Sun transmitter batteries

[34fordy]

Does anyone know a source or an answer for the 1.35 volt batteries that the Sun Tachometer transmitters require--I know that Williamson's can modernize but would rather find batteries if possible--Don

[flatheadmurre]

Easiest to me is to fit a diode in series with the feed to get a voltagedrop and then use regular litium batteries commonly available for Photo equipment.
No harm done to the unit that cant be rewersed.

[51 MERC-CT]

Understand that these are the same size as AA batteries in series.
Just wondering if two rechargeable ni-cads although slightly less than the 2.7 volts required would work.

[flatheadmurre]

Problem is that the mercurycell was very voltage stable during different load and its entire life.
An alkaline cell starts at 1.5v soon dropping to 1.3-1.4 and then going down until its drained.
That means you get an uncalibrated tach the hole time.
Best is to get a voltageregulator and use the car battery but then you get loose wires...

[supereal]

We have had good luck finding odd and unusual batteries for our test equipment at a local Interstate Battery store. You can find one on their web site. We also obtain Optima batteries. We bought a six volt one last week for $153, the lowest price we have seen lately.

[Mike in AZ]

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from a post on the HAMB, a Duracell PC12a mercury battery is a direct replacement for the battery in the transmitter...if you can find the battery.....good luck...Mike

http://www.jalopyjournal.com/forum/t...mitters.37497/

[petes 50 merc]

i have duracell procell industrial batt. in both senders on my 50 merc and my 67 ranchero they work good been in them for a few years. look them up on ebay

[flatheadmurre]

The PC12a is a 1.5 volt battery.
The unit will work with a regular AA cell...only it wont be accurate.
It will be a happymeter telling you high numbers

[Bruce Lancaster]

This has been discussed multiple times on the HAMB. Amongst the many solutions and kludges, someone posted a very simple schematic and parts list for a little voltage regulator to produce stable correct voltage from the car's power. If that works, it should be a good route to stable operation.

[flatheadmurre]

As i wrote ealier a voltageregulator is the way to go if you can accept the extra wires !

[flatheadmurre]

What it takes is a LM337 regulator and 2 resistors cost about $1
way less then the batteries.

[jimTN]

If there is a simple way to do the above, I wish someone would post a diagram, list of ready available parts and source for the parts all in language a non wirehead can understand.

[flatheadmurre]

Ill grab a transmitter in the weekend and wire it up.
Give me a day to checkout that it runs nice without the regulator overheating inside the box and then i can post a diagram and a shoppinglist for Mouser or some other major company of choice.

[jimTN]

That would be great! I have a new unit and a used unit, both need power.

[flatheadmurre]

Ok the regulator is togetter on the bench.
Then i start thinking....thats never good !
So i made it adjustable.
Would be nice if it could be used to drive a 6v instrumentation in a 12v car to...
So the question is what you want.
I can make a PCB that accepts 6 or 12v in and puts out 1.5a adjustable from 1.35v to 6.2v.
I make it shortcircuit and overload proof with screwterminal connections.
Perhaps easier to work with a PCB then a birdsnest of components.
The cost of the components still about $2

[flatheadmurre]

Next version is togetter no extra wires outside of the box.
It gets its power from the signal from the coil doesnt care about if it positive or negative ground.
Running steady at 1.35v and 3000rpm on the bench.
Time to start thinking about if it can affect the ignition in some way or what else i might have overlooked...
Next is to get it all into a smaller footprint to nicely fit the box.

[34fordy]

Originally Posted by flatheadmurre

Next version is togetter no extra wires outside of the box.
It gets its power from the signal from the coil doesnt care about if it positive or negative ground.
Running steady at 1.35v and 3000rpm on the bench.
Time to start thinking about if it can affect the ignition in some way or what else i might have overlooked...
Next is to get it all into a smaller footprint to nicely fit the box.

This is really getting interesting!!!!!!!!!!!!! Don

[tipetu]

Hi, this is an old thread, but could you please share a schematic for this conversion?

[jimTN]

How about a step by step picture layout and parts list.

[fortyonerag]

Ditto on the above requests. I like to keep things original if possible, but I have heard the Sun transmitters die young if the wrong battery is used.