Sorry, another solar question

[sciencenerd]

Originally Posted by Spower

Standard panel not flexible. Current panel is 190w, new will also be 190w.
I guess they would be in series? Comes with m4 connectors that both panels plug into then they plug into roof connection going to controller.

Do you think I could use vhb tape on my roof?

Was your panel flex or standard??

It depends on your solar charge controller: PWM: You need to connect in parallel (may need to upgrade the wiring depending on the gauge, because the current doubles). MPPT: You can connect in series (no need to upgrade the wiring because current stays the same).

I would not attach panels to a rubber roof without screws. I screwed my mounts into the rafters at the front. At the back, there were no rafters in the right place, so I used rubber well nuts. Just screwing into the 3/8 inch decking felt very flimsy.

[pconroy]

Originally Posted by Spower

Standard panel not flexible. Current panel is 190w, new will also be 190w.
I guess they would be in series? Comes with m4 connectors that both panels plug into then they plug into roof connection going to controller.

Do you think I could use vhb tape on my roof?

Was your panel flex or standard??

Bear in mind I'm not sure another panel will solve the original issue. But, one thing about Solar is that no one ever says "You've got too much."

My fault in assuming it was two 100 watt panels; didn't know you had one 190. Yep - matching the same panel (volts and amps) will cause the least amount of heartache.


Like others have said, before you double your capacity - check to make sure the other parts in the chain can handle the additional load. Look up your controller's specs and find out voltage and amp maximums.

Head up to the roof and see if you can see the "gauge (wire thickness)" printed on the cables already up there.


Once you have that info, you can get some guidance on parallel vs series connections. (*)


My panels are the plain ol' standard looking 100 watt panels. Yes, I used VHB tape when many, many others will recommend against it.

I bought long Aluminum angle "iron" and my panels have about 3' of HVB tape on each side holding them down. To be extra safe, I attached a safety strap to each panel - if the come loose, they'll not fly off the roof.

Two years on one panel, one year on the other with no loosening. But clearly, drilling into the metal roof trusses would be ideal (if you're ok drilling holes in the roof).






(*) Remember two panels in Series doubles the voltage but keeps the amps the same. Summary - you can safely use the existing wire but your controller may NOT be able to handle the doubled voltage.


Two panels in Parallel - keeps the same voltage but doubles the amps. So now the controller is fine, but you need to make sure the wire up there is thick enough to handle the doubled amps.

[pconroy]

Originally Posted by sciencenerd

It depends on your solar charge controller: PWM: You need to connect in parallel (may need to upgrade the wiring depending on the gauge, because the current doubles). MPPT: You can connect in series (no need to upgrade the wiring because current stays the same).

what he said!

[Lmbrjk]

Spower - One thing that is being overlooked - 12.7Volts at your battery with no charging input is 100% not 88%. The problem is not with your batteries - your problem is with your monitor panel. The panel thinks that the charging voltage (13.2 volts and above) is 100% and anything less is - well - less %.
Also - Your solar panel is plenty of capacity for your setup and it looks to me that nothing is really wrong with what you have.
I would however also recommend the Victron battery monitor. Had one on a Sailboat for years and it helped me keep my batteries in great shape. A little learning curve with it but you won't regret the purchase.

[Spower]

Originally Posted by Lmbrjk

Spower - One thing that is being overlooked - 12.7Volts at your battery with no charging input is 100% not 88%. The problem is not with your batteries - your problem is with your monitor panel. The panel thinks that the charging voltage (13.2 volts and above) is 100% and anything less is - well - less %.
Also - Your solar panel is plenty of capacity for your setup and it looks to me that nothing is really wrong with what you have.
I would however also recommend the Victron battery monitor. Had one on a Sailboat for years and it helped me keep my batteries in great shape. A little learning curve with it but you won't regret the purchase.

I totally agree with you!!

[Spower]

Update......i know its been a while but had a family emergency.
Anyway, had the batteries tested 2 different places, they are fine. So my conclusion is that my 1 solar panel was not completely charging the batteries from what I had used the night before.
So I am adding another 190w panel this week.
Stay tuned......

[Screwby]

Originally Posted by Spower

Update......i know its been a while but had a family emergency.
Anyway, had the batteries tested 2 different places, they are fine. So my conclusion is that my 1 solar panel was not completely charging the batteries from what I had used the night before.
So I am adding another 190w panel this week.
Stay tuned......

Standing by...

