T5 camper lighting from vehicle battery and/or leisure battery

Thread Starter

dazifier

Joined Aug 7, 2017
8
Hi All, I hope that you are well.

I am seeking advice for my VW T5 Transporter camper van conversion project.

As standard fit these vans have a courtesy light in the back which can be either off / on / on when door opens. There is a permanent live, and a switched live which also turns off the light after a minute or so, as it does so the voltage is reduced slowly to produce a dimming effect which is quite pleasing.

I am converting my van to a camper, in the back will be several led bars for lighting, in normal use these will be powered by the leisure battery.
What I would like to do is have them come on when the door is opened using the original circuit, this will give the occupant time to get into the van and turn on the lights using the leisure battery circuit. I'm no electronics expert but I suspect this is not straight forward, here are my possible solutions:

1/ Use a relay, I can turn on the leds by energising the leisure battery circuit using the existing van circuit. I like this solution because the 2 power sources and circuits are kept separate but I will lose the dimming effect ( provided the leds can be dimmed but that's another story ).

2/ Place diodes into the + of each circuit to prevent flow. This should allow the dimming effect but I don't know what other issues might arise - over voltage? too many amps? I just don't know and since my kids will be in this vehicle I don't want to take any chances but I would like the lighting to be nice and trick.

Any suggestions on how I can accomplish this safely?

Regards,
DarrenIMG-9491.JPG
 

crutschow

Joined Mar 14, 2008
25,645
How will the leisure battery be charged?
That will help determine my answer to your question.
 
Last edited:

Thread Starter

dazifier

Joined Aug 7, 2017
8
How will the leisure battery be charged?
That will help determine my answer to your question.
Hi Crutschow, the leisure battery will be charged on the move via a Voltage sensitive relay, probably a Durite VSR. When parked up if mains is available the leisure battery will charge from an onboard mains battery charger.

Regards,
D
 

gerty

Joined Aug 30, 2007
1,292
We use something like this in our emergency vehicles. Sometimes we have to sit on the side of the road with our flashing red lights and 2 way radio on, on hot days the motor can over heat. we fixed it by adding a smaller (garden tractor) battery and powering everything from it. We charge that battery through a battery isolator..https://www.waytekwire.com/item/800...MIx5jzyMfK1QIV2BeBCh3zbwgIEAQYAiABEgIM6_D_BwE

The smaller battery can now go stone dead and the original vehicle battery will start the truck, thereby charging the smaller battery.
You don't have to use a smaller battery, we just do because it fits better..
 

crutschow

Joined Mar 14, 2008
25,645
the leisure battery will be charged on the move via a Voltage sensitive relay
Than won't that disconnect the leisure battery from the vehicle battery when parked, as you want?
The permanent live and switched live for your lights than can come from the leisure battery.
 

ian field

Joined Oct 27, 2012
6,539
Hi All, I hope that you are well.

I am seeking advice for my VW T5 Transporter camper van conversion project.

As standard fit these vans have a courtesy light in the back which can be either off / on / on when door opens. There is a permanent live, and a switched live which also turns off the light after a minute or so, as it does so the voltage is reduced slowly to produce a dimming effect which is quite pleasing.

I am converting my van to a camper, in the back will be several led bars for lighting, in normal use these will be powered by the leisure battery.
What I would like to do is have them come on when the door is opened using the original circuit, this will give the occupant time to get into the van and turn on the lights using the leisure battery circuit. I'm no electronics expert but I suspect this is not straight forward, here are my possible solutions:

1/ Use a relay, I can turn on the leds by energising the leisure battery circuit using the existing van circuit. I like this solution because the 2 power sources and circuits are kept separate but I will lose the dimming effect ( provided the leds can be dimmed but that's another story ).

]
I wouldn't recommend trying to use the old dimming circuits - even if an LED string was in play, it'd be pure dumb luck if the combined Vf tally in series coincided with the struck voltage of a fluorescent tube. You'd also need a bridge rectifier that could handle about 20kHz.

If you use an LED bar driver module - try to find one with a dimming input - reducing its supply voltage probably won't work so well.
 

Thread Starter

dazifier

Joined Aug 7, 2017
8
Hey Guys,

Thanks very much for the advice, keep it coming, it's helpful.

The VSR will split the two batteries but the original light circuit from the van is still fed from the van battery and still remains live.

