After 13 months of very heavy use at various events, festivals & boat trips, the Li-Po battery pack at the heart of my portable power supply has died.
What initially started as one cell inflating spread to the other cells in the pack over a period of about 3 months, so I have completely replaced the pack with a larger unit.
The old pack was an 8.8Ah unit at 12.6v. By using smaller burst capacity cells, I have managed to squeeze in a total of 13.2Ah, still leaving space to spare for an extra 3 cell string along the top.
Here is the end of the battery pack, with all the cell interconnects. There are 3 2.2Ah cells in series to give the 12.6v terminal voltage, with 6 of those strings in parallel to give the total Ah rating.
A new charging circuit will be implemented to better handle the volatile chemistry of Li-Po cells, hopefully this will result in the pack lasting longer than a year!
The new higher capacity will hopefully help with power requirements at future events, still being charged during the day by a 24W solar panel, but at night will have to cope with charging two smartphones, two eCigs & running a few watts of LED lighting.
The trial-by-fire will be this year’s Download Festival in June, when I will be operating off-grid for 6 days.
More updates to come on improvements & failures!