When we picked up our 1965 2a the battery was discharging and we seem to have found the problem. When we took the voltage regulator lid off when all the wires were connected to the box, the points that stop the dynamo discharging the battery stuck when they were pushed as if it was like a magnet there. But when we disconected the ammeter the contacts diddnt stick.
What is going on here?

martinbennett said:

When we picked up our 1965 2a the battery was discharging and we seem to have found the problem. When we took the voltage regulator lid off when all the wires were connected to the box, the points that stop the dynamo discharging the battery stuck when they were pushed as if it was like a magnet there. But when we disconected the ammeter the contacts diddnt stick.
What is going on here?

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Some where in the wiring you have on that car there is a LIVE wire connected to the Regulator that should not be connected.

When the engine is NOT running, the ONLY live wire should be the big one connected to the battery.

The D is connected to the BIG terminal on the dynamo.
The F is connected to the small terminal on the dynamo.

My guess is the AMMETER is WRONGLY CONNECTED and sending live back to the control box on the wrong side of the cut-out which then holds ON and flattens the battery.

CharlesY

Just to help your thinking ....

When the engine is stopped, the battery is at 12 volts (say) but the dynamo is showing NONE volts.

BECAUSE battery volts is MORE than dynamo volts the "CUT OUT" stays OPEN circuit, and the battery live is disconnected from the dynamo live.

Now start the engine.

On tickover nothing changes as the dynamo barely charges and cannot make enough volts to be MORE than the battery.

Now start driving, and engine speeds up, so dynamo speeds up and LO!
Now it makes more volts than battery and this is good 'cos now it can CHARGE battery up, so CUT-OUT contacts are CLOSED to connect battery to dynamo D (output) and will stay connected until engine slows down so much that dynamo volts is less than battery volts which makes CUT-OUT open, and disconnect battery from Dynamo.

Is that clear I wonder ................. ?

There are now solid state regulators available these days which are probably the Bees' Bollocks.

CharlesY

Thanks I'll try tomorrow

Turned out to be a duff voltage regulator

martinbennett said:

Turned out to be a duff voltage regulator

Click to expand...

Pity .... the solid state ones are good.

CharlesY