Solar energy when battery disconnect is applied

[mockturtle]

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?

[mockturtle]

Thanks again, DiploStrat. Yes, I'll contact Jay at Tiger to confirm that for my model.

[DiploStrat]

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]

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]

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]

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]

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]

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]

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]

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]

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...

[time2roll]

Can you check on the battery once a week or more? Do you have a method to recharge if found dead?

I would tend to disconnect the main RV power cable and leave the 200w solar connected if possible. Need to review how all is connected.

[mockturtle]

OK, I'm convinced. 🙂

[BFL13]

For just three weeks IMO leave it all connected, but turn off your 12v loads as much as is practical. Do not disconnect in this case, so the solar can keep the batteries from going down.

[Lwiddis]

I never disconnect my solar controller/panels from the batteries. Why would you want to do so?