Hi Bob

When looking at a Lipo battery you should understand how the cells work firstly. The cell is a wrap of basically two films separated by a gel allowing the voltage to be generated and stored. This is called the dyelectric and is the main cause of bloating the cell if it begins to breakdown. When you look at the internal resistance of the batter is show the health of the cell below 10 is OK. If the gel is damaged between the two films or one of the film coatings is damaged you will see the internal resistance climb.

Once the cell is bloated it is no longer considered normal and can become unstable causing gas to be released its very rare to explode (its called thermal runaway and can reach 500 plus degrees and is normally cause by internal issues or a dead short of the battery) . I would suggest being very careful with storage and charging ie not to 100 percent.

So what causes this :-

1 temperature operating outside spec which I cannot see you would have done this.

2 over voltage never take it over 4.2v on a charge or discharge below 3.2v. There is a rule for storage between 75 and 80 percent.

3 over rating current draw. Your battery is 25 to 30c which means

25 x 5000(ah capacity). = 125000 which is 125 amps which is continuous discharge. Which is higher rated than the speed controller.

4 manufacturers issues weakness. Its possible but as you have another 2 batteries with same batch number I would. Monitor them.

5 charging at low temperatures below 0 degrees which most chargers block.

I know no definitive cause is clear which is a problem. I would just monitor the bloating is does look slightly but any boating is not good. Keep them in isolation bag and only charge to 80 or 90 percent.

I terms of fixing the bloating there is nothing you can do. There are no ways to fix the battery.

Hope this may help

Adam

Carry On (for now).

The two bloated 3C LiPo packs that I have been using in my Remora were checked and charged again this evening.

LiPo 1. Before charging the cells resistance was 3 4 2. After charging to 98% the resistance was measured again at 4 2 1.

LiPo 2. Before charging the cells resistance was 3 5 2. After charging to 98% the resistance was measured again at 4 2 2.

Both LiPo packs remained cool during a Balance Charge at 2.5 amps.

Before charging the voltage on both packs measured the same as each other (3.9 3.9 3.9 volts per cell) and were also the same as each other after charging (4.16 4.16 4.16 volts per cell) so both packs still have perfectly balanced cells.

The above readings continue to confuse, I will keep these two packs in a fireproof LiPo sack and continue to use them with caution but monitor them during use in the boat and during charging.

Bob.

Still Working Well.

Both of the “Bloated” LiPo batteries were run in the Remora again this morning and both worked OK.

Both were checked to see if they were running at all hot, but both were only very mildly warm after a full session of driving the Remora “briskly” around the lake.

I will check them again this evening as they are both being balance charged and take a resistance reading both before and after charging as well.

At the moment these cells are the cause of some concern as they are definitely swollen, but both run and charge perfectly without getting hot and both have very low resistance readings.

I am more than happy to dump them both if they show any signs (other than the swollen heat shrink covering) of getting hot when being run or during charging - or showing any high resistance readings, but it would be a shame to throw away two perfectly good working LiPos when both of them display no fault other than a bloated heat shrink covering.

Bob.

Double Bloated.

The picture I showed on here yesterday of the LiPo in the Remora hull identified it as NOT being the same LiPo as the one I noticed as being “bloated” - as it was marked Remora 2.

The “blown” LiPo that I had concerns about was marked Remora 1.

I remember when HobbyKing had an offer on these LiPo’s that their postage costs made buying one a “non-starter” (their LiPo delivery costs to the UK are very high) - so I bought 4 of them to make the cost per battery more affordable.

I marked them as Remora 1, 2, 3, and 4 although they were not all necessarily going to be used exclusively in the Remora hull, it was a way of identifying them.

I took a look inside the “fireproof” LiPo sacks that I store them inside and took all 4 of them out to be checked.

The LiPos marked Remora 3 and 4 had only been charged once - probably after delivery to check they were OK and to see if the cells were balanced. These two LiPos coverings are completely FLAT with no bloating of the heat shrink coverings.

The LiPo marked Remora 2 had only been charged 5 times, and it was found to be almost as bloated as the one marked Remora 1 that first caused me some concern after it had only been balance charged 8 times.

This does prove that all 4 of these LiPos had FLAT heat shrink coverings when they were new (I would have noticed if two out of the four had puffy coverings) and that only the two that had been used now have “blown” heat shrink covers!

The answer to keeping these particular Turnigy 5000mAh LiPos safe is seemingly NOT TO USE THEM !

