Hooking 4 15-Watt Panels Into a Controller For Camping?

[KenRyan]

Sunking,

That's is awesome!! Thank you soooo much for the detailed advice. Luckily I have a week or so before we set off. So I'm off to research where I can get the things you recommend.

Again, I've very grateful.

Ken

[Sunking]

You are welcome and good luck.

[KenRyan]

I do have another question. I've been looking for "grid-tie" solar panels and keep running into definitions that have to do with the system and not the panel themselves. How do I know if panel is a grid-tie panel or a battery panel. Also (I guess that's 2 questions), did you recommend the grid-tie panel because of the price? Or was there a different reason?

Thanks!

Ken

[mapmaker]

I do have another question. I've been looking for "grid-tie" solar panels and keep running into definitions that have to do with the system and not the panel themselves. How do I know if panel is a grid-tie panel or a battery panel. Also (I guess that's 2 questions), did you recommend the grid-tie panel because of the price? Or was there a different reason?

In the old days, panels had voltages that were matched to batteries in a way that a PWM controller could charge the battery. Grid-tie systems use string voltages of 100's of volts, so panels got larger and with higher voltages. Battery based systems are a niche market, so the best prices are on the high voltage panels which we call grid-tie panels. With an MPPT controller you can use the higher voltage GT panels to charge a battery. --mapmaker

[Sunking]

I do have another question. I've been looking for "grid-tie" solar panels and keep running into definitions that have to do with the system and not the panel themselves. How do I know if panel is a grid-tie panel or a battery panel. Also (I guess that's 2 questions), did you recommend the grid-tie panel because of the price? Or was there a different reason?

Battery panels are 36 cells which limits the power and voltage. Battery panels Vmp (voltage maximum power)is around 17 to 18 volts, and upper limit power is about 150 to 180 watts. In addition battery panels cost about 2 times as much ($/watt) as Grid Tied Panels.

Gid tied panels use 50 to 72 cells (25 to 36 volts Vmp) which means higher voltage and power up to 300 watts and cost about half of what battery panels cost.

Battery panels can use inefficient but cheap PWM controller and more efficient MPPT controllers. Grid Tied panels must use MPPT controllers.

But here is the bottom line. It takes a 300 watt PWM system to generate the same power as a 200 watt MPPT system. A Battery panel cost roughly $2 to $3 per watt, and a Grid Tied panel roughly $1 to $1.50 per watt. If you were to buy a 2-150 watt battery panels with a 15 amp PWM controller will cost you around $650 to $900. Or you can buy a single 200 watt panel and a 15 amp MPPT controller for around $400 to $600. Both will generate the same amount of power of 15 amps charge current.

[KenRyan]

Great. Thanks again guys! Lots of learning taking place.

Ken