What will cause a battery to puff. I have a Tracpower 4S 5400mah 50c battery that I haven't used much. I charged the battery a week ago and never got the chance to use it until yesterday. When done the battery was puffed out. Will this battery still be good to use? The battery was never overcharged and was stored with correct voltage but sat all winter. I searched for this issue but the search function brought up too much to filter through. I just need to know what I did so I don't do it to another battery. I'm also in need of a good charger for these batteries, what would be a good choice that will charge at least 2 at the same time? I really don't want to spend more than $200 but would like to stay under $150. Thanks for any help. Ed

Leaving a lipo charged or discharged is the worst thing for them. Put them in storage mode when you are not using them.

Another thing is trackpower batteries don't use very durable cells. I've had 5 trackpower packs over the last year or so and they always swell up. Even with proper usage and storage. Vant batteries, Fantom batteries, smc batteries, LRP, venom... these are all good packs with very durable cells inside. They usually need to be mis treated for a long time before they start showing signs of fatigue and start to fail.

Personally I wouldn't use the puffed battery because the batteries are cheaper than the car with electronics. Look at it this way. The battery is cheap compared to replacing everything if it were to go wrong.

You should never leave the battery fully charged for more than a few days. It's better to even run a little bit of a discharge on it on your charger just to take off the pressure on the cells even if you only take them down to 4.0. Ideally taking them to storage charge.

The battery puffing up may not necessarily have been due to its sitting at full charge you could've overtaxed it causing it to puff up, I've done that with batteries in my MonsterTruck. Do you have a picture of how much it puffed up? A little or a lot?

Regarding the batteries in the off-season you should really cycle the batteries at least every 2 to 3 months. Do a full charge, a full discharge, and then a storage charge. It helps their lifetime. It's a bit of a tedious task to have to do but I do it on my batteries and it has extended the lifetime of many of them longer than I thought.

There are lots of good chargers to choose from. If you're willing to spend $200 spend just a tad more and get this one, I have the earlier version of it ( that did 7 A in and 2 A out ) and it is a phenomenal charger. With that much power to charge and discharge and storage charge and four ports that gives you a lot of flexibility and saves you a lot of time ... Well worth the money in my opinion. Particularly if you have a lot of batteries and don't want to waste a lot of time sitting around. And realistically what's another 50 bucks over the course of 5 to 10 years?

https://www.amainhobbies.com/protek-...k-8517/p488513

Heat makes them swell. Hard cases do not let them get cooled off. The battery's need cooling just like motor or esc. Hard cases on the battery's is not smart. It's a scam. You have been duped. I have a mountain of lipos. (Car planes Heli) most if not all have puff! There's a bunch of info about cooling discharging Lipo cells. http://ideaexchange.uakron.edu/cgi/v...earch_projects And many others. But whatever.

It's not a scam man. It's insurance. There's a reason ROAR and IFMAR or any other respectable race organization requires hardcase packs. I agree they need cooling. But he hasn't been duped.

That's a good charger for 2s/3s lipo but I'm pretty sure at 4s you'd only get around 5a or less. That's be quite the slow charge but if the time it takes is no biggie then it's great.

I have mixed feelings about hard case packs as well, but to the OP's point... there really is no danger in leaving packs fully charged provided you follow very specific restrictions. It's generally a bad idea to vary the ambient temps of the charged state where an increase in temp will also increase voltage. So let's say for example, if you charged your pack inside at cool 72°F then stored the pack outside in a hot garage with 92°F+ temps then that would easily cause the pack to swell in no time.

I have heard of cases where folks charged all their packs at home (brand new never before used), and placed them in the trunk of their car just long enough to commute to their favorite bashing spot and by the time they arrived, every single one of their packs were swelled up and had to be discarded

I make it a point to charge my packs at the same ambient temp that they will be used and I also try to minimize the amount of time the pack is fully charged to ensure the longest lifespan possible, more info here:
Is it bad to store my LiPo at full charge? - Electric Motors, ESCs, batteries, etc. @ URC Forums

Take a look at The ultra power UP120AC dual battery charger and under $150 look on eBay or Amazon...
I have had mine for over a year and it's the best $100 I spent in this hobby...

Bill,

Do you place your lipos in the refrigerator with some sort of bag (lipo bag or zip lock bag)?

Thank you so much for the link and fantastic knowledge.

Based on my experience and reading credible posts I like to charge my lipos at the track and will always discharge a fully charged pack before I go home. If I ran the car I may discharge it when I get home as the voltage has already been somewhat depleted. I do not leave my packs fully charged. This may help my fellow racers/bashers....

Many years ago I had experimented with storing my packs in a mini-fridge (out in the garage) to keep them reasonably cool, but over time this didn't work out for me. I live in a relatively humid area and condensation would quickly generate shortly after pulling the cold packs from the fridge and rust started forming on the connectors/tabs causing premature wear.



I eventually migrated to keeping my packs installed in each car and storing all my equipment in an HVAC controlled hobby room that is adjacent to my garage.

For NiCd and NiMH that is fine but for Lipo I would definitely keep them in a fire safe box away from the cars.
I've not touched my RC cars and its Lipo for months, but every other month I go back and check storage voltage
to make sure the cells do not drop below 3.80v. (I keep them 3.80v to 3.84v range)

Soft pack LiPo batteries are fine for off-roading. You just gotta make sure they are very secure in battery tray. Negate the possibly of the batteries bouncing around while you are tearing up the place. Tiny rocks with pointy edge, and soft LiPo packs...not the best combination to have while lollygagging, or bashing RCs in loose terrain. Take precaution and they are fine.

I still have my first LiPo packs from 2010. Two soft, and two hard cased packs. Along with two other soft cased LiPo packs dedicated for one platform, they all "swell" after a good run. The swelling, in my case, is not noticeable to someone just looking at the packs. You can feel a bubble after a run, but as the packs cool down the pack's case shrinks back to normal size.

A swelled pack with a visual bulge, or hard case split open...now that's bad. You start smelling a sweet odor from a warm pack...that's bad news as well in my book.

Someone commented about the Ultra Power UP120AC Duo charger...I think they are a great value if you want to charge at modest levels.

I think it's a difference of opinion for what strategy works for you. My theory is that storing all my LiPo's in a single fire proof box would easily create a chain reaction causing a significantly larger fire with far more toxic smoke than a single pack would produce. Most of my cars have an aluminum chassis with the battery tray opposing the rest of the electronics. I think it will be less expensive to replace a melted battery tray + Lexan body than to replace 10+ LiPo packs

There are pro's/con's to every storage method and I understand the risks that I'm taking... another concern I have is any potential increased risk of storing too many packs together with having 2 or more packs short each other out... I would want to ensure that the connectors had some sort of covers over them to prevent any short circuits while in storage