Couple of questions for the sparkys!

andyrap · Post by **andyrap** » Wed May 23, 2007 3:34 pm

I am in the process of fitting a leisure battery with the invaluable information all over the site courtesy of corblimey, Pippin and alpha (amongst others - thanks all). I now have a couple of other questions which I would be very grateful for a second (or third, etc) opinion on.

Question 1

I have a Kenwood stereo with the usual permanent live connection and a switched accessory feed to allow it to switch on and off. I can connect the permanent to the leisure battery no problem, but I don't want to connect the acc feed permanently - I would like to keep it switched from the ignition. BUT, in addition, when not running off the ignition (i.e. camping), I would like to be able to turn the radio on/off from the back using a separate switch.

My idea was to wire a switch in parallel to the accessory feed (an OR switch if my memory of logic circuits is correct). The problem I saw was that the acc feed is from the main battery ,and the permanent from the leisure so to keep them isolated from each other, I was thinking of introducing a relay to the party. So, the ignition feed (or switch wired in parallel) would trigger the relay which would switch a direct feed from the leisure battery giving the radio it's 'on' power.

Does that make sense/sound right? Would it work? Have I missed anything or am I barking up the wrong tree altogether?

Question 2

I have installed a couple of additional lights to the interior that I would like to come on when the interior lights do, and then also be able to switch them independently from a switch in the back. I was thinking a parallel arrangement again but I'm not sure where to take the feed from. The lights will be routed from the leisure battery at the fuse box so no worries about relays this time round.

Would be very grateful of anyone's suggestions on this. It's a while since I've dabbled with anything electrical and I'd really like a 2nd (3rd, 4th...) opinion!

Many thanks,
Andy

francophile1947 · Post by **francophile1947** » Wed May 23, 2007 3:54 pm

Gosh Andy - I wish you luck, you're gonna be running lots of wire through the old van

- no idea how to help I'm afraid.

andyrap · Post by **andyrap** » Wed May 23, 2007 5:51 pm

hehe - tell me about it John! There's a lot of stuff in the old fella already - TV, DVD, freeview box, aerial amplifer, mobile phone kit - all of which is hidden away in various places. Am getting the van set for summer and I know what I want it to do, just not how to do it!

Andy

alphabetter · Post by **alphabetter** » Wed May 23, 2007 7:54 pm

I can't let this kind of thing be, so here is a circuit that should work for your first requirement. As you say you need a relay to stop the leisure and starter batteries being connected together via the radio.

When the ignition is off the relay is deactivated and current will flow through the top (leisure) circuit if the switch is on. When the ignition is on the current will flow through the bottom (starter) circuit. You could take the "acc" feed from the existing radio connection.

If you want the on/off switch in the back I would use fairly thick wire as I would worry a bit about too much voltage drop.

Personally I think this would be more trouble than it is worth to install, but it's not me that's doing it.

For the lights you should be able to tap a continuous +ve and a switched circuit from one of the existing lights. All you need to do then is to put a switch on your new lights to choose between the sources.

andyrap · Post by **andyrap** » Wed May 23, 2007 9:29 pm

Brilliant! Thanks Alpha. That looks ideal. I need to get another relay (only have a SPNO at the mo) but other than that perfect.

Presumably I could connect the leisure battery to both poles, i.e. instead of where you've put Start +v, so regardless of whether it's the ignition or the switch that's in action, the power is always from the leisure battery?

On your advice, will probably fit the switches somewhere nearer the middle (end of centre console distance) to avoid too long a run of cable.

Appreciate your comment about the effort involved. I've got an automatic front on my stereo and it 'hides' itself when the ignition goes off. I like the automated aspect of it and don't want to lose that post leisure battery hence going through all of this

With the lights, if they were connected to a cont live with a switch, as well as the original 'switched' light feed, wouldn't that turn all of the lights on?

Thanks again - really appreciate it.

alphabetter · Post by **alphabetter** » Wed May 23, 2007 9:47 pm

andyrap wrote:Brilliant! Thanks Alpha. That looks ideal. I need to get another relay (only have a SPNO at the mo) but other than that perfect.

Presumably I could connect the leisure battery to both poles, i.e. instead of where you've put Start +v, so regardless of whether it's the ignition or the switch that's in action, the power is always from the leisure battery?

Yes you are quite right, and you can use your existing relay like this. There isn't much difference between the two circuits in fact because normally you'll turn the ignition on and the leisure battery will connect to the starter battery anyway.

I've also drawn the circuit I tried to describe for the lamp.

mikeonb4c · Post by **mikeonb4c** » Wed May 23, 2007 10:25 pm

bluddy hell how good is this forum with talent like alphabetter knocking up circuit diagrams at the drop of a hat. I'm a lateral thinker myself. By opting to read a book, I avoid a lot of extra wiring in the van. Clever or wot

PS - no I don't in fact, cos the kids want all that DVD, PS2, telly on the move stuff

andyrap · Post by **andyrap** » Wed May 23, 2007 10:40 pm

mikeonb4c wrote:bluddy hell how good is this forum with talent like alphabetter knocking up circuit diagrams at the drop of a hat.

I thought that as well. Brilliant information and very helpful people. Thanks Alphabetter. I'll let you know how I get on

andyrap · Post by **andyrap** » Thu Jun 14, 2007 10:18 am

Have hit a stumbling block with this. The wiring for the lighting seems a bit odd. There's a permanent live as expected, as well as the earth, but the switched connection is the opposite of what I expected. It is -ve when the door is open (not checked if to ground or just disconnected) and becomes live when the door is shut.

This is the case on the fluorescent light. Need to investigate for the front - presume it's the same.

alphabetter · Post by **alphabetter** » Thu Jun 14, 2007 8:23 pm

andyrap wrote:Have hit a stumbling block with this. The wiring for the lighting seems a bit odd. There's a permanent live as expected, as well as the earth, but the switched connection is the opposite of what I expected. It is -ve when the door is open (not checked if to ground or just disconnected) and becomes live when the door is shut.

This is the case on the fluorescent light. Need to investigate for the front - presume it's the same.

Assuming the switched goes to ground (and not disconnected) then you need to connect one side of the blub to permanent live. The other side you connect via a switch to the switched ground and permanent ground.

Apologies for bad ASCII art below

Code: Select all

                   Bulb        /-------------- NC (off)
+ ve --------------OOOOO-----/   ------------- Switched ground (Door)
                               ------------- -ve  (on)