Stater battery voltage display question.

[Savage]

I have a Pilote on Ducato base, with Schaudt EBL267 controller, on the display panel the had battery and the starter battery voltages are displayed.
Just fitted a new starter battery and on staring the engine the starter battery display goes from (a normal) 12.2v to 11.0 and flashing.
I've not noticed it before so it may have done this always, but is it correct or is there a fault?
No issued noticed in use, things seem to behave re. charging etc.
Ian

 

[Richard n Ann]

Our car usb socket has an LED voltage display, it often reads 11v with the engine off and it's a new battery. It's just the voltage drop on the wires. Use a multimeter straight into the battery and compare it

 

[autorouter]

Sound quite normal to me. The battery voltage is only a good indicator of the the battery state of charge after it has rested with no load or charging for an hour or more. Right after a huge current burst from powering the starter motor, the voltage drops, and recovers slowly over the next hour or so. Helped by the engine alternator that pushes charge back into the battery as the engine is running, which should take it up to over 14 volts.

 

[Richard n Ann]

Just re read your post, if it's 11v with the engine running there's a fault

 

[Two on Tour]

Just re read your post, if it's 11v with the engine running there's a fault

Have a read again Richard, as it reads to me while the starter motor is engaged and turning that the OP reads the voltage drop, but of course I could be wrong, it had been know.

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[Sandancers]

Our car usb socket has an LED voltage display, it often reads 11v with the engine off and it's a new battery. It's just the voltage drop on the wires. Use a multimeter straight into the battery and compare it

If we had a 1.5v to 2v volts drop on any wire not supplying a big current I'd be worried.

 

[Richard n Ann]

Our car cranking voltage is 9v sometimes it's only 8 always starts perfectly though

 

[Savage]

Just to clarify the starter battery is at 12.2v not running and the display agrees when running it is being changed by the alternator at 14ish volts, checked on a multimeter. It is the display that is showing 11.0v (minimum value) and flashing which I believe to mean less than11v i.e. possibly 0v, when engine is running, as if the control system switches off the starter battery display.
If there is someone out there with a SCHAULD EBL system on their MoHo that can check if this is normal.
Thanks

 

[funflair]

You say "a normal 12.2v" but I would call that low rather than normal.

 

[Savage]

You say "a normal 12.2v" but I would call that low rather than normal.

I'm not concerned over a point or two of standing voltage.
I want to know why, when the engine is running and the starter battery is being charged at14v+, the display is showing less that 11v.
Ian

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[funflair]

I'm not concerned over a point or two of standing voltage.
I want to know why, when the engine is running and the starter battery is being charged at14v+, the display is showing less that 11v.
Ian

Ah OK, have you got a B2B fitted?

 

[Savage]

Yes a b2b is fitted with a single leisure battery and a solar panel.
With engine off and sun shining leisure batt voltage display shows well over 13v and starter batt a bit over 12v

 

[Taran_Las]

I believe (which is what Funflair is alluding to above) that a B2B fools the alternator into charging the cab battery (even when full) by lowering its voltage. This could be what you are witnessing.

 

[pappajohn]

Have a read again Richard, as it reads to me while the starter motor is engaged and turning that the OP reads the voltage drop, but of course I could be wrong, it had been know.

If you're correct, which I suspect you are, it's normal.
The starter may be pulling 250a/350a and will result in a low battery voltage.
My 3L V6 diesel Chrysler has a permenant dash voltage display and when cranking shows less than 10volts with a fully charged battery.

 

[autorouter]

Is your fridge supposed to run from 12V when the engine is running? Does it actually run from 12V when the engine is running?

The starter battery voltage is sensed by the display along the supply wire to the fridge 12V element. That wire is powered by the hookup, solar and by the starter battery through the fridge relay.

Edit: Sorry, the fridge relay is on the far side of the voltage sense connection, so a bad relay won't cause the problem you describe. There should be a 20A fuse near the starter battery that's worth checking.

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[Savage]

Interesting I'll have look in the morning.
Thanks

 

[Adam+Jude]

I'm not concerned over a point or two of standing voltage.
I want to know why, when the engine is running and the starter battery is being charged at14v+, the display is showing less that 11v.
Ian

Fridge?
Do you have a 3way fridge set to auto, cooling while being driven?

 

[Savage]

Main fuse, starter batt to habitation, is ok.
Also to repeat, the display shows correct starter batt voltage, engine off. After starting, not during cranking! the display shows 11v flashing.
As I said at the beginning this maybe normal and I've just not noticed it before, who looks at the control panel when driving!

