Need some help w/ Main Disconnect and solar

[Boxster1971]

Originally Posted by FlyFishinRVr

..... I guess in the grand scheme of things that isn't horrible since AGM's don't develop "memory". As long as the system is able to keep them above 50% they won't be harmed, but being an engineer "less than perfect" bugs me.....

Your 50% assumption is wrong. If the Lifeline AGM batteries are not brought to 100% at float at least once a week they will be damaged. Best way to get them fully charged is to plug in and let the Magnum Inverter/Charger top off the batteries.


- - Mike
2013 Interstate Lounge EXT on 2012 Sprinter

[FlyFishinRVr]

Originally Posted by Boxster1971

Your 50% assumption is wrong. If the Lifeline AGM batteries are not brought to 100% at float at least once a week they will be damaged. Best way to get them fully charged is to plug in and let the Magnum Inverter/Charger top off the batteries.

Interesting. Everything I read indicated AGM's are far more resistant to sulfation vs. flooded cells if not regularly topped up, but then nothing I read gave specifics like what "more resistant" means in terms of SOC vs. time.

With luck I won't need to worry about it, assuming I can figure out why my charge controller is letting the batts run down and not "waking up" to give them some juice. Still waiting on a reply from Airstream......

[FlyFishinRVr]

As promised, here's a follow up to this thread now that I've heard back from Airstream:

In summary, the solar kicks on when the house batteries fall below 12.2-12.4v. Per the tech, the likely reason my solar was off with the Main Disconnect (MD) off and then turned on when I switched the MD on was because my batteries were close to the 12.2v level and by applying a load, it tripped the solar charge controller into action. Seems plausible to me. Note that once the house batteries are charged, the system switches the solar charge over to the chassis battery.

Couple other points: The solar is meant to charge the batteries, but won't top them off. This is the same behavior as the alternator. The only thing that will keep your batteries topped up is connecting to shore power.

I hope this helps others to better understand how these systems work. It certainly helped me!

[felixkagi]

Originally Posted by FlyFishinRVr

Thanks for the feedback.

@amirm - by "the battery" I assume you mean the house batteries (vs. the chassis battery)? Since the reading was showing the house batteries were already down to 95%, it seems there was already a parasitic draw on them. Since it obviously wasn't enough to trip the charge controller into action, do you know if there is some magic level that's set somewhere that tells the charge controller to start charging once the house batteries go below that mark, even when the disconnect is off? If so, do you happen to know what that level is and if it can be set (like via the charge controller)? None of this is mentioned in any of the manuals that I've read so far......

@Mcrider - I don't think the '17's get that SB as I thought it was only relevant to previous model years.....???

IMHO the AI solar system with Atkinson controller & monitor is mediocre at best.
The addition of 2 x 100W solar panels, a Morningstar PS-30 controller, a Tri-Metric TM-2030-A battery monitor, necessary wiring and misc hardware makes for a system that will take care of batteries right in their place, including parasitic draws. RV sitting outdoors in a five month winter, in Summer the fridge keeps the beer cold 24/7.

This is a worthwhile investment for a vehicle like this, something that really should be OEM equipment. Yes it isn't easy to fish all the wiring through the various walls and you have to drill some holes and ad grommets and sealing compound, which takes a good bit of gymnastics. A boat dollar will get you a long ways and AM solar has just about all the the items you need.

[FlyFishinRVr]

Originally Posted by felixkagi

IMHO the AI solar system with Atkinson controller & monitor is mediocre at best.

I would agree that there are certainly more "robust" systems out there that have been installed and tested and found to be quite good.....for a price.

My journey thus far with the solar/charging systems on the '17 AI has been to determine 1) are they working as intended (I can now say with confidence the answer is yes), 2) is this sufficient for my needs (I'm going to give it a year and see), and 3) if not, what are my options.

I think the answer to #3 will be dependent on the answer to #2, which is what exactly am I trying to accomplish with the solar. I have no dillusion that it will assist with boondocking because I don't plan to camp out in the open in full sun. For now, my goal for the solar is simple: keep the batteries healthy between trips. This might mean 2 weeks to 2 months of sitting parked outside. Based on my observations thus far, it appears the solar charging system as-installed by the factory is capable of doing this, at least during this time of year where my rig is getting 20+Ah of energy per day. This seems to be more than enough to recover what little parasitic draw exists (all systems off, propane off, fridge off, etc). Will it be enough to recover from a week (or more) of no sun? That's yet to be seen.....

[73shark]

Just remember that as previously stated that the solar won't keep the house batteries at 100% all of the time.

[FlyFishinRVr]

Originally Posted by 73shark

Just remember that as previously stated that the solar won't keep the house batteries at 100% all of the time.

Understood, and this is my one concern as it will degrade my batteries faster than if I was able to keep them at 100%, but since my current situation doesn't permit that, I'll have to live with what I've got.