LiPo Storage and charging information

[Tony Jacuzzi]

I dont know anything about LiPos so would like some information. I am considering changing over my starter box to Lipo but I am worried about these things:

• I have always just left my starter box in the trailer or basement no special considerations other than I always have the 2 12V gel cells not connected to the Dynatron . Can I still do that, or do I have to reduce some of the charge in the 6s and then store the battery alone in a crock pot or something that wont catch fire?
  
• I have always charged the gel cells in the basement, with the Lipos is there a real risk of fire when charging? Do I have to charge them in a charge bag etc? Do I need to charge them in the garage ?
  
• Is a single 6s safer that 2 3s hooked in series or does it really matter.
  
• Are all of these safety cautions overblown or are they real
  

Thanks Tony J

 

[bmazor]

Hi, Tony! I have some experience in using LIPO battery.

My own rules are:

1. Use only automatic charger/balancer, cheap or expensive does not matter.

2. Never use charge rates more 60% of C.

Is a single 6s safer that 2 3s hooked in series or does it really matter.

One battery is more suitable in maintenance and in most cases cheaper.

Are all of these safety cautions overblown or are they real? Yes, they are real for high charge rate.

Boris

 

[Brian Sorgente]

From what I've read I believe the LiFe batteries are supposed to be safer than the normal lipos.

 

[lohring]

We've been running lithium polymer batteries for years. They are much more durable than lead acid batteries. I use my old 4S 5000 mah lipos on my starter and it starts gas engines all day with one charge. I've never run them down to the danger point, but I charge them before every race day. Mike Bontoft has a workshop containing the 42 6S 5000 mah packs we used on our 2008 record setting electric hydro along with a newer spare set. He charged them last year and found most of the packs still had lots of charge left and only two had an elevated internal resistance. He left the packs fully charged again.

All this is to show that the horror stories about lipos are no longer true in my experience. I've seen them abused so they puffed, but they did not burst into flame. I've seen some spectacular crashes where the batteries were fine. Getting them wet doesn't cause problems with the battery, but may cause failure through corrosion of the connectors. For race boats, if you use modern balancing chargers and a speed control with a low voltage cut off, you should be fine. All my lipos are in a pile in my garage with the terminals covered. They have a racing lifetime of around one season for low cost packs, longer for expensive packs. Charged, they contain a lot of energy so putting the terminals together evaporates the connectors and is hard on any skin in the area. Otherwise they are lots safer than gasoline that some people still smoke around.

Lohring Miller

 

[Lennard Cuenco]

We've been running lithium polymer batteries for years. They are much more durable than lead acid batteries. I use my old 4S 5000 mah lipos on my starter and it starts gas engines all day with one charge. I've never run them down to the danger point, but I charge them before every race day. Mike Bontoft has a workshop containing the 42 6S 5000 mah packs we used on our 2008 record setting electric hydro along with a newer spare set. He charged them last year and found most of the packs still had lots of charge left and only two had an elevated internal resistance. He left the packs fully charged again.

All this is to show that the horror stories about lipos are no longer true in my experience. I've seen them abused so they puffed, but they did not burst into flame. I've seen some spectacular crashes where the batteries were fine. Getting them wet doesn't cause problems with the battery, but may cause failure through corrosion of the connectors. For race boats, if you use modern balancing chargers and a speed control with a low voltage cut off, you should be fine. All my lipos are in a pile in my garage with the terminals covered. They have a racing lifetime of around one season for low cost packs, longer for expensive packs. Charged, they contain a lot of energy so putting the terminals together evaporates the connectors and is hard on any skin in the area. Otherwise they are lots safer than gasoline that some people still smoke around.

Lohring Miller

unfortunately, there are some who will focus on the 2% that have "gutted a van" or "burned down the house" with these batteries...

for me...its a hobby, and if i cant handle taking 2 12v gel cells from my tent to the pits..i'll go play golf instead

 

[Joe Warren]

Google Commonsense R/C look at the Resources on the left side of the page then view battery education

 

[Don Ferrette]

Google Commonsense R/C look at the Resources on the left side of the page then view battery education

Common sense.The absolute key 2 words here.

As long as you are careful and respect the potential issues if you're not you'll be fine. That of course goes without saying to buy the best quality stuff that your budget will allow. Personally I use and prefer Hyperion packs and their chargers as well, the quality speaks for itself.

 

[Andy Brown]

What about storing them at 60% capacity? How important is that? From what I am hearing it's not important, but I would like some feedback from anyone with long term Lipo experience.

