Vintage Sun tachs

[James F.]

Re: Just shoot me

Good memory Bill!! Duracell RM12R is the replacement (mercury) battery for the Mallory. They were not available when I was looking 5 or 6 years ago. Regards,

[Terry M.]

Re: Just shoot me

I just had an obsolete battery made for a computer. Dave Heitzman found the place for me. Might be worth a try tomorrow:

Battery Wholesale
They have outlets in Toledo OH, Oregon, OH, Monroe, MI, Adrian, MI

Dave dealt with a store at 1825 S. Reynolds Rd., Toledo, OH

They don't show an area code, but phone number is 381-1337

[G B.]

RM12R replacement?

The eBay seller claims his unnamed $25/pr battery is a replacement for the RM12R. It even says so right on the package. They couldn't print that on eBay if it wasn't true, could they?

[Harmon C.]

area code 419 *NM*

[David G.]

Re: RM12R replacement?

Jerry: You have more than enough battery info, so I will add nothing to that part of the Sun Tach discussion. However, you mentioned back earlier in this thread that you were also looking for a new chrome cup. Do you have one now that is pretty beat up, or are you looking for one? I have restored several of these and have a local chrome shop here in St. Louis that does a great job of taking out small dents and rechroming. I have an operating unit, with the calibrating needle, that uses the old style cup and has the identical face to the transmitter earlier style units, and DOES NOT require a sending unit (12v/8cyl), on my '34 Ford, (383 sb)looks greeat and works great. Let me know specifically what you are looking for and I will see what I have hiding in the garage. Jerry: are you getting hit by the rains and wind from Frances? Stay safe, it looked like it was heading your way on the weather channel. DG

[Mike M.]

Re: RM12R replacement?

As mentioned earlier, the reason for the mercury battery was life as compared to the standard AA batteries of that time. Why not just add a resistor in series with the battery. I don't know what ohm rating to use, but can tell through experimentation. Should be able to put it in series with one of the battery connections. I have a 9000 rpm Super Tach at the house with the sending unit. I'll check on how to install resistor.
Ni-cads have a NOMINAL rating of 1.2 volts, but after charge go to 1.3 to 1.4 volts. However, their charged life in this application would be short and to take out for recarging would be a pain.
Mike

[Dick W.]

Re: Vintage Sun tachs

Jerry, I was just in Staples this afternoon. They have some 1.2V telephone batteries that look to be the AA size. They are listed for AT&T 2.4 Ghz cordless phones. Close to what you need