Adding another 12v battery to camper

[JohnB]

Originally Posted by Photokit

And since I am shopping new batteries and a new set of panels, I'm in search of the best operating current for the panels. I will probably upgrade to 200watts, 2-100 watt panels in series. At 26 lbs each, with a protective case for storage under my bed (or I'll build a case).

Hi Kit,

On connecting your 2 panels, you mentioned "in series". To go series or parallel has a quantity or pro's and con's and is a good question. You are only looking at 2 cells now but the question remains the same for more then 2 panels. At this point I let Tod and Mainah comment on this

From what I'm learning,

Going series up's the voltage going to the controller to help with wire voltage loss.

Going series, if there is shade, the shaded panel can pull down the output of the other cells. A diode setup on the panel itself for each cell might help this but need to know if the panels you are getting have them.

Going parallel helps on the shaded issues but you have to deal with larger wires to keep the voltage loss down.

Part of this also can depend on the controller max voltage. If it can handle the combined higher voltage from a series connection, then it can work. If the controller cannot handle the higher voltage from the array, then you have to go parallel.

Curious on opinions from those who have this working. Right now, I know enough to ask the questions.

Thanks

John

[Tod Osier]

Originally Posted by JohnB

Hi Tod,

Yes, I enjoy the learning. It shows that much??? I'm a techno-geek through and through...

Handy Bob, https://handybobsolar.wordpress.com/ Thanks for the tip. Never would of found that if you didn't mention. Thank you! I started reading and hours went by quickly... Still lot's more to dig into. He for sure has an opinion... and once past the opinion, by his background it raises all the right questions to dig into. I can find a lot of good there technically that I can connect the dots on.

John

Bob makes it easy to tell where the questions to ask are, which is what I liked. I ended up following his suggestions to a “t” after everything that I looked up checked out. I was looking for a solid, well performing system and I seem to have gotten it after 5 culumative months of use in long trips in mostly shoulder seasons over the past 2 years.

We are set up for mostly western camping and long trips, I can understand the concerns you have and don’t know what I’d do in your shoes. Camping under deciduous forest doesnt charge all that well .

[Tod Osier]

Originally Posted by JohnB

Hi Kit,

On connecting your 2 panels, you mentioned "in series". To go series or parallel has a quantity or pro's and con's and is a good question. You are only looking at 2 cells now but the question remains the same for more then 2 panels. At this point I let Tod and Mainah comment on this

From what I'm learning,

Going series up's the voltage going to the controller to help with wire voltage loss.

Going series, if there is shade, the shaded panel can pull down the output of the other cells. A diode setup on the panel itself for each cell might help this but need to know if the panels you are getting have them.

Going parallel helps on the shaded issues but you have to deal with larger wires to keep the voltage loss down.

Part of this also can depend on the controller max voltage. If it can handle the combined higher voltage from a series connection, then it can work. If the controller cannot handle the higher voltage from the array, then you have to go parallel.

Curious on opinions from those who have this working. Right now, I know enough to ask the questions.

Thanks

John

I went parallel for panels for the shading concerns noted and just put heavier wire to compensate. I built my system to add a third panel if needed, but so far I think I’m happy with 200 watts on the roof. It is important to understand that with many panels that if some cells are shaded, it is like shading the whole thing, so putting them in series multiplies this risk of a small area shaded taking down the whole array.

I wanted my panels mounted on the roof, so I could have the benefits of solar at all times (like when driving and away from the camper). Lot of charging going on without having to do anything. Works for us.

[Wess Boucher]

Originally Posted by Photokit

Hi all, The dilemma I ran into last week winter camping showed me two things.

1. Without sunny days I cannot run my furnace, as the battery gets sucked of power (below 10v)



2. I need to add another battery so I can continue to camp off grid through the seasons. I charge my battery with 100 watt solar panel and am happy most of the time.



So. My current 12v is mounted behind my propane bottles on the tongue. I have limited space there for a second 12v battery. I'm thinking of installing the second under my bench seat, within a few feet of the current battery (meaning I would buy a sealed lead acid), and run a parallel connection to the outside battery.



Any thoughts on this? I installed my charge controller in that location, so I can read battery power/solar input while IN the camper. I ran the wires to the charge controller from the outside battery, under the bench seat. So I'm thinking I can use the same hole I drilled to run the 2 or 4 AWG battery cables to the new battery. The run will be about 3 feet. I know I'll have a bit of loss but I'm not too concerned with that.



Thanks for your feedback.

Are you running a generator? Then running trailer off batteries, furnace will kill both batteries, your good for a few hours, but that’s it.

[enormiss]

I find the regular heater loud and not just an electric hog but propane too.
If you do a lot of cool weather camping maybe a different heater.
No experience with this, just came up in Google search
http://www.campingworld.com/olympian-wave-8-catalytic-safety-heater?

[mainah]

Panels have diodes this keeps them from draining the battery at night. The controller deals with voltage it sees if one panel is shaded it just will make less watts in the overall picture it's kind of like half blocking one working panel. The panel working voltage is close to twice battery voltage the controller modulates the incoming voltage depending on the battery voltage when the battery voltage is low it will dump close to 15 volts into the battery and drop as it charges.

[mainah]

Originally Posted by enormiss

I find the regular heater loud and not just an electric hog but propane too.
If you do a lot of cool weather camping maybe a different heater.
No experience with this, just came up in Google search
http://www.campingworld.com/olympian-wave-8-catalytic-safety-heater?

Yes nice heaters they are power vented by a small blower what I'm not sure of is makeup air I don't know if or how they address that.