Quote:
Originally Posted by mill
Ok everyone seems to assume a laptop is running on full power all the time 
That is not true at all.
A laptop will only use full power when everything is set on full and you use the full processor cycles (eg stacking or long calculations).
The power supply only charges the internal batteries and the amperage fluctuates between 0.2 and say 4 Amps when charging the batteries while using the lappy (measure this if you don't believe me  ).
The rest of the time there will be just a trickle charge.
When there is no battery in the lappy the amperage will flutuate a lot more.
Just my 2 cents here about lappy's. |
Agreed - Jaycar told me the DVD player is usually the culprit in laptops needing more than about 2.5 amps. I ended up buying a more expensive higher amperage converter. In their words, you don't want anything going bang when you accidentally put in a DVD at the same moment the laptop is going flat out on something with the disk drive running and every USB port plugged in. Unlikely but could happen in the field....
My Acer laptop is rated at about 3.5amps, but only seems to draw 1-2 amps in the field. I've written a basic script to blank the screen when I'm imaging and leave it alone for a while.
Another option is to buy something like an EzyPC that draws about 1amp. Won't help with dew heaters etc though.
I bought a deep cycle AGM from this ebay seller without troubles:
http://stores.shop.ebay.com.au/best-...34Q2ec0Q2em322
Worth including cost of a decent charger too to prolong battery life - not cheap.