I did a long road trip recently and decided to use a 300W inverter plugged into cigarette lighter socket to provide power to the usual 57W charger. Worked fine and kept 4 battery packs and the remote controller fully charged throughout the trip. I did notice some interesting observations after inadvertently disconnecting the inverter prior to the battery being fully charged. I observed the charging routine very closely afterwards and noted the following: Usual charge times are 1hr & 10mins/20mins always. I accidentally powered off after 40 minutes charging. Powered back on straight away. LED's on battery did not illuminate and battery did not charge any further. I then used that battery on the next flight. Battery at 100% charge and all cells same voltage.Worked fine and recharged fine. I stupidly turned the power off again after 20 minutes of charging while inverter fan was still running(doh!) and noted the following: Started the inverter and battery continued charging and completed in usual time. I then started paying more attention to charging and noted the following: Begin charging and inverter cooling fan starts - indicates high capacity electrical load. After 30'ish minutes inverter cooling fan stops - indicates reduced electrical load. LED's continue flashing till the usual recharge time is reached and then stop normally. My conclusion are: Batteries should not be disconnected for any reason during the charging phase. Top up charging is "iffy". Battery appears fully charged after only 30 minutes. Battery technology is beyond my comprehension! I don't know if this helps but at least adds to the archive of battery information.