This may be a bit severe and I will check the resistance of all 4 packs, but the two that have bloated have only been used in the same Remora hull so I would not think they had been put under any great strain in use whatsoever.

This does cause me some concern as I have no reason to suspect that the two unused cells will not also puff-up their coverings when they are actually used.

All of these LiPo’s have only ever been “balance charged” from new at 2.5 amps, which I don’t think is an excessive charge rate for them.

The two that have been used have powered the small Surpass C3548 1100KV out-runner drive motor via a 90amp SeaKing “forwards only” ESC and have not been allowed to run down low enough to cause the ESC to cut-in and stop the power delivery before it could drop below the terminal voltage.

After each run the Remora was always driven back to shore when still able to deliver its full performance, and when re-charged the LiPos still had around 40 - 50 % Fuel in them, so they have never been allowed to run too low.

At the moment I am thinking that I may have bought 4 “duff” Turnigy LiPo batteries, but until number 3 and 4 have been run I wont know this for sure.

Bob.

All of the batteries I use in my larger models are 35C which I think I arrived at when researching when I first got into the hobby.

Problem is that most manufacturers overstate the capacity of their batteries, though the better brands do it less so. But even for them the reality is probably that the capacity in use is less than that stated due to what I mentioned earlier, the internal resistance. Whilst your figures were very good some of the power is still being used to provide heat (all batteries heat up to some extent when being worked). One of the links I posted earlier, the detailed one, says that the actual capacity can be a lot less than the manufactures stated and so like with an ESC it is better to err on the higher side I think.

It's interesting that they quote a range of 20-30C rather than a fixed value like other manufacturers, wonder why that is?

I think the bottom line though Bob is that you now have replacement batteries and the existing one is always going to have a question mark over it in your mind so the best course of action is to dispose of it.

At least with the new ones being stated as 50C you have some leeway. That's what I was going to get for my Swordsman as it needs a 4S and being a bigger heavier boat than my others and requiring a higher rated ESC then components are going to be worked a bit harder.

Chris

Edit: Did a search and this was the AI response. And this from Overlander Batteries. https://overlander.co.uk/understanding-c-rating-how-much-power-does-your-rc-need/?srsltid=AfmBOorrB2PDzzkfQNsfYcLrhkV4nKw2HfLwjSE3VOEc3llT26Hpl0Gf

@zooma at 20c you are assuming a greater disscharge than 100 amps, thats quite unlikely, have you measured how many amps you're using? Sounds like a duff battery to me

Wrong LiPo Choice?

I have only ever used this battery in my Vic Smeed Remora, and I am wondering if the spec of the battery is not good enough for the boat?

The 5000 mah bit is impressive, but the 20-30C Discharge bit may be where the problem lies?

Maybe I am grasping at straws here to try to find a reason why this LiPo has swollen after so little use?

The Remora is quite a nippy little boat, but it is also quite a lightweight little boat that is only 30” long, so maybe it is just a “duff” battery?

Bob.

In one of the high performance laptops the first indication that you have battery issues is random keyboard problems but I have seen some bad cases where the whole case has distorted as the battery bloats

Hard Case.

I share Chris’s observation that a hard cased battery could make it harder to detect if the cells inside the case are swelling?

All of my Overlander LiPo’s that I have been running in my Rapier 1 and my Kopy Kommander are also hard cased.

I am guessing that if the LiPo cells do start to deteriorate and swell they will easily be capable of pushing the two halves of the plastic case apart?

I have been running LiPo batteries of one sort and size or another since they first became available initially for use in r/c helicopters where for the first time they provided a “power to weight ratio” that was good enough to allow a battery powered model helicopter to be able to fly!

This was rapidly followed by their use in competition r/c racing cars and r/c model aircraft where they are now almost universally the only choice of battery chosen to power them with.

I still have some of these early(hard cased) LiPo battery’s that must be 30 plus years old - and I still use them to power my 1/10 racing cars - and they are still able to power the cars competitively against those drivers that have the latest (and most expensive) types of LiPo available.

Interestingly, I also have some of the latest type of racing LiPo battery packs, and they are no better in power output or duration than these originals - and for many years these original LiPo batteries never had the benefit of being charged with the sophisticated types of charger that we have today!

Different balance plugs were used on these early LiPos to those that we use today, but fortunately I still have some of the matching period balance boards that I can plug into my current chargers - so I can still charge them!

These early LiPo helicopter batteries were made in Malaysia. I have no idea if any are still made there any more, but their production quality must have been superb.

