Leisure Battery not Charging from VSR

[Thom.milburn]

Hi guys,

Hoping you can help.

We replaced our leisure battery in July due to the previous being dead - it was tested by our local garage and confirmed so I replaced it.

Since then we appear to be having an issue with the split charging system - when on EHU we have endless power which appears to top up to the leisure battery but when simply driving around our leisure battery is becoming depleted.

I sense the split charger isn’t sending ‘charge’ to the leisure battery but I can’t really comment on how the system works.

It’s a pro conversion with a Sargent system and what appears to be a generic split charger under driver seat. I can’t see anything has blown or tripped.

Any help would be much appreciated and pictures of split charger attached!

thanks

Thom

 

[T6ChrisO]

This happened to me earlier this year and the guys at @AJCConversions sortted it for me. I cant quite remember what exactly had gone wrong but ended up putting in a Victron smart charger. I believe it was an issue with my Sergent EC160 panel (I think.....). Hopefully Brandon will pop along and provide more info

 

[Scottish Scrutineer]

Lots of information on this thread [Guide] DC-DC Charger (for leisure battery) -- How I Done It --

Basically a split charge relay like you have, isn't suitable for the Smart alternator system that is in your T6. The split charge relays do not start to charge the leisure battery until the alternator has charged the starter battery to 13.7v. With the T6 charging system, they really only output at that level in certain circumstances, so result is the leisure battery doesn't get charged as it needs to.

 

[Thom.milburn]

Thank you - very insightful although it does make me wonder why All Seasons chose to install it on their 2018 vans it has been working well up until this just.

 

[roadtripper]

Out of interest what type of battery (normal/EFB/AGM) did they replace it with?

What might be happening is the your main battery is aging and so not holding as much charge - it may be that when newer the voltage on the main battery stayed higher and held the VSR in for longer. Now the battery is aging the voltage is dropping below 12.8 so the VSR is dropping out but you might be in a region where the van is happy with that so the alternator doesn't cut in for a while

Thing is using a standard relay can work enough, after all VW do it on the OEM California, but it really doesn't make best use of the power and batteries. It may be that your system has been getting away with it enough to suit your use of power but now things have shifted.

 

[Thom.milburn]

Thanks guys. I’ve been doing some poking about with a multimeter - I’m hoping someone can offer further technical input please

With the leisure battery disconnected, At 2500rpm I’m achieving approx 14v to the VSR but no output (relay isn’t engaging).

At 900rpm I’m achieving approx 14v at the relay, again, no output.

The relay should engage at 13.7v - it is not and the indicator light does not illuminate. Would this suggest I’ve simply got a dead relay?

Whilst I have digested what has been posted above and it is a perfect solution, my pockets are not that deep at present I’m afraid so I’m hoping to simply return my current system to being operable!

Thanks

 

[roadtripper]

How long are you holding that voltage for - the more modern VSR tends to have a small delay to account for engine starting attempts

 

[roadtripper]

Also I wouldn't do this test with the battery disconnected - this is a dual sense VSR so it will engage when either battery meets the criteria - the intent being it will charge the starter when the leisure is full on EHU charging.

If it doesn't detect a battery on both sides I would expect it not to engage for safety reasons - you wouldn't want an accidental short of alternator positive to ground...

 

[roadtripper]

Your VSR looks to be the same (with different branding) as this one from 12v Planet - there is a basic datasheet there that may be of use

PPT Voltage Sensitive Split Charge Relay - 12V 140A

12V 140A voltage-sensitive relay from Portable Power Technology for 2-way split charge applications in camper vans, motorhomes, 4x4s, boats etc.

www.12voltplanet.co.uk

 

[roadtripper]

If you do decide to replace like for like (and I can understand why that might be pragmatic in the short term) then for the best chance of success it's really important that both your batteries are the same TYPE as there are different voltage requirements.

 

[AJCConversions]

Yes if the relay doesn't engage at 14v it's simply a dead relay.
As mentioned it is not the correct type, but if funds are tight then a simple swap would be fine and keep in mind to upgrade when funds allow.
Make sure you disconnect cable from engine battery and leisure battery before changing the relay

 

[t0mb0]

If you’re going to replace the relay with another rather than a DC-DC, it might be worth considering a standard ignition switched (or even better, engine run switched) relay rather than a voltage sensitive one. The voltage switched version is going to be at the mercy of all the factors already discussed. VW use a engine run switched relay for their factory leisure batteries - ensure the starter/leisure are of the same type with any relay system though.

 

[t0mb0]

Also, check the earth connection to the relay, if the earth is dodgy, it won’t measure the voltage correctly and will not switch on.