Fitting TX-2000 / DCU3 charger into Auto Sleeper

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Fitting TX-2000 / DCU3 charger into Auto Sleeper

Postby 937carrera » 11 Sep 2017, 17:04

I have recently acquired a 1990 Auto Sleeper Trident and done a couple of trips in it.

It seems that it is a similar spec to the one owned by James & Caitlin of the Sir Adventure blog and I discovered on my first trip that the radio runs off the main battery, meaning that the van only just started one morning and though the van has a leisure battery with split charge, the mains hook up does not charge the leisure battery. This was a bit of a voyage of discovery as I didn't know there would need to be a separate charging unit, where it might be, or indeed if there was one but it just wasn't working. James's modified wiring diagrams were particularly helpful in becoming convinced that my van didn't have the charging facility, so my thanks for those.

I managed to pick up a Zig TX-2000 charger (slightly newer than the DCU3 ?) and set about trying to find a way to install it. The job is done, everything is tucked away tidily and it was suggested that I should share what I had done on here, so here goes. Note I didn't expect to do this so the instructions / photos were done after the event, they might be a bit brief but I hope you will get the idea and find them useful if you want to take on the same task.

Installation of TX 2000

Auto Sleeper Trident T25, already had leisure battery and split charge system installed.

Having removed the leisure battery, first job is to get access to hidden areas to be able to route cables correctly.

There’s a shelf at the bottom of the larder unit. I removed this by removing the air vents from the Propex heater and using a long screwdriver to push the base of the larder upwards so it could be removed.

I decided to put a loop of cloth on the base, which can then be pulled from the top side so that it can be easily removed for future maintenance.

Then there’s a single thin panel separating the Propex compartment and the bottom right “portapotti” cupboard. Remove the batten for the portapotti and then the 4 screws securing the divider.

Next job was to get rid of nearly 30 years of dust.

After reading around I decided that the best place for the charger was under the sink which is pretty much dead space. I saw a photo of one mounted on a plinth (in case of leaks ?) so got a piece of ½” ply ready to mount the charger on. That then left 3 items to sort out:

• 240v feed
• 12v to MC2000
• 12v to leisure battery

240V feed is easy. It only has a 2A fuse so I simply used some standard 3 core cable with 1 sq mm core.

Before you do this you need to remove the back of the second cupboard. This is made of a thin ply and covered with carpet. It’s a tight fit and I used some plastic body trim tools to start to pull out and slide down the panel at the lower right hand corner. You’ll need to be patient / careful to remove it without damage. The water pump then becomes visible

This mains cable gets routed from the MCB under the seat, along the existing orange / white cables near the propex unit and then up the back of the right hand units utilising the routing for the cold water feed to the pump. You’ll need to drill a hole on the back of the unit, behind where you are locating the charger. I used a connector block to finalise the connection to the charger, which I then screwed onto the rear vertical panel – again, in case of a water leak.

Next is the 12v to the MC2000. This is where I got lucky / managed to figure out what to do. If you remove the MC 2000, and pull; the connectors / relays free you will just be able to see that some of the wires disappear through the metal structure of the van with a rubber seal protecting from chafing. They then run down the vertical brace at the centre of the van.

If you then explore a little further you will see a second hole to the left with a rubber bung but no wires passing through. The challenge now is to get the 12v cable (I bought 7m of 65 strand thinwall 2 core cable) through the hole and routed to the charger. For me this was a three stage process. Firstly I used a brake cable from a bike (about 2m long) and pushed that through the hole at the top. Eventually you should get to a position where the cable appears, I used a mirror and light to assist, and you will need to have a flexible arm to grope up the place where the brake wire appears. Once that was done I taped some 4mm cable to the wire and pulled that through to the top. Then did the reverse and pulled the thinwall cable through to the bottom. Each time I had about 3 inches of overlap and used tape at 3 or 4 points to provide almost complete coverage on the overlap so it did not come undone as I pulled. You then route the cable the back of the cupboard and through the hole you just drilled under the sink

Next was the wiring to the TX 2000 and MC 2000. The TX 2000 was easy, there are two +ve outputs (both from the same winding) and 4 common earths. On the MC2000 end you might be wondering why there is that additional connector block on the wiring diagrams . It becomes apparent when you realise that there are just too many cables needing to be put into the existing +ve feed, connection 8. I therefore removed the existing connections to connector block 8, used a 2” piece of the red 65 strand cable to a new, large connector block (60A rating) that all the wires could be slotted into. I just managed to connect the –ve cable into the existing connector blocks.

Before connecting the hook up I made sure that the 240v connections had been made securely, and that there was zero continuity between live, neutral and earth, charger in the off position. Prior to fitting the charger I removed the rivets to see what was inside. It's very simple internally, just a transformer, standard bridge rectifier and a good quality 33000uF chunky capacitor. So no method of varying the output and no other components to fail.

You can, if you wish, stop at this point as the MC2000 connection will back feed charge to the leisure battery, which I confirmed with a meter. The 12v electrics will also be working from the 240 hook up at this point.

Having gone this far I decided to complete the wiring as Auto Sleeper original.

After a fair bit of thinking I decided that the best routing would be to force the thinwall cable through the existing hole on the left hand side of the battery box. You can then tie wrap the cable onto the routing for the fresh water from the tank and across to the other side of the van. You will need to drill a new hole for the thinwall cable to come through the floor. I drilled from the top, about 2” inward of the fresh water pipe. Try not to do what I did – the carpet got tied up in the drill and pulled a row of carpet weave away. I painted the hole with some etch primer to stop rust, fed the cable through and after fitting a chunky tie wrap to prevent the cable being pulled too far then sealed the hole with black rubber mastic (Sikaflex) and painted over the primer.

I used a 20A fuse at the leisure battery end, as par AutoSleeper specs, again connected using the 60A connector blocks.
After that just route the cable up to the charger, make the connections and use 4 screws to secure the charger onto the plinth and base of the sink aperture.

Then test everything is working and reassemble

Here are some after the event pics

Larder with webbing secured to base to allow it to be pulled up easily


Divider than needs to be removed

Batten and other side of divider that needs to be removed

Next cupboard up, showing rear panel that has to be pulled out from the base

TX-2000 in situ

Mains connector screwed to backwall with hole for mains / 12v cables visible


After that was done I used James' instructions to rewire fuse 3 to the leisure battery
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine
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