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12v to 24v
Posted: 27 Mar 2008, 21:44
by syncrodoug
Long story but I'm considering using electrically operated solenoid valves to switch vacuum to the diff locks.
It appears that 24Vdc is the industry standard so how feasible/practical is it to step the voltage from 12 to 24V?
Current needed is only a couple of amps.
Posted: 27 Mar 2008, 21:59
by syncrosimon
maplin do this, but it's the wrong way around.
http://www.maplin.co.uk/Search.aspx?cri ... Price=9999
I am sure that there is something that will work.
Posted: 27 Mar 2008, 22:29
by kevtherev
could you series up a couple of 12v motorcycle batteries?
Posted: 27 Mar 2008, 22:46
by amazingdave
You could use a couple of small sealed lead acid batteries (yuasa 7Ah for example) wired in series to provide the power for the solenoid, charge them via diodes off the engine battery (separately), use a 12 volt relay to switch the 24 volts....
Or, you could use the original valves, mount them in a frame and use 12v solenoids to activate them, you'd need a spring to pull the valve back when you de-energise the solenoid...
So what's the long story?
Posted: 27 Mar 2008, 22:54
by peasant
Some folks in Germany have used the electrical difflock from audi (part nos: 893 919 173, 893 971 833 ) to replace the pneumatic one ...don't ask me why or how, though
Posted: 27 Mar 2008, 22:56
by andysimpson
Done this on my 2wd with diif lock, i had a 12 volt soleniod which i have had for years. Works really well.
Posted: 28 Mar 2008, 07:22
by DiscoDave
although industry standard is 24v, that does not mean to say the there are no 12v ones out there, that would be the first port of call, also see if 12v will fire the solenoid! otherwise you may end up with a whole heap of comlicated ness!
Posted: 28 Mar 2008, 08:20
by amazingdave
Just had a brain wave (and yes it was lonely),
The shuttle valve in a trumatic gas heater is 12volt and would do the job just fine, try emailing truma and asking how much for a spare....
Posted: 28 Mar 2008, 18:09
by peasant
Posted: 28 Mar 2008, 18:47
by syncrodoug
Many thanks for all the advice.
The long story revolves around a protracted 1.9TDI (PD) transplant into my Syncro DOKA.
I have re-wired the vehicle which involved routing a load of cables from the engine via the fuse/relay plate, which is situated behind passenger seat, to the instrument panel (Golk Mk 4). The diff lock controls were in the way so I decided that electrically operated soleniods would be a good idea!
I have 'converted' the rear diff on my T4 syncro using a 12v solenoid by way of a trial which works very well but the solenoid was rather expensive.
I've been keeping a eye on eBay and 24V solenoids appear fairly regularly at favourable prices - hence my query!
I think I initially get a 24v solenoid (about £10)and see whether it will work with 12v if no then I try a 12V to 24V step-up converter (about £20).
Again many thanks......
Doug