I wonder how many of our current LiPo manufactures are capable of making LiPo batteries that will still be as strong in 30 plus years as these are?

My current Turnigy LiPos that have been mentioned here never got as far as having 10 charges from new before swelling!

………quite some comparison…………

Bob.

Bob, if that was my battery it would be condemed

The two LiPo batteries that I bought from Amazon do look like they are good value for money (for the specification), but time will tell if they can perform and last without any problems.

I put them on my charger just to see what condition they were delivered in. I only have one charge lead with a Deans plug on it so both were connected to the B output (the lower scale on the charger) .

The first battery came with 48% Fuel and the three cells were closely matched.

The second battery came with 47% Fuel and again the three cells were also quite well balanced, but no doubt both battery’s cell balance can be improved after some balance charging to align them even closer to each other?

Overall a good pleasing start.

Bob.

As regards the bulging it's difficult isn't it. I've come to the conclusion with mine that it isn't puffing and that it's the heat wrap - I hadn't looked at the battery for awhile and as I said it's probably always looked like that?

But with yours it has obviously changed for you to notice the difference, not much but enough. But the readings say it's OK. A quandary!

Those new batteries look like hard cased? At least you won't be able to see any puffing with those! 🤔 They are a good price though as one battery can be getting on for that two-pack price and good spec. for the price.

Roaring Top LiPos from Amazon.

I saw these battery’s on the Amazon UK site at a fair price and so I thought I would give them a try, they came with a free next day delivery - and here they are!

The size will fit into the Remora’s LiPo retaining frame that I built into the hull so I can use them without having to alter the mounting in any way.

Although “taller” than the original Turnigy battery, the length and width are the same so they fit well and the extra height still fits easily under the rear deck cover.

……I am still not sure about the swollen Turnigy LiPo….

Bob.

Trying to show the bulged heat shrink covering in a photo is proving to be much more difficult than I thought it would be.

When squeezing the LiPo the covering can be pushed in and out in what feels like quite a lot of movement.

The pictures don’t really show the bulging anything like as much - but here is a picture of each side anyway to show the front and the back as both are swollen
.
Bob.

@ChrisF I appreciate your research & subsequent comments regarding resistance testing. That said I appreciate even more your saying you dispose of a suspect pack immediately. The cost of the battery V the cost of the risk is overwhelming. That’s my two cents worth.

@ChrisF I appreciate your research & subsequent resistance testing. That said I appreciate even more your saying you dispose of a suspect pack immediately. The cost of the battery V the cost of the risk is overwhelming. That’s my two cents worth.

And this is worth a read. Same sort of info. but goes into more detail.

https://www.rchelicopterfun.com/lipo-internal-resistance.html

I tripped into the internal resistance thing when I was searching for other info. on Lipos a year or so back. As the guy says rarely mentioned but very useful.

Like you Bob, I'm very wary of Lipos and the slightest hint of anything being up with them then the defective battery will be gone. I take all my spent "normal" batteries to our local tip/recycling centre as they have an area specifically for batteries. Not sure they would welcome a dodgy Lipo though! I've read about that salt water method as well.

Chris

@ChrisF That is very interesting.

Hi Chris,

I did see your post number 12 thanks, but I also found the original charger handbook under the foam packaging at the bottom of the box. It had plain white paper covers over the printed handbook covers so it was very well disguised under the white foam !

The handbook also gave the search sequence to call it up onto the screen which was helpful as this charger has a LOT of functions available.

This has proven to be a helpful blog as it suggests that there is nothing wrong with my battery…….but I admit to buying a replacement from Amazon last night that will be here today !……so now I have a useful spare (of the right size to fit the Remora battery box) as well!

I have tried to picture the bulge for you in the previous pictures I put on here, but the bulge is not big enough to make a significant difference to the profile of the battery but is is very easy to see and feel the bulge on the top and the bottom of the battery.

If it should get any worse (and bad enough to make a good picture), I will not be keeping the battery, no-matter what the resistance figures tell me - because I am naturally nervous of swollen LiPo batteries - but for now, I am happy enough to give this one another outing in my Remora - but I will be monitoring it carefully for heat and swelling both when in use and during charging.

Thanks for your help.

Bob.

Just done a search based on internal resistance of Turnigy Lipo batteries and the AI response pretty much validates what I've said.

Hi Bob, did you miss my post #12!

