Solar Configuration Issue ?

[bucketfan]

Hey All,

Having a little issue. Bought a Coleman 40W folding solar panel and have a set of 2 Trojan T-105 batteries, they are 6 volts and wired together in series. The power to the camper and accessories works perfectly!

Usually, I charge it while towing behind my truck and it works great, but I want to have a solar maintainer / charger in case we're going to be somewhere for a while.

I check the batteries charge with a 1000w inverter with a LED display, it ranges from low 11's when it is low, to 13.3 when it is fully charged (off the truck or off a regular charging box - non solar).

I plugged this solar panel on to the batteries, the positive on the "positive battery / positive post" and the negative on the "negative battery / negative post". Then, the 2 batteries have a connection from positive battery (negative post) to negative battery (positive post).

The batteries do not seem to increase even after a couple weeks on the solar panel. I just tested the panel with a volt meter and it seems to work. I am scratching my head as it seems to put out a charge, but doesn't increase the battery level. The batteries work fine, charge fine off the truck and charge fine off a regular battery charger. But no increase off the solar panel.

Any thoughts ??

 

[calicamper]

Couple of things. Your missing a solar controller and a 1000watt inverter simply left active, with no load will wipeout your battery/s. Isolate the inverter and leave it off unless being used.

A solar controller manages the actual charge process, to bring the batteries up. Be shure you havent toasted the resistor in the panels with a direct connect load. The panels are probably OK but you should check panel output with a multi meter.

 

[calicamper]

Sorry missed the end regarding the panel voltage.
You simply need a solar controller between the panel and battery.

With out it you can have several possible issues. For one panels pump voltage out regardless of battery status, no controller to monitor that and a panel can cook your batteries. Also the controllers can manage the charge process to optimize the battery life.

 

[ajmaudio]

is the inverter on all the time? 40 watts is small for that much battery for anything other than keep the batteries topped off in storage, but the panel is big enough to need a controller. Also, dragging your batteries down in the the 11 volt range is a nono. Those are pretty nice batteries and you will want to take much much better care of them than that if you want to get good performance and longevity out of them. I recommend a bogart 2030 or tristar controller, and some bigger solar for expo type use. What are you running with batteries?

 

[SoCal Tom]

The Coleman 40w solar panel includes a charge controller according to what I found on line. The system makes about 3.5 amps per hour of perfect sun. Your batteries hold over 200 amps. Assuming nothing is using power it will take over 8 hours to add 10% to the battery, which is about 0.07v.
Tom

Sent from my Lenovo A7600-F using Tapatalk

 

[NatersXJ6]

AC/DC

In your photo, your multi meter seems to be set on AC voltage. shouldn't you be measuring DC voltage? I assume this is at the charge controller output?

the charge controller seems to be a separate piece in the online product descriptions I found. Is it installed and connected well?

 

[Joe917]

you are checking battery state of charge with your inverter's led display?
Without a battery monitor you are just guessing. Trimetric or similar quality(and cost).

 

[meental]

What inverter are you using? Do you know the idle draw? Is the inverter on all the time? I bet your inverter is pulling 10-20w just sitting idle.

A 40w panel is pretty small for a 225ah battery setup, general rule of thumb is 100w per 100ah.

Like others said, you need a solar controller even with that small of a panel to not overcharge the batteries.

Your meter is on AC V, it needs to be on DC V to measure the output of your solar panel.

Are those the leads(ring terminals) from the solar panel directly? The wire looks a bit small but it is only 40w so it should be fine.

There are many factors that could be contributing to your not seeing any charge but i think the biggest problem is the small size of the panel compared to the battery size and load (1000w inverters pull a lot of power.)

Sent from my RTT while stargazing