Battery dies in two weeks - how much current draw is normal?

chrispitude · **Posted:** Sat Apr 12, 2008 2:58 pm

Hi folks,

Now that nice weather is here and the diesel prices are still high, my wife is no longer driving the CRD to work on a daily basis. We have found that the battery dies in two weeks if the vehicle is not driven. This does not seem right to me.

The steady-state current draw from the battery is 238mA. This webpage says that the maximum current draw for a vehicle should be 25MA. I opened the underhood fusebox and began pulling fuses. The heavy hitters were fuses 3 and 7, both of which are marked "JB POWER". With both 3 and 7 pulled, the current draw is zero.

Next I tried pulling the fuses in the driver's door area. The only fuse that registered was the one that feeds the radio and BCM. I think the current draw dropped to 190mA with that fuse pulled, but I would need to go reconfirm.

The next thing I'd like to do is repeat the experiment with spring clips holding the DMM between the battery terminal and the hot terminal connector, so I can leave it that way for some time and see if the car goes into a lower current sleep mode. Beyond this, does anyone have any advice for troubleshooting this?

Thanks!

- Chris

litton · **Posted:** Sat Apr 12, 2008 4:50 pm

That does not seem normal. I have left mine for over 6 weeks and it still started just like normal. It was not locked so if the alarm system draws power, I would not have see it.

05infernoCRDL · **Posted:** Sat Apr 12, 2008 5:41 pm

chris,

for S&G what battery is in it?

Joe Romas · **Posted:** Sat Apr 12, 2008 6:04 pm

Back in June of 06 there was a flash for the body control module that turned something off to keep it from running down the battery. F45 maybe

chrispitude · **Posted:** Sun Apr 13, 2008 4:55 pm

Hi 05infernoCRDL,

It's the factory battery. I'd like to upgrade to a larger capacity battery, but there's not much point until this is fixed.

Joe, thanks for the pointer. I will ask about this next time I am at the dealer.

I think I made some progress today. I used spring-loaded plastic clamps to hold the ammeter probes in place. I decided to leave the ammeter connected for awhile to see what the current draw is once the various computers go to sleep. With the EVIC computed connected, the current draw is 228mA after 30 minutes. With the EVIC computer disconnected (but the lights and sunroof still connected), the current draw is 9mA. I have my man.

Now, why is it doing that? The EVIC computer has a switched 12V and an always-on 12V. I followed Uffe's lead and wired both to the switched power in the OBD-II connector. The EVIC computer sits on the PCI data bus with other bus drivers. I suspect what is happening is that since the EVIC is not powered when the key is out, the whole EVIC is essentially dead and it must become a floating load on the bus. I suspect if the always-on power were powered, it would consume just enough current to know that it's supposed to pull its bus drivers back to the high impedance state.

So, the next step is to find a good source of always-on power and rewire the EVIC feeds properly. Then, I'll perform some more current measurements and report back. If anyone has an easy under-dash source of always-on power, I'd be interested to know where it is.

- Chris

dieseldawg · **Posted:** Sun Apr 13, 2008 7:27 pm

To test your theory, the cigarette/power outlet is always on.

Uffe · **Posted:** Mon Apr 14, 2008 4:15 am

chrispitude wrote:

Hi 05infernoCRDL,

It's the factory battery. I'd like to upgrade to a larger capacity battery, but there's not much point until this is fixed.

Joe, thanks for the pointer. I will ask about this next time I am at the dealer.

I think I made some progress today. I used spring-loaded plastic clamps to hold the ammeter probes in place. I decided to leave the ammeter connected for awhile to see what the current draw is once the various computers go to sleep. With the EVIC computed connected, the current draw is 228mA after 30 minutes. With the EVIC computer disconnected (but the lights and sunroof still connected), the current draw is 9mA. I have my man.

Now, why is it doing that? The EVIC computer has a switched 12V and an always-on 12V. I followed Uffe's lead and wired both to the switched power in the OBD-II connector. The EVIC computer sits on the PCI data bus with other bus drivers. I suspect what is happening is that since the EVIC is not powered when the key is out, the whole EVIC is essentially dead and it must become a floating load on the bus. I suspect if the always-on power were powered, it would consume just enough current to know that it's supposed to pull its bus drivers back to the high impedance state.

