I have replaced my old dynamo with a dynamator but I am confused by the wiring options if anyone can help.
The control box has a D terminal ie. power in and a B terminal power out.
There are 2 x 10mm flag terminals on B which are linked. One goes to the lighting switch on the dash and one goes to the solenoid switch so is connected to the battery effectively. Looking at the electrical diagram there is a direct link from B terminal to the ammeter but this cable does not exist? There are 4 terminals on the ammeter and the 2 smaller ones go to the ignition switch and I guess the “radio link”.
So if I connect the dynamator output via awg8 and a fuse to the old B terminal connectors is the power going via the ammeter. Should I connect the new power direct to the solenoid with heavier cable. I thought I would run a cable from Dynamator via the ammeter but this is not how it’s wired at the moment and it all looks original.
What am I missing?
I THINK that you just need to connect the D wire from the dynamo, now an alternator to the B wire or wires on the electrical board where the Lucas regulator used to sit, if you want to keep it looking “original” you could gut out an old RB340 or RB106? depending on age and connect the spade terminals under inside the gutted unit, at least that is whet I am planning on doing…
I don’t see why you need to run new wires all the way to the dash.
The dynamator needs to have heavier gauge cable to the battery as the output is higher. As far as I understand the charging current all goes via the ammeter to the battery so not upgrading the ammeter in/out cabling leaves it subject to overloading? Some remove the ammeter and use a voltage gauge to avoid high current behind the dash but I want to keep the ammeter and upgrade the wiring but I can’t see where the connection from old regulator B post/dynamator output goes to the ammeter. The ammeter definitely has two heavy gauge wires attached but where do they actually go? I would think one comes from B post to ammeter but a continuity test proves it does not. I traced one to Ignition switch and one to the lighting switch but the cables are not heavy gauge at these points!! .DAIMLER WIRING.pdf (3.9 MB)
Someone who really knows will surely post a proper reply but I don’t think you need to upgrade the cables.
The old dynamo would produce (let’s say) 45 amps when needed by the state of the battery and the demands of the car at the time so unless you think your demands will be more than this (more than the max output of the old dynamo, whatever that is) you don’t need bigger wires?
Because they are big enough to cope with the maximum output of the original dynamo, when needed, which is far higher than normal use?
The main advantage of an alternator when compared to a dynamo is that it produces a useful output at lower engine revs, not that it’s max. output is bigger???
Thanks for the reply. I have been working on this today and solved the problem I think.
Firstly the dynamo puts out 25amps according to my manual. The dynamator can put out 45 amps allegedly.
So I re checked the continuity and had zero between the B tab cables and the ammeter. I decided to close the ignition switch and see that there was then a circuit and sure enough (battery disconnected) there was continuity between B tab cable and ammeter. I then turned the key off and I still had continuity to the ammeter!!?? So by turning the key something changed and the circuit was completed with key on or off as I think it should be.
I can’t explain that.
Also while I was at it I removed the Dynamator and reversed the Ignition light cable tag putting the nut on the inside and the screw head on the outside thus it now clears the oil filler tube with no danger of earthing. If anyone else does this it’s better to know before you bolt it in.
If you put 45 amps into your battery you will boil and ruin it, the original wiring will be fine for an alternator, the alternator will only put out what is required to balance the cars use and an extra two volts to charge the battery, do not over think it!
When I had a rally car with four Cibe Oscars strapped to the front I had heavy duty wiring for the spots but never needed to upgrad the rest of the car,
I do not think the battery is the issue as the alternator will not boil it however if there is a large load on the system outside the battery the 60 year old cables have to carry that higher load all via the ammeter wiring and that may be less capable then when the car was built. If I fit an electric fan or power steering the electrical load via the existing wiring will be higher and that is the point of upgrading particularly the ammeter circuit as I understand it. If there is no ammeter then all the heavy current is in the engine bay. Looking at the amount of furry insulation behind the dash any little electrical overload could be fatal as extinguishing that material would be impossible. I am going to install a complete electrical rewire with proper fused distribution box but that is a big project later on so I just want to avoid risks that can be easily averted.
My point about boiling the battery was to illustrate that you will not get anywhere near 45 amps draw, the copper wiring does not really deteriorate except the very ends where it can tarnish and anywhere it bends on a daily basis, i.e. the boot lid wiring needs a careful look around the hinge area, the few wires going to the engine should also be inspected and repaired / changed but the bulk of the wiing wold normally be fit for service, I will be fitting an ebay five relay ten fuse board in place of the voltage regulator, I could hide them inside the case if I wanted an original look, I will be relaying and fuseing the head and spot lights, the horns etc. that will mean that the original dash wiring and light switch will be carrying a much smaller amperage as they will only be powering the relays rather than the actual lamps, power for the relayed items will come from the starter solenoid battery terminal, but if you wish to construct a new wiring loom go ahead, electric power steering should have it’s own dedicated power feed fused from the battery, when it gets to full lock it can draw a high current, I would not use any of the car wiring for PAS, locally there has been a Mk2 burnt out due to a poor electric LAS installation,
Thanks. I have now connected a fused link from Dynmator to loom. Having had all the dashboard out and changed all lamps for LED etc. and checked all connections and cleaned up the wiring loom nest behind the dash I was pleased when it all came back to life and is charging correctly now.
Noted comments re power steering supply.