How to wire a balanced Lipo battery pack...

[Parellax]

I found a good wiring diagram for for the popular five cell 18.5 V 18650 Lipo mod for Sergey's board. The other links show you examples of the pigtails, and a compatible charger.

What balancing does is it allows the batteries to be monitored while they are being charged, and adjusts to each cells needs accordingly during the charging process.

This has not been overlooked by the "Fun Buster's" however. I read that it's actually illegal to solder Lipo batteries. This is probably if you intend to sell them, but I really don't know so do at your own risk.

The real problem is the positive terminal on an 18650 is so close to it's negative side which is the housing itself. If you accidentally solder the gap you put the battery in a dead short. At the least you will ruin your battery. At worst the battery will explode.

There are a few different types of connecters so if you already have a balancing charger find out what kind of connector's it will accept. Also below is what I use by showing you a couple of random site's. If you are not familiar with this stuff please post your questions on the new forum after you have registered.

http://scriptasylum.com/rc_speed/lipo.html

http://www.ebay.com/itm/10-PCS-5S1P-Balance-Charger-Silicon-Cable-Wire-JST-XH-Connector-Adapter-Plug-/221813732243?hash=item33a520f393:g:2eYAAOSw9N1Vkfws

http://www.batteryjunction.com/tenergy-90263-tb6b-chgr.html?gclid=CjwKEAiAkb-zBRC2upezwuyguQ4SJADZG08vhpBL--7Cj5QnjTqcnInN4_L_SbLurwRbp_K0VlbtPRoCZ1fw_wcB

[camracer]

Good info, thanks.

I think I posted about that back on the old forum before somewhere. I saw that "scriptasylum" page and another like it before.

I even have photos of my 18650 pack stuffed inside my Blackbird that is set up for balanced charging.

I'll post it here If I can find it and if anyone is interested.

---Cam

[Parellax]

I was thinking of doing your battery stock mod just for the fun of it. I was thinking I would mount the balancing connector in the seam on the top of the bottom portion of the stock. That way I can plug a digital low voltage alarm into it, and it will be out of the way. Do you have a link the motor speed controller you used? 

[camracer]

Did you find my thread on how to do my stock mod on the other forum? If you did post a link here to that thread for others to see.

Here is the motor speed controller I used:

http://www.amazon.com/Unique-Goods-Adjustable-Reversible-reversing/dp/B0100KN9IY/ref=sr_1_fkmr2_2?ie=UTF8&qid=1450889639&sr=8-2-fkmr2&keywords=DC+12V-24V+5A+Motor+Speed+Control+Adjust+PWM+Controller-10000134

As an idea for you, rather than using an alarm, I would suggest you do what I did and wire in a LED display voltage monitor:

http://www.amazon.com/DROK-Digital-Voltage-Voltmeter-Monitoring/dp/B00C58JGE6/ref=sr_1_8?ie=UTF8&qid=1450890177&sr=8-8&keywords=mini+led+display+voltage+monitor

[camracer]

BTW, I removed the big aluminum heat sink on the controller to make it fit inside the stock easier. You don't need it anyway.

Also, I wired in a momentary on switch to the LED display so it would not stay on all the time, just when you push the switch. You can see me pushing the switch for the display in the photo, and where I put the adjustment knob for the speed controller:

[Parellax]

Thanks for the links. I was thinking about doing that in conjunction with the low voltage alarm. I have been using them, and they give you a better idea about where your cells are under a draw. Sergey found them some time ago when the debate of how to accurately measure battery drain under a load in a pulsing system was going on. Maybe you saw my video a while back. I didn't run the batteries to my set low voltage alarm, but when it goes off you will definitely hear it without looking at it.

https://www.youtube.com/watch?v=gBaGe9_Vr4k

http://www.hobbypartz.com/79p-8003-voltagemonitor.html

[camracer]

Yeah, I have seen those battery checkers.

Does the display stay on all the time?? If so, you could wire in a momentary switch if you want.
 It is nice you can choose to disable the alarm, if you want to.

[Parellax]

Yes. They stay on, and cycle through each cell's voltage. Then they give you the current voltage of the entire pack. You can program them to the desired low voltage you want the alarm to sound. I bought a voltage controller from the link you posted. I have some voltage monitor displays I bought a few years ago when I was on the same path you were without knowing. Several of them didn't work. They were super cheap from China. I will have to see if I have one that works.

[Parellax]

My motor speed controller came today. I got to playing around with it. Very cool! I couldn't see a way to install it in the stock with five 18650's without the stock being closed all the way though (even with the heat sink removed). I can easily fit six 14500's in there though, but then it's kind of like, "What's the point?" So it's a toss up. I can wire six 14500's in the stock being able to monitor them digitally, or I can just keep using them in the battery compartment periodically testing them in the gun with it on using a volt meter on the exposed terminals with the battery compartment door open. The only downside to using the compartment is if the batteries are damaged they can swell, and be a bitch to get out. I recommend anyone using the 14500's in their battery compartment to lube the sides of the batteries lightly with silicone oil.

Why not? I think I will try this configuration. I have everything I need except the balancing connector. Maybe I will wire a switch so I can utilize the battery compartment for auxiliary power when the alarm sounds.

[camracer]

Yeah, it is a tight fit in the stock. You can do what I did and expand the stock for more room if you want.

[camracer]

Here's a link to my how-to thread on the other forum. I originally expanded the stock to fit a 13 c.i. HPA tank. Lots of room left over.

http://bb.bbboy.net/straferbbmachinegunownersgroup-viewthread?forum=10&thread=3165&postnum=30

[Parellax]

Thanks for the link. I missed that one. I tried searching the old forum last night, and it looks like the search function doesn't work at all anymore. I like the high drain batteries DUBB pointed out. Sorry for the gigantic pic. I thought I was shooting a lower resolution. Here is my circuit excluding the bypass switch for auxiliary power.

https://youtu.be/acsVBMEGI0Q

[camracer]

Yup. That's a good demo of how it works.

You'll be able to precisely experiment with bb feed rates once it is installed.

[Parellax]

One of my customers suggested I add a tachometer so I found this to throw in the mix. I figure it can tell me when the clutch is slipping as well as give me good rpm data while the gun is firing. I think I will mount it, and the volt meter on the top rail somehow.

http://www.ebay.com/itm/DC-7-30V-Power-Digital-Speedometer-Tachograph-Tachometer-Yellow-LED-Display-/351295189450?hash=item51cad331ca:g:-0YAAOSwEK9TxvBy

[TBK]

Has anyone tried using the round cell holders that hold three batteries?  I was going to put two of those in a tube.

http://ecx.images-amazon.com/images/I/414UANmUtRL.jpg

http://www.amazon.com/uxcell-Parallel-Connection-Holder-Battery/dp/B00K86S3QE/ref=sr_1_4?s=electronics&ie=UTF8&qid=1451625103&sr=1-4&keywords=battery+holder+for+18650