Chassis battery drain

[targaboat]

There apears to be a common problem with numerous examples of the chassis battery loosing charge over a period of 5 or more days on some Winnebago produces manufactured after 2000. Has anyone acutully fixed this problem? I have read many opinions of "could be" but I have heard of no other fix than adding another charger. I am sucessful with a small trickle charger but thought I would ask for actual sucess examples.

[Thudman]

What kind of rig do you have?

Thudman

[targaboat]

We have an 04 Horizon. Our previous low end Safari product charged the chassis battery when pluged into 120 and it just seems tackey that the horizon does not what with all the nice things they have put on the unit. It is one of those things that you do not think about when you buy an unit so Winnebago just cut a small corner on $. Our friends have a Journey where the battery does not run down but I am not sure it is being charged. Thanks

[JudyandJim]

We have the same problem. Had to replace original battery after 9 months of use. We were told that the wiring had been "modified" so that the coach batteries charged the engine battery, which drained all of them. We bought four new batteries - 3 house and 1 engine last May -- and had them correctly wired by the dealer.

We have been very diligent in checking water levels on the first of each Month since then. However, after 5 months, the engine battery stopped holding a charge. After driving for 100 miles, it has just enough charge to put the jacks down and the slides out. Then it is dead. Talked to dealer yesterday and they said we must be doing something to drain it. Not so! We are very careful about that.

So, now we must buy another battery, again! We bought a Battery Minder and will put it on this new one.

[targaboat]

First thanks for the reply. I am going to be Walmarts finest for about $60 where you can take it back under warrenty almost anywhere in the country. Some major mafgr makes those battery and they are probably the same as the ones that are three kinds as much. You see lots of opinions on these about forums but I do not beleive it is much than you get what you pay for which is correct lots of time but not allways.

On your comment on driving 100 miles and the battery is down, that sounds like the alternator. The battery, even a marginal one, would be up and fat and sassy. Get a digital volt meter and check your voltage while running and it should be close to 14v,

[CaptBill]

I think Targaboat is right about the alternator. Check the voltage at the engine battery terminals, with the engine running. Should see that 14v alternator charging voltage.

BTW, I know lots of people who have bought the Battery Minder, and it does tha job. One issue with it is that if left connected to the battery, but unplugged from an AC power source, it will drain the batteries eventually.

A competetive product has come out, addresses that problem, and it sells for about $10 less. Here's a link to one source, and no, I have no interest in them or the company that makes the charger. Battery Defender

[Gary CA]

Targaboat: The solution that has worked for me was; purchase 3ft of 8 gauge wire, 2 heavy 30amp clips, make a jump wire. Connect red posts coach to red chassis. While plugged to shore power everything will remained charged. Costs about $3. Put a tape reminder over ignition to remove jumper before starting coach. Good luck

[CaptBill]

Gary, just a thought. If one of those clips pops off the battery terminal and hits any chassis or frame parts, you will have a toaster wire that could cause a fire.

An in-line fuseholder with about a 5 amp fuse, will protect your motorhome from such an event. Additional cost; about $2.00.

[targaboat]

I am running an 1.5amp battery minder and it is keeping up. I could not beleive it. As for it draining the battery, that is occuring without the minder. Relative to the wire connection between the two battery banks, I have done that with a very small wire. The voltage difference between banks is at the most 2 volts unless you start the engine. That does not take much wire to carry. The small wire acts as a fuze by itself for there would not be much energy if it came loose. I do not really know anything wrong with this approach except I wanted something I did not have to remember to remove.

I really started this post to discover where the drain is in the coach. In leu of that there are at least four solutions that have come from this post, all appear to work.

As a side issue I found I have lights in the engine and from service compartments. However, I have not found were the drain is occuring. Guess I need to get another hobby!

[CaptBill]

Guess I need to get another hobby!

Targaboat, you don't need another hobby; you already have found one! Finding the mysterious current drain!

Do you have a digital (or analog is ok) multimeter? If so, disconnect the red engine battery terminal, and insert the multimeter in series with that wire and the battery positive. With the meter set on a low range DC amp scale, and with everything you can think of turned off, make a note of the amperage reading. That is your mystery battery drain.

