[volt-nuts] Fluke 750a batteries.............
dgminala at mediacombb.net
Fri Sep 25 11:12:27 EDT 2015
I have a (recently purchased) 750A as well, but haven't used it yet. I have
the same problem with the batteries. I found this post in the archives from
On 11/22/2012 7:49 AM, Steve Smith wrote:
<snip>> Regarding the 750A batteries:
> I replaced mine with four ER14250/LS14250 1/2AA 3.6V 1200mAh lithium
> cells. Remove the original mercury battery holder and replace it with
> a dual AA cell holder. Use the kind that has the batteries
> side-by-side because you need to connect to the center tap between the
> cells. Wiring is pretty much identical to the way the mercury battery
> holder was wired. Install the lithium cells in a series string and you
> have +/-7.2V which is a bit higher than the +/- 6.75V of the mercury
> batteries but still works. The lithium cells have slightly more mAh
> capacity than the mercury cells and a much longer shelf life which
> works well for the 750A as the protection circuit draws very little
> current. Don't disable this protection circuit, it's too easy to fry
> the divider string if you're not paying attention.
> Thanks - Steve
>My guess is that the trip voltage will be changed a little bit, but not
>enough to allow damage in case of overload. Sounds like a reasonable
David Garrido wrote:
> Hello All,
> I posted this over at the HP yahoo group as well, so pardon the
> redundancy if you belong to both or more.
> My new to me Fluke 750a reference divider arrived last evening and I
> have been having one heck of a time finding info on replacement
> battery options others have used on their 750a's. Fluke spec'd (2)
> 6.7v mercury cell batteries for the overload protection circuit and
> these are clearly no longer available. What is everyone using for
> power? I am hoping to not use a separate DC supply for this app.
> The only manual I can find is here:
> I have been able to find Wein batteries that are 1.35v zinc/air and I
> could stack and shrink wrap 5 of those in series to arrive at 6.75
> very stable volts, but they are a minimum of $4.50 each cell. I was
> hoping to find a more affordable / elegant solution.
> Will the circuit handle (2) 3.6v Li-Ion in series instead?
> Any thoughts?
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