Inverter and EHU problems as fitted to our Hymer (1 Viewer)

[Vennwood]

I have recently bought a Hymer that has a Sterling Inverter fitted. It is plumbed directly into the main EHU supply via an automatic changeover switch. when on EHU the changeover selects external and when not available it looks for the inverter and if available it selects that. EHU and inverter both use the same 240 v circuit. So far so good. The problem arises when off grid and you switch on the inverter, the control panel thinks it has 240 v supply and powers all the sockets AND the on-board battery charger. So we have the leisure battery supplying the inverter that supplies the battery charger that then charges up the SAME BATTERIES that its getting its power from. To add insult to injury the control panel isn't smart enough to realise this and thinks its charging the batteries and so the AH reading goes UP and eventually says the batteries are fully charged however the battery voltage drops showing the correct level but this isn't accurate enough to give a clear picture of true battery state. Has anyone ever come across this and if so how did you get around it. Clearly it is wasting energy going around in circles and also the control panel is giving a false reading.

 

[Techno]

Switch the charger off

 

[Vennwood]

I'm not sure its that easy to switch off as the charger is integrated into the whole fuse box/transformer unit. I'll have a closer look on the unit

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[Techno]

Presumably you have an electrobloc? so it may only be as simple as unplugging the mains lead into it or if it is fed via a circuit breaker switch that off

 

[Vennwood]

Hi Andy,
It is an Electrobloc EBL 99 and it's located outside in a locker behind the leisure battery. There isn't a separate battery charger switch but there is a power in plug but if I disconnect this I'm not sure what will or will not work. It wouldn't be a long term solution as I would have to go out every time I wanted to hook up so maybe an inline on/off switch just before the plug may be a solution.

 

[Techno]

Unplugging it should only disconnect the charger, all the 12 volt circuits are still fed via the battery. Are you sure there isn't a switch already hidden somewhere?

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[Vennwood]

No other switches - just a battery cut off switch that isolates the batteries. I think you are correct in that it only disconnects the charger so would it solve the problem if I put a switch on the positive 240 v lead to the Electrobloc and located it inside the camper? What do you think?

 

[Techno]

Yes but I cannot imagine that whoever installed the Sterling did not consider this issue.

@Don Quixote

 

[Jaws]

The power lead that goes in to the Electrobloc EBL 99 needs to be disconnected from where ever it is at the moment and connected directly to the EHU feed in.
That way it will only work when on hook up.. simples

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[TheCaller]

With any luck, the EBL99 might be fed via an individual circuit breaker on the Mains Consumer Unit. If not, then follow Jaws' suggestion.

 

[Techno]

The changeover should have been fitted in the radial that does the sockets not the hook up input

 

[TheCaller]

Yes but I cannot imagine that whoever installed the Sterling did not consider this issue.

Hymer + Sterling + auto changeover sounds like an after-market fitment to me.

If you added up all the auto-electricians with M/H experience that you have ever seen recommended on this forum as competent at this level, I doubt you would run out of fingers. I know there will be more, but there are plenty I wouldn't let near it.

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[Techno]

http://www.motorhomefun.co.uk/forum/threads/auto-changeover-relay-for-inverter.55467/

 

[Jaws]

The changeover should have been fitted in the radial that does the sockets not the hook up input

yessss,, shoulda coulda... but we all know 90% of auto electricians who might be quite good with a car, aint got a bloody clue when it comes to motor homes and or mains wiring !

 

[Jaws]

What are the boxes you use Andy ? Project boxes are so damned expensive

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[Vennwood]

Hymer + Sterling + auto changeover sounds like an after-market fitment to me.

If you added up all the auto-electricians with M/H experience that you have ever seen recommended on this forum as competent at this level, I doubt you would run out of fingers. I know there will be more, but there are plenty I wouldn't let near it.

It was an after-market fit by a well known company

Andy's diagram looks to be the answer however not knowing how or even where the autochanger over switch is fitted may take me some time to figure out. It appears (from the Hymer manual) that the Electrobloc was fitted under the passenger seat but as part of the after-market installation of the inverter it has been moved outside into the leisure battery locker and is now behind the battery. It appears that non of the wires are marked

BTW the flexible tubing above is the fuel filler pipe.....

 

[Vennwood]

The power lead that goes in to the Electrobloc EBL 99 needs to be disconnected from where ever it is at the moment and connected directly to the EHU feed in.
That way it will only work when on hook up.. simples

This would work as well but there are so many wires it looks like a bag of knitting gone wrong

 

[Techno]

What are the boxes you use Andy ? Project boxes are so damned expensive

It's beaker from ASDA

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[dpsuk999]

In my Dethleffs I have a normal household consumer unit with RCD's, 4 in total which allow me to isolate the EBL, sockets, air con unit and boiler so when I'm off hookup and using the inverter (which is wired into the consumer unit) I simply switch off the EBL, air con and boiler switches which then just leaves all my 240v sockets in the MH live.

