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FlyFishinRVr · 08-22-2016, 11:47 AM

I was hoping someone who has done something similar to what I'm thinking of can chime in and let me know how it worked out.....

There will be times when my AI will be sitting for a few weeks outside with no power available. I live in northern California so I'm not worried about the house batteries because I think the 100W solar panel can keep them topped up just fine. The chassis battery however is a concern. To address this, I think I can do one of two things:

- Just disconnect it. It won't lose much charge over a 30 day period so don't worry about it (manual says 1-3% at 85*F).

- Get creative (yeah, here we go.....). I was thinking of getting a small 20W solar panel and propping it up on the dash so it gets sun through the front window (I'd park facing S for max sun). Many of these come with a 12V charge controller to avoid overcharging a battery, but I'm not sure I trust it so I don't want to just direct-connect it to the chassis battery. Here's where my crazy idea comes in (and where I need some feedback): Why not use the 12V output of the solar panel to power a small inverter, then plug something like a Deltran BatteryTender into the inverter and use that to charge the battery. The reason for doing this is the BatteryTender type devices have well-proven "smarts" to reduce the chance of hurting the battery. I realize this setup will only work during the day, but I think it would run long enough to keep the chassis battery topped up, and it would be totally self-contained so there won't be any chance of it hurting the chassis electrical system. My only concern is the behavior of the solar panel's built-in 12V charge controller and how that may impact the life of the inverter, i.e. will the current output drift around enough to fry the inverter, or does the inverter have enough smarts to deal with that.....

Thoughts?

Protagonist · 08-22-2016, 12:02 PM

Too much effort for too little gain. The reason they have that disconnect plug down by the accelerator pedal is so you can use it, so keep things simple and use it.

It doesn't disconnect everything, otherwise the remote key fob wouldn't unlock the doors, but it disconnects enough.

If after a couple of months using the disconnect plug the starting battery doesn't stay charged up enough to start the engine, THEN it's time to look at alternatives. But jumping to alternative charging methods first before trying the OEM solution is wasteful.

Marks71 · 08-22-2016, 01:43 PM

That chassis disconnect is the easiest, simplest thing going. Can't imagine needing another method

FlyFishinRVr · 08-22-2016, 02:01 PM

@Protagonist and @Marks71 - Yep, totally get that, and that's why I included the "use the disconnect" option in my post. If we're only talking 20-30 days, that's the smart way to go.

I'm really just curious if someone has done something similar to the small solar panel option and how it worked out (or if it worked at all). Would be cool if it did work because the parts are pretty cheap (less than $100) and they could be used for other purposes while camping.

amirm · 08-22-2016, 03:10 PM

The cigarette lighter plug is live all the time in the front dash. Get a portable solar and put it in the window and plug it into that.

73shark · 08-22-2016, 03:17 PM

My solar panel kept both the house batteries and the chassis battery charged. Did AS change that?

LB_3 · 08-22-2016, 03:30 PM

A 20 watt charging panel will likely not be able to overcharge a battery. A nearly full battery probably won't take more than a quarter amp. And with only 5-6 hours of full sun per day, I don't think you would even need to check the water level more than a couple times per year.

FlyFishinRVr · 08-22-2016, 03:30 PM

Quote:

Originally Posted by 73shark

My solar panel kept both the house batteries and the chassis battery charged. Did AS change that?

Looking at my schematics it appears to me that the rooftop solar panel is only connected to the house batteries, but I'd be very happy if that weren't the case so someone please chime in if you know. Thanks!

Mcrid · 08-22-2016, 03:50 PM

It is my understanding that the BIM will connect the chassis battery to the house batteries (so the 100 watt solar circuit) when the chassis battery drops below a certain level and there is a charge voltage available from the House battery/solar charger or Magnum.

Sebtown · 08-22-2016, 04:19 PM

I've been using a 20 watt solar panel to maintain the chassis battery for a few years now with great results. No need for a charge controller. I plug it into the cigarette lighter after every outing and it keeps an already charged battery topped off.

Protagonist · 08-22-2016, 04:40 PM

Quote:

Originally Posted by LB_3

And with only 5-6 hours of full sun per day, I don't think you would even need to check the water level more than a couple times per year.

