solar panel hook up

[lefoster]

Me again! Can y'all tell I am a new camper owner!
I have a small solar panel I want to hook to my batteries to keep them from draining down. Here is my set up:
two batteries -
battery 1 has pos. and neg. cables running to battery 2. also, a cable off the neg. terminal going to the battery disconnect and ground
battery 2 has cables coming off the pos. terminal going to the camper, jack, and emergency brake switch

what terminal on which batteries do I hook the leads from the solar panel to?

I have included a pic

[lefoster]

hmmmmmmmmm, picture did not show up?

[Mustang65]

The leads from the SOLAR Panel do not go to the batteries. They need to be connected to a SOLAR Charge Controller and the SOLAR Charge Controller connects to the batteries (with an inline fuse). Some panels have a SOLAR charge controller attached to them. Check to make sure you have one. If you connect the panels directly to the batteries without a SOLAR charge controller, and there is no blocking diode in the panels, when the sun goes down the panels will become a LOAD and start to discharge the batteries.

The NEGATIVE cable from your SOLAR Charge Controller (you need one of these) connects to battery #1 ground (battery with negative cable going to frame ground).

The POSITIVE cable from your SOLAR Charge Controller will go to the POSITIVE terminal of battery #2 ( the battery positive cable that goes to the TT, jack....)

Your batteries are wired for best performance!

Don

My Registry

RVing with SOLAR

[lefoster]

great! thank you! the panel is about 12" long, 5" wide. can that put out enough power to over charge the batteries without a charge controller? I think is puts out 1.5V

[Mustang65]

Originally Posted by lefoster

great! thank you! the panel is about 12" long, 5" wide. can that put out enough power to over charge the batteries? I think is puts out 1.5V

To keep a 12VDC battery charged you need at least 17VDC coming from your panels. Not sure as to what your solar panel is from or to be used for, but 1.5 volts is not for your batteries. Sounds like flash light batteries to me.

At minimum you will need at least a 50 watt SOLAR panel to only keep your batteries topped off (with no TT load), not for recharging them. I do not recommend anything less than 100 watts, reason is the output specifications for a SOLAR panel are at MAX sun (like between 11AM and 2PM. Other than that time slot, they are no longer putting out max wattage. With 100 watts, you build in a buffer and get more useable charging hours each day... unless of course it is a cloudy or rainy day, then all bets are off.

Take the SOLAR panel outside, at noon, and take a voltage reading to see what the panel is producing.. a 12" panel will not be doing much at all.

Don

My Registry

RVing with SOLAR

[lefoster]

my goal was to keep them from dying while not in use, like a trickle charger. the guy at the battery store told me it would do that. of course, I don't know about stuff, so that may not be true.

[Mustang65]

Can you give us the Mfr and model # on the SOLAR panel. Should be printed on the back somewhere, or on the shipping box. You also have 2 batteries so the needs to keep them topped off is 2x that of one battery.

When you use these VERY small panels, you need to have a FULLY charged battery to start with before connecting the panel.

Don

My Registry

RVing with SOLAR

[lefoster]

will have to get that for you later today. thank you so much! I will get info to you!

[Mustang65]

Originally Posted by lefoster

will have to get that for you later today. thank you so much! I will get info to you!

No rush... I am installing an Energy Monitoring system (20 current sensors) in my house's Electrical Service Panel today... then the communications wiring for it... and the actual monitoring unit. Should keep me busy for a while

Don

My Registry

RVing with SOLAR

[lefoster]

ok, it is a Coleman
2W SOLAR PANEL
MODEL # 58012
Maximum Power - up to 2W
Open Circuit Voltage - 23V
Maximum Power Point Voltage - 15V
Short Circuit Current - 133 mA


I tried to attach picture of label

[Magnolia Tom]

Originally Posted by lefoster

ok, it is a Coleman
2W SOLAR PANEL
MODEL # 58012
Maximum Power - up to 2W
Open Circuit Voltage - 23V
Maximum Power Point Voltage - 15V
Short Circuit Current - 133 mA


I tried to attach picture of label

I'm no expert on solar (Mustang65 is the expert), but that looks like something for a tent to charge a lantern.

[Mustang65]

Originally Posted by lefoster

ok, it is a Coleman
2W SOLAR PANEL
MODEL # 58012
Maximum Power - up to 2W
Open Circuit Voltage - 23V
Maximum Power Point Voltage - 15V
Short Circuit Current - 133 mA

Based on the specs, let's do the numbers. 2watts @ 15 Volts = 0.16Amps and that is at 15VDC under a bright sunny day with not a cloud in the sky from about 11AM to 1 or 2PM, and a totally clean surface. Then 2 watts @ 12.6Volts = 0.15Amps. Doesn't sound like much, but it adds up over 5 hours each day. I do not know of any place, FL included, that gets max sun every day. Since your battery is at a 12.6 volt level FULLY charged this means that you are not going to be getting 0.16Amps. But wait, you have 2 batteries... so double the power needed to keep them topped off. If you do not have a disconnect switch, the TT's parasitic drain will wipe out the battery is a week or 2 as the parasitic drain on my TT is a little below 0.5Amps, yours may be around 0.2 or 0.3Amps. Although, you could disconnect a battery cable.

