Li-Po Danger

[E-RevoVXL]

How dangerous are Li-Pos? It seems like if the manufacturers give you all these cautions about fire and Li-Po safe bags, shouldn't they be really dangerous?

As long as you handle them properly, they should be fine, right? How many of you have had a Li-Po explode under normal conditions?

I just don't want anything that's going to burn down my house, and the Li-Fe packs that I was looking into only came in under the stock battery capacity.

[RC-Fan]

If you don't know how to handle it, yes it can be dangerous, I have them for some time without issues.

[tha-mule]

I've had lipos for almost 2 years now with no issues. They are what's in all cell phones. So if they were really that dangerous, wouldn't you think you would hear about cell phones blowing up all the time? Just my thoughts.

Sent from my DROIDX using Tapatalk

[Dadx2mj]

I believe nimh are more prone to vent than lipos are. Lipos get such a bad reputation because when they do vent they are much more violent than a nimh or other types of batteries. If you watch some You Tube videos you will see that when a lipo goes up it is spectacular with big flames and lots of toxic smoke where a nimh usually pops and smokes a little but rarely flames up like a lipo does.

[westcoastmerv]

Just take simple precautions like charging them in a lipo box , bag or I personally drop them into a coffee mug if im going to charge them unattended. Ive never had one burn up or explode.

[Slono]

Just take simple precautions like charging them in a lipo box , bag or I personally drop them into a coffee mug if im going to charge them unattended. Ive never had one burn up or explode.

So what is the proper way to charge them unattended? If I get a lipo charger and charged them overnight would I damage anything?

[Dadx2mj]

So what is the proper way to charge them unattended? If I get a lipo charger and charged them overnight would I damage anything?

Charging them unattended or over night is NOT proper care of the lipo and how things go wrong. You should always be there when charging and follow manufacturer recommondations on charging your packs. This holds true for any type of battery IMO

[KILO-DELTA]

lipo's only take about 1hour most of the time its less than that so there is no need to charge overnight. I charge mine on a table away from anything that could catch fire but as long as you dont abuse them eg charge too fast or drop them on a hard surface but even then ive dropped mine and they have been ok. so as long as you look after them they are safe.

[CosmosGoat]

I had similar thoughts when i first got my lipos. I have since learned that proper care goes a long way. I only charge at 1C and do my charging on a metal bench so no worry of ti catching fire. I am not always in the room when charging but i dont leave the house. I also make use of the external temp sensor. Never had it shut down the charging and its set at about 80 deg F.

[comatoast]

When I was concerned about the Lipos I talked to Traxxas techs and the local hobby shop... Both said its Carelessness in charging most of the time.. ie. Charging to fast ( higher amperage than the battery can accept , for instance charging a 2200 mAh batt, @ 5+ amps, just to get it done quicker ) sometimes, using the wrong charger, no balancer etc etc..

Bottom line if you just throw them in a Lipo bag, Use the balancer, keep an eye on the cells as its charging, and charge at the right rate, there should be no issues ..

[comatoast]

If this isnt the best reason to spend $10 on a Lipo sack, you probably shouldnt be using lipos in the first place

http://www.youtube.com/watch?v=z3o_2mwRPdw

[E-RevoVXL]

When I was concerned about the Lipos I talked to Traxxas techs and the local hobby shop... Both said its Carelessness in charging most of the time.. ie. Charging to fast ( higher amperage than the battery can accept , for instance charging a 2200 mAh batt, @ 5+ amps, just to get it done quicker ) sometimes, using the wrong charger, no balancer etc etc..

Bottom line if you just throw them in a Lipo bag, Use the balancer, keep an eye on the cells as its charging, and charge at the right rate, there should be no issues ..

OK, thanks for the information.

[Slono]

Hm. Thanks for all the information, I guess lipo stuff just needs to be given the right amount of attention and precautions.

[comatoast]

Yea its all pretty much common sense, taking care of the batts and not leaving them on chargers overnight, and charging with to much amperage.. It shoulld sy right on the battery what the charge rate is.. Usually a good stand by is 1000th of the mAh .. So if its a 3000mAh battery, charge it @ 3 amps, 1200mAh 1.2 amps etc

[Slono]

How much would 2s lipos with a decent charger run? I'd like to get them, but I just broke a bunch of stuff on my MERV so depending on the price - I don't know any brands either, maybe venom - I may have to hold off.

[comatoast]

$100 will get u somthing nice

[Slono]

$100 will get u somthing nice

hm... ebay chargers from china or hong kong won't cut it will they?