So, the next step is to find a good source of always-on power and rewire the EVIC feeds properly. Then, I'll perform some more current measurements and report back. If anyone has an easy under-dash source of always-on power, I'd be interested to know where it is.

- Chris

Good research. I'm in for listening to new advice on my setup, most definatly

However, don't get your hopes up too much. If you follow the original plan instead of mine, you will need to hook the EVIC up to an output switched with ignition, which is what B(+) on the OBDII port is. Now, maybe they wrote something wrong in the original mod guide, so I am all ears to find out what you discover.

Actually I think I will go and do some measuring myself so we can compare values of current draw when the KJ is shut down. Since we both have the same setup on the EVICs we might get identical readings (well, just maybe, it's worth a shot I say).

chrispitude · **Posted:** Mon Apr 14, 2008 7:01 am

Uffe wrote:

Good research. I'm in for listening to new advice on my setup, most definatly

However, don't get your hopes up too much. If you follow the original plan instead of mine, you will need to hook the EVIC up to an output switched with ignition, which is what B(+) on the OBDII port is. Now, maybe they wrote something wrong in the original mod guide, so I am all ears to find out what you discover.

Actually I think I will go and do some measuring myself so we can compare values of current draw when the KJ is shut down. Since we both have the same setup on the EVICs we might get identical readings (well, just maybe, it's worth a shot I say).

Hi Uffe,

If you could do that, it would be a big help. I bought the EVIC off Ebay, so it has an unknown past. I have certainly considered that maybe this was why it was being sold... I've also seen that many others have hooked up to switched power, and I've not seen this reported.

If you could spring-clip your ammeter into the battery circuit and let me know what the current measures after 20-30 minutes, that would be great. Thanks!

- Chris

Uffe · **Posted:** Mon Apr 14, 2008 8:36 am

chrispitude wrote:

Hi Uffe,

If you could do that, it would be a big help. I bought the EVIC off Ebay, so it has an unknown past. I have certainly considered that maybe this was why it was being sold... I've also seen that many others have hooked up to switched power, and I've not seen this reported.

If you could spring-clip your ammeter into the battery circuit and let me know what the current measures after 20-30 minutes, that would be great. Thanks!

- Chris

No problem, I just stole what I need for the test from work, will post back what I find. I think this is now also a good time to do an oil check on the car if I got to wait 30 minutes for this reading

EDIT

My plan was to measure current when the vehicle has been locked remotely and waited until it dropped (took about 30 seconds or so, by the feel of it). Procedure was to open the bonnet, put clamps between negative battery terminal and ammeter and then lock the vehicle with remote (doorlocks draw about 10-12A).

I tried with the EVIC connected, and with the data-plug unplugged on the EVIC. No other changes were made.

Work done:

With EVIC:

Without EVIC:

Uffe · **Posted:** Mon Apr 14, 2008 10:17 am

chrispitude wrote:

So, the next step is to find a good source of always-on power and rewire the EVIC feeds properly. Then, I'll perform some more current measurements and report back. If anyone has an easy under-dash source of always-on power, I'd be interested to know where it is.

- Chris

I know where that is. Pry away the little bezel below the dash to the left of the steering wheel (the one diagonally opposite to the light height adjusting switch). You will find a plug with 8 holes but only 7 connectors.

Ah sod it, here's a pic:

The plug is shaped as a follows:

Code:

______________________________
|                             |
|  2    3   4   5   6      7  |
|    ___________________      |
|    |                  |     |
|  1 |                  |  X  |
|____|                  |__ __|

X is empty, no connector there.

1) 12v always on
2) inserted key on
3) ignition on
4) light controlled on
5) ??
6) ground

chrispitude · **Posted:** Mon Apr 14, 2008 10:35 am

Hi Uffe,

Nice testing setup! It looks about the same as mine.

