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new parasitic chassis drain 07H


Art
 

I’ve picked up a new parasitic drain on my chassis.   At first I just thought it was my older battery not taking/holding a charge but I charged it up, disconnected it and left it for a week, tested and hooked it up again and it was fine so the battery holds a charge.   But from a full charge, without shore power and trk-l-start maintaining it within a day or 2, sometimes just overnight, it won’t start without the boost button (dash lights go out).  It’s down to 12.1 to 12.3v reading.  Far less time than any “normal” drain from the steps etc, it means overnight boondocking is pretty much off the table.

 

The only recent modifications have been adding the trk-l-start itself, and a change to how I’d grounded my inverter to my house batteries but I disconnected both as a test and it had no impact on the duration of the chassis charge.

 

Any debugging suggestions?

 

Art 07H


old_b4_my_time
 

Is this something either "brand new" or "worse"?  (Assuming also here that your definition of "chassis" is that of the engine compartment and not "house" or "leisure battery" as most define the batteries supplying the living quarters.)  The reason I ask if this is a new problem is this seems a constant problem for everyone, at least regarding the true "chassis".  The vehicle computer must stay alive to retain it's memory, the alarm module must remain "awake" with its radio receiver listening for your key dongle and the step logic remains active to interpret any door closure and opening to signal the step logic, so the "engineers" who designed this vehicle were short sited in believing that the engine would be started at least every couple of weeks (after all, what driver in the US doesn't start his vehicle every few days LOL).  The Winnebago "engineers" were short sighted not checking that the step has a small parasitic drain.    Now I haven't tested the slide-out but it could just as well have a small drain from other engineers who didn't think in terms of something which is seldom used.    So it is my experience and of everyone I've read about so far that this is something you just have to deal with when driving a Sprinter.   I've now been through two batteries while foolishly ignoring that this is a problem.   My battery will last from 2-3 weeks if I don't keep it charged by some method.    Some use Tric-L-Start to bridge the chassis batteries to the coach (to charge or "maintain" from them) while one assumes they are being constantly charged or "maintained" by some source as well, such as by the built-in shore power "converter" (which basically means battery eliminator, charger and maintainer).   I make a side-note here that I simply use a manual flip 20A circuit breaker to bridge the batteries when parked but that's only because I wanted to spend $3 for a solution instead of $50 or more for the Trik-L..)

You can add one of two popular style battery disconnects and go that route with only the slight price to pay of disconnecting the battery (when you can remember LOL).   Of course if your state inspection requires a vehicle computer reading, every time you have it inspected you have to go for a hundred mile trip or so to rejuvenate the car computer with data and sometimes the engine runs a little rough until it re-establishes i's running calculations (or most other vehicles do that I've had this same issue with, there's a possibility the Sprinter computer has non-volitile memory but I wouldn't hold my breath) so in short, battery drain and the hassle with loss of computer memory, potential inspections requiring a lot of driving or very simply the hassle of dealing with this issue are simply part of the cost of doing business.
--
Don - 2006 Navion J


old_b4_my_time
 

Anecdote 1 (same story; short version): You may actually be seeing reducded battery capacity due to the weakening from repeated "run down to flat" condition.

Anecdote 1 (same story; long version): These are just musings from someone who grew up on a farm, servicing tractors and grain trucks and dealing with the perils of day to day living in that hellish and frustrating environment but with that experience one often discovers being over-taxed without the time that we often have today where we adopt the "Sunday polisher" style mentality of someone who shines his RV every weekend and spends all week philosophizing about it (which I've morphed into LOL).   So in short and if you want to know where I'm going with this, we gave the old tractors and trucks a "three strikes and you are out" definition of battery performance over time.  A battery usually never actually died from old age, it mostly died from either abuse of lack of maintenance.   Because we had to "just deal with" misfortunes while too constrained time-wise to put any TLC into our vehicles, the batteries were always running flat on us and we came to realize that one could be allowed to run completely down and left dormant perhaps 3 times before it was time to buy a new one.   

