Quiescent current

Just a bump to this thread.

Now more people have a vehicle anyone volunteering to run some clamp tests?

Yes, I was just thinking about it.

But I have not yet dealt with the wiring. My car is equipped with two batteries. And with the CTek in between, I don't have an idea yet where to put a sensor that will pick up all the current, not just some of it.

The main problem I have is simply time. Hook up a multimeter is a five minute job, but to figure out where, I would appreciate some advice.

DCPU said:

Despite having the auxiliary battery and Smartpass feeding charge to the main battery, I note that a 96% charged battery after a few days shows just over 80%. So it looks like there's something drawing it down.

On the precautionary principle, I'm now permanently plugged in when parked:
View attachment 7813841

Click to expand...

Can you elaborate on the set up here? Using the NATO plug to charge?

Tomdoc said:

Can you elaborate on the set up here? Using the NATO plug to charge?

Click to expand...

That doesn’t look like the NATO plug that’s attached to but the 13 pin towing electric socket using something like this attachment

Tomdoc said:

Can you elaborate on the set up here? Using the NATO plug to charge?

Click to expand...

Not to take this thread off topic - info is here - post any additional questions there:

emax said:

Yes, I was just thinking about it.

But I have not yet dealt with the wiring. My car is equipped with two batteries. And with the CTek in between, I don't have an idea yet where to put a sensor that will pick up all the current, not just some of it.

The main problem I have is simply time. Hook up a multimeter is a five minute job, but to figure out where, I would appreciate some advice.

Click to expand...

Well my reading of my own setup and this (a 2 seat arrangement where things appear a little clearer):


Is that both the main fuse boxes labelled S and A are only fed from the starter battery; but there's two cables coming off the positive (I'm assuming you'd clamp the cable off the positive terminal?). One goes directly into the 7 way fuse box as the shunt/feed & the other I'm currently uncertain about until I remove more of the trim (but think it has to be to the input terminal of the Smartpass).

So the one I'd clamp at the moment is the one goes directly into the 7 way fuse box. On mine that's the one circled in green.

Thank you for the starting point.

I don't want to disconnect the whole system from the power before I know what will happen: There are still too many quirks in the system for my taste.

However, the measurement can be made with a good clamp meter.

I had the idea to measure at the negative cables. In this case, I would have to jumper them so that there is only one connection to ground left. That shouldn't hurt as long as the starter is not being used. I could put the jumper on first and then disconnect the auxiliary battery negative cable from the body.

I just ordered a clamp meter for my Fluke since it has a data logger and is pretty accurate. I have been looking for a reason to buy this pliers adapter for three years ....

Now I have one.

Measuring current with an inline multimeter (I dont't have proper shunts) is not a good idea. Mine will only hold 10A regularly and 20A for 30 seconds. The Fluke 11A 1000V fuse is 20€ including shipping ...

I'll have a look at it on Sunday ... I hope:

- Tomorrow - at the customer's site.
- Saturday - 70th birthday of one of my oldest friends.
- Monday - starting a new project with a customer from Berlin.
- Tuesday, Wednesday, Thursday ... I better not look at my Filofax ...

Tazzie was right: Retirement is just a concept.

Get round to it when you can ~ the results will be interesting and worth waiting for.

DCPU said:

Despite having the auxiliary battery and Smartpass feeding charge to the main battery, I note that a 96% charged battery after a few days shows just over 80%. So it looks like there's something drawing it down.

On the precautionary principle, I'm now permanently plugged in when parked:
View attachment 7813841

Click to expand...

Hi @DCPU. In preparation for the imminent arrival of my Grenadier, I purchased a CTEK MXS7.0 and an adaptor to plug it into the 13 pin socket. The part I purchased was BRITPART 0049029 13 PIN CHARGING ADAPTOR DA1410, which looks similar to the adaptor you are using.

I do not have any knowledge of 13 pin wiring, but I was surprised to note that when I did some continuity testing using my multimeter, the adaptor appears to have the negative wired to pin 3 and the positive wired to pin 9. I was expecting the negative to be wired to pin 13. Is that a problem?

