XRAY - Model racing cars

Hello everybody.

The most of my lipo batteries are inflated. What advice would you give me for the maintenance of the batteries?

Thank you very much.

Having most of your batteries inflated surely isn't right and you are maybe doing something wrong. How many Amps do you charge them with? How often do you balance them? Do you store them properly? Are they all the same brand LiPO or are they different? Some guys at my track had puffing problems with new packs but usually it was with the same brand of battery

It would be interesting to know how old the batteries are.
The key maintenance on this topic is to discharge the battery(ies) if you know you are not going to use them for several weeks (not always easy to gauge if you race outdoors and the weather intervenes).

PERSONALLY if I know I am not going to race over the next two weeks or longer then I discharge them. From experience I would say you can go longer than two weeks because occasionally I get caught out by bad weather and have gone longer than two weeks without racing, with no ill effects.
But you need to set yourself a discipline.

I am guessing that most LIPO chargers, if not all, have a storage function. This takes the voltage down to the required 7.6 volts (or thereabouts).

If your batteries have expanded significantly then you probably need to dump them. Place them in a bucket of salty water for about a week – which I think fully discharges them (I could be wrong on this point) and then take them to an official place for disposing of batteries, maybe your local refuse place.

I have 2 Intellect packs that are 1 year old and have swelled slightly due to leaving them fully charged for a week, when I realised I made sure to storage charge them and measure the swelling after each event (2mm so far) they are still punchy and not getting worse so still using them

Ok, think about what is happening, ie why your lipo battery has swollen.

Your battery has a hard outer case, its purpose being to protect the lipo cell(s) inside of it (this only goes so far though). Your lipo battery has 2 Lipo cell packs inside and each pack is surrounded and sealed by a thin covering of aluminium.When a Lipo cell gets damaged gasses are emitted and begin to build up inside the pack. As it is sealed by the aluminium there is nowhere for the gas to escape, so the pack blows up like a balloon.

Do not forget that the gas is looking for an EXIT and once pressure builds to a certain point an exit will be found.
You have a potential fire hazard.

Will the battery last one cycle more or 500 cycles more before it becomes a fireball – who knows?

But do you really want to risk 600-700 pounds worth of RC car.
Personally I would chuck them but if you are going to keep them then I would ask you to do me one favour, please do not charge these swollen packs indoors- do it outside on concrete or tarmac.

Yellowshark What lifespan do your lipo's have?

You also need to be careful not to over discharge them during a run - particularly during practice.
Sometimes it pays to set a timer so you make sure you stick to a 5min to 5.30min run and no more.
Running for 6-7 minutes will cause the lipo extreme stress as the voltages start to drop.

I have different experiences with cheap vs. brand name LiPOs, but mostly I didn't have serious problems with LiPOs puffing. I do take care of my packs, always store them when I know I will not use them for more than a week, always charge with balancer. I never go crazy with charging them, mostly at 1C, sometimes at 2C, even though the charger is capable of 20 Amp. I also time my runs for 6 minutes (heat lasts for 6 minutes 10.5T boosted). I only had problems with one pack, it was a brand name LiPO. It puffed after one season, but I must admit I used it extensively, charged it more times a day without letting it rest for 30 minutes- I didn't have many packs back then. It is now still puffed and the performance has dropped, so now I use it to power my projects such as work in progress tire truer etc. - I am afraid to use it in a car though. Many people at my track had problems with top line LiPOs with them puffing very soon in their life, although I don't know their charging habits. I have one such pack with no problems. Note I have now my first, almost 4 year old LiPO still working perfectly, it is a no name chinese pack It doesnt have performance figures that match todays electronics standards so I dont use it in my racing car, however it is still good enough for my hobby cars. I don't like to go with names due to bad publicity, but if anyone wants to know names of problematic packs from my experience, feel free to send me a PM

Thank you for your answers.

UrabusDenis:
I charge my lipo with 5amp. I always charge with the balancing.
I have some inflated of differents brands.

My charger is this:
http://www.rc-mushroom.com/product_info ... er-p-20281

But I am going to buy this:
http://www.rc-mushroom.com/product_info ... ue-p-24038

Yellowshark:
I have 2 differents batteris (SMC C-Max 5200 and Orion 6500). The most of they are inflated.
The SMC have some years old (about 2-3), the Orion are 1 year old right now.

I never had discharge the batteries... You suggest discharge complete the batteries, If a have not race in next 2 weeks?

beale:
I have heard that exactly. Never leave the battery full charged storage for a time.


Well, conclution:
- Always balance when charging
- Never storage the batteries fully charged for a week
- Dischareg the battery If I know that I won't use next 2 weeks??????

i would say the charger you have is fine and no need to change it most lipo chargers work on the same software so it's not about higher cost charging better they ALL should use the industry standard CC/CV (Constant Current/Constant Voltage).

as for storage i just leave mine with what is left after a race and they have been fine for a couple of months storage, just check their voltage once in a while


your words

Well, conclution:
- Always balance when charging......... definetly
- Never storage the batteries fully charged for a week........definetly
- Dischareg the battery If I know that I won't use next 2 weeks??????......... never go below 3v per cell or they are dead!!

The best storagevoltage is about 7,4 Volts (3,7 Volts per cell).

Thank you UrabisDennis, he did indeed mean that

I use a TrackPower BC6 charger which I bought 4 years ago and is still going strong. A previous posting mentioned 3.7v per cell which I have seen elsewhere in various technical write-ups but using 'storage' mode on my BC6 sets the voltage to 3.8v

Hello

Do you use the Capacity cut-off?

Well yes and no.
I have my Tekin RS set at the factory default for cut-off which is 3.0v per cell. It doesn't happen in racing but when practicing I have occassionally had the power drop and if that does happen I have immdeiately stopped; which does make me wonder whether 3.0v per cell is right. Somewhere in my brain is telling me that I have seen a figure of 6.5v per pack as the danger point.

Thank you YellowShark.

I just buy the Muchmore Hybrid. But I don't know how to configurate the max voltage. For example in ETS races, the maximum voltage is 8.44 Voltage, but when I charge my lipo batteries, always stop at 8.40 Voltage.

Any idea?

Yup my Trackpower charger goes to 8.40 too. I doubt that with today's capacities a variance of 0.04v is going to make any difference

Oki, thank you very much.

But, in the charger configuration:

- Do you use the capacity cut-off? For example I charge a lipo battery of 5300 Mh, ¿how many do you configurate? or you don't use that?