Do solar panels burn thru batteries?

2oldman wrote:
Your experienced friend should take up another subject.

As you can see, the group here has the knowledge and many have gained that by coming here and asking for help and information. Just a suggestion, here. Go fishing, or watch a game with your buddy, but come here for Truck Camper advice.

Everyone sharing about a charge controller will correct any issues of overcharging your batteries, is giving you sage advice. Much like a spillway does for a dam. When too much "Power" comes down the cable, it diverts this from reaching your batteries. These are "spikes" that occur when Clouds come between the sun and your solar panels. The panels go down in collection and then "spike" when the cloud moves on. This is one of the reasons you have a charge controller and hopefully Catastrophic fuses at your battery bank and an additional one for your inverter. Solar collection is much like a Roller Coaster Ride throughout the Solar Collecting day. That is one of the reasons you don't want to connect your solar batteries directly to the battery terminals with alligator clips. Also, only get a charge controller that can be adjusted for the type of your battery, Temperature Control and if possible programmable for the size of your battery bank.

Do you have your battery bank set with the converter interrupted when solar charging?

As for longevity, you will KILL your first set of batteries learning this process of solar, use and storage. So, be prepared for this as you increase your learning curve of discharging limits, charging % and temperature compensation, then through in Bulk, Absorb and Float Charges as well as the time in mode depending when and length of the previous day's charging cycle.

As for longevity. Batteries life are dependent on cycles. Use them or they will die. Use them a lot and they will die sooner. Monitor and use your batteries properly for this optimum design parameter and they will exceed your expectation in life and value to you.

As others have suggested, go do an inventory of what you actually have and where everything is located within your truck camper.
What are the Solar Panels you have? (Mon or Poly)
How are they wired? (Parallel or Series)
What type/size cables do you have? (4ga-6ga-8ga-12ga-14ga)
Do you have interrupter Switches? (Breakers before and after Charge Controller and inverter)
Do you have Catastrophic Fuses rated for your Battery Bank? Inverter?
What type of Batteries do you have? (FWC-AGM-LiO)
Do you have a maintenance plan for battery bank, if needed? (H2O-Equalizing)
Do you have a battery charger modern enough to cycle the batteries through Bulk/Absorb/Float so as not to “Cook” your batteries during periods you fall below 50-55% minimum discharge rate determined by battery type?

By all means, have a great time with your new truck camper and something I am passionate about, instruct and write about; Solar. Solar can be a life changer for how you enjoy your time in your camper and might just migrate to your own home. Me, I full Time (as I have no place to return to) and have lived entirely off the grid (only solar) for more than 7 years with 1,860 watts of solar (13 panels) and 1,460AmpH of batteries, traveling the west in a truck camper.

Welcome to the TC forum, too!

b

Edit: Double Post

We have been full timing in our truck camper with Lifeline AGM and 1100 watts of solar. The solar runs through a Midnite Classic charge controller and keeps the batteries at around 13.4V (it has a battery temp sensor so that number varies a bit). I have not even looked at the batteries in 11 months. If you build a system right, it just works.

The short answer is, only cheap and/or poorly-designed solar controllers burn through batteries. A good solar system is smart about charging the batteries and will only charge them when they need charging.

Since one of the major selling points of solar is being able to leave the camper in the sun between trips so the batteries will always be maintained and ready to go, disconnecting the batteries and allowing them to self-discharge seems counterproductive.

When a proper solar charger wakes up, it will take the batteries up to the absorption voltage, about 14.4V. It should then drop back to float voltage, about 13.2 for flooded and 13.8 for AGM. This is where cheap and more elaborate solar controllers differ: a cheap one will hold the battery at the 14.4V absorption voltage for a time period (typically 2 hours) while a better one will drop it back as soon as the charge current has dropped below a set threshold. On fully charged batteries this may happen in only a few minutes. The former strategy is a little harder on the batteries than the latter. Neither is as bad as letting them slowly discharge in storage.

Another detail is the correct float voltage varies quite a bit with temperature. Since solar is charging all the time, temperature correction becomes more important. The more elaborate solar (and line) chargers will have a temp sense on the battery and correct accordingly.

barngal wrote:
Hi, I"m so new to this that I bought my camper but haven't even picked it up yet! But I'm excited and glad to find this forum, lots of important info here.

My camper has a solar panel to keep the batteries topped off. My experienced friend recommended that solars tend to overcharge the batteries and you end up replacing your batteries more frequently than you would have to without solar. I'm not the person who will be charging my batteries EVERY 2-4 weeks (I'm assuming that would be optimal when not using the camper?)

Could you comment your experiences on this? Solar or no...
thanks!

I've noticed that when my camper is left on Solar power every day and without actually using the camper, the charger will start the morning after the sun is up by charging at 14.4 volts or higher.

I think that this higher charging rate is not really needed because the battery is not really drawn down at all over night. A simple maintenance charge would be sufficient.

Based on this experience, I can see how someone might think that it would shorten the battery life (however incremental that may be).

There may be a grain of truth in your friends admonition.

2oldman wrote:
Your experienced friend should take up another subject.

I needed a good laugh this morning. :D

The small panels with no controllers are used on new cars shipped to US from other continents as well.
Their design is simply to keep the batteries from going dead, but have no intention to maintain the batteries aka prolonging their lives.
So when the solar panels do provide the power, it is good controller who is maintaining the batteries (or killing them).

I'm going on 7 yrs on a pair of group 24 Interstate. We do mostly dry camping I also had the solar on a previous TC. I've never replaced a battery in any of my trucks and I tend to keep them more than 6yrs.

I think the odds are good this is a very small panel with no controller.

barngal wrote:
Thanks for pointing me in the right direction! I'll check on the controller. Its a 2005 Arctic Fox 990 (immaculate condition)
I can ask the old owners how often they replaced them too, since they were the original owners.

Do well maintained batteries last as long as car batteries?

The factory battery disconnect on my 2006 AF 811 is located underneath the sink and I believe that in your 990 it should be in the same location on or next to the forward bulkhead. Hope this helps.
TG