One battery or two?

[Granger]

Following your sage advice in response to my previous post I have just had the Votronic 250 charge controller to connect my two 120W solar panels to my 2x85Ahr Gel batteries. One of the attractions was the Votronic's ability to trickle charge the starter batter as well through the EBL 208S. I previously obtained the Mate'n'Lok plug (thanks Lenny B from a previous post) for the EBL solar panel connections and have prewired the three cables, 2 positives, for the leisure and starter batteries and a common(?) negative.

I plug in and the three cables are now ready for connection to the Votronic which arrived in the post today so now to plug everything together. To make absolutely sure, I checked the wiring diagram for the EBL (thanks Spriddler from a previous post). To my surprise the connections to the solar panel regulator do not show any connection to the starter battery (see diagram below taken from the Schaudt operating instructions). So I put the voltmeter on the different cables expecting the central ('starter battery') cable to show zero - unconnected - but find both positives give me 12.5v against the negative. Looks like the central cable is connect to a battery.

Can I do any harm by connecting the Votronic as though I hadn't seen this pesky diagram? (I know I appear a bit risk averse, that's because I am!)

 

[Richard n Ann]

I connected our Votronic according to the diagram that came with it. Didn't connect anything to the van's fuse box at all.

 

[paddymcc]

Certainly on my EBL 101 the pin 2 is connected to the starter battery. You could email Udo Lang at schaudt to check. I guess you don't know if pin 2 is connected to starter or leisure? You might need to isolate the leisure battery and then check the voltages. Pin 3 should then be showing no voltage and pin 2 the starter battery voltage

 

[autorouter]

So I put the voltmeter on the different cables expecting the central ('starter battery') cable to show zero - unconnected - but find both positives give me 12.5v against the negative. Looks like the central cable is connect to a battery.

On the EBL211, pin2 is connected to the starter battery. It's very similar to the EBL208. If you think pin2 on your EBL might be connected to a battery: first disconnect the EHU. The mains charger trickle charges the starter battery, so might be giving a similar voltage. Then pull the 15A fuse near the starter battery, that powers the fridge heater element. If the voltage disappears from pin2, then it could well be connected to the starter battery.

However if you want an alternative SB connection, you could look at Terminal 7. That goes to the SB, and normally feeds the fridge heater element. One way to connect is to make a short extension wire with a male and female terminal connection, and crimp in an additional length of wire long enough to reach the Votronic unit.

Using a wire extension makes it easy to put everything back as it was, if you change your mind. If that's not a concern, you could simply cut into the wire on Terminal 7 and crimp on an additional wire.

By connecting to Terminal 7 you are simply connecting the wire outside the EBL, instead of the internal connection (Pin2 to Terminal 7) as found on the EBL211.

 

[Granger]

Thanks yet again, MH friends!

When I went back to the van I noticed that pin 2 v pin 1 was now showing 12.6v and pin 3 against Pin 1 was 12.5v - different so I now expected the starter battery to be at 12.6v and the leisure bats to be at 12.5v - bingo! Now 99% sure that pin 2 was connected to the starter. As a final check I then turned off the battery switch on the EBL and disconnected the leisure battery (both terminals) and followed Paddymcc's advice. Rather than the expected 0v on Pin 3, paddymcc I got 2.3v which I was surprised at but since it was clearly not reading across the leisure battery then I guess there was some cross talk wit hthe starter through the EBL and I went ahead and made the connections. Pin 1 Voltronic Bord 1 -ve, Pin 3 +ve and Pin 2 Voltronic starter +ve. All good.

Pity that Schaudt didn't give the correct wiring diagram in the first place but MH members saved the day.

Thanks again for all your great advice.

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