On an NCV3 Interstate, the starting battery is a Group 49 AGM mounted under the driver's footwell. No wet-cells anywhere in the van.

FlyFishinRVr · 08-22-2016, 05:01 PM

Quote:

Originally Posted by Sebtown

I've been using a 20 watt solar panel to maintain the chassis battery for a few years now with great results. No need for a charge controller. I plug it into the cigarette lighter after every outing and it keeps an already charged battery topped off.

Great to hear, thank you!

FlyFishinRVr · 08-22-2016, 05:22 PM

Quote:

Originally Posted by Mcrider

It is my understanding that the BIM will connect the chassis battery to the house batteries (so the 100 watt solar circuit) when the chassis battery drops below a certain level and there is a charge voltage available from the House battery/solar charger or Magnum.

Interesting......

So, that would only be possible if you kept the chassis battery connected and the Main Disconnect on (i.e. keep everything connected), correct? That would be awesome as it would basically keep all of the batteries topped off assuming you had fairly regular access to sunshine.

The only thing that would need to be turned off would be the propane so the switch doesn't draw the batteries down faster than the solar can top them up (and I think I read that switch draws something absurd like 1Ah when on, so it would kill the batteries pretty quickly).

Just for my education, does "BIM" equate to the "Battery Separator" in the 2017 manual?

Thanks!

lewster · 08-22-2016, 06:58 PM

Mcrider has it right. The
BIM (also known as a battery separator) will close the contacts on the solenoid to join both battery banks together when one bank is below the contact voltage AND there is a charging source present.

As this is a bi-directional system, it will charge a low chassis battery if a charging source is present at the house batteries and conversely will charge the low house batteries if the alternator is operational and adding charge to the engine battery.

Lew Farber

c21 · 08-22-2016, 07:17 PM

I just tried unplugging my chassis battery under the driver footwell and found that it prevented unlocking with my key fob. I am unable to squeeze my 270# self between the driver door and my carport to unlock the door with the key blade so I guess I wont be unplugging mine.

Protagonist · 08-22-2016, 07:29 PM

Quote:

Originally Posted by c21bill

I just tried unplugging my chassis battery under the driver footwell and found that it prevented unlocking with my key fob.

Good to know, and thanks for the correction.

I must have mis-remembered that, because I could have sworn that the key fob still worked with the disconnect plug unplugged. But you know how it is; the more senior I get, the more senior moments I have!

c21 · 08-22-2016, 07:33 PM

Quote:

Originally Posted by Protagonist

Good to know, and thanks for the correction.

I must have mis-remembered that, because I could have sworn that the key fob still worked with the disconnect plug unplugged. But you know how it is; the more senior I get, the more senior moments I have!

Seems to be my problem too protag but only since I turned 70.

Mcrid · 08-22-2016, 08:11 PM

This will help

Protagonist · 08-22-2016, 08:13 PM

Quote:

Originally Posted by c21bill

Seems to be my problem too protag but only since I turned 70.

Unfortunately, I'm living proof of the old adage, "Too soon old, too late smart." Especially the "too soon old" part.

Although, if I was feeling more defensive about my shortcomings, I'd point out that ever since I installed my Viper alarm system in early February 2012, I haven't been able to unplug the disconnect plug at all without setting off the alarm system, so that was a long time to remember how the disconnect actually worked, since I only ever used it for one month and then never again for 4½ years.

But that's only when I'm feeling defensive. Right now life is good and I have no need to defend my lack of memory, so I won't point it out.

c21 · 08-22-2016, 09:10 PM

Quote:

Originally Posted by Protagonist

Unfortunately, I'm living proof of the old adage, "Too soon old, too late smart." Especially the "too soon old" part.

Although, if I was feeling more defensive about my shortcomings, I'd point out that ever since I installed my Viper alarm system in early February 2012, I haven't been able to unplug the disconnect plug at all without setting off the alarm system, so that was a long time to remember how the disconnect actually worked, since I only ever used it for one month and then never again for 4½ years.

But that's only when I'm feeling defensive. Right now life is good and I have no need to defend my lack of memory, so I won't point it out.