The symbol is for Ohms and so the measurement is milli-Ohms. Anyway, those results are very good, as I said earlier, the lower the better. Mine were higher than those and varied by a greater amount. So on that basis and the fact that the cells charge to a good and equal voltage I'd say the battery is fine.

To be on the safe side I'd still charge outside though and check how hot it gets after use, getting warm is normal. The risky times for LiPos are when charging and when being worked hard which is more applicable to race boats being driven fast for lap after lap. Your white water but relatively short run times shouldn't cause any problems.

Still be interested to see the puffy part of the battery.

A check of my 2S batteries also gave higher readings than yours at 6 and 7 for one and 8 and 5 for the other, which from what I've read are fine. My 2S and 3S batteries are 3300mAh which I think are lower than yours - I mentioned that resistance tends to be lower the higher capacity you go, which probably explains the lower readings you are getting compared with mine. Out of interest I checked one of my small capacity LiPos yesterday, 7.4v/1500mAh and the results were in the 20s which seems to bear this out as did a 7.4v/2200mAh with results of 16 and 15.

Battery Resistance.

I have found the Battery Resistance Meter on my charger and recorded the results.

The charger shows the numbers followed by a small “m” and what looks like the outline of a tree. I have recorded this second figure here as an “A” as I have no pictures that look like a tree on this keyboard !

The battery with the “puffed” heat shrink cover that I have been using on my Remora is a 3 cell LiPo and has given the following readings:-

Total:- 5 mA.

Individual Cells:- 1 2 2 mA.

I have no idea what this means except that all the readings are very low and that one cell is lower than the other two.

My way of comparison (only), I took one of the two cell LiPo batteries out of my Kopy Kommander and put it on the same program and got the following readings:-

Total:- 4 mA.

Individual Cells:- 2 + 2 mA.

Any help with identifying exactly what the reading for the 3 cell LiPo that has the puffy heat shrink covering tells me about its safety would be greatly appreciated as I have no idea what it means, other than identifying that one cell has a lower reading than the other two cells.

The comparison with the 2 cell battery from my Kopy Kommander has not helped much other than to note that both cells also have low readings of 2 mA that are the same as each other.

Bob.

Just as you suggested Chris, my charger does have a Lithium Battery Resistance Meter.

Page 21 of the Overlander RC-D100 charger shows this function and how to read the display.

It can display the highest resistance, the lowest resistance and each cells resistance.

I am not sure what to do with this information, but I will gather it now and see if I can find out if this LiPo is safe or should be disposed of .

Bob.

The Turnigy battery that I have is no longer in stock from HobbyKing , and has no delivery date.

Maybe after blowing following only 8 balanced charges at 2.5 amp I should try a different type anyway?

WhenI looked this afternoon they had fewer LiPo batteries in stock than I can remember seeing there before.

Maybe they are about to re-stock?

Bob.

Turnigy batteries are good but what is available at any one time tends to vary. I use Giant Power (which Dave Milbourn recommended to me) from Component Shop and Overlander Batteries.

Hi Chris,

We have just walked back from Ainsdale Village and it is really hot, but later I will get the charger out and run through the menu options.

To be honest, I have only ever used the charger to charge and balance my batteries and have never used it for anything else, but knowing about the resistance of each cell is not something I had thought of previously, but if it can be used as a “heath guide “ for each individual cell, it would make sense to check it now and again - if especially on a LiPo pack that has a puffed sleeve covering like this one has.

I chose this particular battery to fit in my Remora and made a close fitting battery holder to keep it safely located during use. I think I will check to see if they are still available or if I can find any other 3 cell LiPo packs of this overall size and shape as I think a replacement may well be needed in the near future……and it would be good to have one here ready !

Bob.

Hi Bob

That's my servo and battery checker. My charger is a Turnigy. If I was buying now I'd get an Overlander as I buy a lot of their stuff and the Turnigy has been discontinued, good charger though.

If you haven't got the instructions they are available to download from the Overlander web-site. This is the relevant page.

Hi Chris

Thanks for your contribution.

You also use an Overlander LiPo charger (these are FlySky re-labeled as far as I know) and I have found them to be very accurate and reliable - but I was unaware of their ability to check the resistance, so I need to scroll through into “unknown areas” until I find it.

I always check the temperature of my motor, ESC and LiPo after every run (nothing clever - just by touch) and I have never had a “hot” LiPo yet, but they do usually feel slightly warm.

This LiPo does have a slightly “puffed” cover that can be pushed in and out a little - like it has some air trapped between the heat shrink and the battery itself.

