High parasitic(?) draw on a Hymer (1 Viewer)

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Jonathan=B584

Free Member
Feb 13, 2023
3
0
Nottingham, UK
Funster No
93,984
MH
Hymer B584 Classic
Exp
I'm a newbie
Hi – I'm a new Hymer B584 Classic y2000 owner and I have a peculiar problem with the 12v electrics. With all the van side circuits off (including the switch above the door and in the Electroblock), I have a draw on the leisure battery of over 2 Amps, as measured by a multimeter at the battery. This increases at times for no apparent reason up to 5 Amps. Interestingly, if I completely disconnect the battery, I measure a 1.8V voltage in the circuit.
Removing the leisure side fuses makes no difference to the draw, nor does removing the vehicle fuses in the cab. The leisure battery is new and the vehicle battery starts OK and holds a charge. There is usually solar feeding the leisure battery, but I physically disconnect the solar charger from the battery for the above tests. Any ideas. Thanks in advance.
 
Apr 26, 2015
2,930
7,186
Ottershaw
Funster No
36,067
MH
Hymer S820
Exp
First motorhome May 2021
Hello and welcome, how old are the batteries? I think I might get a proper test done on the batteries as a first step.
 
Apr 14, 2022
292
530
Carvoeiro, Portugal
Funster No
88,080
MH
Bavaria T71LP
Exp
50 years of boating, just one on motorhomes.
Having spent hours looking at circuit diagrams for an Electrobloc (mine is an EBL 267) there are more than one connection to the house battery. Removing the 50a main fuse will only stop the vehicle charging, there are a number of other constant supplies, as well as the feed for the refrigerator. I check this circuit as well.

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Jonathan=B584

Jonathan=B584

Free Member
Feb 13, 2023
3
0
Nottingham, UK
Funster No
93,984
MH
Hymer B584 Classic
Exp
I'm a newbie
Thank you all for your welcome and responses. The leisure battery is new, and the van battery holds its charge and appears to function OK, although its age is unknown. I'll look into getting it tested and replaced if necessary.
Regarding constant supplies from the Electrobloc (EBL 119), I removed all the connectors from the top of the block (which I assumed would cut off any constant supplies) but this did not alter the raw on the leisure battery.
 
Apr 27, 2016
7,027
8,233
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
Very near the leisure battery are two fuses that supply the leisure battery feed to the EBL - a 50A and a 2A. Very near the starter battery are three fuses that connect to the EBL - a 50A, a 20A and a 2A. The 2A is the D+ signal from the alternator, not actually a supply, but a possibility if the alternator is faulty. If you remove all those fuses there should be no connection between the batteries and the EBL. So if there is still a current draw, it's not an EBL problem.

If there's still a current draw, it could be an alarm or tracker, a radio not switching into sleep mode, a tank heater, or even a light in a locker not switching itself off. Or some gadget added by a previous owner.
 
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Jonathan=B584

Jonathan=B584

Free Member
Feb 13, 2023
3
0
Nottingham, UK
Funster No
93,984
MH
Hymer B584 Classic
Exp
I'm a newbie
A full day today tracing the 2A drain on my LB. Amongst other checks, I disconnected everything, including the engine battery ground and all wires from the LB except the + and -ve to the Electrobloc (EBL 119). 2A draw is still there. The only wires connected to the EBL were the LB and EB +&- on the underside of the EBL. Time for me to learn about Electroblocs!
 
Apr 26, 2015
2,930
7,186
Ottershaw
Funster No
36,067
MH
Hymer S820
Exp
First motorhome May 2021
A full day today tracing the 2A drain on my LB. Amongst other checks, I disconnected everything, including the engine battery ground and all wires from the LB except the + and -ve to the Electrobloc (EBL 119). 2A draw is still there. The only wires connected to the EBL were the LB and EB +&- on the underside of the EBL. Time for me to learn about Electroblocs!
I'm fairly sure that some things remain live even with the main habitation power turned off, for instance the steps are always live on my Hymer S820 and I think there is also a feed to the fridge that remains live but not 100% sure on that one, have you turned the fridge off at the fridge?
Also I notice you haven't paid any subs yet so you only have two more posts left before you become read only, if you become a paid member you get access to the resource pages and you will be able to send and receive messages from other members, it's well worth the £20 sub.

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Apr 27, 2016
7,027
8,233
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
A full day today tracing the 2A drain on my LB. Amongst other checks, I disconnected everything, including the engine battery ground and all wires from the LB except the + and -ve to the Electrobloc (EBL 119). 2A draw is still there. The only wires connected to the EBL were the LB and EB +&- on the underside of the EBL. Time for me to learn about Electroblocs!
So have I got this right, you disconnected all the connectors from the front panel of the EBL, and also the Starter Battery wire into the EBL at the terminal block on the underside. And the only connections left were the + and - to the Leisure battery from the terminal block on the underside.

I presume as a sanity check you pulled the 50A LB fuse, and got zero on the meter.
 
Apr 26, 2015
2,930
7,186
Ottershaw
Funster No
36,067
MH
Hymer S820
Exp
First motorhome May 2021
There are several methods of finding a parasitic drain, if you have access to a thermal imaging camera any devices consuming power will show up as warmer then the surrounding area, another method is measuring voltage across the back of fuses, circuits that are dead show no voltage, circuits that are live will show a small voltage across the back of the fuse. The video below shows a thermal imaging camera being used to find a failed alternator diode.

 
Apr 27, 2016
7,027
8,233
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
The EBL has two high power 'latching' relays that turn on the habitation circuits. One is turned on and off by the '12V' switch on the panel, and both are turned off by the Battery Cutoff Switch (Batterie Trennschalter). Ein = ON, Aus = OFF. This small switch has a bad reputation for reliability, and I try to avoid switching it if at all possible.

A latching relay is one that has two stable states, on and off. If the power is removed, it will stay in whatever state it is in, until a power pulse flips it into the other state. As opposed to a standard relay that has one stable state and one powered state. If power is removed, a spring pulls the contacts back to the stable state.

These relays are flipped on and off by command pulses from a special control module inside the EBL. If that module has gone wrong, or one of the latching relays is faulty, then it can be stuck in say the ON state, and not switch off when commanded. These relays are reliable, but it is possible one of them is faulty.

Do you have a wiring diagram for the EBL119? They are available from the Schaudt website. There isn't a simple link to it, you have to select the EBL119, then choose the manual language (English is available) and enter your email. They send an email with a download link. Near the end of the manual is a wiring diagram.

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