DC-DC charger- which one?

**BigJon** · 13th May 2015, 06:08 PM

Originally Posted by p38arover

Most of the electrics on a P38A are, I believe, Valeo who, unfortunately, haven't released a smoke replenishment kit as yet

When I worked at a dealer we were convinced that Valeo was French for Lucas.

**p38arover** · 13th May 2015, 06:12 PM

Originally Posted by BigJon

When I worked at a dealer we were convinced that Valeo was French for Lucas.

I thought the same - 5 letters.........

**jonesy63** · 13th May 2015, 07:22 PM

Originally Posted by Tombie

Exide AGM are calcium-silver plate

Mike - you missed the point of that post... 2014-on had Exide AGM, and there was a pile of dead ones at the dealer... coincidence? Hmmm

Tombie · 13th May 2015, 11:26 PM

Originally Posted by jonesy63

Mike - you missed the point of that post... 2014-on had Exide AGM, and there was a pile of dead ones at the dealer... coincidence? Hmmm

Possibly - until the TSB...

**mhewitt** · 17th May 2015, 08:54 AM

After ploughing through 21 pages of this, I wonder if some people are overlooking the fundamental law of electricity - it sucks, it doesn't push.

Tombie · 17th May 2015, 09:55 AM

Originally Posted by mhewitt

After ploughing through 21 pages of this, I wonder if some people are overlooking the fundamental law of electricity - it sucks, it doesn't push.

Electron flow would elude to that

**letherm** · 17th May 2015, 09:59 AM

Originally Posted by mhewitt

After ploughing through 21 pages of this, I wonder if some people are overlooking the fundamental law of electricity - it sucks, it doesn't push.

Ah!! That's why it doesn't fall out of powerpoints when the switch is turned on.

**ytt105** · 17th May 2015, 10:05 AM

Originally Posted by letherm

Ah!! That's why it doesn't fall out of powerpoints when the switch is turned on.

Thank you. That's worried me all my life!

**Mungus** · 18th May 2015, 06:58 PM

Food for thought regarding the 12.2V system voltage reported. (other than the TSB previously mentioned)
It appears the 'Battery Monitoring System' will periodically deplete the battery voltage as part of it's self calibration. An extract from the workshop manual.

BMS Control Module Self Calibration

Periodically the BMS control module will initiate a self-calibration routine. To self-calibrate, the battery monitoring system first charges the battery to its full condition.

NOTE:If the vehicle is only driven for short periods the charging process could takea number of days to complete.

Once the battery is fully charged, the BMS control module will discharge the battery to approximately 75% of its full state of charge, but never lower than 12.2 V. The time taken to complete this part of the routine is dependent on the electrical load on the vehicle.

When the second part of the routine has been successfully completed, the BMS control module will return the battery to its optimum level of charge. The optimum level of charge will be between 12.6 V and 15 V, depending on battery condition, temperature and loading.

The BMS control module also monitors the primary battery condition with the engine switched off. If a low voltage condition is detected the BMS control module can request the infotainment system is switched off to protect battery voltage.

**drivesafe** · 20th May 2015, 07:39 AM

Originally Posted by Mungus

BMS Control Module Self Calibration

Periodically the BMS control module will initiate a self-calibration routine. To self-calibrate, the battery monitoring system first charges the battery to its full condition.

NOTE:If the vehicle is only driven for short periods the charging process could takea number of days to complete.

Once the battery is fully charged, the BMS control module will discharge the battery to approximately 75% of its full state of charge, but never lower than 12.2 V. The time taken to complete this part of the routine is dependent on the electrical load on the vehicle.

Hi Mungus and thanks for that info.

I'll lay good money on that process being the route cause of the problems many D4 owners are having, where their D4 runs the battery discharge part of the process and then fails to reset the operating voltage levels of the alternator to the correct running levels required to charge and maintain the cranking battery.

In every case I have been involved with, where there has been a problem with continuos low voltage operation, as soon as the upgrade is carried out, the D4's voltage levels instantly rise to the high 14v levels.

This is a clear indication of a software problem and not a problem with the D4's alternator or anything else in the vehicle.

Also, as this discharge and test procedure is a periodical test, would point to why many of these constant low operating voltages just suddenly happen in vehicles that have otherwise been working fine.

I would suggest any owners of late model D4s should keep an eye on their operating voltage to see if they end up with this problem.

Continual low operating voltages like this will stuff the cranking battery, and while it is not an owner cost while under warranty, it could be very expensive outside warranty.

Originally Posted by Mungus

When the second part of the routine has been successfully completed, the BMS control module will return the battery to its optimum level of charge. The optimum level of charge will be between 12.6 V and 15 V, depending on battery condition, temperature and loading.

This part also clearly indicates, without any question, that under normal operation, the BMS DOES NOT ( SHOULD NOT ) allow the voltage to drop bellow that of a fully charged battery, contrary to some of the claims made earlier in this thread.

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