I also note that when I connect the adaptor to my CTEK, the red error light illuminates on all modes other than SUPPLY. Again, is this a problem?

Any advice would be much appreciated.

Michael H. said:

I do not have any knowledge of 13 pin wiring, but I was surprised to note that when I did some continuity testing using my multimeter, the adaptor appears to have the negative wired to pin 3 and the positive wired to pin 9. I was expecting the negative to be wired to pin 13. Is that a problem?

I also note that when I connect the adaptor to my CTEK, the red error light illuminates on all modes other than SUPPLY. Again, is this a problem?

Click to expand...

From memory 13 is a 2nd auxiliary earth. see pic.
The Ctek needs to be connected to a battery to assess a suitable charging regime so will error when it can't sense the battery. Supply mode doesn't need a battery, it just supplies a constant 13.6 or 13.8V to power any suitable 12V device you connect. It can also be used via a battery to supply a load. I use a 30A Meanwell DC 13.6V power supply to run the van 12V stuff when plugged into shore power, saves cycling the batteries down overnight. It can also run the 20A DC2DC charger to charge the batteries when on shore power, saves having a separate battery charger onboard.

Michael H. said:

Hi @DCPU. In preparation for the imminent arrival of my Grenadier, I purchased a CTEK MXS7.0 and an adaptor to plug it into the 13 pin socket. The part I purchased was BRITPART 0049029 13 PIN CHARGING ADAPTOR DA1410, which looks similar to the adaptor you are using.

I do not have any knowledge of 13 pin wiring, but I was surprised to note that when I did some continuity testing using my multimeter, the adaptor appears to have the negative wired to pin 3 and the positive wired to pin 9. I was expecting the negative to be wired to pin 13. Is that a problem?

I also note that when I connect the adaptor to my CTEK, the red error light illuminates on all modes other than SUPPLY. Again, is this a problem?

Any advice would be much appreciated.

Click to expand...

MarkH said:

From memory 13 is a 2nd auxiliary earth. see pic.
The Ctek needs to be connected to a battery to assess a suitable charging regime so will error when it can't sense the battery. Supply mode doesn't need a battery, it just supplies a constant 13.6 or 13.8V to power any suitable 12V device you connect. It can also be used via a battery to supply a load. I use a 30A Meanwell DC 13.6V power supply to run the van 12V stuff when plugged into shore power, saves cycling the batteries down overnight. It can also run the 20A DC2DC charger to charge the batteries when on shore power, saves having a separate battery charger onboard.

Click to expand...

Thanks for the reply, @MarkH. Some of the diagrams I saw labelled pin 13 as “earth for pin 9” and I was wondering why there is more than one earth pin.

Regarding the error light, I was confused because if I turn the charger on and just plug in the extension cable to the output, there is no error, but if I plug the adaptor in, I get an error.

Michael H. said:

Thanks for the reply, @MarkH. Some of the diagrams I saw labelled pin 13 as “earth for pin 9” and I was wondering why there is more than one earth pin.

Regarding the error light, I was confused because if I turn the charger on and just plug in the extension cable to the output, there is no error, but if I plug the adaptor in, I get an error.

Click to expand...

They will have wired it to 3 instead of 13 because some may not have wired all pins. (ie Grenadier) 3 will be wired because it is the earth for vehicle/trailer lighting. Since you can't drive off when charging no issue. The Grenadier for what i can gather hasn't pins 10-13 connected so it is wired with "foresight"

Eric said:

They will have wired it to 3 instead of 13 because some may not have wired all pins. (ie Grenadier) 3 will be wired because it is the earth for vehicle/trailer lighting. Since you can't drive off when charging no issue. The Grenadier for what i can gather hasn't pins 10-13 connected so it is wired with "foresight"

Click to expand...

Thank you for the explanation @Eric.

Michael H. said:

Thank you for the explanation @Eric.

Click to expand...

What’s the deal with charging via the towing electric socket. Why not connect the CTEK to the jump start post under the bonnet the CTEK charger is then kept safe and dry when the bonnet is shut

Logsplitter said:

What’s the deal with charging via the towing electric socket. Why not connect the CTEK to the jump start post under the bonnet the CTEK charger is then kept safe and dry when the bonnet is shut View attachment 7818599

Click to expand...