[Maxxismobster]

I know there are threads about chargers for different types of batts, but a small piece of advice from a novice(even though Im new to the forum), stay with the more well known manufacturers that most of the experienced guys are using or talking about. Like Dad for one. A Traxxas Marshal is sure to know alot about proper equipment than even some experienced RC'ers here, I have noticed some of the seasoned RC'ers tend to experiment with different brands as they usually have the know how to use and compare them to other products. I scan these forums for the ones who really know alot about these models and take from them before buying any aftermarket parts. Don't be afraid to ask the senior members questions as well, I find they are always willing to give you thier personal opinion on different things.

[comatoast]

hm... ebay chargers from china or hong kong won't cut it will they?

I won't buy much from china or foreign countries unless I have to. As far as chargers. No I wouldn't go cheap. You don't have to spend $150 but get something good. I just ordered 2 3s lipos and a thunder ac6 charger from got2gorc.com. Quality batteries and even tho the charger he sells is just a thunder ac6 he gives you all the charging adapters and great customer service ( so I've heard )

Btw I have a thread about chargers when I started looking a week or so ago. Check it out. It should be on the first 2-3 pages of this forum. The ac6 came very highly suggested

[Slono]

I won't buy much from china or foreign countries unless I have to. As far as chargers. No I wouldn't go cheap. You don't have to spend $150 but get something good. I just ordered 2 3s lipos and a thunder ac6 charger from got2gorc.com. Quality batteries and even tho the charger he sells is just a thunder ac6 he gives you all the charging adapters and great customer service ( so I've heard )

Btw I have a thread about chargers when I started looking a week or so ago. Check it out. It should be on the first 2-3 pages of this forum. The ac6 came very highly suggested

Okay thanks. I'll check that out.

[Slono]

Is this the charger you were going to get before you settled for the AC6?

Venom Pro Charger

FEATURES:

* Charges 1-6 Series Lithium Ion or Lithium Polymer batteries
* Charges 1-15 cell NiCd/NiMH batteries0.1A - 5.0A adjustable charge current
* Includes 7 different plugs: General, Tamiya, Traxxas, JST, Receiver, Glow Ignitor and Aligator Clip Charge Adaptors
* Lipo balance charging adapter for 2-6 cell batteries
* Temperature Probe
* USB adapter for PC link
* LCD display shows voltage and current
* 12V DC input with alligator clips
* Built-in cooling fan
* AC Adapter
* 90 day warranty

INCLUDES:
Venom Pro Charger Battery Charger, power leads with alligator clips, Charging adapters, temperature probe, USB cable and instruction manual

SPECS:
Length: 5.3" (136mm)
Width: 3.5" (90mm)
Height: 1.2" (30mm)
Weight: 12.3oz (350g) with power wires
Operating Voltage Range: 11.0- 18.0V
Circuit Power: Max 50W
Charge Current Range: 0.1 - 5.0A
Current Drain for Balancing LiPo: 200mAh/cell
NiCd/NiMH Battery Cell Count: 1 - 15 cells
Li-Ion/Polymer Cell Count: 1 - 6 series
Discharge Rate: 0.1 - 1A
Pb Battery Voltage: 2 - 20V

[Evgen]

http://www.helifreak.com/showthread.php?t=175568

I believe that the basic electronics are extremely similar between the Venom and the Accucel-6. In other words I would not be surprised at all if both were made in the same factory and just put in different boxes
...
They look and operate identically as far as display, buttons, fan position etc. Venom is just all blinged out and costs $100 more

so you think if you simply pay more for the charger then you can feel safe?

then what would you say about my charger?
*************************/v/#51


it's just all about marketing. situation is similar to maxamps lipos (they're not bad, but for those money you can buy 3 similar or 1 much more powerfull)

speaking of liposack. can someone tell me exactly why they are better than those from ebay for $4?
http://shop.ebay.com/?_nkw=lipo%20ba...&_stpos=&gbr=1

[comatoast]

http://www.helifreak.com/showthread.php?t=175568

so you think if you simply pay more for the charger then you can feel safe?

then what would you say about my charger?
*************************/v/#51


it's just all about marketing. situation is similar to maxamps lipos (they're not bad, but for those money you can buy 3 similar or 1 much more powerfull)

speaking of liposack. can someone tell me exactly why they are better than those from ebay for $4?
http://shop.ebay.com/?_nkw=lipo%20ba...&_stpos=&gbr=1

Does your post have a point?

[comatoast]

Is this the charger you were going to get before you settled for the AC6?

