jrdetar

Is any amount of swelling or puffiness acceptable with a Lipo?

I have 2 recently acquired Thunder Power 2S 1900's. Ater a hard landing, the one pack has a small amout of puffiness (approximately 1/8") compared to the other pack.

The pack re-charged up fine on the AstroFlight lithium charger. Went through the whole three stage process fine in about 35 minutes at 1C. (Yes, I charged it outdoors, on concrete, with a bag of sand arched over the pack on the ground).

Should I be concerned? Should I write off this pack?

Greg Covey

Jim,

I have used packs like this without issue. It is possible that the puffyness was already there before the crash and the crash only made you notice it.

Some puffyness can occur in Lithium packs if you approach the current limits of the cell or the voltage limits of a charge.

I have some packs that have gone back to normal size as the gas escapes. The pack may also just have been squashed a bit so that the extra thickness is not from internal gas. These packs seem to work as well.

If the packs has an open gash, then you should discard it.

Mike Parsons

The two easiest ways to see if a lipo is headed south is swelling and odor. If there is ever a sweet smell coming from a lithium, soak the entire pack overnight in salt water and discard. This means that you have a seal leak. Swelling is normally not mistaken however as if it is danger, it is very noticable.

-mike

jrdetar

Greg,

Thanks for your reply.

I flew the pack yesterday, and recharged it after the flight. The puffiness is gone!! Also put up a flight with the second pack. Could notice no difference between the two flights/packs. Maybe pack longevity will be effected.

Will continue to charge with sand, concrete and watchfulness, and store/transport the batteries in the Sentry fire proof safe.

Matt Kirsch

My Feedback: (21)

...and you thought nobody would touch it with a 10 foot pole.

I thought of this last night after the club meeting: You might want to check cell balance from time to time if you don't already. The ballooning might be indicative of some minor damage, and over time the cell could start to self-discharge at a higher rate than the rest in the pack. Charging an out-of-balance pack has proven to be interesting.

PortCityFlyer

My Feedback: (1)

I am flying a ESPAD 3D with GWS 350 6.6/1 and 12 x 6 prop. I have been flying this aircraft with kokam pack and recently bought a Thunder Power 2 cell 1320mah. I flew the aircraft three times with the Thunder Power using a Triton set at .4 amps for charging. During the 4th flight the pack was not providing the usual power. On inspection I found a swollen pack with two tears in the foil. One tear was charred. I thought these were high quality cells but now I will stick with Kokam. My Kokam has seen much higher useage and has been in a few boinks while the Thunder Power had not suffered through any significant boinks. Yeah for Kokam - boo for Thunder Power.