On Sun, 31 May 2020 16:43:04 +0000, Jan Panteltje wrote:

> I have 2 Canon A470 camera, those also uses 2 AA.
>
The K100 uses 4 x AA.

> I was experimenting last week with an other thing with 2 AAA and
> replaced one AAA with a dummy battery, and the other with a Lifepo4
> (about 3.2 V nominal).
>
This was a while back, and I'm convinced it had more to do with the very
poor quality of NiMH batteries which were all that were available at the
time. I eventually discovered Maplins Hybrids which worked well in it and
didn't fail on 2nd or 3rd charge.

Four years ago I went to India and decided I needed to take something
less bulky than the K100 + batteries + charger. The small Pentax was an
obvious non-starter - no viewfinder and trying the see the backside
display outside in Indian daylight was an obvious non-starter, so ended
up buying a Panasonic TZ-70 bridge camera: electronic viewfinder, Leica
lens, 12 MP. That has excellent resolution and is very good in low light
- so much so that its now my main camera.

Thanks to the TZ-70 I haven't tried putting Sanyo Eneloop batteries in
the K100 but must try it. I bet that would solve the problem.

> I charge lifepo4 on the lab supply, set voltage and current limit, watch
> the time.
>
My preferred charger is a Ripmax Pro-peak Prodigy II (a model-flying
charger) which both charges and measures capacity for SLA (lead-acid),
NiCd, NiMH, Li-ion and LiPO chemistries, though its really only good for
Li-ion and LiPO single cells since it doesn't do charge balancing.

If you need a good automatic charger/capacity measurement charger, the
ones made for RC flying and electric models are a good place to start as
they tend to be a bit cheaper than a lot of the stuff sold for charging
phones/cameras/Li-ion power packs and are generally a lot more versatile
in terms of what they can do, the battery chemistries they support, and
multi-cell balancing - the latter ability is vital if you use multi-cell
lithium batteries.

> An ebay seller ?accidently? did send me a lifepo4 charger a few years
> ago...
>
A very good battery chemistry. Somewhat lower capacity for a given
battery size/weight than Li-ion or LiPo but a lot less prone to
combustion when misused.

As with all of these Lithium-based chemistries, you should use a charger
that has a charge/discharge profile for the specific chemistry of the
cells you're using it with or bad things can happen.


--
Martin    | martin at
Gregorie  | gregorie dot org

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