Battery drain

[Baja Bilo]

Hello.
My 2003 Chinook Baja has been in the shop since last Thursday. It has a parasitic battery drain
going on and the mechanic working on it is about to tear out what little hair he has left. The
shop that it's at is an auto electric repair shop and has been in business for probably 50 years.
He thought that he found the problem in the smart solenoid and replaced it but that didn't fix
the problem. Have any of you guys had a similar problem and if so what was the culprit? The
rig only has 65000 miles on it and it has the 7.3 Powerstroke engine. Any help or ideas is greatly
appreciated. Thanks, Steve.

[Blue~Go]

I don't know how large your parasitic drain is, but the way that Chinook wired up the stereo that is in the "house" part of the RV can be a culprit.

So car stereos (which is what they used) have two power wires. One provides the power (duh), and the other one keeps things alive such as station presets and the like. Chinook wired the coach stereo so that the main power comes from the brown box/DC panel near the kitchen, as you'd expect. BUT, they wired the other power wire to the cab/start battery system.

BobW is the one who first noted this, and my very first electrical project on my Chinook was to change that (thanks to his posts). I took that wire and put it also on the "house" power supply. That does mean that if I turn off power to the Chinook house bank, I'd lose presets. No issue for me as I don't turn that power off very often, and plus when traveling presets don't do me much good anyway as I'm in new places.

I don't know if this is your culprit (or one of your culprits), but it's a possibility.

(If you pull that stereo out, you can see the wires. On my '99, the main power wire to the stereo from the house bank was circuit #9, a 14 gauge green wire. BobW had found that for some reason the other wire (that was originally wired to the start/cab system) did not like being on the same circuit as the first power wire. I didn't explore this too much, because I had the circuit #8 12 gauge black wire there powering the original VCR, so I used that to take over the "cab" wire.

If it's something you end up wanting to pursue, I could probably dig up some photos of the back of the stereo (the one up in the entertainment center in the coach).

[Baja Bilo]

Thanks for the info. I do know that stereo I have comes with a remote and when
you turn off the stereo with the remote it will display OFF but it still has power
to it and to shut it off all the way you have to press the button on the stereo.
I think the mechanic said that there was a 3 amp draw on the battery. I will give
him your info on Monday, thanks again.

[Blue~Go]

I just took a look into the past, and on my '99 that wire was a red one, in a group of three wires that were electrical taped into their own group. The group was the red one that goes to the cab/start batt, the green one that comes from the house fuse block (brown box) to power the stereo from the house bank, and a white (negative) wire. It's the red one in that 3-wire group that power(ed) the stereo on my '99.

Edited to add: I see I had put a tag on that red wire that (in my cased used to) powered the memory part of the stereo from the cab. It says "Fuse #4 from cab stereo memory." Mind you I made that tag 7 years ago and it was my first project on the Chinook.

[BobW9]

Just to be certain we're all on the same page, you are talking about a current drain on the engine/starter system, not the coach, correct?

I take it this issue is something new for your Baja? Or did you just purchase it and found the starter battery dying on you after a couple days undriven?

Unless something is rusted with a bad connection (and I doubt even then), there is no way the radio turned off has a parasitic current drain over maybe a few hundred milliamps. Enough to drain things over a week or three, but not much compared to 3A. All the parasitic drain on my starter battery including an alarm system is < 1 Amp.

Did he measure the drain while the smart solenoid was disconnected? So we know nothing strange is going on between the engine/starter system and the coach batteries/system?

[Blue~Go]

Ooh, good point, BobW. I "assumed" we were talking about the starter battery due to mentioning which engine it has, but we don't know that. Good to clarify.

Also agree that I don't think the stereo would draw 3 amps. These are normally dashboard stereos and that would be too outrageous a draw for a stereo in the normal car position (I think).

My buddy with the E-450 RV had something like a 1.5 amp parasitic draw and I'm trying to remember what we tracked it down to (he changes rigs often, so that was 4 RV's ago for him!). (It was not a Chinook but same Ford chassis.)

If it is a start/Ford battery draw, guess I would think about things where the "coach" interfaces with the Ford system as possible culprits. Things like electric steps that open with an ignition cue, coach stereos, electric dump valves (which luckily have apparently gone the way of the dodo bird), heated console cup holders (RV makers upgrade consoles sometimes), etc. Not sure whether it could somehow cause a draw, but (?)

Since we know that a stock Ford van, say, doesn't usually have a big parasitic load problem, there is a good chance it has something to do with some way in which the RV builder (or someone else later) "interfaced" the cab and RV systems.

PS: If you have the stock Surepower 1315 combiner, I would change that just out of principle. Many were recalled as a fire hazard, plus it's an outdated design for the job it does (and at least in '99, installed in a hot/damp location on the driver's side fenderwell - not recommended).

[Baja Bilo]

Ooh, good point, BobW. I "assumed" we were talking about the starter battery due to mentioning which engine it has, but we don't know that. Good to clarify.

Also agree that I don't think the stereo would draw 3 amps. These are normally dashboard stereos and that would be too outrageous a draw for a stereo in the normal car position (I think).

My buddy with the E-450 RV had something like a 1.5 amp parasitic draw and I'm trying to remember what we tracked it down to (he changes rigs often, so that was 4 RV's ago for him!). (It was not a Chinook but same Ford chassis.)

