My solar does not add up.

RvPaul

New Member
Joined
Jul 31, 2021
Messages
2
I have a 100w panel I am trying to use instead of running a generator while camping. Cuts in at 13v out at 14.2 according to documentation. I have rv batteries (2 6 volts = 12 volt system) attached to coulometer . rv uses about 1 amp per hour doing nothing. So in 16 hours 16amp hours used. Plug in solar panel and it will charge for maybe an hour then dummy light says charged and no more amps going to battery. In 1 hour thats max 5.5 amps. Cannot be full. Is my math correct? Is this a problem with the rinky dink charge controller that comes with the Noma model 011 2514 0 panel? When I use generator and smart charger, it seems to think the battery is between 50 and 75 % charge and will continue to push 5 amps into the battery.
 

MisterSandals

Participation Medalist
Joined
Nov 5, 2019
Messages
5,094
Location
Silicon Valley
Cuts in at 13v out at 14.2
Seems reasonable for rinky dink.

In 1 hour thats max 5.5 amps.
5.5 amp hours?

100W x 1 hour / 12.8V = 7.81Ah
Not operating at 100% and rinky dink, this sounds reasonable.

You have a tiny solar panel to begin with. Why not get a real charge controller and give yourself a chance at actually harvesting some solar energy?

Here is a great investment (get the bluetooth version, trust me):
 

Sun

Solar Enthusiast
Joined
Nov 1, 2020
Messages
35
I’d spend $10 more for a 75-15 instead of a 75-10, just in case I wanted to add another panel in the future. 75-10 would work for two 100W panels but I’d feel more comfortable being conservative and not maxing it out (for $10 more).
 

RvPaul

New Member
Joined
Jul 31, 2021
Messages
2
I have a 100w panel I am trying to use instead of running a generator while camping. Cuts in at 13v out at 14.2 according to documentation. I have rv batteries (2 6 volts = 12 volt system) attached to coulometer . rv uses about 1 amp per hour doing nothing. So in 16 hours 16amp hours used. Plug in solar panel and it will charge for maybe an hour then dummy light says charged and no more amps going to battery. In 1 hour thats max 5.5 amps. Cannot be full. Is my math correct? Is this a problem with the rinky dink charge controller that comes with the Noma model 011 2514 0 panel? When I use generator and smart charger, it seems to think the battery is between 50 and 75 % charge and will continue to push 5 amps into the battery.
So day 2 of figuring this out. So according to my battery monitor Id used 50 amp hours. Connect the solar charger and after half an hour at 5 amps it says full again.....no way. So I have removed the controller and connected the panel directly to the battery. It is charging at 13.4v about 5 amps...I will disconnect when not in bright sun. I only just wanted this one panel to work for starters. Met up with another camper who recommended (for inexpensive solution) a PWM controller from Renogy Voyager model. Which at 37.00 Canadian sounds like a much better solution than the junk controller that came with the panel.
 

MisterSandals

Participation Medalist
Joined
Nov 5, 2019
Messages
5,094
Location
Silicon Valley
Which at 37.00 Canadian sounds like a much better solution than the junk controller that came with the panel.
I would say better but not sure you should say "much better".
Trying to cut corners with "value priced" SCC's rarely results in any monetary savings in anything but the short term.
 

Whinny

Solar Addict
Joined
Dec 24, 2020
Messages
350
The Wanderer controller is fine as well-just don't get it too wet-comes with usb charging

For some applications pricey MPPT controllers are certainly better-for a single 100w portable PWM is fine IMHO....
 
Top