# Starter Battery Charging from Electroblock



## Borisd0 (Jan 3, 2006)

Hymer B574 2002.

For the second time in recent years the starter battery was not being float charged when on hook up.

There are 3 fuses in the engine compartment near the battery.
From reading the diagrams (in German);

1. A 50amp fuse from the Starter battery feeds into the ELB.
2. A 20amp (30 I found in mine) feeds the fridge from the Starter battery when the alternator voltage operates a relay in the ELB. In other words if the engine is not running the fridge does not flatten the leisure battery. 
3. A 2 amp fuse feeds volts from the alternator to the ELB to operate the relay mentioned above. 

This is my thinking on the fuses. 

Looking at the diagram, the 20 amp fuse is also capable of feeding a current to the starter battery as a float charge.

My fault was the 20(30) amp fuse was corroded in its carrier and therefore there was no float charge.

The panel volt meter(reading engine batt) with no hook up was zero with no back light. Having re-seated the fuse, the volts and back light are ok. 

The ELB diagram says, my translation, " The refrigerator cables are separate to all other cables going to the battery".

So far so good, now the QUESTIONS.
Does the trickle charger use the 20a fuse circuit?

Block 12F 3 Pin 8 on the ELB 99 D is shown as going to the Starter Battery. Is this the charging circuit?
Does anyone have a wiring diagram that would show where this circuit goes after leaving the ELB?

Any information gratefully received.


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## pippin (Nov 15, 2007)

I will get back to you shortly on this, as soon as I dig out my well annotated cct dgrms from the MH.


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## pippin (Nov 15, 2007)

OK - diagrams to hand.

12F-Block 3 pin 8 is the connection to to the control panel simply to measure the engine battery volts, no other function.

As you correctly surmise, the engine battery trickle charge path IS via 5F-Block 2 pin 1 and the 20A fuse to "+ Starterbatterie fur Kuhlschrank".


From memory on our 2007 Hymer there is a subsidiary fuse assembly with the 20A starterbatt fur kuhlschrank (fridge) fuse (as above) and the main 50A starterbatt fuse.
That's where the two feeds are joined.

That 50A fuse connects to the choc block at the REAR of the EBL.

Just beware that Hymer use a RED wire to the engine batt +ve and a BLACK wire to the habitation/wohnraum batt +ve.

The -ve (chassis) connections for both are BROWN wires.

To confuse even further, most of the 12V wiring from the EBL to the various ccts in the MH are BROWN -ve and BLUE +ve!

Our MK7 Transit base has dedicated +12V engine "on" which is not derived from the alternator control.

Tucked away by the EBL is a module DP02 which is an amplifier for the ignition on signal so it can drive the various other modules.
EBL99 fridge relay, step switch control EMS02 and warning buzzer (& poss other stuff)

The DP02 interposes between 5F-Block2 and some of the stuff mentioned above, like your troublesome 20A fuse.

By the way, well done on your diagnosis!

If I can help further just ask.


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## Borisd0 (Jan 3, 2006)

Thanks Pippin for your quick response.

When I replaced the over hob fluorescent tube with a LED strip I noticed the unusual wire colour coding that Hymer use.

A bit more detail on my problem. The 20 amp fuse has developed a poor contact on one spade and does not blow but becomes open circuit. Sufficient heat was generated to deform the fuse but insufficient current drawn to blow it. I may have to install a new fuse carrier if I fail to clean it up. I thought a smear of petroleum jelly on the fuse may help, what do you think?

Thanks again.


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## pippin (Nov 15, 2007)

I would definitely replace the fuse carrier, from memory ours sort of mates with the 50A one adjacent.

As for the petroleum jelly idea - no idea!

Unfortunately it ain't easy to get at our gubbins as it involves removing the rotating base and entire passenger cab seat.


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## SueandRoger (Apr 14, 2008)

Borisd0 said:


> Thanks Pippin for your quick response.
> 
> When I replaced the over hob fluorescent tube with a LED strip I noticed the unusual wire colour coding that Hymer use.


Hi Borisd0

I was under the impression that for some reason the fluorescent tubes in A Hymer could not be replaced with an LED so could you please tell me where you got it from?


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## Borisd0 (Jan 3, 2006)

Hi Sue & Roger.

The type of LED I fitted are as the URL below.

http://www.ledhut.co.uk/bulb-room/k...er-warm-white-best-price-on-the-internet.html

The 2.5 meter strip has connecting wires at each end so can be cut into 2 pieces. I cut mine into four (3 for under kitchen cabinets and 1 for the Hymer), the middle cuts need to have connecting wires soldered to the strip, a simple job.

The brightness exceeds the old florescent tube. I ditched all the electronics needed for the tube and made a connection directly to the switch. I took the whole unit down to give it a clean and clean up the fan etc. The strip is self adhesive so the contact area need to be completely de-greased.

You need to check the polarity of the 12v supply, from memory the colour coding was not what I was expecting, I think brown was -ve.

Good luck.


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## SueandRoger (Apr 14, 2008)

Thanks Borisd0, that is most helpful and I will add it to my list of jobs to be done on the Hymer over the next few weeks.


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## Hymie (May 9, 2005)

*Fuse Holder*

Use a little ACF-50 or corrosion block on the corroded fuse holder.
Happy Tra vels


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## Hymie (May 9, 2005)

*Fuse Holder*

Use a little ACF-50 or corrosion block on the corroded fuse holder.
Happy Tra vels


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## Borisd0 (Jan 3, 2006)

Re ACF-50.

I'll give a go .

Thanks,


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## SueandRoger (Apr 14, 2008)

Thanks Borisd0, the improvement is 'Brilliant' if you excuse the pun!
I opted for Cool White and used a 120cm length across the full width of the light fitting over the kitchen; the 'Head Chef' is most impressed! I also replaced the fluorescent tubes above the long near side bench and the reading light over the bed with equally excellent results.
Top Tip thank you


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## garethjjones (May 1, 2005)

Hi, Hope someone can help me.

having trouble with the vehicle battery, so it's on a ctek charger at the moment. I removed the fuses at the rear of the compartment before hooking it up - as I've been previously advised so I don't blow anything in the EBL.

I though I had an existing picture of where each fuse went - but I don't :-(

Could someone confirmn the order please.

I think, from reading the first post above, that it's 
Rear 50amp
Middle 30 Amp
front 2 amp


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## jiwawa (Jun 22, 2007)

Sorry I can#t he;p Gareth but I'm just bumping this to the top.


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## garethjjones (May 1, 2005)

Thanks Jean, 

I think I've worked this out.

The rear fuse is the 50 Amp - it's a different size so that's easy.

Looking at the fuse holders more closely, there are two different gauge wires going to them. The middle wire is thicker, so it will be the 30 amp fuse, and the front one is quite thin so will be the 2 amp fuse.

All quite obvious, but sometimes you need so time to look at things and think - which has been a bit lacking here recently!


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