Lipo PCB?

[bananabotdan]

I am new to the world of Lipo batteries (having just purchased one yesterday). I have been given the basic overview on the dangers of these batteries however I still know very little about devices used to protect lipo batteries and their users. Devices such as low voltage tweeters and PCB's. So I have a few questions. Are PCB's required to run a lipo battery? What dangers am I putting myself, my gun, or my battery in without a PCB or tweeter? Why do I need a PCB for airsoft. And finally where can I find a PCB or tweeter for a decent price online or locally (Canada / ASC)? As far as charging goes I already have a digital charger that does everything I need including cell balancing and partial capacity charging so I do not require overcharge protection, I simply need something that can protect against an over discharge. The aplication will be for an src mg36, the batery is 11.1v, 3000mah, and discarges at a max of 15c. Thank you for your help.

-DAN

[Skruface]

Originally Posted by bananabotdan

Are PCB's required to run a lipo battery?

No.

Originally Posted by bananabotdan

What dangers am I putting myself, my gun, or my battery in without a PCB or tweeter?

Death and severe burns, not to mention toxin inhalation. Lipos when overcharged (or over DIScharged) have a tendencey to do this:

YouTube- Lipo Fire Video

Originally Posted by bananabotdan

Why do I need a PCB for airsoft.

To prevent damage to your batteries, you guns, your house, your car, your playing field, and yourself.

Originally Posted by bananabotdan

And finally where can I find a PCB or tweeter for a decent price online or locally (Canada / ASC)?

http://www.airsoftparts.ca/store2/in...oducts_id=1311

[Blackthorne]

Best answer post ever Skru...

This shit should be stickied or added to an existing thread.

[bananabotdan]

Thank you. I did look trough all the lipo related threads that I could find but none went this in depth and I did not really find the information usefully. So thank you for the clear no nonsense answers. It looks like I am going to be ordering a PCB in my future. Also with a computerized charger so I really need to worry about over charge protection seeing as the charger itself has this feature?

Originally Posted by Blackthorne

Best answer post ever Skru...

This shit should be stickied or added to an existing thread.

I totally agree these are the best and most clear answers I have seen thus far.

[SHÖCK]

Does anybody have the lipo protection boards from Huang? I bought two of them for $15 each and they won't work at all with the 3 batteries that I tested.

I can't get them to work with my Lipo batteries at all. Gearbox won't fire at all unless I hold down the reset button which is basically just turning the device off and opening the circuit. If anybody wants, you can try these and let me know if they work for you. They only have the 4 pin connector to accept 3 cell lipos (11.1v normally).

[warbird]

Same thing with me, they don't work.

[The Saint]

It's far easier to blow up lipo packs through over-charging than over-discharging in an airsoft gun. Most airsoft-suitable lipo packs will stop cycling moderately powered guns before hitting the point of serious cell damage, and as a result avoid the point after that, very dramatic cell damage. Your gun will stop working well before your lipo explodes.

Think of your airsoft gun as a drinking straw (fixed length and position), electricity as water, and lipo pack as a drinking cup. If the straw drinks all the water in the cup, the cup explodes. However, the straw is not long enough to reach the bottom of the cup, so it can never drink all the water.

Simple lipo rule of thumb: if your ROF tanks, stop shooting and switch the pack.

PCB is still useful, as it means you don't have to pay attention to your ROF, and you have a bigger margin of safety to preserve your cell from accumulating minor damage. It also gives you considerably more warning for when your gun's about to stop.

Just to illustrate, I killed my first lipo pack, not sure how, though I suspect the charger. But it sure as heck didn't explode and burn down the town, even though I pushed every last possible shot out of its last charge (I don't have a PCB nor MOSFET). Lipo should be thoughtfully handled, but they do not explode on a whim.

[bananabotdan]

@ warbird and Shock
Did either of you guys check the polarity of said PCB's? it could be that they are wired for the opposite polarity battery (I made this mistake when buying a battery as the polarity of my charging cable was not the same of my charger, stupid I know, but apparently older chargers used reversed polarity) to remedy this problem could try running the PCB backwards or buy a conversion cable like this.
http://www.commonsenserc.com/product...roducts_id=198.
Really I have no idea if it will work it is just an idea.