If it is a start/Ford battery draw, guess I would think about things where the "coach" interfaces with the Ford system as possible culprits. Things like electric steps that open with an ignition cue, coach stereos, electric dump valves (which luckily have apparently gone the way of the dodo bird), heated console cup holders (RV makers upgrade consoles sometimes), etc. Not sure whether it could somehow cause a draw, but (?)

Since we know that a stock Ford van, say, doesn't usually have a big parasitic load problem, there is a good chance it has something to do with some way in which the RV builder (or someone else later) "interfaced" the cab and RV systems.

PS: If you have the stock Surepower 1315 combiner, I would change that just out of principle. Many were recalled as a fire hazard, plus it's an outdated design for the job it does (and at least in '99, installed in a hot/damp location on the driver's side fenderwell - not recommended).

They did change the Surepower 1315 to a new one but it's a different brand. It is installed an the drives side
just under the coolant reservoir. Not an ideal spot but I'm not sure where else you could mount it.

[Baja Bilo]

Just to be certain we're all on the same page, you are talking about a current drain on the engine/starter system, not the coach, correct?

I take it this issue is something new for your Baja? Or did you just purchase it and found the starter battery dying on you after a couple days undriven?

Unless something is rusted with a bad connection (and I doubt even then), there is no way the radio turned off has a parasitic current drain over maybe a few hundred milliamps. Enough to drain things over a week or three, but not much compared to 3A. All the parasitic drain on my starter battery including an alarm system is < 1 Amp.

Did he measure the drain while the smart solenoid was disconnected? So we know nothing strange is going on between the engine/starter system and the coach batteries/system?

It has had this problem since I purchased it. It's not a problem if I start it everyday or
have it plugged into shore power. I think the previous owner may have dealt with the
problem and never got it solved. When I was driving it home the coach low battery
alarm went off. It has 2 new coach batteries in it. Not knowing much about RV's I
started poking around in the engine bay and found that the cable from the coach
batteries wasn't hooked up to the vehicle battery which meant the coach batteries
weren't getting charged from the alternator. I'm wondering if the reason the cable
wasn't hooked up was because the coach was draining the vehicle batteries. I don't
want to tell the mechanic how to do his job but I hope he checked to see if the drain
was still there after disconnecting the coach batteries from the vehicle battery. I
think that would have been the first thing to check to find out if the drain is from
the vehicle or the coach. I think I'll go there Monday and disconnect the coach stereo
and see if that stops the drain on the vehicle battery. Thanks for the input.

[Blue~Go]

They did change the Surepower 1315 to a new one but it's a different brand. It is installed an the drives side
just under the coolant reservoir. Not an ideal spot but I'm not sure where else you could mount it.

You can mount it anywhere along the positive cable that runs from the start battery positive terminal to the house battery positive terminal. That cable actually runs (on mine) across along the firewall right up by the hood hinge line (my gas start battery is on the passenger side by the headlight) and then once it's on the driver's side of the steering column it takes a little detour to the original 1315, and then back to where it was by the steering column, then down and under the frame area to the house bank.

Since this electrical cable is connecting two positive terminals (start batt positive to house batt positive), you can interrupt it anywhere along the line and it's the same thing electrically.

[Blue~Go]

It has had this problem since I purchased it. It's not a problem if I start it everyday or
have it plugged into shore power. I think the previous owner may have dealt with the
problem and never got it solved. When I was driving it home the coach low battery
alarm went off. It has 2 new coach batteries in it.

Okay so it is draining your house batteries not the start battery? That's a different scenario than I was envisioning at first (good sleuthing, BobW!).

Not knowing much about RV's I started poking around in the engine bay and found that the cable from the coach
batteries wasn't hooked up to the vehicle battery which meant the coach batteries weren't getting charged from the alternator. I'm wondering if the reason the cable wasn't hooked up was because the coach was draining the vehicle batteries.

This is one of the main functions of a "separator" (aka combiner aka isolator). When either bank drops below a set voltage (for Blue Sea, 12.76), the connection opens so current can't flow between them. Some combiners are bi-directional, so charge power could go either way (1315 for example), while others are uni-directional so power can only go one way, which is typically from start bank to house bank (to charge while driving).

I don't want to tell the mechanic how to do his job but I hope he checked to see if the drain
was still there after disconnecting the coach batteries from the vehicle battery.

Your mechanic may be a crack diagnostician, and totally on top of it. He'd be the exception in my experience. many "regular" mechanics would probably have no idea how an RV is wired (a boat electrician would have a better chance). So while he may be fantastic, if it were me I'd not assume that.

I think that would have been the first thing to check to find out if the drain is from the vehicle or the coach. I think I'll go there Monday and disconnect the coach stereo and see if that stops the drain on the vehicle battery. Thanks for the input.

Can you just clarify one more time what the symptom(s) are?

1) Which battery is running down, start or house? Or both?

2) Are you saying this was happening even when the cable connecting start and house banks was not connected at all? If yes, then which bank was running down, start or house?

3) When does this happen? While driving only? While parked only? Both?

There is one other little "gotcha" on the Surepower, which is that many of them have "start helper." What this does is (sneakily, without telling you) if your start battery is too weak to start the vehicle, it combines your house bank with your start bank to help start the vehicle BUT NEVER TELLS YOU. So you could have a dead or weak start battery for eons and never know it. Since a diesel takes a lot of oomph to start, if this had happened and then you drove away, maybe a cascade starts and then your house bank trips the low voltage warning?

The above scenario may not apply, but if you want to explore this further it would be great if you could elaborate on the answers to the questions above.

BG