Low chassis battery on start up

[NLOVNIT]

As I found out, the dash lights up like a Christmas tree when turning the key to accessory. This wknd, after I waited for the "wait to start" light to go out & the air pressure to build, I noticed the red low voltage (battery icon) light was still on. When turning the key to start...nothing. So I used the Aux Start rocker switch to jump & the engine started right up.

This happened one other time, a month ago during the PDI walk through. The tech just brushed it off saying "it happens sometimes" & I didn't think anything of it. It's started first time, every time since.

But it happened again this wknd. Coach is hooked up to 30a power 24/7/365. The only thing different this time around (that I know of for sure) was it was unhooked from power for about 5 hours while DH installed the PI power protector. All 3 main switches in the bays were turned to the OFF position while that was going on.

I did a search & found a lot of posts in the Newmar Owners Forum saying this is normal as there's a lot of things that have to power up on start that can put a load on the chassis battery, causing that light to stay on for a bit.

I have no problem using the Aux Start to boost the chassis battery, but it just doesn't seem right having to.

Am I supposed to leave the ignition in the acc position until that low voltage icon light goes out? How long is that?

Lori-

[Skip426]

I would say load testing of the chassis batteries is in order.

I do get a low battery warning , on cold start up when the engine intake heater is cycling even with the engine running , and the load shows up on the dash voltmeter.
But my dash lights don't come on with the ignition in the acc. position , that I only use when leveling.

The fact that the coach will start when the shore power has only been off for moments , would indicate to me that one or both of the chassis batteries will hold a surface charge , but won't tolerate any load after the surface charge is gone.

[Lt Dan]

Lori, this is a common issue with the Power Glide chassis. There have been several discussions on here and over on the Tiffin network about this same thing. The intake air heater grid comes on and draws a lot of power when you first turn the key on. The colder the weather the longer it takes to warm up. This has been the way ours has worked since new. I've watched actual voltage on my Coach Proxy and it drops momentarily to about 11.9 volts then comes back up. The starting batteries turn the engine over with plenty of power when the wait to start light goes out so I've pretty much learned to ignore the low battery light. The software in the system is probably set too sensitive for a momentary drop in power.

[luvlabs]

This has been an ongoing question of Powerglide chassis owners for at least the last 10 years. Lt. Dan is correct. This question used to come up much more frequently when there was a 10 minute delay built into the engine driven charging system.

[NLOVNIT]

Thanks Dan & Roger. I guess I didn't go far enough in the Google search results to see Tiffin threads - just a lot of Newmar ones.

The reason I asked is that the coach didn't start after the wait to start dash light went out. I had to use the Aux Start switch.

Should I just have waited a bit longer for that low batt light to go out or just continue to boost the engine batts?

Lori-

[Lt Dan]

Originally Posted by NLOVNIT

Thanks Dan & Roger. I guess I didn't go far enough in the Google search results to see Tiffin threads - just a lot of Newmar ones.
The reason I asked is that the coach didn't start after the wait to start dash light went out. I had to use the Aux Start switch.
Should I just have waited a bit longer for that low batt light to go out or just continue to boost the engine batts?
Lori-

Would it not crank after the wait to start light went out? If not, then you may very well have a bad battery or it was very low charge. You should not have to use the battery boost.

Are you turning the chassis batteries off when in storage? Do you have it plugged in? If so, you need to leave the 12v turned on and the Spyder system active so the batteries will stay charged. There is a pretty good parasitic draw on the chassis batteries so if it's not on shore power when stored, the shutoff switch in the second to the rear PS compartment should be turned off. I turn that one off when stored even though I leave the coach on shore power. The Spyder system will keep it charged but there's not as much of a charge/discharge cycle as when it's turned on.

PM me if you have specific questions.

[garykk]

As mentioned, the low battery light is a common sight in the dash of the Powerglide chassis but not being able to turn over the engine is not. Sounds like one or both batteries are defective.
We are assuming that the charger is enabled when plugged in to shore power.
The Spyder system monitors the batteries and when the chassis batteries fall below 12.4 volts, the system will charge them. You can monitor this on the Spyder main panel.

[NLOVNIT]

I do think I'm going to need them tested. As I mentioned in my opening post, it's on shore power (30A) in storage & this is the 2nd time (1st was at dealer PDI) the Aux switch was used because it didn't crank after the wait to start light went out (low batt light was still on).

Being without power for the relatively short time for the PI install shouldn't have resulted in that low batt condition.

Thank you all. You're the best! I will report back when I get results.

Lori-

[JohnH12]

I don't think it's only common for the Tiffin Powerglide. My current 33AA and the previous Fleetwood on Freightliner chassis did the same thing.
The low battery light should go out within a minute or so. We have the original chassis batteries in our 2018 and the voltmeter doesn't come up to normal until a minute or so after the engine is running.
Any longer than that or trouble cranking the engine warrants a deeper look at battery condition.

[mscress]

LOW BATTERY! same applies to Freightliner Chassis models. will come on for btref period on reasonably cool morning, if all is well in the "sytem should not stay on longer that 30 seconds, remember diesel have no spark plugss

[HaRVey 74.5]

I had the same issue on our 2018 Palazzo that I didn't remember seeing when we first got it and when I called Freightliner they said it was normal and due to the in air intake heating element on the Cummins engine during "cold" (below 50°?) ambient air temp, which made perfect sense since it didn't do it when we bought the coach last July...

[NLOVNIT]

It seems I should've titled this Dead chassis battery on start up. The issue isn't the dash light showing low, as that's normal on start up & it does go out within a few seconds. My issue was my chassis batteries were so low they wouldn't start the coach.

I've pretty much concluded the previous owner didn't take proper care of them (probably leaving the coach in storage, no power, without turning the disconnect switch OFF) & they've degraded to where they won't hold a full charge for a normal length of time.

The Spyder will continue to charge them as designed, they just won't stay fully charged anymore.

Lori-

[96 Wideglide]

Originally Posted by NLOVNIT

As I found out, the dash lights up like a Christmas tree when turning the key to accessory. This wknd, after I waited for the "wait to start" light to go out & the air pressure to build,

Your air pressure ain't building till your engine is running !!