So this is what I see with the Sprinter and all vehicles historically I've dealt with, and that's anything that is a low utilization vehicle or not a "daily driver". each time you let their battery run flat, they loose a little of their capacity and longevity.   In other words lets say with your Sprinter you start with a fresh battery and the known PITA parasitic load then runs your battery completely flat in 3 weeks.   OK now if that battery sits for a couple of weeks before you discover it, you quickly charge it up.   Now it lasts only 2 weeks next time under that same parasitic drain because it is in a damaged state and after 1 week if you discover it's again flat, you quickly charge it back up and then after 1 week now under that same parasitic drain you may actually come to the conclusion that "hey some new parasitic drain has depleted my battery" when in fact all you are witnessing is your battery losing capacity after being allowed to go flat one or more times while it's that same parasitic drain over and over that continues to haunt you.
--
Don - 2006 Navion J


Art
 

On Fri, Oct 23, 2020 at 11:21 AM, old_b4_my_time wrote:
Is this something either "brand new" or "worse"? 
Well new-ish.   As I haven't gone too many places lately it could have been like this for up to a year.  I only noticed because I was boondocking in Aug, Sep.  The change to the inverter ground was last year as was the triklstart install.  The battery was load tested 2 years ago when I was having starter issues and it was at/near original rating at the time.     I notice the trklstart provides low amp power to the chassis side even when the chassis battery is disconnected so that's confusing the readings too.

As you say it could be an accumulation of partial run downs over time has shaved it's life, but it seems to have dropped of a cliff.   I'm not ruling it out but not declaring it the smoking gun either.    I could replace it on spec but since I'm not going anywhere for the next 6 months I'd likely wait 'til closer to post-covid so I'm just wasting warranty time a new the battery.   But then if that's not it I'd have to continue to deal with it mid trip so penny wise, pound foolish.    My next step is just to pull fuses &breakers one by one and monitor  for a "significant" change with a multimeter.   

Yes I'm aware of the standard parasitic drain, previously I could go 2-3 weeks as well off a charge , now I can't go overnight.    (I would put a dedicated charger on it when shore power was available before I bought trkl-start)


Dunc 18ND W.CO
 

Have a knowledgeable technician measure the residual current draw when everything is "Off". Then start disconnecting wires and note if the draw decreases. Keep a list, and you will easily find the culprit.
--
Dunc, W.CO, 2018 N24D
800W Solar, 10kWh Tesla Coach
Gyrocopter Toad


waydigs
 

You can also sometimes start by pulling fuses and keeping track of which fuse changes the draw.  Easier than disconnecting wires.
Wayne '16 "V" in Ca.

On Fri, Oct 23, 2020 at 2:12 PM Dunc 18ND W.CO <n185ra@...> wrote:
Have a knowledgeable technician measure the residual current draw when everything is "Off". Then start disconnecting wires and note if the draw decreases. Keep a list, and you will easily find the culprit.
--
Dunc, W.CO2018 N24D
800W Solar, 10kWh Tesla Coach
Gyrocopter Toad


Dunc 18ND W.CO
 

Ok, but how do you measure the draw? That's where a knowledgeable tech with good instrumentation is needed. 


On Fri, Oct 23, 2020, 8:32 PM waydigs <diggsmail44@...> wrote:
You can also sometimes start by pulling fuses and keeping track of which fuse changes the draw.  Easier than disconnecting wires.
Wayne '16 "V" in Ca.

On Fri, Oct 23, 2020 at 2:12 PM Dunc 18ND W.CO <n185ra@...> wrote:
Have a knowledgeable technician measure the residual current draw when everything is "Off". Then start disconnecting wires and note if the draw decreases. Keep a list, and you will easily find the culprit.
--
Dunc, W.CO2018 N24D
800W Solar, 10kWh Tesla Coach
Gyrocopter Toad


--
Dunc, W.CO, 2018 N24D
800W Solar, 10kWh Tesla Coach
Gyrocopter Toad


old_b4_my_time
 

Do you have a "clamp meter" that measures "DC amps" (not all clamp meters measure DC amps)?   One can be very handy when tracking down phantom loads of any sort.  I spent around $40 for one several years ago and it is quite dependable in situations like this.   In fact I use it a lot more often than I first imagined.   I see some now on Amazon starting at around that same price that have some relatively high ratings.    Now be sure NOT to use some old clamp meter from a father's tool box, garage sale or antique auction because the old ones (as well as some of the new cheap ones) won't measure amps when the current is direct current (DC).   However if you add one of these (that reads AMPS for DC current) in your tool set, it's easy to just clamp around the battery cable as well as other single cables and see how many DC AMPS are going through that battery cable and that will let you know how significant the load is compared to the assumed battery capacity (only one wire should be running through the clamp-center).   