@ the saint
from what I have read deep discharging can cause damage to the cell however it should not cause it to burst into flame or even produce smoke. The real danger is in recharging the battery after said deep discharge as the damaged caused by the deep discharge may cause the battery to swell and even explode wile recharging. This is why many mid to high end lipo chargers have a safety feature which will not attempt to charge a cell if it has an internal voltage of <3 volts. Interesting l enough the instructions that came with may battery regarding recycling indicated that a deep discharge was needed before recycling as cells have a greater ability to explode if punctured when charged I found this quite interesting.

[Kos-Mos]

Just so that you guys know, unless the battery have been completely drained, physically damaged or you are using a charger not designed to charge LiPo. You have more chance to burst a NIMh battery than a LiPo.

LiPos are not that much more dangerous than NiMh (Ever seen a Sub-C cell explode and send a metal case through the room?). They are just not dumb proof. As long as you don't hook it to anything that says "electricity" and you don't run your gun until it does not shoot and jam, you will be fine.

The video shown is charging the battery 10 times too much to make the packs explode. In the examples, they where using cheap 1200mAh packs, similar to the ones sold for buffer tubes. They have been charging them at 10A (maximum charge rate is 1.2A). Most airsoft player that is not sure how to handle LiPo do not have a LiPo charger that can push at 10A anyways.

[ThunderCactus]

Furthermore, if you DO damage a lipo, it gives you plenty of warning before it goes up
The pack inflates, then vents a small amount visible smoke, and it will take a minute or so for it to actually start to flame
The pictures you see of people's kitchens burned down and stuff destroyed by lipo fires was from people charging them unattended and without a lipo charging sack

Anyway, wolfdragon makes awesome PCB's
http://projectwolfdragon.com/Products/Products.htm

His site kinda sucks, but the product is good lol
Now you should be using a mosfet switch with your lipo to get maximum efficiency out of your gun.
His PCB's will work with either a standard MOSFET kit or plug into a more advanced SW-COMP (like a triggermaster)

Apparently there's an SW-COMP out there that has a PCB built in but I forgot what it's called (help?)
Either way, the SW-COMP not only acts as a mosfet but also allows you to use burst fire, semi auto fixed, change your rate of fire and it monitors your battery voltage

[Azathoth]

Originally Posted by SHÖCK

Does anybody have the lipo protection boards from Huang? I bought two of them for $15 each and they won't work at all with the 3 batteries that I tested.

I can't get them to work with my Lipo batteries at all. Gearbox won't fire at all unless I hold down the reset button which is basically just turning the device off and opening the circuit. If anybody wants, you can try these and let me know if they work for you. They only have the 4 pin connector to accept 3 cell lipos (11.1v normally).

I have a couple friends who have this problem. What they purchased is not a lipo protection board but a LiPo Balancing board. Bad english translations...

[SHÖCK]

It's a balancing board? So you can use a regular wall adapter with the balancing board with the lipos? Sounds pretty dangerous.

I should get my money back from Huang but it's been a couple months.

How can ehobbyasia say the same thing? That's it's an overdischarge protection board? This is the same thing I got:

http://shop.ehobbyasia.com/king-arms...uit-board.html

video of the problem:
YouTube- lipo discharge protection board strange behavior

[ThunderCactus]

Did you read the notes on ehobby?
"- Prevent 11.1V Li-ion or Li-polymer battery from ``Over-Running``"

Sounds to me like it protects from over-current draw instead of overdischarge. Congratulations, you bought a $14 fuse

If it is an over-current draw protection board, then it may think your AEG is drawing more current than it's supposed to.
The smallest king arms lipo I saw is only capable of providing 15.6A continuously, makes sense they would design their protection board to their smallest rated battery. Plus a safety margin, so it would cut off before it got to 15.6A
And of course there's peak discharge and continuous discharge rates, it takes more power to get a motor going than it does to make it run, so your motor might just be spiking above 15.6A on startup, triggering the board.

[bananabotdan]

@ SHOCK
Are you saying that these King arms boards do not work? DOH I was looking at the king arms PCB a a top contender. Looks like its back to the drawing boards unless someone comes up with some positive feed back about said king arms lipo protector boards.

[Amos]

Wolfdragon PCB + Trigger Master MKIII MOSFET

That's what ThunderCactus and Myself use in our AEG's