12v vs 24v panels

[Allen_C]

What are the advantages and disadvantages of each? I believe the 12v panels require thicker gauge wire to minimize loss when traveling longer distances, 24v panels are less susceptible.

Is there also an amperage difference when a 24v panel is rated at 200w and ~8amps when it is converted to 12v by the charge controller? Will a pwm do this well or is an mppt controller with the additional cost for this process?

I tried to search here and elsewhere but did not find specific answers. Thanks for responding!

[Subaru297]

If you go with higher voltage panels 24v or higher you will need a MPPT charger. The MPPT charge controller will decrease the voltage and increase the amps to match the voltage needed by the battery.
A PWM charger will just pass along the volts and amps to the battery.

You can also wire your panels in series to increase the voltage and again you would need an MPPT controller but I would always recommend keeping panels wired in parallel to avoid shading issues.

Advantages of 12v panels are their size mainly. They are physically smaller and will give more mounting options.
High voltage residential panels are typically cheaper and you get less voltage drop through your wiring. The only real downside is having to purchase the more expensive MPPT controller.

Hope that helps.
Cheers

[bdreinv]

Originally Posted by Allen_C

What are the advantages and disadvantages of each? I believe the 12v panels require thicker gauge wire to minimize loss when traveling longer distances, 24v panels are less susceptible.

Is there also an amperage difference when a 24v panel is rated at 200w and ~8amps when it is converted to 12v by the charge controller? Will a pwm do this well or is an mppt controller with the additional cost for this process?

I tried to search here and elsewhere but did not find specific answers. Thanks for responding!

There is a company in Flagstaff Northern AZ wind and sun.Have easy to surf web site.Call them they are solar only guys,lots of free info.We purchased one 275 watt 60 cell panel.A a 30 amp mppt controller,they are worth the money.Totally automatic, only disadvantage that controller is limited to 290 watts of panels.The larger panel allows you not to have to tilt.Happy Trails!

[Allen_C]

Originally Posted by bdreinv

There is a company in Flagstaff Northern AZ wind and sun.Have easy to surf web site.Call them they are solar only guys,lots of free info.We purchased one 275 watt 60 cell panel.A a 30 amp mppt controller,they are worth the money.Totally automatic, only disadvantage that controller is limited to 290 watts of panels.The larger panel allows you not to have to tilt.Happy Trails!

Is that one 275w panel 24v? If so, what was the amp rating (for 24v) on it and what are you actually getting to the battery at 12v?

It sounds like 24v panels are bigger but cheaper and the mppt controller is more expensive than the savings on the panel(s), but worth it?

[bdreinv]

Originally Posted by Allen_C

Is that one 275w panel 24v? If so, what was the amp rating (for 24v) on it and what are you actually getting to the battery at 12v?

It sounds like 24v panels are bigger but cheaper and the mppt controller is more expensive than the savings on the panel(s), but worth it?

Iam a rookie with solar started out with portable 40 watt panel from HFreight.Your correct the more watts in the panel the cheaper they
are.The275 watt panels are called industrial panels.Maybe 60x30 I paid 250 last summer.One cheap add on was the battery temp monitor 25 bucks.If you can find more pros and cons of the controllers.The mppt is like comparing a candle to a light bulb.We love the set up, with a little help getting the panel on the roof.The rest is pretty straight foreword.I would suggest the 40 amp mppt controller,you can never have enough PV panels.Hope that helps!

[bdreinv]

PS the more cells the better this 275 watt panel has 60!

[Mustang65]

Take a look at the RVing with SOLAR social group on this forum. It will answer just about all your questions regarding SOLAR and BATTERIES and installations by members. It has a link to a YouTube video explaining the difference between a PWM and a MPPT SOLAR charge controller. PWM charge controllers use the panels Amp output and MPPT use the SOLAR panel's WATTs. A battery needs at a minimum 17VDC to properly charge a battery and maintain the 13.2 Float.

Your decision on what parts you want need depends on what you want to accomplish with SOLAR! If you want to only keep you batteries charged and topped off, there is no reason to sink a lot of money into the system.

If you are unsure with what you want to do in the future, but you want to get started then you put extra $$ into your basic system that allows for expansion to meet your future needs. You don't want to buy expensive parts twice.

I would not even think about the 12Volt panels. I went with the residential 250 watt panel (31Volts VMP) and a 60 amp Morningstar MPPT charge controller. Meets our needs.

Don