Now, check if the step switch is off; if wired wrong at the switch, the under-step lamp may be lit. How about radio/cd changer? Remove the fuse at the fuse panel (or back of the units), and see if battery drain had changed or is gone. Youget the idea... check for any possible unexpected drains by pulling fuses (after ALL switches have been turned off). Has anything changed?

It could be possible that the drain is coming from the engine or transmission computer, one of which has a seperate hot wire (smaller diameter) going right to the battery terminal. It does on my rig, andway. Disconnect it and put the ammeter in line there. How much draw? Should be minuscule. If you are seeing more than a few milliamps, you may have found the problem.

Remember that several seperate current draws will be cumulative in effect, so a hundred milliamps here, a few more there, etc, and you will have enough to pull a battery bank down in a week. Good luck, whatever you do.

[Gary CA]

CatpBill: Good suggestion on the 5amp fuse, I will also down-size my jump wire, any susggestions on the gauge of wire? I first thought the thicker the wire the better. I now realize the low amp draw from the research posted. Good suggestions, Thanks

[dirko]

Hi Ho: Your jumper wire is a possible solution, but has a couple of problems. Having another thing to do is one (connect/disconnect etc.) The second is replacing lots of 5 amp fuses. The current that will flow from one battery to another is dependent on the relative charge condition of the two batteries. If they are both fully charged, there will be a small current and little problem. If one is discharged the current may be tens of amps until an equilibrium is reached. My coach will sit for months without draining the batteries. Finding out where the current is going would be interesting in finding a real solution. If the current flow is 0.5 amps and remains constant for 4 days that is 48 amp-hrs and is approximately the rating for most chassis batteries. Does your coach really pull 0.5 amps will sitting?

[Joe-K]

Unfortunately I live in one of those northern states were we only get to use our motorhome 6 months out of the year. The first winter, I stored the motorhome and found a dead engine battery when trying to start it in the Spring. I called Freightliner about it, and they told me that there is three items on the chassis that will draw from the battery when the rig is parked. The engine computer, transmission ECU, and brake drier. I'm puzzled about the brake drier, but they claim it draws current.

Conveniently, Freightliner told me that the next year when I store it to go the the bundle of red battery cables and I will find a inline fuse older that supplies constant power to the three items that cause the drain. They said the fuse is put there so the coach manufacturers can pull the fuse to save the batteries if they have a buildup of chassis and store the chassis for long periods of time.

Year 2, when storing the coach for the Winter, I found the fuse and pulled it. Fast forward to the Spring and when I went to start the motorhome, the batteries were not dead, but were low after 6 months. The coach cranked, but didn't start right away so I used the emergency start and it fired up.

Fast forward again to last year. I pulled the negative battery cable for the 6 month storage. Two weeks ago, I went to pick up the motorhome and it started right up after connecting the battery cable.

My conclusion is that the engine and tranny ECU's along with the brake drier will drain the batteries completely if left long enough. By pulling the fuse on the positive cable, you should be fine for at least 4 months but for storage of 6 months or longer, disconnect the battery cable.

I suppose I should take some measurements of the actuall current drain through the fuse one of these days.

[dirko]

Hi Ho Joe: Just curious how long it takes to drain the chassis battery with nothing disconnected. Some have reported 4 or 5 days.

[Joe-K]

Hi Dirk,

During the summer months, I've never had the battery run low that I noticed any problem in starting the rig. We tend to use the rig a lot, but in the Early Spring, it has sat for 3-4 weeks with no problem. I've never had it sit for longer than a month though other than the 6 months in storage over the Winter. I think if I was going to be someplace for longer than a 6 or 8 weeks, I'd pull the fuse just for precautionary measures.

