Can I rescue a Lipo

[sd330ml]

I have 3 1s500mahl lipos for a sr120, if I use them when fresh charged I get a good 5 min flying from them but if I charge and leave for any time at all lucky to get 1.5 min
am I to late or can I rescue them
thanks

stuart

[jamiem]

All lipos degrade when left charged, so can't you only charge them when you know you are going to use them? I charge all my big lipos the day before I'm going to use them for this reason

[cjcj1949]

There are a lot of rules with lipos if you want them to last. The real problem is that the specs tell you what you can get out of them but not how long they will last if you use them flat out. Some lipos are much better than others as well. The major rule is not to use them until they go flat. Only use about 80% of the capacity, more batteries and shorter flights are even better. They don't work so well in the cold so try to use them above 20 degrees C. When not in use store them at 3.85V a cell, that's called the storage charge or voltage. Some lipos can be charged at 2C or more but some not so good ones need to be kept down to 1C. Lipos rates at 25C or above are usually worth getting. Lipos are said to be dead when the initial capacity is down to 80% of the original. If your lipos are down to 30% after a few days then they may be leaking a lot of current and could be about to die with lots of flames. It's more likely that the internal resistance has increased a lot and that you are managing to lower it by charging. Warming the cells up to body heat will help a lot, but I wouldn't keep them close to any valuable personal equipment.