Solar panel overkill?

Probably is overkill but can't hurt to have more solar. $150 is great price. The trick is going to be the controller.

You could have two $102 20a Eco-Worthy controllers, (42Voc limit each) in parallel on the battery bank. I don't know the specs on the Tracer for max Voc intake rating--be careful of that. It costs about twice the Eco-W so that is a possible break-even, if the T can do both panels.

Going to the usual suspect higher Voc limit MPPTs for a single controller would run you $300 or so.

I would not recommend a 200+ watt solar panel for any RV. Unless you have a really large area that is not over a curved roof that will make it to high in the wind while driving.

The problem with 200 watt panels is there is to many square feet of panel, and typically only 4 mounts. You can have a lot of uplift during certain driving conditions. Or the pane can act like a wing, and take off, ripping it's mounts from the top of the RV.

My larger pair of panels are 120 watts and the pair cover the front 4' of my motorhome. They whistle while driving, probably catch a lot of air, but have not managed to pull their mounts loose in 10 years of use and about 25,000 miles driving.

A RV can use 35 amp hours daily to run just the refrigerator, CO and propane detectors. Then add your other loads.

I like to watch a lot of Direct TV, and that means about 7.5 amps per hour of running the TV, many days that is about 15 hours per day.

Lights use about 1.1 amps per hour. Figure about 15 AH daily, and you will be able to run 13.5 hours of light. This can be 3 for 4.5 hours, or 2 for 6.5 hours, or a mixture.

The water pump is a nominal load - 7 amps per hour, and 1 hour can pump 2 GPM and empty a 120 gallon tank. So a 60 gallon tank is only 3.5 AH for the whole trip.

Furnace is much larger load. Running it 3 hours per night will be 18 to 24 amp hours.

Good luck with this project.

Fred.

I think overkill is a good thing but I have to tell you that if you get those batteries down to 12.0v in 24hrs. two panels isn't overkill.

BFL13 wrote:
Probably is overkill but can't hurt to have more solar. $150 is great price. The trick is going to be the controller.

You could have two $102 20a Eco-Worthy controllers, (42Voc limit each) in parallel on the battery bank. I don't know the specs on the Tracer for max Voc intake rating--be careful of that. It costs about twice the Eco-W so that is a possible break-even, if the T can do both panels.

Going to the usual suspect higher Voc limit MPPTs for a single controller would run you $300 or so.

Was thinking of paralleling 2 MX Solar 235 watt panels that are actually $158.00 each (was rounding down to make myself feel better). With the remote meter the 40 amp Tracer is $265.99 on eBay. The tracer specs are as follows:

Model
Tracer-4210RN

Rated system voltage
12/24V auto work

Rated battery current
40A

Rated load current
20A

Max.battery voltage
32V

Max.PV open circuit voltage
100VDC

Max.PV input power
12V 520W? 24V 1040W

Self-consumption
<10mA?24V?

Charge Circuit Voltage Drop
?0.26V

Discharge Circuit Voltage Drop
?0.15V

Communication
TTL232 / 8 pin RJ45

Temp.compensation
-30mV/?/12V?25??

Golden_HVAC wrote:
I would not recommend a 200+ watt solar panel for any RV. Unless you have a really large area that is not over a curved roof that will make it to high in the wind while driving.

The problem with 200 watt panels is there is to many square feet of panel, and typically only 4 mounts. You can have a lot of uplift during certain driving conditions. Or the pane can act like a wing, and take off, ripping it's mounts from the top of the RV.

My larger pair of panels are 120 watts and the pair cover the front 4' of my motorhome. They whistle while driving, probably catch a lot of air, but have not managed to pull their mounts loose in 10 years of use and about 25,000 miles driving.

The panels measure 65.55" X 39.57". Was thinking of making them tilt not so much for the angle of the sun but for roof access so I could tilt them out of the way. I could make 6 mounts instead of 4 if that is advisable. Would just be one more knob to unscrew for tilting. Not sure yet how much roof is arched - will have to get up there again and check. Do you think that molly bolts or toggle bolts would rip out of the roof from wind?

What is your daily usage (when camped in the Pac NW)?

Steve

It's not overkill IMO. Keeping batteries fully charged is best for them. If you have the roof space for them and the money, I say go for it.

SteveAE wrote:
What is your daily usage (when camped in the Pac NW)?

Steve

Not sure. We typically watch TV for about an hour and use computer for about 3 hours however these are limits we've set so we only have to run the generator for a couple of hours a day and we slowly loose amp hours every day running the generator that long. Wife would like to watch a lot more TV during the day. When using the furnace to take the chill off of the night we have drawn the batteries down to 60% often. We have to park overnight in front of residences quite often because of our business and would like to not use the generator at all if possible. I am also trying to plan ahead when we might someday fulltime and would like to set the RV up now to make use of the business deductions to purchase a system.

If you're writing off the expense of the system as a business expense, it's a no brainer, install two modules. I have a single MX Solar 235w module and it is performing well.
I would suggest you consider the Rogue 20 amp controller. The company has very favorable reviews, the controllers have a lot of functionality, and price is similar to the Tracer.

westend wrote:
If you're writing off the expense of the system as a business expense, it's a no brainer, install two modules. I have a single MX Solar 235w module and it is performing well.
I would suggest you consider the Rogue 20 amp controller. The company has very favorable reviews, the controllers have a lot of functionality, and price is similar to the Tracer.

Would this controller handle the 470 watts?