. in morning.

Here is my answer to the above questions. My panels are wired with 10/2 uv solar wire that run from each panel separately to a junction box on the roof. This junction box is about 8 feet above my Morningstar Tristar 45 controller using #6 awg wire. My controller is a couple of feet from my battery bank and wired to the battery bank with #4 wire. My inverter is 3 feet from the battery bank and wired with 2/0cable. 2/0 cable between batteries. My charging voltage is set at 14.8 volts.

Wire sizes should be stamped on the coating.

This is not rocket science and I'm sure your problem can be solved fairly easily. You have already paid for the equipment which is a major factor. I know you paid good money for that system and it should work for you and not against you.

I originally paid someone to do mine and they screwed it up so I had to educate myself and redo it.

[Steve Ownby]

Tell us about your 3 12 Volt house batteries. There are really not many 12 volt batteries that are true deep cycle batteries so most are using 6 volt golf cart size in the role.

[Eriik]

I will take a look at the battery pack and report back. The reason I originally installed the solar panels was to keep the house batteries from draining over the winter and then freezing. I destroyed several sets of house batteries that way, including some fancy (and expensive) gel cell batteries. The solar system works fine in this regard, but with four giant panels on the roof, I really was expecting more! Eriik

[wonderer1]

let's check the math 4- 130 watt panels. 4x130=520 watts 520 watts / 12 volts = 43.3 amps in mid day sun in theory. you're getting 7.5 amps ????? i'd do some checking you've got problems. maybe bad connections, to small a wire from the panels to the controler and to the batteries. sounds like you have enough panels to at least start with. if you haven't been to handybobs site, you might pick up some pointers. good luck and keep us posted. i'd also use a hydrometer on the batteries to look for bad cells. any auto parts store has them and they are not expensive. ( 1- 130 watt panel at 12 volts should equal 10 + amps ) one other thing to check when checking your panels is the connection coming off the panels to the pig tails.

[bluepill]

Fully testing your batteries is always the first step. If any of the batteries in poor health it will affect the whole system.

1. If you can remove the caps, check & fill with water.

2. Disconnect the batteries from each other on the negative side.

3. Fully charge each battery, including an equalization charge. If you have a built-in converter/charger that has 3 stages plus equalization use it. Otherwise you will have to use an external charger with those features.

4. Upon completion of charging, test each battery individually.

Only if all 3 batteries pass testing should you continue to testing of your solar system.

[John Hilley]

Originally Posted by wonderer1

let's check the math 4- 130 watt panels. 4x130=520 watts 520 watts / 12 volts = 43.3 amps in mid day sun in theory. you're getting 7.5 amps ????? i'd do some checking you've got problems. maybe bad connections, to small a wire from the panels to the controler and to the batteries. sounds like you have enough panels to at least start with. if you haven't been to handybobs site, you might pick up some pointers. good luck and keep us posted. i'd also use a hydrometer on the batteries to look for bad cells. any auto parts store has them and they are not expensive. ( 1- 130 watt panel at 12 volts should equal 10 + amps ) one other thing to check when checking your panels is the connection coming off the panels to the pig tails.

He gets 7.5 amps per panel. They are 18 volt panels, so you divide the 130 by 18. He must have a battery problem.

[Eriik]

I will check out all of the things you guys have suggested. However, based on what I am reading, and my history with this vehicle, my guess is that it is not a battery issue, it is an inverter issue! We shall see!!! Eriik

[vsheetz]

1) check for bad/weak battery(s)
2) what solar controller - does it tell you status info enough to have confidence the system is performing ok
3) the inverter is bad - drawing down the batteries way too fast

If all is woking properly this should be a good system - system capacity should not be the properly.

[TexasTwoStep]

Originally Posted by John Hilley

He gets 7.5 amps per panel. They are 18 volt panels, so you divide the 130 by 18. He must have a battery problem.

The specs on my 12v Kyocera 130 watt panels indicate that they are capable of 7.63 amps each.

[TexasTwoStep]

Originally Posted by wonderer1

let's check the math 4- 130 watt panels. 4x130=520 watts 520 watts / 12 volts = 43.3 amps in mid day sun in theory. you're getting 7.5 amps ????? i'd do some checking you've got problems. maybe bad connections, to small a wire from the panels to the controler and to the batteries. sounds like you have enough panels to at least start with. if you haven't been to handybobs site, you might pick up some pointers. good luck and keep us posted. i'd also use a hydrometer on the batteries to look for bad cells. any auto parts store has them and they are not expensive. ( 1- 130 watt panel at 12 volts should equal 10 + amps ) one other thing to check when checking your panels is the connection coming off the panels to the pig tails.

Bad math, these panels generate around 7.6 amps at max.

[okmunky]

Eriik,

I know it won't fix your solar problem, but have you considered a 12 volt LED TV? My 22' TV can run 14 hours and use very little power. I paid $215 for it and Jensen makes a 32" for about $600.

I have less than 300 watts of solar panels and 2 golf cart batteries, but seldom have any low battery issues while boondocking.