I got that same first current drop (very roughly ~50-100mA drop or so). But when I left it alone for 20-30mins without the EVIC plugged in, it went down to 9mA. With the EVIC plugged in, it never experiences that second drop. I think there is a computer somewhere that takes awhile to go into its sleep mode.

Hmm, I wonder if the BCM doesn't go to sleep when the EVIC floats? Maybe that's the one that takes longer to fall asleep in the first scenario?

Regarding why no one else has come across this, it's also possible that most EVIC upgraders are also CRD enthusiasts, and don't let their vehicle sit for a couple weeks like we have. I sure hope diesel prices come back down!

- Chris

danoid · **Posted:** Mon Apr 14, 2008 11:46 am

Uffe wrote:

The plug is shaped as a follows:

Code:

______________________________
|                             |
|  2    3   4   5   6      7  |
|    ___________________      |
|    |                  |     |
|  1 |                  |  X  |
|____|                  |__ __|

X is empty, no connector there.

1) 12v always on
2) inserted key on
3) ignition on
4) light controlled on
5) ??
6) ground

I think that's the connector for the off-road light bar. Not available in the States with a CRD. Might have been a 'give away' plug for export vehicles.

Uffe · **Posted:** Mon Apr 14, 2008 12:43 pm

danoid wrote:

I think that's the connector for the off-road light bar. Not available in the States with a CRD. Might have been a 'give away' plug for export vehicles.

Oh darn - another difference between my euro KJ and those US KJs

blacksmoke · **Posted:** Mon Apr 14, 2008 10:28 pm

Just adding my 2cents: I had the same problem until I realized I inverted the always on with the Ignition... the full EVIC core was powered all the time, but the display was coming on and off the normal way. Took me a couple of dead battery cycle to figure it out.

Uffe · **Posted:** Tue Apr 15, 2008 2:23 am

blacksmoke wrote:

Just adding my 2cents: I had the same problem until I realized I inverted the always on with the Ignition... the full EVIC core was powered all the time, but the display was coming on and off the normal way. Took me a couple of dead battery cycle to figure it out.

Could you do us a favor and measure your current draw for us?

Both of us have got no "always on" power to our EVICs. We installed both power wires into an output which follows the ignition on position. All we got it connected to which may be always on is the PCI bus.

blacksmoke · **Posted:** Tue Apr 15, 2008 10:55 pm

OK, disconnected and plugged the ammeter: reading started at 1A (things being initialized I suppose) then stabilized quickly at 120ma. Let it there for 20min and came back to check: it was then reading 25ma.
In my setup, one wire of the EVIC is connected to the Ignition, the other one to the always on. I got those 2 signals from the radio but don't remember where because I use an ISO connector with my hands-free. The third of course goes to the PCI and fourth is ground.

I'm guessing there's some circuitry that sense the first 2 wires and let the EVIC "sleep" for real, if you only have PCI connected you may be drawing more current. It will work the same, but will draw current all the time. Might be wrong, but I know my problem stopped when I used the always on the way it was "designed".
Hope this helps

Uffe · **Posted:** Wed Apr 16, 2008 3:10 am

Good info. Now tell us which wire you connected to always on, I can't remember!

chrispitude · **Posted:** Wed Apr 16, 2008 7:10 am

blacksmoke wrote:

ome circuitry that sense the first 2 wires and let the EVIC "sleep" for real, if you only have PCI connected you may be drawing more current. It will work the same, but will draw current all the time. Might be wrong, but I know my problem stopped when I used the always on the way it was "designed".
Hope this helps

Fantastic, thank you blacksmoke! I agree with your assessment. I think having the EVIC completely unpowered causes it to keep the other components on the PCI bus from sleeping.

- Chris

blacksmoke · **Posted:** Wed Apr 16, 2008 11:42 pm

I used the diagram here http://www.wjjeeps.com/evic_wiring.jpg
Good luck!

Uffe · **Posted:** Thu Apr 17, 2008 3:46 am

Okay I must have misunderstood the "Fused(B+)" - because the other wire is the ignition switched output. Does Fused (B+) mean always on? There is a Fused B(+) on the ODBII connector which I used for my installation...

Battery dies in two weeks - how much current draw is normal?

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