lipo help regarding balance plug and heat

[r2ryan]

i am a newbie concerning lipos. havent used them in yrs and only for rc purposes. I'm building a e-bike.
my plan is to use 2 6s1p lipos(5000mah) to put in series to make a 12sp1 at 5000mah pack. i plan to stuff these in a sock like
protective foam or cushion. i will be cutting out quarter size holes in the foam to allow 50-60% of the batter to be exposed. i am then planning on stuffinf the 2 batteries down say a 2.5" -3" pvc pipe. i am allowing air flow to be able to flow from one end of tube to the other for cooling if need be. i plan on using a 48v(60v nominal) controller witd max 22amp output.
so question number

1.. if i decide to keep the pvc sealed what am i looking as far as heat build up. would like to be able to use sealed system if possible due to weather proofing. but dont want to worry about over heating.

2. If these two packs are put into series , can i buy (2) s6 lvc audible alarms and plu them into the balance plugs of each s6p1 pack? wiil this cause a short sense they are wired for 44.4v with current running through the discharge wires at the same time?

i was thinking of buying a Tenergy 100A 3 in 1 Self-Balance, Voltage and Watt Meter http://www.all-battery.com/valtagewattmeter01019.aspx and wiring the discharge cables through it to monitor the realtime voltage and AH's used but pluggin in one of the balance plug from the batteries in serious to it as well. using the second feature allow a battery gauge. i though in principle that if the batteries are identical and in series while in use then AH in each should run pretty close when being used.

i plan to plug each battery into device( one at a time of course )to use the balance feature to balance the batteries after use then charge them one at a time after.

any help is great , thx

 

[dogman dan]

If I understand you correctly, your plan should work except for the part about connecting the device to both a balance plugs of one pack, and the whole 12s at the same time.

Definitely you will want all the plugs to be outside the pipe so you can connect to balance plugs to monitor, and to balance the packs when you do occasionally need a balance charge. I assume you may want to paralell the packs to charge, then series connect to 12s to run.

To monitor the whole pack voltage as you ride, you can simply put a voltmeter on the bike, or better still get a cycleanalyst eventually. But monitoring the watthours or ah used on one pack will work fine. Then you could put a cheaper low voltage monitor on the other pack if you like.

The heat issue is a non issue I think. Sure, the packs will heat up some as you discharge, but in the real world you will have either A or B

A is the pack never gets all that hot, because you bought good lipo and discharge it at 2-3c.

B is the pack gets discharged at it's max c rate, and does get hot, but not for that long because the ride is over in 10 min.

Either way, not that much heat is generated. It will take longer to have that heat dissipate, so maybe put a remote temp sensor inside the tube so you know what is happening. 10 bucks for a cheap automobile indoor outdoor thermometer. But the total heat generated won't be much, with just 5 ah in there. The better the c rate lipo you buy, the less heat you will make. Needing just two packs, get the nano's if you can.

With a 22 amp controller, you are looking at A, so I really wouldn't worry. When I put 20c lipo, 5 ah on the same controller, the packs do actually get slightly warm. But only slightly, unless you run 40 amps.