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rivy asked

Problem Victron 12v 30A DC-DC on a Peugeot Boxer with smart alternator

Hoping someone can help here, perhaps having had the same issue with the same or similar vehicle.

We installed a Victron 12v 30A DC-DC non-isolated charger into a motorhome built on a 2022 Peugeot Boxer with smart alternator.

We’ve installed many DC-DC chargers, quite a few on vehicles with smart alternators. In some cases we have had to tweak things but always got it working.

In this particular case the DC-DC charger seems to not like the base vehicle at all.

Before we give up on this particular base vehicle and charger combination just checking to see if someone faced this issue and found a solution.


The Problem - Low Input Voltage causes lock-out

After starting the vehicle the input voltage builds up in the usual way and the charger kicks in with around 30A (usually max 13v).

After a short time of running the charger detects a low input voltage, sometimes right down to 7v.

Then the input voltage lock-out kicks in and the charger stops charging (as expected).

The input voltage comes back up and the process is repeated again and again.

The charger is working at around half the time.


The Setup

Victron 12v-12v 30A DC-DC non-isolated charger

460AH 12v LiFePO4 battery

16mm² (5awg) cables used throughout

Pos 1.2m (4ft) from starter battery pos terminal to the DC-DC.

Pos 0.6m (2ft) from DC-DC to the LiFePO4 battery.

Neg 1m (3ft) from DC-DC to the chassis (good solid connection) and LiFePO4 battery

D+ cable connected to the green terminal block on DC-DC (Right “H” connector)


We’ve tried

With and without using “Engine shutdown detection” (don’t really need it because we have D+).

When using Engine shutdown detection we’ve tried default (smart alternator) plus a whole bunch of variations

Lowered the input voltage lockout right down to 12v with 12.5v reset

Different 30A charger (same model) just in case of fault (same result)

Lower amp 18A Victron DC-DC charger (same result)

Different cables (same result)

Orion DC-DC Converters not smartorion dc-dc
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2 Answers
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rvicev answered ·

No answer, but a bit surprised / worried about the 7V.

Vehicles with smart alternators (Euro 5/6) can have low(er) voltages (much lower than the 14V would typically see with euro 4 and older systems). But at 7V you would likely face all sorts of problems (head lights dipping, heating system fan, etc). Did you measure this voltage drop behaviour separately (that is, separate from what the Orion reports), e.g. direct on the car battery - alternator link ?

My Renault Kangoo (euro 5) doesn´t go nearly as low (as far as I know). It detects low voltages and then may refuse to activate the start/stop system (e.g. when engine cold and very low outside temperature, in combination with head lights on), but even then it still sits around 12V. There must be some serious voltage drop somewhere (clearly can´t be the 16 mm2 cable, but perhaps connectors ?).

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rivy avatar image rivy commented ·
We did measure significant voltage drop over the 16mm cable running from starter battery to DC-DC. So we tried a different cable, even shorter - no difference.

Mostly the drop is down to around 10-11v, only once or twice even less.

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pwfarnell answered ·

The cycling suggests an alternator or voltage drop problem between the alternator and the starter battery as you have tried 3 different DC to DC with the same result. If the alternator works the vans heavy load items OK then this suggests that alternator to battery wiring may have a high voltage drop or some other issue like this as you should never see 7V. Do some trouble shooting on alternator and starter battery voltages.

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rivy avatar image rivy commented ·
I have suspected that either there is a wiring issue or an alternator issue, but was also wondering about this particular base vehicle.
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