My ignorance of solar energy and controllers is colossal. I'm planning to leave my RV for a few weeks with the house batteries disconnected to avoid dead batteries when I return. What will happen to the solar energy from my 2-100W panels during this time? If the battery controllers work off the battery how will the energy be controlled?

Some types of controllers (MPPT is one) warn against having solar connected to the unit w/o a battery connection. I installed a switch on my controller to disconnect the panel from the controller before disconnecting the battery.

You need to VERIFY whether your solar is wired directly to batteries or is "down-stream" of the battery disconnect switch.It could be wired either way.

You have solar to avoid dead batteries. Why not just leave them to do their job?

You could leave it all connected and let the solar look after the batteries, but there is a chance the float voltage will be wrong and cause the batteries to lose "water".First disconnect the array from the controller by taking out the two wires in the controller's "array" terminals. Now you can disconnect the battery bank by removing the wires on the battery posts, including the ones linking the two batteries.That will prevent the two from interacting while not being on a charger, and will make sure there is no draw on them. On return, hook up the batteries first, then put the two wires back into the controller's array terminals.Put red tape on all the wires on the pos posts. Take a photo of the battery bank with the wires still on it, so you will put them back on the right posts.When you get back, bring jumper cables in case the engine battery has run down too far to start the truck. Also, on that, disconnect the 7-pin too if any before leaving.

2oldman wrote:You have solar to avoid dead batteries. Why not just leave them to do their job?This. Battery disconnects are there to prevent dead batteries due to small parasitic loads when the rig is being stored. As others have noted, many charge controllers MUST be connected to the battery at all times if connected to solar panels. Also, your system may be wired so that the solar is not run through the battery disconnect, but you need to find out for sure before you disconnect those batteries. Regardless, the panels develops a charge if there is no battery or load, but they will not produce power because no current will flow. You can safely leave the panels out in the sun even if they aren’t connected to anything. The solar charge controller’s job is to tame panel output and maintain full battery charge regardless of powers in or out. It will charge the battery full tilt until it is full, then cut back to only the power needed to overcome self-discharge. Let the solar system do it’s job.If the system was properly engineered and built, the solar does not pass through the disconnect. But there’s no guarantee of that. We all know of stuff designed by knuckleheads and/or built by idiots, don’t we? BTW, one day when you have to replace that battery, remember, you MUST disconnect the panels first.

Solar energy when battery disconnect is applied

mockturtle
Explorer II
Feb 18, 2020
Thanks again, DiploStrat. Yes, I'll contact Jay at Tiger to confirm that for my model.
DiploStrat
Explorer
Feb 18, 2020
With the caveat that I no longer own a Tiger and that my Tiger was not exactly the same as yours, yes.

The "Battery Disconnect" switch, the thing with the red tag under the sink, is a bit of a misnomer. It is a load disconnect, not a battery disconnect. (There is probably a real battery disconnect under the coach or near the batteries, right next to the main fuse. Do not disconnect this.)

Turning off the red switch should disconnect your loads - lights, pumps, refrigerator, etc., but should not disconnect the solar controller or the shore power charger from the battery. BFL13 is exactly correct. If the solar controller shuts off, then disconnect all of the loads individually.

With 200w you will see a bit over 10A with good sun and, of course, less on cloudy days. 10A isn't much, and so even with a poor quality controller, you would not run much risk of hurting sealed AGM batteries. Certainly your AGM camper batteries will be MUCH happier connected to a charge source than they would be disconnected.

So I agree with all of those who have posted telling you to leave things alone.

Depending on when your Tiger was built, you may have a Blue Sea Automatic Charge Relay between the camper batteries and the starter batteries. If you do, leave it in the automatic position and your starter batteries will be charged as well - up to the limits of the sun in the PNW.

I am assuming that you will NOT have access to shore power while in storage. I am guessing that you have the old Progressive Dynamics "converter" and I do NOT know if those are safe over extending periods of time. The Magnum inverter/charger is.

All of the above to the best of my knowledge and memory. If in any doubt, give Jay a call.
time2roll
Nomad
Feb 18, 2020
mockturtle wrote:
Nah, I'm just going to leave the batteries connected. At the worst, they'll be dead when I get back. They're over five years old (AGMs) and, though they are still good, replacing them wouldn't be a crisis.
Yup. If you are not going to lose any sleep over it then by all means let the solar do its thing.
BFL13
Explorer II
Feb 18, 2020
The controller gets its own power from the batteries. If you use the disconnect switch and the controller goes dead, don't do that. Turn off your 12v loads individually in that case.
mockturtle
Explorer II
Feb 18, 2020
Thanks, DiploStrat! I wondered if that was the case and why they would have such a prominent switch for battery disconnect without being able to use it safely. So the red switch will just cut off the loads but the batteries will still be connected to the solar?
DiploStrat
Explorer
Feb 18, 2020
Give Jay a call, but I am willing to bet that the solar charger on your Tiger is connected directly to the batteries. In that case, shut of your loads (the red switch should do it) and park it in the sun.

Your batteries will thank you. ;)
mockturtle
Explorer II
Feb 18, 2020
Nah, I'm just going to leave the batteries connected. At the worst, they'll be dead when I get back. They're over five years old (AGMs) and, though they are still good, replacing them wouldn't be a crisis.
time2roll
Nomad
Feb 17, 2020
mockturtle wrote:
Can you check on the battery once a week or more? Do you have a method to recharge if found dead?
Nope. I'll be overseas.
If it makes you sleep better, disconnect the solar panels from the controller then remove a battery cable to isolate the fully charged battery while you travel.
mockturtle
Explorer II
Feb 17, 2020
Can you check on the battery once a week or more? Do you have a method to recharge if found dead?

Nope. I'll be overseas.
librty02
Explorer
Feb 17, 2020
I would think even the cloudy days would be good enough to keep the batteries charged. Leave it all plugged in and if worried about extra loads on the battery why not just pull some fuses inside the rig so there is no extra draw on the batteries while you are away...

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