RC Bashers

So grabbed some of this from another site I just dont have the fingers to type up this much info lol. It is all sound info just faster to post pasting sorry. Gonna look for more soon as I can find this one site.


How dangerous are these Lipo batteries while charging? ?My hobby room is in my house not my garage?

Like all batteries, you must restpect them. I've seen more burnt/exploded IB4200's in the last year than lipo. Mine have the "hard" case and are very well protected. Also they were designed for car/truck use, and are high quality. These are very safe as long as you charge them with a proper charger at the correct settings. I'm not scared of them at all, but I respect them.


What is a good charger?

I use a Duratrax Ice. I love it. Would highly recommend it. There are plenty of other good li-po chargers on the market as well. Don't buy anything that doesn't use the CC/CV method.

What does balancing mean?

Equalizing the cells in the pack. It's a must for 3S and 4S lipo. It's more optional on the 2S. Both Kokam and Peak/Orion claim their testing shows no need to balance the packs I have unless they are
overcharged/overdischarged. Though they do have a port, and you can balance them. I can also charge each cell individually once in awhile, but not quite as good as something like a Astroflight Blinky Balancer.


Does my esc require a low voltage cutoff switch, and what is the LVC for?
Most people use one, I do. If you overdischarge them, you'll ruin them. My new version Rooster has integrated li-po cutoff. All Novak and Mamba brushless systems now come with integrated cutoff, even the older model of the GTB is now shipping with it, though not widely advertised. You can use an esc with an external LVC as well, such as the Apogee LOA. That sux though.... I personally think you'd have to be mildly retarded to not notice the dropoff even without a LVC. But maybe that's because I haven't run mine with brushless yet.

Do these batteries need cycled like my NIMH cells?
NOPE!

What is the proper storage for these cells when not in use?
Supposedly no performance gain in repeaking if used within 10 days or so. From 10 days - 6 months you'll want to repeak for racing, but for play you may not notice any difference.
Li-po rock. I would rather have a colon scope while being awake then to ever use Ni-MH again. This pack weighs half what my IB4200's weighed. The power is equall to a good matched IB4200 and the discharge when you run it in the car/truck seems more linear. Runtimes are unreal. They are so efficient. The 3200 runs as long or longer than a matched IB4200. I get about 17 minutes of runtime never stopping, as hard as I can run, with lots of constant acceleration (which kills the runtime). This is in my pede with a Titan12T. Don't use Lipo without a wheelie bar unless you like buying bodies.

The biggest thing is this. Mine are very similar to a matched IB4200. A matched IB4200 will fun you a good $65. You'll be lucky to get to the 50 cycle mark before it goes downhill. You'll be lucky if it lasts 100 runs even with poor performance. NOW........ with these I caught three of them on sale for $62 each to my door from Tower. Regular price $89.99 each. I told lots of people about it and nobody took advantage of it. I'm so glad I did. So it was the same price or cheaper than a good matched IB4200,but these go 300+ runs and maintain 95% of their new performance. IMO, just a way better investment. Why anyone would use Ni-MH now is beyond me. Normally every message board has a "villiage idiot" who runs around shouting fire/explosion without even knowing much about them. Don't get me wrong, if you misuse them, fire is a very real risk. If you have an ounce of brains and respect them, they aren't any more dangerous than any other battery. We always fear what we don't understand, and in general, the rc car/truck community doesn't understand li-po (yet).

Does Temperature Affect Lithium Polymer Batteries?
Yes, lithium polymer batteries are affected by temperature. All batteries use a chemical reaction to provide electricity, and a low temperature slows this reaction down significantly. You cannot harm a lithium battery by running it at a low temperature, but you will notice a significant decrease in performance. Allowing lithium polymer batteries to freeze is generally not recommended, so be sure to store the lithium battery in a cool, dry location over the winter months.

What does “3S4P” mean?
Every lithium polymer battery consists of a set of individual cells, which can be wired in either series or parallel. Cells wired in series (positive to negative) increase the overall voltage of the pack, while cells wired in parallel increase the capacity. As an e 3S4P pack consists of 3 cells wired in series, and each array of three cells is wired in parallel four times. This means that the pack consists of twelve cells in total. Because all 3S batteries consist of the same number of cells wired in series, they all have the same voltage.

What does the C rating mean?
The C rating is a measure of how long it takes a battery pack to discharge under a given load, expressed in fractions of an hour. As an example, a battery discharging at 1C would be empty in 1 hour, a 2C discharge would empty it in 1/2 an hour, and so on. For example: a 4000 Mah battery being discharged at 4000 ma, then it would be empty after an hour, and discharging at a rate of 1C.

Is it true that the storage of the battery can effect the performance?
Yes, it is. How you store the battery severely affects it’s capacity, and thus it’s useful lifetime. You should not store lipos at 100 percent charge, and you should not store them at near minimum voltage. Either of these situations will result in the battery internally “rusting away”, and will decrease it’s capacity over time. The best way to store a lipo is at about a 50% charge, in a cool, dry location.

--Use the Taps. Before you charge a new Lithium pack, check the voltage of each cell individually. Then do this after every tenth cycle there after. This is absolutely critical in that an unbalanced pack can explode while charging even if the correct cell count is chosen. If the cells are not within 0.1 volts of each other then charge each cell individually to 4.2 volts so that they are all equal. If after every discharge the pack is unbalanced you have a faulty cell and that pack must be replaced.
Taps are provided on most new lithium packs. Taps give you the ability to check individual cell voltages and charge one cell at a time. Make sure and get the appropriate connector to go into your taps. Don't try to stick you volt meter probes in the taps to measure voltage. They could slip and short your cells. Don't try to charge more than one cell at a time from the taps. Unless you have an isolated ground charging system, you'll short your batteries out. Refer to your individual cell maker for tap pin-outs.


