[Soekris] New model net6501
lev at serebryakov.spb.ru
Tue Feb 1 20:17:44 UTC 2011
You wrote 1 февраля 2011 г., 22:24:59:
>>> * onboard NiMH batteri charger/controller.
>> After some thoughts, however, I wonder why NiMH?! How it could be
>> usable in modern world?!
> NiMH is very usable, and certainly more current than lead-acid.
Sealed, gelled lead-acid from modern UPS is very current :)
> Although not used in high-capacity cells (mostly due to patent
> issues), it works very well in small applications - it's trivial and
> cheap to get set up with 4xAA NiMH cells @ 2200MaH each and be able to
> run for long periods with no heavy battery.
Let's calculate. 4xAA @ 2200 is 1.4*4*2.2 = 12.32Wh. net6501 requires
30W PSU. So, 4xAA at 2200 is about 30min of working. And 2200mAh is
typical "true" capacity of new AA, even if they are rated as 2500 or
even 2750mAh, I'm using many AAs for photo flashes, and tested many of
them with "smart" LaCross BC-900 charger.
4xAA costs about $20 (if we speak about good ones -- Varta, Sanyo,
"industrial" not-labelled Panasonic, Energizer-labelled Panasonic,
etc, we don't speak of GP, for example, which could have capacity
from 1900 up to 2400 in one 4xAA pack).
Typical "3rd party" UPS battery is 12V @ 7.5Ah for the same $20, which
gives 12*7.5/24 = 3.75 hours of work... Yes, it is much heavier...
> An added bonus to the NiMH chemistry is simplicity of management.
> They're better off staying fully-charged than doing any discharge
> cycles like some chemistries want
But it is better to charge them with independent channels. It is not
clear, how many channels will have net6501 and which charging current
will be available.
// Black Lion AKA Lev Serebryakov <lev at serebryakov.spb.ru>
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