Venom Pro Charger

FEATURES:

* Charges 1-6 Series Lithium Ion or Lithium Polymer batteries
* Charges 1-15 cell NiCd/NiMH batteries0.1A - 5.0A adjustable charge current
* Includes 7 different plugs: General, Tamiya, Traxxas, JST, Receiver, Glow Ignitor and Aligator Clip Charge Adaptors
* Lipo balance charging adapter for 2-6 cell batteries
* Temperature Probe
* USB adapter for PC link
* LCD display shows voltage and current
* 12V DC input with alligator clips
* Built-in cooling fan
* AC Adapter
* 90 day warranty

INCLUDES:
Venom Pro Charger Battery Charger, power leads with alligator clips, Charging adapters, temperature probe, USB cable and instruction manual

SPECS:
Length: 5.3" (136mm)
Width: 3.5" (90mm)
Height: 1.2" (30mm)
Weight: 12.3oz (350g) with power wires
Operating Voltage Range: 11.0- 18.0V
Circuit Power: Max 50W
Charge Current Range: 0.1 - 5.0A
Current Drain for Balancing LiPo: 200mAh/cell
NiCd/NiMH Battery Cell Count: 1 - 15 cells
Li-Ion/Polymer Cell Count: 1 - 6 series
Discharge Rate: 0.1 - 1A
Pb Battery Voltage: 2 - 20V

Yessir.. That was one of them.. But then I started looking at , voltage, and charging adapters, safety, options, customer support, and overall quality of chargers, without having issues, and decided on the AC6 .. I would seriously avoid the Venom

[Slono]

Yessir.. That was one of them.. But then I started looking at , voltage, and charging adapters, safety, options, customer support, and overall quality of chargers, without having issues, and decided on the AC6 .. I would seriously avoid the Venom

The AC6 is "safer"?

[comatoast]

The AC6 is "safer"?

Uhh well it comes with a full warranty .. I dont know how you couldn't be safe with a charger... Unless your an idiot

[Slono]

I don't get the difference in chargers then. Why do some people bother buying expensive ones when you could get a cheaper one that does the same job?

[comatoast]

I don't get the difference in chargers then. Why do some people bother buying expensive ones when you could get a cheaper one that does the same job?

Who knows. Lots of people Aretha on the Internet to see these deals by online companies. So they just buy whatever the hobby shop recommends. My hobby shop showed me 2 chargers. The cheapest was $129 and did nothing better Or fasterthan the ac6

Same deal with tv sets. Why do ppl buy at best buy when amazon is 15% cheaper for the exact same set with no tax and no shipping

[Dadx2mj]

I don't get the difference in chargers then. Why do some people bother buying expensive ones when you could get a cheaper one that does the same job?

The cheap chargers may list the same specs and features but that does not mean they do the same job. Cheap chargers are more prone to false peak or over charge a pack and rarely last as long as a quality charger. I wasted a lot of money trying to save a buck before I learned this lesson.

[BellyUpFish]

The biggest "no-no" with lipos is charging them unattended..

Every single major lipo related accident (cars burning, houses burning, etc) has resulted from not following one simple rule of lipo charging - don't charge them unattended.. You're asking for it, if you do.

I've been flying lipos since they came out ~10 years ago or so.. I've only had 2 lipo packs blow up while charging, and it was my fault.

Follow the "rules" and you'll be fine..

I'm pretty partial to Hyperion chargers myself.

[comatoast]

The biggest "no-no" with lipos is charging them unattended..

Every single major lipo related accident (cars burning, houses burning, etc) has resulted from not following one simple rule of lipo charging - don't charge them unattended.. You're asking for it, if you do.

I've been flying lipos since they came out ~10 years ago or so.. I've only had 2 lipo packs blow up while charging, and it was my fault.

Follow the "rules" and you'll be fine..

I'm pretty partial to Hyperion chargers myself.

What caused your batts to blow?

[BellyUpFish]

I was using one of the earliest lip chargers out there, an Astro 109. This charger has blown up more packs than any other charger on the planet, I'm sure of it..

I didn't follow directions, basically..

I plugged a fully chsrged 2S 1200 onto the charger and let it start charging.

The way the 109 worked is it read voltage and assumed/guessed what voltage pack you had. It saw 8.4v and said "oh, this must be an over-discharged 3S pack" and started charging as such.. Boom..

After I took the blown pack outside, I did the EXACT same thing within 10 minutes..

I currently have 50-60 lipo packs of my own and I know I've been through 2-3 times that many and those are the only 2 I've lost while charging..

[comatoast]

I was using one of the earliest lip chargers out there, an Astro 109. This charger has blown up more packs than any other charger on the planet, I'm sure of it..

I didn't follow directions, basically..

I plugged a fully chsrged 2S 1200 onto the charger and let it start charging.

The way the 109 worked is it read voltage and assumed/guessed what voltage pack you had. It saw 8.4v and said "oh, this must be an over-discharged 3S pack" and started charging as such.. Boom..

After I took the blown pack outside, I did the EXACT same thing within 10 minutes..

I currently have 50-60 lipo packs of my own and I know I've been through 2-3 times that many and those are the only 2 I've lost while charging..

Wow. Yea I will be picking up a lipo sack Monday for sure. My ac6 and my new 3s boost batts should be here Tuesday. Kinda excited and worried at the same time.