[JimD]

Just added my 4th 100 watt panel 2 days ago. Looking forward to seeing what it can do to keep my batteries up while I use the inverter to run my TV. Previously with only 2 panels the voltage would steadily drop during the day.

Camping starting Sunday. Hope this works as I want. I have a Renology controller with bluetooth and will enjoy watching it.

[Spower]

New panel on roof (not screwed down yet) and plugged in. I now have 380 watts. Wow what a difference!
I decided to ignore what the controller said last night and just ran what I wanted for several hours. The batteries were fully charged, ive been on shore power for a while now. Ran some more stuff this morning while still kinda dark. Then with the sun barely up I was already getting 5 amps.
Today I am installing the DC digital multi function meter you guys recommended to see the draw on the battery. But so far it all looks good!! Im a happy camper now!

[Screwby]

Originally Posted by Spower

New panel on roof (not screwed down yet) and plugged in. I now have 380 watts. Wow what a difference!
I decided to ignore what the controller said last night and just ran what I wanted for several hours. The batteries were fully charged, ive been on shore power for a while now. Ran some more stuff this morning while still kinda dark. Then with the sun barely up I was already getting 5 amps.
Today I am installing the DC digital multi function meter you guys recommended to see the draw on the battery. But so far it all looks good!! Im a happy camper now!

Good to hear! Yeah we’ve had the 400w kit for years and I’ve never wanted for more power (aside from wishing I could run the AC lol).

[klassic]

I have 520 watts and used to have 210ah of batteries. With a residential fridge I could barely make a weekend boondocking
Up graded to 470ah of batteries, and now I could almost go full time if I had full summer sun.

[Spower]

So I hooked up the multi function meter....I have direct sun on my panels right now...the picture is what the meter is reading right now, is this right??

[JimD]

It is probably right. The solar controller will only charge as needed. Mine has 4 different charging stages depending on what the battery needs. It ranges from low 13s to mid 14s. I assume your controller might do the same thing.

Just look at the reading now and then and you will see it change. If your battery is down you may get into boost mode which is mid 14s.

If you have the shunt connected properly the meter is reading no current being drawn from the battery. Turn some stuff on and see it the current reading goes up.

[klassic]

If you want to see how much current is GOING into the battery, reverse the wires from the shunt to the meter.
If you like the idea of being able to look at current out and current in, then you can hook up those wires to a dpdt switch and switch between the two “modes”

[JimD]

Originally Posted by klassic

If you want to see how much current is GOING into the battery, reverse the wires from the shunt to the meter.
If you like the idea of being able to look at current out and current in, then you can hook up those wires to a dpdt switch and switch between the two “modes”

That may not work as it depends on how the solar is connected to the battery. On my monitor the shunt is connected inline with the negative battery terminal. As I have 2 batteries and the solar controller is next to one of them, I just connected it directly across the 2nd battery which is cabled right across to the other battery.

To read the solar charge to the battery it would have to be connected to the outer connection on the shunt rather than to the battery terminal.

I liked your idea of the switch. I think I saw some monitors out there on Amazon that could measure both ways.

Another easy way to test solar is with a current reading clamp on meter that can measure DC. 4 Days ago I added a 4th 100 watt panel and did extensive testing of my solar system because I thought I had a bad panel. My meter along with my custom built adjustable load showed me what each panel was putting out plus all of them together. Learned a lot about solar.

[klassic]

Yes. Jim I correct.. it would depend on where your controller ground is.

[Spower]

I'm only looking for battery readings, this meter has nothing to do with my solar.
I'm hoping I'll get the other readings at night when solar is off?

[klassic]

Originally Posted by klassic

Yes. Jim I correct.. it would depend on where your controller ground is.

geezzz I wish there was an edit button here

it was suppose to say "Jim is correct"

Spower, it seems like you used your solar quite a bit...?
I think you should ditch the PWM controller and invest in a decent MPPT

[JimD]

Originally Posted by klassic

Spower, it seems like you used your solar quite a bit...? I think you should ditch the PWM controller and invest in a decent MPPT

I agree. I upgraded my controller to a Renogy that has bluetooth. It appears to do a better job but the best thing that I like is the bluetooth. Previously if I wanted to see what the solar was doing I would have to crawl under my slide out to open the cabinet I have the controller in. Now I just look at my phone, which I do a lot of, to keep track of what it's doing. Caused me to add additional panels because I wasn't getting what I had wanted.

[Spower]

How hard is it to switch? Plug and play?
Now that I know a little better of what's going on not sure if I would switch unless its easy to do.