I will see if I can find the function to check the resistance of each cell, but the LiPo charged normally up to 95% (when I stopped it) last night and each cell had the same voltage reading, so the pack is still balanced nicely.

The heat shrink covering is very tight at each each, so any gas (or air when the pack was made and covered) may be unable to seep away, but I would have thought that any gas (including air) that was under pressure would be able to leak its way out ?

Anyway, the battery has now had 9 balance charges from new, has good balanced voltage readings on each cell…….but it still worries me (a little) so I will search for that internal resistance measurement function on my charger and see if I can find it.

Bob.

Hi Bob

Your charger may be able to check the internal resistance, mine does and yours looks like a good one. As for values, when I checked my 3S I got 7, 5 and 6 milli-ohms for each cell. For info. search for "internal resistance of Lipo battery". But note that any checks will only give you a comparative result as they vary on battery temperature and charge. Hence my comment to check when new to give a baseline. The lower the better but the results will vary on the capacity of the battery.

With my battery, looking at it more, I think it is due to the heat wrap being tighter at the ends as the curvature is only slight from end to end - see photo. What does yours look like side on? I need another one anyway and so will get the exact same battery and compare it.

Lipos can start to puff if worked too hard, did you notice if yours was hot? Some guys carry on using them if they puff but in less power hungry uses like torches - no bloomin' way!!!

For the number of charges you have carried out there shouldn't be a problem with your battery so maybe it had an issue from the start? That's why the internal resistance check is useful as comparatively it will show if a cell is much different from the others.

Jumpugly - I've got a couple of those little units. But bought mainly to use for servo checking as I prefer to use my battery charger for battery functions as it cost somewhat more and I trust it more!

Chris

Edit: Just checked again and internal resistance is 8, 5 and 5 with each cell being at 3.82v. I've had that battery for a few years now but those values are fine.

DaveyBoyzToyz fun run at the Babylon town park yesterday. Damn Lipos...and the mighty effort to save a gorgeous Chris Craft Corvette. 🙄😬😪

https://www.facebook.com/1479377005/videos/pcb.1729376108185245/1580268093488445

As much as I complain about lipos. This particular video and the item it describes has been invaluable.

What to Do?

At the moment I have put the LiPo into a “LiPo Safe Bag” while I give the situation a little more thought.

Like Chris’s LiPo, this battery may have been a little bloated when I bought it from new - it certainly wouldn’t be the first or the only one - but I do think that this one is a little worse now.

I am not sure how to check the internal resistance or know what is an acceptable reading, but I would like to find out both.

As far as disposing of a LiPo is concerned, back when we were first using much larger LiPo packs for large r/c helicopters and large 1/5 scale racing cars, we were advised of a method to dispose of them that worked and made them safe .

The method was to place the LiPo in a bucket of salt water and leave it for 24 hours (or longer). This had the affect of completely draining it and leaving it “inert” and safe to dispose of.

That was a long time ago. If anyone has any other more up to date method of rendering a LiPo “safe” before disposing of it, I would like to know about it please.

Bob.

I keep a log of all my LiPos from new recording charging and discharging voltages and use. Each battery has a unique number on it.

Hi Gang...
Truth be told, as much as I like the high speed and high output I am not too thrilled with Lipos as It seems you need a phd to fully understand them. I don't like the small margin for error in charging and discharging them either. But I do know that a bloated battery is a battery that has gone bad and can be a huge problem.
I don't mean to run around like the sky is falling, but I found this particular article helpful. 👍

https://www.ufinebattery.com/blog/how-to-dispose-of-swollen-lithium-polymer-battery/

Man, I would. I put it in my neighbor’s yard to charge! Not really as this is, as Jump states a SERIOUS problem! Get rid of it ASAP. (Not sure how one does that).The bloating is caused by one or more of the cells outgassing. Quite probably a prediction of a boom & or a fire.

Imho. Stop the charge asap. A bloated lipo is a lipo to be disposed of. There is some sort of chemical breakdown occurring during use. The trapped gas in the bloat is a fire hazard. Get rid of it.

My 3S looks a bit bloated as well but it could be that it was always like that but I can't remember. But like you it has only ever been charged and storage charged using a smart/intelligent charger. One thing I did read about awhile ago is checking the internal resistance of the battery which I was able to do using my charger and it was within acceptable limits, so I will do that again. What is recommended is that you do this when the battery is new as a reference point, which I will do with any new batteries I get.

Chris