If you were to stand in the van today you'd see a plug connector poking out from the back of the headlining in the front of the van, this becomes live for 30 seconds ( timed it yesterday ) when the side door is opened. I wish to connect this to the led lighting in the back of the van as a courtesy light - door opens, light comes on, get in van turn on main light switch. Now the main light switch should power the very same led lights but use the leisure battery instead.

So you see, there is a potential to power from 2 separate sources even with the VSR in place which is probably bad - I think that is what Ian is getting at but I don't really understand the terminology he uses ( sorry, I'm useless at electronics, I'm a unix system admin, I write scripts for a living ;).

I've had some more thoughts on this, how about I use a relay powered by the lights leisure battery circuit, the relay could open the van lighting circuit when energised thereby isolating the led from the van battery. The only danger here is if the relay fails since it's default setting is closed to allow current to flow. If I can figure out how to protect from such a scenario then I think I'm good.

Cheers,
D
 

crutschow

Joined Mar 14, 2008
25,645
How about using a SPDT main light switch (or SPDT relay controlled by the switch)?
The common terminal is connected to the LED lighting, the NC contact goes to the 30s wire, and the NO contact goes to the leisure battery (see below).
That way the 30s wire will momentarily light the LEDs from the main battery when you get in the van, but then the light switch will turn on the LEDs from the leisure battery.
And no possibility of the two batteries being connected.
upload_2017-8-9_17-34-27.png
 

Thread Starter

dazifier

Joined Aug 7, 2017
8
How about using a SPDT main light switch (or SPDT relay controlled by the switch)?
The common terminal is connected to the LED lighting, the NC contact goes to the 30s wire, and the NO contact goes to the leisure battery (see below).
That way the 30s wire will momentarily light the LEDs from the main battery when you get in the van, but then the light switch will turn on the LEDs from the leisure battery.
And no possibility of the two batteries being connected.
View attachment 132618
Crutschow I think that this is the solution, thank you! Just one last thing, how should I mitigate against relay failure?
 

Thread Starter

dazifier

Joined Aug 7, 2017
8
Yes of course, you're right. It took me a little while to figure out how to wire this thing up. I guess the negative sides of both van and leisure circuits will connect to the led negative and we're done!

Good work my friend, thanks!
 

Thread Starter

dazifier

Joined Aug 7, 2017
8
I know, sounds daft right! It's because I always want to run my negatives back to the negative of the battery, I struggle with the fact that the van body is effectively negative / earth. It's even worse when I'm thinking about 2 circuits but I think I have my tiny brain around it now!

Actually I would like to take this a step further since I found out that the rear door has it's own in van lighting circuit too!

Now I would like to be able to:
Open the sliding door and have ALL of the living area lights come on as a courtesy.
I would like to be able to open the rear tailgate and have just one of the living area lights light up in the rear of the van, tricky not to light the other leds when opening the rear door and I still need to keep these circuits separate.
I think I have a solution involving 3 relays - see following pictures, one is the circuit design for which I'd be eternally grateful for an appraisal and the other is a photo of the relay diagram on the SPDT relays I purchased.

Do you think that this is workable?

Cheers,
DIMG-9544.JPG IMG-9546.JPG
 

crutschow

Joined Mar 14, 2008
25,645
Do you think that this is workable?
Not from what I see.
The two bottom relays are energized when the leisure battery is switched on, disconnecting both sliding door and rear door switches.
Is that what you intended?

Note that schematics and wiring diagrams are normally drawn with the power on top and the ground/common on the bottom.
It makes it difficult to follow when it's drawn upside down. :rolleyes:
 

Thread Starter

dazifier

Joined Aug 7, 2017
8
Whoops, I kind of knew that but I found it pretty difficult to draw the diagram and have it even partially legible :)

That is correct, I need to keep the leisure circuit and the vans original lighting circuit separate. Also, both door positives only energise when the doors are opened.

The idea here is that the standard courtesy circuit lights the living area so you can jump in and then switch the lighting switch on which will power the leds from the leisure battery and turn off the courtesy circuit.

Also when the rear door is opened the upper relay is energised so that only the rear door light comes on. If the interior lighting is turned on the lower right relay opens isolating the van circuit from the leisure circuit and the upper relay returns to NC so that all of the living area lights including the rear light up from the leisure battery.

:D
 
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