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Discussion Starter #1
I smelled that burned electric smell the other day, while driving.

Some days after my leisure battery was empty. Today I realized it wount charge from the factory installed split charging system. I can not find any fuses that have gone or any other indication of something being wrong. Where do I start?

The battery is located under the drivers seat, left hand drive. The starter battery is charging ok 14.4 V when measured with multimeter. But the leisure battery is getting 0V.

Transporter T5 2008.
 

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Discussion Starter #3
It is for the battery under the left front seat, this T5 is fitted with a Webasto that heats the water if under 10C. And it is powered from that battery. Here is a picture, there is a relay that says 100 and a fuse I think one of them is 80A and the other is 40A, both intact. The Webasto started of it self a lot since the controlboard is broken, so I have pulled the 40A fuse to prevent it to drain the battery. Could this be something installed after production?

Skärmavbild 2021-01-13 kl. 11.06.05.png
 

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140 DSG Shuttle SE full Camper
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Don't know about in Sweden but my O.E. Webasto Thermotop, like you've got, runs off the starter battery, but to be fair that's all it had from new.
 

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Discussion Starter #6 (Edited)
The manual for my T5 says that, "depending on the equipment level of the vehicle two or three batteries can be installed" and in vehicles with two batteries the extra battery is located under the drivers seat (left hand drive). So since mine had a battery installed I guess it has to have some kind of charging from facory? As you can see in the pictures there is a space for the battery under the seat. It all looks pretty factory to me, it is welded holders for the fuse / connector-panel inside the seat-frame. Also a 80A fuse for the bigger cables. And one 40A for the Webasto.

Sorry for the mess in the pictures, the one above in earlier post from me also show som of my own installed cables for second diesel heater and USB-charging.

20210113_123901.jpg 20210113_124245.jpg 20210113_124237.jpg
 

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My mates Caravelle has a 2nd factory-fitted battery under the passenger seat like yours. I'd be testing the leads to the 2nd battery with a multimeter when it's supposed to be charging to check what voltage is coming through. If it's not getting a charge then you can start tracing the fault back through the nest of wires under there. Check for continuity - could well be the split charge relay that's died.
 

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The second battery doesn't seem to have been fitted much to UK spec vans. One suggestion though - have you checked the large fuses in the E-box in the engine compartment?

Unfortunately I've only got the fuse assignments for 2010-onward, but it looks like one of the fuses there may be dedicated to the 2nd battery and associated split charge. Fuse SA3 - but be aware that this is for the facelift so it may not be correct for yours.
 

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Discussion Starter #9
I have now :) Really wish it was a bit warmer than -1C outside. The 100A fuse was blown. Guess I try to find a new one, but something caused this. The only thing I have changed from original is to install a 100Ah Lithium Battery, with its own BMS so it should be able to charge via the split charge system. Thanks @triffic one step closer!


20210113_145704.jpg Foto_-_Google_Foto.png Skärmavbild 2021-01-13 kl. 15.39.58.png
 

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You would think that would blow with quite a pop! I wonder what the max charge rate for the Lithium battery charge system is? It's ~probably~ inverter based so it could be quite high, but I don't think it could exceed 100A by design. Have you checked the lithium battery charger to make sure it hasn't turned up its toes [edit: that might not translate well - has it died]?
 

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You would think that would blow with quite a pop! I wonder what the max charge rate for the Lithium battery charge system is? It's ~probably~ inverter based so it could be quite high, but I don't think it could exceed 100A by design. Have you checked the lithium battery charger to make sure it hasn't turned up its toes [edit: that might not translate well - has it died]?
I have no specific Lithium charger, I have just replaced the original battery with the new Litihium, has been working for over a year before. According to the manufactor this should work since the battery has it's own management system that will handle the charge.
 

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I am not an expert on Lithiums by any stretch but I recently installed a 100ah lithium on my T5 and all the research I did indicated that even with the internal BMS on the lithium it is not advised to use a standard charger as the lithium requires a specific charging sequence and levels which standard chargers do not have. Also basic split charge system will not charge an acid or AGM to 100% without a DC/DC charger in the system but I do not know what the effect would be on lithium. I think you need to look at the way you have been charging the lithium as it may have damaged it. I suggest getting your lithium battery a maintenance charge with a lithium specific AC/DC charger to check it is still functional.
 
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