Automatic Generator Start suggested settings?

[MarkMaxPayne]

I recently purchased a 2023 Newmar New Aire and am having some issues with the generator starting on the first try either manually or via AGS. The rig came with two Lithionics batteries (640AH combined) and AGS is set to come on at 30% charge left from the factory.

Whenever I try to start my generator, either manually or via AGS, it doesn't start the first try. It'll prime the fuel, crank a couple of turns, stutter as it tries to catch, but not fully start. This causes a generator fault. If I manually tell it to try starting again, it'll catch right away that second try and run with no issues. However with AGS, are there settings to either prime longer, crank longer, and/or try again? It appears with the AGS once you get a failed start and fault it is out of the picture until you manually reset things so it can try again. As it stands today, it will not auto start and run to then recharge my batteries on its own.

Best,
-Mark

[PeteDr]

Sounds like fuel drain back/air getting in the fuel line during idle periods. Given it is a 2023 coach, warranty claim at the closest Cummins/Onan dealer would be my suggestion. If you want to get some more facts, do a test of how long it takes for the problem to develop. One day of idle off time, then two days, etc. until problem presents.

[MarkMaxPayne]

Turned out that the chassis batteries were just garbage after being abused at the dealership. I replaced them as it was becoming obvious they just were not taking and holding a good charge after owning the rig for just a month. Now that I have new chassis batteries the gererator leaps to life very quickly.

Best,
-Mark

[FOLEYMECH]

are the new batteries lead acid, or agm?

[alank]

Just a question or suggestion, in your first post you mention letting the batteries get down to 30% charge before starting the generator. I don't let my batteries get down near that low before starting the generator, or charger in storage.

I'm no expert on batteries, just go by what I read and in a battery article of an RV magazine, the statement was made that continually discharging wet cell and AGM batteries to less than 50% charge will drastically reduce the life of the battery. They also said that keeping the charge above 50% will keep it in a condition to last twice as long.

When I'm in storage and I see the batteries down to 12.4V (considered 80% charge) the charger goes on the batteries. My AGS is also set to similar settings.

Just some food for thought you may want research further. I've asked here on the forum about AGS settings and have never had any response, so I haven't been able to find any good, qualified opinions on how the AGS should be set.

[MarkMaxPayne]

The batteries I replaced were the chassis batteries. Lead acid.

The batteries I was referring to in the original post which are configured by the factory to drop to 30% before the generator auto start kicks in are the house Lithium Iron Phosphate batteries. The BMS on those can let them hit near 0 for 3000 to 5000 times without doing any damage. 10 years later after that many full cycles they'll still hold over 80% of their storage capacity.

Very different battery chemistry and dynamics than traditional lead acid or AGM.

Now that the chassis batteries have been replaced, the generator auto start for the lithium house batteries is working fine.

Best,
-Mark

[redbaron73]

Originally Posted by MarkMaxPayne

The batteries I replaced were the chassis batteries. Lead acid.

The batteries I was referring to in the original post which are configured by the factory to drop to 30% before the generator auto start kicks in are the house Lithium Iron Phosphate batteries. The BMS on those can let them hit near 0 for 3000 to 5000 times without doing any damage. 10 years later after that many full cycles they'll still hold over 80% of their storage capacity.

Very different battery chemistry and dynamics than traditional lead acid or AGM.

Now that the chassis batteries have been replaced, the generator auto start for the lithium house batteries is working fine.

Best,
-Mark

I would probably set it to 15% when dry camping and feel very safe, knowing it can go to 0 and still be ok

[hamm2018]

The AGS in our big Road Warrior toy hauler is set at 20% to start. Last September we had lithium batteries with 960AH installed along with 1600-watts of panels.