I'll have the charger set up in my garage, and it will be convenient just to plug into the towing socket when required. I agree it's not necessary, but I just want to be like @DCPU.

Michael H. said:

Hi @DCPU. In preparation for the imminent arrival of my Grenadier, I purchased a CTEK MXS7.0 and an adaptor to plug it into the 13 pin socket. The part I purchased was BRITPART 0049029 13 PIN CHARGING ADAPTOR DA1410, which looks similar to the adaptor you are using.

I do not have any knowledge of 13 pin wiring, but I was surprised to note that when I did some continuity testing using my multimeter, the adaptor appears to have the negative wired to pin 3 and the positive wired to pin 9. I was expecting the negative to be wired to pin 13. Is that a problem?

I also note that when I connect the adaptor to my CTEK, the red error light illuminates on all modes other than SUPPLY. Again, is this a problem?

Any advice would be much appreciated.

Click to expand...

Sorry - wasn't ignoring you - I just needed to get to this machine with all the relevant info on to check my answer before replying.

Also, conscious this it taking the OP's thread off topic, so I'll answer over here:

After starting a new project (professionally) on July 3, today was the first evening I was able to look at the battery and Ctek cables, as well as the ammeter.

The latter is a clamp that I can connect to my DMM, and it seems to work fine.

I had first purchased a Fluke i1010 which was not suitable for my needs. I don't need to measure 1000 amps and so it lacked the resolution for the lower ranges.

Now I have the much cheaper Hantek CC650, which allows you to switch between 65 and 650 amps, which makes much more sense for my purposes (the Fluke cost around 600€, while the Hantek is a bargain at 90€). So I returned the Fluke. Precision difference between the Hantek and the Fluke is not an issue here as I don't care about 10 mA more or less. And the errors are more due to the setup (cable routing and noise) than to the precision. The noise alone easily causes deviations of 100 mA. But in an Excel sheet (which I can hopefully deliver) anybody can average out the curve.

Another advantage of the Hantek is the coax plug, which I can plug directly into my oscilloscope (which I won't do for the Grenadier, as it's quite a mess to run 230V to the car and stow the oscilloscope safely). Instead, I'll use my Fluke DMM to record the measurements.

In the video below , which features the Hantek clamp meter, the man uses his Picoscope to visualize the data. This is very responsive - unlike my Fluke which only stores one value per second. However, I think we are not interested in millisecond accuracy or small peaks, but in overall consumption and behavior over perhaps an hour or two after shutdown. However, if needed, I can install my oscilloscope in the car and examine the peaks as well, but I would like to avoid that.

View: https://www.youtube.com/watch?v=PrxXLuD5ic4


I just took a look under the rear seats and now have some questions.

The CTEK 120S has some in and out sockets:


Upper left is the Generator input.
Upper right is the output for what they call the "service battery".
Lower right is the output for the load(s).

I am wondering why the "load" output is in the Grenadier not connected at all. As far as I understand the manual, one of the advantages of the 120S is that it can manage power distribution so that the loads are primarily fed by the generator and the batteries are conserved to the maximum. But in the installed configuration this feature is not used at all.

Now to the battery cabling.

I am thinking about how to measure the quiescent current. If I connect the clamp to only one battery (the main one, I assume), I will never know what the currents are on the other.

So does anyone know how and if the CTEK is even drawing current from the second battery when the engine is off?

If not, the measurement setup is simple. But if there is power coming from the second battery as well, it's a bit of a hassle. In that case, I'd have to reroute at least one positive or negative (minus, I guess) connection from the second battery, which isn't much fun.

Anyone have any ideas?
Or maybe even a wiring diagram?

I do btw. not agree to his conclusion concerning the drifting problem in the video: It's a good idea to let the clamp settle for a while and then, after the measurement has been recorded, write down the final drift and overlay a linear drifting curve over the numbers. This should yield reasonably usable data for our purposes.

Interesting thread this. I think my old defender was 200 MA when new, and with all the gumpf installed was 400. Doesn't sound much but over days and weeks if you don't drive that really adds up.