[BellyUpFish]

Just be careful.. Most chargers these days are "smart" chargers.. They won't allow the problem I had, as you have to select voltage, etc..

Don't charge unattended.. If you are going to charge unattended, charge outside on the driveway or something.. I can post pics of my workroom floor.. It's not pretty carpet anymore..

LipoSacks are great. The original sack was designed by a good friend of mine.. My second pack that blew up was in a lipo sack..

The good news - you'll smell it before it blows if you're in the room with it.. You'll be like "What is that smell???"

Just remember a lipo cell is fully charged at 4.2v and is fully discharged at around ~3.5v.. You can take them a little lower, but they don't like you for it..

[comatoast]

Thanks man. I'm sure it will all be less confusing when I actually get my charger and read the manual


I'll look at all the specs on the bats as well. One question tho. I see ppl saying they are charging at 1C. What is that? Each cell seperate? All I know is not to charge my new 3s 1800s above 1.8 amps

[KILO-DELTA]

The C rating from my knoledge is CAPACITY (1c = 1x capacity) so if it says charge rate 2c and you have a 1000mah batt you can safely charge it at 2000mah = 2amp etc etc

[BellyUpFish]

The C rating from my knoledge is CAPACITY (1c = 1x capacity) so if it says charge rate 2c and you have a 1000mah batt you can safely charge it at 2000mah = 2amp etc etc

I wrote an article a few years ago and this is the gist.. It was written for airplanes, so read it accordingly..

Anywhere it references flight time substitute run time..

Voltage in lipo cells can be broken down like this:

4.20v = 100%
4.03v = 76%
3.86v = 52%
3.83v = 42%
3.79v = 30%
3.70v = 11%
3.6?v = 0%


What'sa KV?

KV is basically RPM's per Volt put to the plane..

Usually, but not set in stone, a high KV motor is speedy.. A low KV motor is torquey..

A high KV motor can be put into a gear box and then become torquey.. But that's another deal, since few people are running inrunners these days and most don't install an outrunner into a GB..

So... RPM per Volt..

Let's say your motor is a 1000kv motor..
Let's say you're going to run it on a 3S pack..

3S = 12.6v... 12.6 x 1000 = 12,600rpm..
2S = 8.2v.. 8.2 x 1000 = 8,200rpm..

Let's suppose you have a motor with a 5800kv..
Let's run it on 2S and 3S..

3S = 12.6v.. 12.6 x 5800 = 73,080rpm..
2S = 8.2v.. 8.2 x 5800 = 47,560rpm..

Calculate Flight Time by amp draw..

Flight time can be varied by a number of variables, however, there is a simple equation that can get you "in the ball park."

Example one.. a 1300mah pack with an amp draw of 9.3 amps..

A 1300mah pack = 1.3ah..

Take your ah number and multiply by 60..

1.3x60 (for minutes in an hour) = 78..

Take this new number and divide by your total amp draw..

78/9.3amps = 8.3..

8.3 minutes of WOT..

Example 2 - 1000mah pack at 5 amps..

1000 mAh = 1Ah
1X60 (minutes in an hour )= 60
60/5A=12

12min of WOT

Example 3 - 5000mah pack at 67 amps..

5000 = 5ah
5x60= 300
300/67=4.47
4.47min of WOT...


Or you can use this..

http://www.rtideas.com/battcalc/



C Rating Fun!

The "C" stands for capacity. For example 10C means that you can safely discharge the pack continuously at 10 times the packs capacity. So..... a 2000mAh - 10C pack can be discharged at 20amps. A milliamp is equal to 1/1000 of an amp. So a 2000mAh pack is equal to a 2 amp pack. Ten times two amps equals 20 amps. Also, C rating is a function of discharge over time. If you divide 60 minutes in an hour by the C rating, you will get the duration of the packs discharge ability at the continuous output. Meaning, a 10C battery (60/10) will discharge continuously for 6 minutes.

Some more examples..

A 15C continuous rating on a 2100mah lipo provides 31.5 Amps. 2.1Ah*15C=31.5 A
A burst C rating, say for example 50C, is usually only for 30 seconds. That burst time interval depends on the Lipo.


3s 1500 15c max ampdraw.
1.5 (1500mha)x 15(c)= 22.5amps.
22.5 amps would be the max amp draw.

How can I measure the voltage of each individual cell via the balance taps?

On the balance plug, starting on either end, measure as follows:

Pins 1 & 2 = Cell 1
Pins 2 & 3 = Cell 2
Pins 3 & 4 = Cell 3
Pins 1 & 4 = All Cells

[comatoast]

Wow. Thank you. I think lol

[BellyUpFish]

Don't worry, there won't be any tests..

[Slono]

So it seems like the most liked chargers are the Thunder AC6 and the Hyperion lipo chargers?