Dead Battery, Or?

67Tiger · 07-23-2021, 11:32 AM

I just retrieved my Class C view from 1 month storage with the Chassis battery disconnected on the mercedes sprinter so there would be no drain. I hooked the battery back up with the quick connect hit the starter and nothing but a click, indicating no charge. This makes no sense as the system had no drain on it and it's a 2 year old RV with 10k miles. I used the house batteries to get it started and put the battery on a trickle charger which showed the battery was charged up, even the control panel on board shows it's charged up. What am I missing? Why do I only get a weak click from the starter with a battery that shows a complete charge, and it takes the house batteries to get the RV going. Could it be the starter is crapped out and needs the extra voltage to get it going? I get no check engine light, nothing. Cheers

**creativepart** · 07-23-2021, 11:39 AM

Was your chassis battery fully charged when you disconnected it? If not... there's your answer.

And, what is making you think your battery "shows a complete charge"? My guess is your looking at charge voltage not battery voltage.

Want to know for sure? Disconnect the chassis battery again. Come back the next day and put a multimeter on it as it sits disconnected. THAT will tell you the story of your battery's state of charge.

If it's connected to your running Sprinter chassis it will always show not only fully charged (12.7v) but over charged like 13.7v or 14.1v, etc.

Morich · 07-23-2021, 12:05 PM

BUT before going fully to the battery at fault, be aware that there are also other things that can come up while the RV is stored. I just got that lesson AGAIN for about the 32d time!

The surface charge as mentioned is one thing to be aware of but do not forget that the power from the battery also has to get from point "A" to "Z" and that means there are several different connections and any one of those can corrode while stored to the point that the power doesn't get there!
Hitting the boost switch can often give a different route for that power so that it bypasses the corroded spot! What it gave me on my Vista was a real runaround as it confused me into thinking the start battery was low and the boost was enough to make it work, but the truth after lots of head scratching and coming around in a circle with thinking I understood batteries, was that the boost switch was not giving the start more power but the different route! Start battery passed every test but when I got down to actually tracing out the cables from battery to starter, I found there is a big connection just behind my front tire on the frame at a big fuse and the voltage was good to that fuse but not on the far side due to corrosion!
Test the battery, for sure and I find a load test is good but if all things say it is good, then go to the cable tracing to see why you have power at the battery but not getting to the starter.
Note that a repair shop assured me it was DEFINITELY a bad starter!
Cleaning connections is much cheaper than replacing parts!

DavidM · 07-23-2021, 12:48 PM

Here is another take on what may be your problem. What do you mean by a "quick connect" on the chassis battery? I don't know of any such things that will take the several hundred amp starting current. A knife switch or a heavy 500 amp rated rotary battery switch yes, but this doesn't sound like one of those.

Using the aux start switch to start the engine worked because it is connected downstream of that "quick connect".

David

Elkman · 07-23-2021, 12:55 PM

I would start by using an external battery charger to recharge the cab battery. Then when it is at 100% I would check the battery voltage using a VOM and starting the engine. When the starter motor load is being applied the drop in voltage provides a good indicator of the health of the battery.

Lead acid batteries will decrease in charge level over a period of months even with no external loads involved.

DesertRatt · 07-23-2021, 02:32 PM

Some new batteries only last 2 years. As we know, when a battery is exhausted the charge falls off a Cliff. Don't assume that a2 year old battery is still good.

Mtn Charlie · 07-23-2021, 06:53 PM

The coach engine should ALWAYS be running when moving slides or levelers. Both run off of the engine battery and can cause a considerable drain on a weak battery.

67Tiger · 07-23-2021, 10:44 PM

Thanks everyone for the input. I'm going to put it out of my mind until I return from this 4 day trip. It started right up with house battery, I don't like doing that but I've got two more starts before we return home. I'll pull the battery first thing and check the voltage on it and if it's good, check the electrical connectors. After our six hour drive today I shut it down and ten minutes later it gave me one start off the chassis battery, but not a second one. I'm thinking we have a spent battery. Any recommendations on a top quality replacement?? Cheers

67Tiger · 07-23-2021, 10:50 PM

On the Sprinter Chassis Winnebago View there is a brass post in the drivers side foot well with what I'd call a quick connect female connector. They suggest disconnecting the hot wire from the post when storing for more than 2 weeks without a start. I seldom do this, but this time I knew I wouldn't be able to start it for at least a month. In theory there would be NO draw on the battery, and there was enough juice to lite the gauges and get a click from the solenoid, and that was it. Thanks for your input.

Morich · 07-24-2021, 07:27 AM

On the start battery, it is just the same qualities we need as a car/truck battery, so from there I just go with getting the right size to fit and I do like to get one rated for three years or more. But this is not a place where I care about AGM or other new designs, so just go with what feels right. I find Wal-mart does fine for me on the start battery.

BobC · 07-24-2021, 10:03 AM

Quote:

Originally Posted by Morich

On the start battery, it is just the same qualities we need as a car/truck battery, so from there I just go with getting the right size to fit and I do like to get one rated for three years or more. But this is not a place where I care about AGM or other new designs, so just go with what feels right. I find Wal-mart does fine for me on the start battery.

Walmart is good, just keep your receipt. I had a problem getting a warranty replacement because I didn't have the receipt and wasn't at the store where I'd initially purchased it (the original store was out of stock). I was finally able to escalate the issue to a manager and got the exchange but it took a lot of convincing. I don't know if this is common but just keep the receipt no matter where you purchased your battery.

Vince5764 · 07-28-2021, 07:06 PM

I think besides the quick connect you also have to remove a fuse from the driver side seat. My view is in storage now. I’ll make a trip to see if I can find that in the manual. The fuse I think disconnects the backup booster battery??