[MrTransistor]

Hello everyone,
A beautiful spring day here in Albuquerque. Just took measurements on the current draw from the coach batteries. Bear in mind that this is an 04 Horizon / 350 CAT engine and the older Journeys may be different.
One of the two large cables (000?) draws only about 3 mA while the other large cable (000?) draws .25 A for about 2 seconds and then drops to about 25 mA continuous. There is a slightly smaller cable (0?) that draws about 90 mA. Two of the three small wires (#10?) draw 22 and 14 mA.
Given the temperature outside right now, I can't say if the brief .25 A reading would remain for a much longer time if it were cold. This could be the break heater that Joe-K talks about (I don't have a clue what it is either). I have no way to tell where or what these lines feed since I haven't received my user name and password to the Freightliner site and don't have any schematics for the chassis yet.
These numbers total up to be a minimum of 151 mA continuous load and could be as high as .35 A. This could explain why everyone including me is having a problem keeping the chassis batteries charged. If the load in cold weather is .35 A then 7 days would consume 59 A hours from a battery bank of 2 that would have a cold capacity of perhaps 150 A hours. If on the other hand, the normal draw is only 150 mA, then the batteries would only be drawn down by 25 A hours in 7 days. But that number jumps to over 100 A hours over a period of 30 days.
I did not find an inline fuse as described by Joe-K. As an electronics field service engineer I would strongly recommend that you not connect a small wire between coach and chassis batteries. If you forget to remove it and try to crank the engine, the current through the wire could cause it to fuse and a fire is a good possibility. An in-line fuse will protect the wire and should be of a size that matches the Amp. Capacity of the wire i.e. #10 wire =30 A fuse. An alternative to this is to install a 12 V bulb between the batteries (50W?). The bulb may or may not light when starting the engine but will allow current for charging the engine batteries. One problem with connecting the batteries together with a wire or a bulb is that if shore power were to fail, you would lose both coach and chassis batteries and lead acid batteries don't like t be discharged to zero and left there. They die!
My suggestion would be to install a divi-charger, the same as is used that allows both the chassis and coach batteries to charge from the engine alternator. But be advised, if this is left to charge continuously, you may have a problem with over charging one or the other banks since starting batteries and deep cycle RV Marine batteries even from the same manufacturer may have a different float charge voltage requirement.
If I get my hands on the schematics for the chassis, I will investigate this current drain further.

[The Shadow]

Gary, when I had a battery boil over (reported back in January) I was in contact with Trojan. I too had connected a positive to positive to charge the chassis batteries. The Tech at Trojan said they did not recommend that approach.

I did a battery check yesterday and all three Trojans gave a reading of almost 1.3 specific gravity (including the one that boiled) and I finally had to add a bit of water to a couple of cells - after two months. Looks like all three batteries are functioning well.

If I ever have to replace these coach batteries I think I'll go for AGM (provided my Dimensions2000 charger/inverter can handle it without problems.

Don

Originally posted by Gary CA:
Targaboat: The solution that has worked for me was; purchase 3ft of 8 gauge wire, 2 heavy 30amp clips, make a jump wire. Connect red posts coach to red chassis. While plugged to shore power everything will remained charged. Costs about $3. Put a tape reminder over ignition to remove jumper before starting coach. Good luck

[MrTransistor]

Hi dleslie125,
I have four 6V 220 Ah AGM batteries configured for the coach and love them! They fit where the original Group 31 Trojan's were. Turned them end to end crossways to the coach and then side by side with the other pair. Had to make new holddown brackets and replaced the cables with #0000, Winnebago tends to scrimp on wire size. Lifeline GPL-4C or equivalent as I remember. Paid $150.00 apiece plus freight. 440 A hour capicity and they don't mind being discharged 50% to 75%. Unlimited charge current also. I have a Prosine 2500 that charges at 100A and I'll be installing the Energy Command 30 for the Onan Quiet Diesel soon.

[CaptBill]

Dirk brought up a good point about the current flow being dependent on the relative charge between the 2 battery banks, and that 5A fuse I recommended would blow if the charging current exeeded whatever the fuse rating was. I don't even condone using a jumper wire, for the very reasons that Mark mentioned. As I mentioned in another thread on this subject, I bought an Intelletec smart relay, which controls whether the battery banks are jumpered together (via the boost solenoid) automatically. These units can but bought for about less than the price of a Battery Minder, and require 5 connections, which all can be done behind the dash, where the module can be located as well.

Once it's installed, you never have to worry about it again. Click the link to read how it works. That jumper wire just seems like trouble waiting to happen.

[MrTransistor]

Hi Capt.Bill,
Looks like that will 'get er done'!