 

[Savage]

Been out for a drive, stater batt has come up to 12.5v but no change on symptoms above.

 

[Savage]

Fridge?
Do you have a 3way fridge set to auto, cooling while being driven?

Yes, I've been out and checked and the fridge is not working on 12v with motor running.
We are now getting somewhere as clearly the Schaudt controller needs to detect the engine is running to switch the fridge to 12v operation. I'll get the wiring diagram out and look for the associated fuses and relays.
Thanks A+J
Ian

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[PeteH]

Hopefully your access to fuses will not involve removing the driver seat!

Because my Rapido is RHD but the "driver door" is on the left the panel access is blocked by the Gas locker!! If I ever have to acces them I intend to relocate the whole panel

 

[autorouter]

Main fuse, starter batt to habitation, is ok.

There is another fuse to check. The main fuse is probably 50A, and you say it's OK. There is a second fuse near the starter battery, maybe 20A, that is dual-purpose. It supplies power to the fridge 12V element while the engine is running. When the engine is stopped, it is the route to charge the starter battery from either hookup or solar.

In other EBL models there is a separate thin wire with a 2A fuse, acting as a voltage sense for the starter battery. However for this EBL, there is no separate voltage sense wire, and the fridge supply wire described above does this job.

The EBL manual including wiring diagram is available on the Schaudt website.

 

[Savage]

Fuses all ok, but found a burnt cable, see photo. This part of the 12v supply from the starter batt, could be other damage on the circuit board.
The MoHo in now in for some routine work with the dealer so getting them to check it through.
Thanks for all your help.

Ian

 

[Jonny1953]

Ah OK, have you got a B2B fitted?

B2B ??

 

[Two on Tour]

B2B ??

Battery-To-Battery chargers (also commonly know as DC-DC chargers) allow you to charge an auxiliary / leisure battery from your alternator whilst driving. They are installed in-line between the positive terminals of two batteries (one of which is connected to an alternator, typically a starter battery) and offer several benefits when compared with traditional split charge systems that utilise a Voltage Sensitive Relay (VSR) or heavy-duty, alternator-triggered relay.

• Direct alternator charging used in a traditional split charge system with a VSR will only achieve around an 80% charge state. VSRs simply allow charge to pass directly from the alternator to the auxiliary battery whereas Battery-To-Battery chargers take the alternator output and boost or reduce it to provide a stable voltage output according to a multi-stage charging profile. This provides a 100% re-charge for your leisure battery in a controlled way and typically achieves it faster than with direct alternator charging.
• Current flow is limited by the charger's current rating, eliminating potentially damaging high in-rush currents and often allowing the use of smaller connecting cable than with VSR-based split charge systems.
• Using a battery-to-battery charger is the only reliable solution if you intend to re-charge a second battery in a modern vehicle that has an ECU-controlled 'smart' alternator (generally Euro 5/6 compliant engines onward). These have a highly variable voltage output that is often too low to provide a charge or (in the case of regenerative braking systems) so high that it can damage some battery types.

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[cmcardle75]

If you do have a B2B and there is a long run from the starter battery to the B2B and the starter voltage meter is connected to the charger end, you may get significant voltage drop whilst it is bulk charging the leisure battery, as there may be up to 30A flowing along that cable. This won't phase an alternator sensing B2B (but might confuse a voltage sensitive one which may see it as the alternator going offline).

 

[Jonny1953]

Battery-To-Battery chargers (also commonly know as DC-DC chargers) allow you to charge an auxiliary / leisure battery from your alternator whilst driving. They are installed in-line between the positive terminals of two batteries (one of which is connected to an alternator, typically a starter battery) and offer several benefits when compared with traditional split charge systems that utilise a Voltage Sensitive Relay (VSR) or heavy-duty, alternator-triggered relay.

So this is controlled by the Schaudt EBL267 that is fitted to the OPs system and the Schaudt EBL271 on mine.
I have an issue with the fridge not working on 12v with the engine running just like the OP but have not checked voltage outputs to the fridge with the engine running, will check this when I get home, in York at the moment

 

[Savage]

Just to close off this thread, the fault was down to the bad connection causing the burnt cables seen in the photo above. This stopped the D+ circuit from detecting engine running also b2b from charging the vehicle battery.
Terminals on the pcb cleaned and cables cut back new spades fitted, all voltages back to normal and fridge working on 12v.
Thanks for your contributions particularly the ones leading me to check the fridge operation.
Ian