8.4V (9V form factor) mercury battery substitution

alanrockwood · Oct 28, 2019

Hi,

I have a flash meter that uses a E146X battery. This is a 8.4V mercury battery that is no longer available. It looks like a regular 9V transistor radio battery, but it is only 1.75 inches tall (44.5mm), which is a little shorter than a regular 9V battery. I am looking for a substitute. There are some 8.4V batteries out there, but they are the size of a regular 9V battery, not the sllightly smaller E146X battery. Does anyone know of of a substitute battery?

Thanks.

Johnkpap · Oct 28, 2019

First answer buy a new flash meter

Next option modify the meter so a standard 9v fits and solder in a diode

Minolta makes/did make a number of nice flash meters

Johnkpap

alanrockwood · Oct 28, 2019

Johnkpap said:
First answer buy a new flash meter

Next option modify the meter so a standard 9v fits and solder in a diode

Minolta makes/did make a number of nice flash meters

Johnkpap

Yes, I think a new flash meter is the best option.

Modifying a standard 9V using a diode won't work in this case because a regular 9V battery is too long to fit in the meter. It needs to be about 3.3mm shorter than a regular 9V battery in order to fit.

bernard_L · Oct 28, 2019

Assuming you won't be using your flashmeter during a hike or in a similar situation, the solution need not be totally compact.

Easiest: use a wall-plug 9V DC supply, and wire it to the battery terminals through a small hole in the battery compartment door. Obviously for studio or other indoor situations.
Small 12V battery, for garage door remote, A23 or A27, plus a voltage regulator (e.g.: LM317). You may have to accept that this power source is dangling at the end of short wire outside the case of your flashmeter.
Stack three 3V button cell batteries CR2032 or similar in a DIY holder, to provide 9V; I don't believe that the difference between 9V and 8.4 matters at all.

AgX · Oct 28, 2019

I would consider making a battery myself by either stacking 1.3V Zn/air cells or by stacking 1.5V cells. In the latter case you even couls insert a voltage dropping diode.
Another approach would be soldering a 9V clip w. cable to the contacts inside the meter and attach a 9V battery to the meter underside, by doublesided adhesive tape.

By the way, first time I hear of a such 8.4 battery in the shape of a 9V battery. Unknown over here.

John Koehrer · Oct 28, 2019

Since you have 8.4V batteries available why not use the hole (post #4) and wire it in? 9V connectors
are simple to find.

Dan Fromm · Oct 28, 2019

Funny, I just looked at Energizer's specs for their E146x Mercury battery (8.4v) and their 522 Alcaline battery (9v). They're identical.

shutterfinger · Oct 28, 2019

Pay attention to the amp hour rating as a lower rated battery may not power the meter or require frequent replacement.

8.4V (9V form factor) mercury battery substitution

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