I use a Sky D100 LiPo charger to fast charge, slow charge, storage charge, Balance Charge and Discharge as well as Resistance check my LiPos.

All in one place and very good at what it does really well - and can Independently charge two at a time (or one).

They come with a pair of balance boards and a selection of charge leads as well as a good instruction book.

These can be bought new or used - I bought my last one used from eBay at a very good price!

Also available as an Overlander RC-D100 and well worth looking out for.

Bob.

@PeterN
Thanks so much for the advice Peter.

When I bought my first LiPo battery I asked the seller for a charger and was surprised when offered a cheap charger which did nothing else but charge and gave you no information. Fortunately I'd picked up enough by then that a smart/intelligent charger was needed so bought the Turnigy Acucell which has been really good. Unfortunately they stopped supplying with the mains charger and then discontinued completely.

That's a nice bit of kit Peter and does have some functions that chargers don't have (does it do resistance?) but its cost would go a good way towards a quality charger that does include all the functions for safely dealing with LiPos etc. and is as accurate as needed.

RC-D100 Charger.

A decent charger like the Overlander (rebranded Sky) RC-D100 probably has all the functions needed to charge, maintain and check the LiPo batteries that I currently use in my R/C Boats, Tanks, Helicopters and Racing Cars.

I have used RC-D100 chargers like these (both brands) since they first came out several years ago and I keep them in my workshop and also one in my van for use when I am away from home.

Charging a LiPo ready for use and then not being able to run it for one reason or another (like unexpected rain!) can catch us all out now and again and I admit that I don't usually bother to lower the voltage to the suggested "storage voltage" very often (if at all) if that happens, but leave it fully charged until I can run it again.

My LiPos are usually charged to 98% and seem happy enough, and I still have some of the original LiPo batteries that have been kept and used like this for many years and they are ALL still running very well.

My recent experience with two Turnigy LiPo batteries is the exception, and I am thinking that this has very little (if anything ) to do with the way they have been balance charged (or stored) from new, but more likely that they are faulty in some way ........but still working and giving good resistance readings........albeit with "puffy" heat shrink coverings.

I will continue to monitor these two LiPo's very carefully , but I may just decide to dump them both and accept that they are the only two LiPos out of the hundreds that I have owned (ever since LiPo batteries first became available) that have a covering that has given me any cause for concern.

Better safe than sorry ...........even if they both still work well and both have good low resistance readings .

Bob.

@AlessandroSPQR I think it is best to invest in a good Lipo checker, I using a ISDT battery checker and that gives me the information that I need.
You can also use this to balance the cells which is also important when you store them for a longer period of time.
Yes it quite an expensive piece of kit but when your charger does not have a storage function, which I actually do not always trust, this thing will do the trick

I agree with Chris.
I'm very interested in this discussion because in the future I want to try LiPos on a planing hull model ship.
I also know that LiPos should not be stored either discharged or fully charged; ideally, they should be 40-45% of their maximum charge, at around 3.80-3.85 volts.
When I used LiPo batteries for a few years (for various types of drones not for recreational use), I remember that storage was guaranteed by certain stations that brought them to an ideal state of charge for long-term storage. Just as Chris said, they were fully charged before the flight.
The charging and maintenance stations were professional and very expensive, dedicated to that type of technology (with housings not interchangeable with other types).
Unfortunately, even though it wasn't that long ago, I don't remember the precise measurements of the batteries in storage because the stations had colored LED indicators, not numbers. Therefore I rely on theoretical knowledge provided by manufacturers and sellers of LiPo batteries.

As Peter says that could well have been the problem, though it is strange that the puffing has only happened on the two that you have used.

Your charger will have a storage charge function and should charge to between 3.75 to 3.85 volts. Good practice is to keep them on storage charge and then fully charge the day before using and then put them back to storage charge if not using for a couple of days rather than fully charging.

I was afraid of that, Lipo's are quite sensitive and should be stored at storage capacity however it is a bit of a guess depending on the make and capacity. Small Lipo's seem to be more resilient to degeneration compared to big 1500 mAh + batteries when stored fully charged

@PeterN In all honesty probably close to full capacity ready to drop into the boat.

This goes for all 4 batteries including the two that have “blown” and the two that are perfect.

All 4 batteries were bought at the same time and all 4 are working OK.

Bob.

@zooma how did you store them, fully charged or at storage voltage +/- 20% capacity