Quote:
Originally Posted by AndrewJ
Gday Wavytone
Looking at the battery, it says it has a 5V charge voltage ( ie they say you can charge it from the equivalent of a USB port ) and can put out 12,15 or 19V.
Im wondering if this beast only has 3.3V cells and uses a DC-DC converter to get the reqd output, in which case, by the time you see a drop in output voltage, its too late.
The manual and data sheets are a joke, so cant tell more than that at present.
Andrew
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Yes, it most likely has 18650-style cells, with a cell voltage of 3.7V. That in itself is not a problem, the DC-DC inverters often have around 90% efficiency these days. However, the capacity (6600mAh in this case) is usually given at cell voltage. This means, the pack can store 24.4Wh, or a mere 2Ah at 12V.
Some of the more reputable battery pack makers quote the capacity in Wh, to remove this uncertainty. With all those that didn't that I ever encountered, the Ah figure was at cell voltage.