Switching the EBL off just means it's not charging the batteries or powering the fridge (as this would be on gas if wilding)

So do you have a consumer unit somewhere allowing you to isolate different circuits?

David

 

[Vennwood]

Hi David,

I've recently bought the camper and still finding out things. Sadly most of the manuals etc. are missing. I'm kind of swamped with problems right now and the folks that should be able to help me out are on annual summer shut down until next week so its a case of seek and discover. If it ever stops raining I will be able to get out and trace a few things but I haven't found any RCD's yet.

 

[Figaro]

Stay calm and have a whiskey !
I bought my first MH (Hymer) earlier this year and there is so much to learn but it does all become clearer with time.
My next planned investigation is into the leisure batteries, I`ve a vague idea one or more is under the passenger seat but I`ve no idea how to get to it or where the second one might be as I think the seller said there were two ! could be wrong though ???
The LB seem to be working just fine which is why I not bother to investigate so far.
Good luck with sorting your issues, I`m sure the techies on here will help.

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[veevee]

Venwood, it may help it people know which model and year you have as others may have the same. Have you tried the cupboard which houses the water heater or blown air heater for the consumer unit?

Last week I wrote to Hymer Zentrum in Bad Waldesee for an English version of the Hymer operating manual (for the non vehicle parts) quoting the Hymer build/serien number, within a couple of days they sent a pdf with the correct manual for our vehicle. It will give you a good picture of where everything is or at least should be and how it works.

Here's the address - servicecenter@hymer.com

 

[Vennwood]

Thanks for the words of support and help. I have now found a consumer unit in the heater cupboard. There is only one circuit breaker so I guess its either all on or all off but its a start. Nothing marked of course but at least I can start there and trace the wires and label them as I identify what/where each one goes/does. Thanks veevee for the Hymer link I'll email them today.
The model is a B 614 SL reg in 2009 but I think its a 2008 model

 

[Don Quixote]

http://www.motorhomefun.co.uk/forum/threads/auto-changeover-relay-for-inverter.55467/

Works for me ( Thank you Andy ) - OP there must be a fuse feeding the onboard charger - remove it )

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[dpsuk999]

Thanks for the words of support and help. I have now found a consumer unit in the heater cupboard. There is only one circuit breaker so I guess its either all on or all off but its a start. Nothing marked of course but at least I can start there and trace the wires and label them as I identify what/where each one goes/does. Thanks veevee for the Hymer link I'll email them today.
The model is a B 614 SL reg in 2009 but I think its a 2008 model

I had to label my RCD's as none was labelled so had to work each one out. When I installed my inverter I also installed a remote switch on the consumer unit so when I switch it on, it reminds me to switch the other circuits off. I'll post a picture in a bit to show.

Regards David

 

[dpsuk999]

This is my consumer unit

To the right is the remote switch for the inverter and the digital display at the side of that is the battery voltage for the inverter. As people will know with Schaudt systems particularly the EBL220 Schaudt recommend NOT wiring any inverter to the leisure batteries but to install a totally separate battery which just runs the inverter. I have a 220ah battery for the inverter which is charged separately via a CTEK charger when on EHU but when not on EHU I have a Durite 140amp split charge relay to the leisure batteries which are charged via solar/EHU/alternator which when above 12.8v passes charge to the separate inverter battery.

I can isolate the CTEK via a switch so I don't have the continuous cycle of trying to charge batteries from batteries same as the OP has at the moment and isolate the EBL via the consumer unit so just the 240v sockets are on when using the inverter.

Hope that helps.

David

 

[Vennwood]

Hi David,

Many thanks for your help. I have spent the afternoon tracing wires etc. and now with the help of Andy's photos (Techno100) I've now figured out how it was wired and have identified all wires and labeled them. It seems to me the easiest way forward now is to place a switch (with neon) in the feed to the Electrobloc so when on inverter I can isolate the charger and when on EHU I can charge the batteries. I can easily mount the switch inside the camper so I won't need to go out and the Neon will remind me to switch it over.

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[eddie]

Are you sure that the Sterling unit isn't an inverter/charger and the electroblok should have been unplugged?

 

[Techno]

I had to label my RCD's as none was labelled so had to work each one out. When I installed my inverter I also installed a remote switch on the consumer unit so when I switch it on, it reminds me to switch the other circuits off. I'll post a picture in a bit to show.

Regards David

The one on the left is the only RCD David. That protects the whole van at 30ma. The four on the right are double pole circuit breakers that provide the over current protection for each sub circuit.

 

[Mr Mousy]

This may help......

http://www.motorhomefun.co.uk/forum/resources/hymer-instruction-manual.110/

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