Lithium What?
Lithium Polymer batteries are used in many electronic devices. Cell Phone, Laptops, PDA's, Hearing Aids just to name a few. Most, if not all, lithium polymer batteries are not designed for RC use, we use them in different applications than they were designed for. They are similar to Lithium Ion batteries in that they each have a nominal voltage of 3.6 volts, but dissimilar in that they do not have a hard metal casing but rather a flexible material encloses the chemicals inside. The "normal" lithium polymer batteries are thin rectangle shapes with two tabs on the top one positive one negative. The reason we use Lithium cells is that they are significantly lighter than comparable NiCad or NiMH batteries, which makes our planes fly longer and better.

Some chargers I have seen others say good things about, most of us have power supplies so makes it cheaper to buy one thats a dc only but if you dont have one then you need one or a ac/dc model. With some research one can convert a pc power supply really easy and those are cheap

http://hobbycity.com/hobbyking/store/uh ... oduct=6478

http://hobbycity.com/hobbyking/store/uh ... oduct=7523

http://hobbycity.com/hobbyking/store/uh ... duct=15168

http://hobbycity.com/hobbyking/store/uh ... oduct=6463

http://www3.towerhobbies.com/cgi-bin/wt ... LXMAJ0&P=0

http://www3.towerhobbies.com/cgi-bin/wt ... LXPYT8&P=0

http://www.nitrorcx.com/thac6smlibac.html

** DISPOSAL OF LIPO BATTERIES **
Unlike NiCd batteries, lithium-polymer batteries are environmentally friendly.
For safety reasons, it’s best that LiPo cells be fully discharged before disposal (however,
if physically damaged it is NOT recommended to discharge LiPo cells before disposal -
see below for details). The batteries must also be cool before proceeding with disposal
instructions. To dispose of LiPo cells and packs:
1. If any LiPo cell in the pack has been physically damaged, resulting
in a swollen cell or a split or tear in a cell’s foil covering, do NOT discharge the battery.
Jump to step 5.
2. Place the LiPo battery in a fireproof container or bucket of sand.
3. Connect the battery to a LiPo discharger. Set the discharge cutoff
voltage to the
lowest possible value. Set the discharge current to a C/10 value, with “C” being the
capacity rating of the pack. For example, the “1C” rating for a 1200mAh battery is 1.2A,
and that battery’s C/10 current value is (1.2A / 10) can be used,
such as a power resistor or set of light bulbs as long as the discharge current doesn’t
exceed the C/10 value and cause an overheating condition.
For LiPo packs rated at 7.4V and 11.1V , connect a 150 ohm resistor with a power rating
of 2 watts (commonly found at Radio Shack)to the pack’s positive and negative terminals
to safely discharge connecting it to an ESC/ motor system and allowing the motor to run
indefinitely until no power remains to further cause the system to function.
4. Discharge the battery until its voltage reaches 1.0V per cell or
lower. For resistive load type discharges, discharge the battery for up to 24 hours.
5. Submerse the battery into bucket or tub of salt water. This container should have a lid,
but it should not need to be air-tight. Prepare a plastic container (do not use metal) of cold
water. And mix in 1/2 cup of salt per gallon of water. Drop the battery into the salt water.
Allow the battery to remain in the tub of salt water for at least 2 weeks.
6. Remove the LiPo battery from the salt water, wrap it in newspaper or paper towels and
place it in the normal trash. They are landfill safe

doing some reading for jamus and ran across this, update on dispossing of lipos.....


"Once the battery is discharged, clip off the battery leads and balancing taps, bag it and toss it - DONE.}

The goal is to discharge the pack with a low current draw to near zero volts. A motor is too much draw, but a 12V car bulb is perfect. I made a simple light bulb discharger with a 12V car/trailer light. Plug in the puffed pack and let it run until the light goes out, for big packs this could take a full day.

Once the light is out, grab a volt meter and assure the voltage reads less than .5V per cell – a 2S packs should be 1V or less. If the pack still has a voltage at or above .5V per cell, clip the light back on and let it sit for another couple hours and check it again. Our bloated 2S pack read less than .25V total after light bulb discharging.

Once the pack has been completely discharged and has a voltage of less than .5V per cell, the pack is harmless and cannot catch fire. The connectors can be clipped off and the pack dropped into a plastic bag and tossed in the trash. That’s it, no pack disassembly, no mess, no fuss.

What About the Saltwater Bath ?

The saltwater discharging method is now no longer recommended by manufacturers. Yes, lithium exposed to saltwater will discharge, however it can be very dangerous and extremely un-reliable. The problem with the method is that to work, the Lithium needs direct contact with the saltwater which means you need to cut a charged and potentially puffed pack underwater, flip it over and cut the other cell(s). You may see the potential dangers with this process and if done incorrectly will yield a LiPo pack on fire. The above light bulb discharge method is a better, safer, easier, and more effective means of fully discharging a battery to a state safe for disposal."

Our goal is a low current consumption close to zero volt battery discharge. Motor is too much a draw, but the 12V car light bulb is perfect. I had a 12V car / trailer with a simple light bulb discharge. Expanded package insert, and let it run until the light goes out, a large bag, which can take all day.