 

[RobertWurster]

Iv ran lipos for a few years in trucks and stuff never boats tho .I fill they are tough if not punctured but they can be danger if they are mis handeled .charge corect and you should be ok.I have a store mode on my charger so i do use it but not sure how important that is,I have found that if you run the batt down to cut off and then just let it sit it can go below the safe volt so the charger wont charge it.One thing to watch for is to not run a low c batt with a high dischare systome or they will puff up and that can be bad.Im my sc truck i run 60 c discharge rates cus of the high rate it can discharge the bat.I would run a lcv to be safe.If i twas me If a lipo gets to low of volts per cell your charger wont charge them I dont charge them in a bag but dont let them charge charge and leave them a lone !.Im not good at explaning things or am i an expert just my experience with them so hope this helps.

 

[Piston1]

All of the above are great posts.

 

[lohring]

I store my cells fully charged except when I'm in a hurry to get home after the last heat. Then they're about 20% charged. The new packs I get are around 50% charged. They all sit around until the next race day when I fully charge them. It doesn't seem to make much difference. The most noticable thing is how little charge they loose even after months. I second the choice of Hyperion Chargers. As you can see from the picture, we have a lot of them. Only one has failed since 2008.

I keep exploring less expensive batteries and comparing them to racers that run higher quality batteries. The key differences are internal resistance and life at very high discharge rates. The low cost batteries have close to twice the internal resistance of the best batteries and don't last as long. In P spec racing at 100 +- amp currents, it doesn't make a lot of difference, but the best batteries may still be faster. The driver I race who runs the best batteries is also a better driver than I am, so that's probably a lot of the difference. The Enerland batteries we ran in 2008 were the best we could find. Today, the inexpensive batteries like the Turnigy or Gens Ace are better at less than half the cost.

Another picture to show how worried we were about battery explosions. Those are half of the 20 batteries we charged at once. The two generators we had couldn't handle any more. (So much for green power.)

Lohring Miller

 

[John Beardslee]

What about storing them at 60% capacity? How important is that? From what I am hearing it's not important, but I would like some feedback from anyone with long term Lipo experience.

Hi Andy,

I flew big electric heli's for quite a while and the 60% storage for LIPOs is only benefical/required if your storing for long periods of time between use. I typically would fly one flight (8min-10min) and then store for the winter months. The "charge kool & fly hot" rule still works with them. I use A123 Racing system nanophosphate cells for my rec'vr power these days in my big gasser planes, they are incredible! I store for months after one flight and the internal resistance is so long I have no problem flying 3 (8-10min) flights before charging. These cells are good for 1000 cycles, and are 3.3v per cell, I use all 6.6v to power my 2.4 systems with no regulators ( except the rudder servo's on heli's). I do error on the side of caution and normally charge at the field before flying and between flights and then fly one last flight and store that way.

John

 

[Jeff Schindler]

What about storing them at 60% capacity? How important is that? From what I am hearing it's not important, but I would like some feedback from anyone with long term Lipo experience.

Andy, Store your packs after you run them. You should be running them down to 3.7-3.8 V per cell, which is conveniently the best storage condition! Do not charge them more than a week before using them as it just hurts them to sit at full charge, it breaks down the chemistry adding internal resistance. Also don't leave them in a hot place like in the garage for the summer. Ideally you would store them around 50 F, but in the house works ok.

I have been listening to the heli guys on allthingsthatfly.com for a long time on this, and it since following these rules, the life of my batteries has much improved.

 

[Andy Brown]

Thanks for the info guys. I got a Zippy 5S 5000Mah 45c pack which was about the same price as 2 - 7 amp gelcells that needing replacing anyway. Also got a Hyperion 606i charger. Hooked it to my 20 yr old 12 volt Sullivan. Went to the test pond 3 times for some short test sessions and then raced two boats for a weekend. Just charged it again today for the second time. They were at about 3.95 Volts when I hooked up the charger. Took about 50 min. to recharge @ 2000 Mah. Sounds like I had not used even half of the capacity.

Now it's time to build a P-spec boat to further justify the cost of the charger!

 

[Jerry T]

Not to change the subject but, what about storing the LiFe batteries?

Does the 60% rule apply to them also?

 

[John Beardslee]

Not to change the subject but, what about storing the LiFe batteries?

Does the 60% rule apply to them also?

Yes, they're the same chemistry as the A123 Racing cells, with the exception of nano technology in the A123's and the LiFe are in a poly bag instead of a can.

John

 

[Jerry T]

Not to change the subject but, what about storing the LiFe batteries?

Does the 60% rule apply to them also?

Yes, they're the same chemistry as the A123 Racing cells, with the exception of nano technology in the A123's and the LiFe are in a poly bag instead of a can.

John

Thanks John