Electrical shutdown

[Dfc]

Just wondering if anyone can shed any light on the following intermittent issue:
This only happens when travelling. Driving along and there will be an audible click and all the hab side electrics go off. Usually noticeable as the radio and sat nav switch off as well. Also includes the fridge. All pre set radio stations lost as well as Truma timer settings and electric step. We have found that by switching on the HAB electrics on the control panel above the door switches everything back on again.
The van is a Burstner 690g on a Fiat chassis.

 

[Diabalo]

Normally the Hab electrics should be off while the engine is running, apart from the fridge as that should run from alternator.

 

[Dfc]

Normally the Hab electrics should be off while the engine is running, apart from the fridge as that should run from alternator.

We always switch off before travelling. Some how switching them on again seems to re reset the system ie Sat nav and radio work again as does the fridge step etc.

 

[Lenny HB]

Normally the Hab electrics should be off while the engine is running, apart from the fridge as that should run from alternator.

That only happens on Brit vans never had a van do that.

 

[Lenny HB]

I wonder if there is a problem with the alternator and electrics are shutting down due to too high voltage

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[autorouter]

What make/model of 12V distribution/fusebox is fitted in your Burstner? Is it a Schaudt Electroblock, if so what model number? It's not just the standard power switch-off when the engine starts, because the fridge controls, Truma heater controls and electric step should stay powered all the time, even when the habitation electrics are switched off at the panel.

 

[Dfc]

What make/model of 12V distribution/fusebox is fitted in your Burstner? Is it a Schaudt Electroblock, if so what model number? It's not just the standard power switch-off when the engine starts, because the fridge controls, Truma heater controls and electric step should stay powered all the time, even when the habitation electrics are switched off at the panel.

Hi yes it’s a Shaudt EBL 119.

 

[Pausim]

Normally the Hab electrics should be off while the engine is running, apart from the fridge as that should run from alternator.

That seems to be a Brit hangover that made some sense in respect of Caravans. I blame the NCC for not working out that motorhomes are different. I also suspect that some manufacturers cling to it because they can then use cheaper electrical/electronic components that are not certified to the standard required for use on a moving vehicle.

 

[autorouter]

Driving along and there will be an audible click and all the hab side electrics go off.

If there's an audible click then that sounds like a relay (or maybe two) switching off. There's two main power relays in the EBL, one for the permanently on devices like the fridge control, step, heater control etc. The other for the lights, pump and all the other things that switch off when you turn off the '12V' switch on the control panel.

Also these two power relays are latching relays, not standard relays. That means they stay in the position they have moved to if the power fails. Unlike most relays that return to a set position with a spring if the power fails.

So the fact that you hear an audible click means that it's not just a power failure, something is actively switching those relays off.There are various possibilities, some more likely than others.

For example, the leisure battery voltage could be very low, or very high, causing the EBL to switch itself off. Or there is a pair of sensor wires that accurately measure the leisure battery voltage. There's a 2A fuse on this wire, located next to the big 50A fuse near the leisure battery. If that fuse connection is bad/oxidised/corroded then the EBL just shuts down. I'm sure there are other possibilities too.

 

[Dfc]

If there's an audible click then that sounds like a relay (or maybe two) switching off. There's two main power relays in the EBL, one for the permanently on devices like the fridge control, step, heater control etc. The other for the lights, pump and all the other things that switch off when you turn off the '12V' switch on the control panel.

Also these two power relays are latching relays, not standard relays. That means they stay in the position they have moved to if the power fails. Unlike most relays that return to a set position with a spring if the power fails.

So the fact that you hear an audible click means that it's not just a power failure, something is actively switching those relays off.There are various possibilities, some more likely than others.

For example, the leisure battery voltage could be very low, or very high, causing the EBL to switch itself off. Or there is a pair of sensor wires that accurately measure the leisure battery voltage. There-s a 2A fuse on this wire, located next to the big 50A fuse near the leisure battery. If that fuse connection is bad/oxidised/corroded then the EBL just shuts down. I'm sure there are other possibilities too.

Thanks for the reply.
I’m ok with mechanical stuff but not so with the electrical side of things.
I will check the fuse as you suggest. As I say it’s intermittent so doesn’t happen on every journey and when it does it can be an hour or so into the journey. The leisure battery appears fine and holds a charge ok.