Sun tach 1.3 volt batteries

[G B.]

I've got a 1965 Sun Super tach that uses a separate EB-9A transmitter box. The box requires two AA size 1.3 volt batteries for power according to the instructions.

A company named Tessco Technologies sells AA size 1.3 volt batteries for pagers. https://www.tessco.com/products/displayProductInfo.do?sku=45591&eventPage=1 These batteries are described as being "NiCd Cell, rechargeable, 630 mAh". I assume "NiCd" stands for Nickel-Cadmium, and "mAh" stands for milli-Amp hour discharge rate.

A common alkaline 1.5 volt AA battery is usually rated at about 2,500 mAh. Am I correct in interpreting that these 1.3 volt Tessco batteries will only have about 25% of the service life of an alkaline 1.5 volt AA battery?

I'm just looking for a better way to keep using this beautiful tach. I've tried using 1.5 volt AA batteries and tolerating inaccurate tach readings. With another Sun tach, I paid some yahoo $200 to convert the transmitter box to run off 12 volts. That tach started reading goofy after about a year (Can you guess how long his warranty lasted?) Now this pager battery seems like a good replacement, but I don't want to start installing new batteries every few months.

[Clem Z.]

Re: Sun tach 1.3 volt batteries

rechargable NiMh batteries are 1.2 volts and have 2100 mAh. they may work

[James F.]

Re: Sun tach 1.3 volt batteries-Jerry

Jerry, I've walked down this "road" several years before you, getting my mid'50's Sun tach and EB -9A transmitter to work (dead1.3V mercury batteries). I can tell you 1.5 V alkaline batteries wil not work. the tach will read low. You really need atwo 1.3V bateries. Don't know about1.3V the ni-cad batteris you found, they may do the job. Neat if you could find someway to recharge them from the Corvette 12V system.
IIn my case I had a GE electrical engineerfriend make me a little "PC" board with electronics which took 12v from the Corvette electrical system and reduced it down to 1.3V. The engineer was a enious and my'50's Sun tach operates very nicely. Regards, Jim

[Joseph T.]

Re: Sun tach 1.3 volt batteries

Jerry..you might try talking to this guy...Joe

http://www.williamsons.com/tachs.htm

An Arkansas outfit that does it for a living.

[G B.]

Thank you all.

I appreciate the time you all took to respond.

I have tried Williamsons in Arkanses. They converted one of my tachs to work from a 12 volt system for $200. This tach worked properly for about a year. Although Williamson's initially said they would give me a "trade-in" value for another Sun tach I sent them at the same time, they did not. Instead they chose to first take that tach completely apart, breaking the glass lens and crimping the stainless bezel, before returning it and saying they didn't want to buy it. I still have the remains of that tach stored in a styrofoam cup.