Seven pin solar connector.

[grantpallen]

So last year at the rally, they were selling a solar panel with a seven pin connector that you could connect to the front of your trailer, this is far more than I need for just sitting in storage. I have since put my trailer in covered storage and have no where to trickle charge the batteries while it’s there. I was thinking about connecting a 5 W solar panel to a seven pin connector and sit it on the front, it should get approximately 1 to 2 hours of sunshine a day. I have a rooftop stock solar panel with ago power connector, and two 6 V AGM batteries.

I was wondering if anybody had done this or if someone with more knowledge on the subject, they chirp in And tell me if they think this is viable?

[Ron in BC]

When solar panels first became available I used a 5W panel, that cost way more than a 100W panel does today, to keep my boat batteries trickle charged when my boat was left overseas. Worked really well and saved me from having to remove them and store them in the battery room at marinas.

Ron

[Charliej]

For years I used a 15 watt panel to keep my single 12 volt battery in my Casita topped off while in covered storage. It only got a few hours of direct sun but worked flawlessly.

[AllanEdie]

With a couple hours sun most days, your rooftop solar should do the job, you don't need more than that. They might even keep up if shaded some of the day. You need very little to keep up with the propane alarm, which as I recall is the only draw when stored.

I would monitor first if I were you, you may not need anything more. But perhaps I have missed something...

[grantpallen]

It’s covered storage and the panels are in the dark, wasn’t enough to keep up. Hoping a 5 watt turned towards the sunny side will help for a couple hours a day.

[AllanEdie]

Too bad that the main panels are in the dark. Your 5 watt panel might do the job fine, but I can't add any specific experience to what Ron supplied earlier. Be careful about assuming that 5 watts would do the job though, Ron's panel may have seen a lot more sun than yours might, and he may not have had an alarm operating all the time. Ron's boat may have been stored in the tropics, with hours of very strong sun pretty much every day. Your location may be different due to both latitude and shading from various stuff during part of the day. If I were you, I would look at a bigger panel just to make sure, the cost these days is pretty small if you diy a setup yourself instead of buying a package.

Good luck with it, I hope you find a solution that works well.

[Ron in BC]

Originally Posted by AllanEdie

Be careful about assuming that 5 watts would do the job though, Ron's panel may have seen a lot more sun than yours might, and he may not have had an alarm operating all the time. Ron's boat may have been stored in the tropics, with hours of very strong sun pretty much every day.

Yes, my first rule of trouble shooting is never assume anything.

My panel was used a lot in bright sunny conditions but it also did the job in countries like Holland, a not especially year round sunny country.

Testing is underway with my panel. Conditions are typical. Cloudy with sun partly obscured by trees. Results later.

Ron

[AllanEdie]

Originally Posted by Ron in BC

Yes, my first rule of trouble shooting is never assume anything.

My panel was used a lot in bright sunny conditions but it also did the job in countries like Holland, a not especially year round sunny country.

Testing is underway with my panel. Conditions are typical. Cloudy with sun partly obscured by trees. Results later.

Ron

Thanks for clarifying Ron, I am sure your experience with this will be helpful.

[Ron in BC]

Well that was interesting. I never thought that 31 years after I bought this little panel that it would still be useful. I bought it because I had to leave my boat in a Greek shipyard, without any power to the boat and a poor battery storage situation for the better part of a year.

Pricey little devil, 5 watts and about $400 Cdn. But I had 3 batteries whose value was more than that. At that time controllers, as we know them, didn't exist. There were manual voltage regulators with points that opened and closed to control the current. I was a little worried about not using one and putting the current directly to the batteries. I soldered in a diode to prevent back flow at night.

I decided to hedge my bets. I put my two large Varta house batteries on the solar panel but not my 3rd battery. The 3rd battery was a write-off and the Vartas lasted an amazing 11 years.

When I bought the panel I thought that output would decline steadily over the years. Apparently not.

Today's test was on a battery with an existing 12.60 charge. Cloud cover varied from heavy to filtered and trees blocked some of the sun.

The battery reading slowly worked it's way up from 12.6V and with cloud/partial sun was in the 13V range.

I think this shows that the small output is more than enough to prevent self discharge.

I also made a bracket that dropped into a winch. I could tilt and swivel it for maximum efficiency when underway. Probably the beginning of my liking tilting swiveling solar panels.

I see a 7.5W unit on Amazon. It'd probably be ideal. OTOH I also see a 25W unit for not a lot more, it'd more than certainly do the job.

Anything to prevent self discharge and sulfation.

Ron

[casejh]

Originally Posted by grantpallen

So last year at the rally, they were selling a solar panel with a seven pin connector that you could connect to the front of your trailer, this is far more than I need for just sitting in storage. I have since put my trailer in covered storage and have no where to trickle charge the batteries while it’s there. I was thinking about connecting a 5 W solar panel to a seven pin connector and sit it on the front, it should get approximately 1 to 2 hours of sunshine a day. I have a rooftop stock solar panel with ago power connector, and two 6 V AGM batteries.

I was wondering if anybody had done this or if someone with more knowledge on the subject, they chirp in And tell me if they think this is viable?

My question is- will a portable solar panel that is bigger, say 100W, do the job if connected to the 7 pin connector on the front of the trailer? I have a 160W panel factory installed on the roof. Thanks

[AllanEdie]

Originally Posted by casejh

My question is- will a portable solar panel that is bigger, say 100W, do the job if connected to the 7 pin connector on the front of the trailer? I have a 160W panel factory installed on the roof. Thanks

If you wire a 100watt panel to your battery bank via the 7 pin, you would connect the panel output to the charge wire in the 7 pin harness. This would apply voltage directly to the battery, not to your solar charge controller and it would likely cook your battery. The reason why the optional solar connector works is because it is wired to supply the solar controller, not the battery directly, and with a strong solar panel, you have to have a charge controller.

[casejh]

Originally Posted by AllanEdie

If you wire a 100watt panel to your battery bank via the 7 pin, you would connect the panel output to the charge wire in the 7 pin harness. This would apply voltage directly to the battery, not to your solar charge controller and it would likely cook your battery. The reason why the optional solar connector works is because it is wired to supply the solar controller, not the battery directly, and with a strong solar panel, you have to have a charge controller.

That makes good sense. Thank you. I do not have a portable panel, at least not yet, but when I do I will connect it through the existing controller.