I also do not know the age of your batteries, the older they get or if they have been dropped below 10.5VDC, the higher the batteries internal resistance.

So, this is why the minimum SOLAR charger I recommend for keeping the batteries topped off is a 50 watt panel. 50Watts @ 18.5 Volts = 2.7Amps, but like the tiny SOLAR panel you will not be getting the total 2.7Amps, but you have a large buffer to work with. Your USEABLE charging hours will be increased.

If you are planning in the future to do some dry camping or overnight stays... while CHARGING your batteries and keeping them topped off.. well that is another plan to look into before purchasing 50Watt panel. I do not like spending money twice to accomplish the big picture.

The way I look at it is you can pay for the correct amount of SOLAR now, or you can pay for new batteries for next years camping season, which will be more than $100.

Don

[lefoster]

ok, thank you so much for sharing what you know!!! I am a little lost on all the electrical terms and what they mean, I have not studied it enough.
I do have a disconnect switch, which is off unless using the camper. so, for this season, living in sunny Lubbock, TX, would my small panel keep the batteries from dying this winter? Not asking them to recharge them after being drained, just to keep them from dying, will that panel do that, or should I go ahead and invest in a 50W? AND, though I don't anticipate doing this, if I do want to go ahead and get one big enough to charge them while dry camping, what size would that be?

[travelingjw]

Watching this thread and have not seen a mention of the SAE Plug (Jayco puts these on some trailers for solar). If you have one, beware and check the wiring. When I checked the wiring from the plug to the battery it was the opposite of what I expected. For Newbies the standard seems to be "black positive, red negative" from the TV to the TT and then "Black positive, white negative," from anyone on the trailer past the batter (I have a 2017 Whitehawk).

[Rj7673]

Originally Posted by lefoster

Me again! Can y'all tell I am a new camper owner!
I have a small solar panel I want to hook to my batteries to keep them from draining down. Here is my set up:
two batteries -
battery 1 has pos. and neg. cables running to battery 2. also, a cable off the neg. terminal going to the battery disconnect and ground
battery 2 has cables coming off the pos. terminal going to the camper, jack, and emergency brake switch

what terminal on which batteries do I hook the leads from the solar panel to?

I have included a pic

I'm new also I have heard that amazon has a 100 watt system with good reviews cost is around &600

[Mustang65]

Originally Posted by lefoster

Not asking them to recharge them after being drained, just to keep them from dying, will that panel do that, or should I go ahead and invest in a 50W? AND, though I don't anticipate doing this, if I do want to go ahead and get one big enough to charge them while dry camping, what size would that be?

Based on the 0.16Amp output of the panel trying to keep up with 2 batteries, the odds are not in your favor. The 50 watt should get you through the winter with no issues.

Look at the $$ perspective of the 2 choices:
- 2 watts / $20 = $10 a watt
- 50 watts / $109 = 2.18 a watt

You will have 2.7Amps, should you go a week or 2 in a row of less than GREAT sun power (partly cloudy, cloudy, rainy, hazy) you will have a much better chance of making it. With the 0.17 Amps you will be in a downward spiral.

If you were to plan for FUTURE dry-camping, the minimum recommended to start with is 100Watts. Renogy has a 100 watt kit that you can eventually add on an additional SOLAR panel without having to purchase a larger SOLAR Charge controller. One 100 watt panel will produce about 5.4Amps.. eventually add an additional panel and your batteries will be charged by 2pm the next day after using the batteries overnight.

If you have any real thoughts of using for dry-camping then you will want to start with the 100 watt panels.

The decision is up to you, just sit down and think about it.

Don

My Registry

RVing with SOLAR

[Mustang65]

A double post of the same information... sorry about that!

Don
My Registry

RVing with SOLAR

[Mustang65]

Originally Posted by Rj7673

I'm new also I have heard that amazon has a 100 watt system with good reviews cost is around &600

$169
My Registry"]Amazon Renogy 100 watt system with 30 Amp SOLAR Charge Controller[/URL]

Don

My Registry

RVing with SOLAR

[Mustang65]

Originally Posted by Rj7673

I'm new also I have heard that amazon has a 100 watt system with good reviews cost is around &600

$169
Amazon Renogy 100 watt system

Don

My Registry

RVing with SOLAR

[travelingjw]

I would look at the Renogy system on Amazon. I have it, it works great and is much less than $600.00