I don't bother much with battery testers in automotive stores in general because many times the employees don't even know how to operate them.    I use a 100A "dummy load" from Harbor Freight to actually test my batteries but you can calculate the amps you see being drained and determine if that is normal or not.   I don't have any figures and I currently am away from my coach so I can't give you a phantom load target to look for as expected but maybe one of our fellow friendly covid-marooned helpers out there can report their findings.   I think I recall measuring the step's phantom load at around 20mA but I'll have to look through my notes and try to find it if you can't find anyone to supply any data for you to compare.

Now with all this I am assuming you are trying to learn how to diagnose and/or save money.   Of course you can just take it in to a shop or hire it out but with anything like this, the hours of labor go sometimes off the scale so it's best to do all you can and then "give up" before you have to face music like that.   (Or at least that's my philosophy.)
--
Don - 2006 Navion J


lou Thomson
 

Good info..also get a hydrometer and check the battery, they dont last long usually the cells at the ends go first no matter what charger you have including progressive dynamics..good luck   09VJ


Art
 

Chassis battery is sealed.

I think for a low tech test I've sourced another 800cca battery and I've hooked it up and will monitor it's drain.  If it lasts the week then I have a stronger indication that it's the chassis battery and not a new drain.


Art
 

BTW does anybody know what the "normal" parasitic draw would be for an 07H?

It's such a well discussed topic there are too many hits when I search the subject.

Thanks,

Art


Bernie Zephro
 

As a general statement any draw over 35 milliamps is too high. That allows for most electronic modules to keep their memory alive. This is for the chassis section. Draw higher than this will usually kills a battery in a couple of days. This is directly from a major auto manufacturer service manual.

On Tuesday, October 27, 2020, 4:09:56 PM EDT, Art <artwmcewen@...> wrote:


BTW does anybody know what the "normal" parasitic draw would be for an 07H?

It's such a well discussed topic there are too many hits when I search the subject.

Thanks,

Art


waydigs
 

Bernie;
In order to preserve my starting battery when parked for any time longer than a week I pull the disconnect above the throttle.  I have never lost anything in any electronic memory modules;  which in fact amazes me !
Wayne '16 "V" in Ca.


Art
 

I'm not sure if the sprinter van was ever within the typical range even before WGO addes stairs etc to it.


old_b4_my_time
 

On Wed, Oct 28, 2020 at 10:34 AM, Art wrote:
the sprinter van was ever within the typical range
Yes, the concerns abound ... this link I found is mostly arguing over type and style of meter to test with and I didn't read every post but with a good slow scan I didn't see any actual measurement numbers discovered but you can at least find some fellow sympathizers here ...
https://sprinter-source.com/forums/index.php?threads/68759/

One thing that just popped back into my memory is that my parasitic drain escalated once and I found it in my Sony radio the original owner had installed.   There was the power wire of course that easily was switched through the radio switch (house/chassis battery switch) but this little wonder had the infamous "keep alive" wire that the tech had wired directly into the chassis battery.   And either from failed electronics of the radio from perhaps the wide voltage differences through iterations of e.g. the main power feed being primarily sourced from the house battery with the tech's "keep alive" being wired directly into the chassis battery, somehow a 1 amp draw developed over time on the keep alive line.   So I originally disconnected this but then I had to deal with the disco light show from the Sony showing up as reverting to "demo mode" each time I turned on the radio which is what happened with no keep alive connected (and what would be the point of a keep-alive when it always dropped to zero during the time the switch contacts moved from chassis to house battery).  

In fact as an aside it really made me lose disrespect for Sony in their effort to emulate a cheezy Jensen line from the 70's, I guess I was most amazed that in 21st century that disco lighting on the dash was still a selling point for any demographic.   But what can I say - money talks.   So in short the radio might be a culprit.  

All I know that Winnie puts on as an additional load is the step electronics and the only way that came to my own attention is when I installed a power switch to lock the steps in place.   There I found if I bridged a LED across the power disconnect switch I added (with proper resistor which was built into my panel lamp) the parasitic load was enough to keep the LED glowing with the step electronics switched "off".  (Note: I used the LED to light up as a warning lamp indicating the stairs were disconnected and that either exiting the door or driving off would be dangerous if the step logic was disabled.)

So dashboard radio or entertainment dash module is an additional area to check-out.
 
--
Don - 2006 Navion J