Ballistic Batteries Warranty

[mattio79]

i just found the data sheet on the ballistic cells. http://info.a123systems.com/Portals/133376/docs/A123%20Datasheet%2026650M1B.pdf max discharge for 10 seconds (burst) is 120A per series set. that's a max of 480A. continuous discharge is 50A per series set or 200A total. cycle life is 1400 cycles at 20A discharge max per series set ( each cell in series adds voltage, so a pack of 4 cells in series will still have the same amperage rating as a single cell by itself). the added benefit of greater cycle life of the prismatic cells is more than twice as many cycles. i was incorrect in my quote of 3500 cycles; that is where the scale ended. the actual cycle life is 3200 cycles or so, estimating by looking at the graph.

 

[mattio79]

the power output of each cell is 1200W. since there is 65wHr specific energy capacity in each cell, the C rating for a 10 second burst is an average of 18.46C still, that's 363 amps. the 60C burst of the 26650 cells that the ballistic battery uses is for 10 seconds as well, but external testing sets the voltage sag all the way down to 2.6v. that's pretty low. 60C X 2.5Ah ( each cell) X4 (parallel configuration) is 600A. the wire they use will only handle 100A. so their ratings are meaningless. http://info.a123systems.com/Portals/133376/docs/amp20m1hd-a%20data%20sheet.pdf

the total power output of the battery that i would make is 4800W.

actually, the voltage sag at 180 watts per cell takes it all the way down to 2.4v/cell after only discharging 40% of its capacity.

 

[mattio79]

actually, the voltage sag at 180 watts per cell takes it all the way down to 2.4v/cell after only discharging 40% of its capacity.

of the 26650 cells

 

[jMike]

I'm interested in seeing a protype. Post up some pics if you're planning on building one.

 

[mattio79]

I'm interested in seeing a protype. Post up some pics if you're planning on building one.

that's the thing. i am what you all might call poor folk. all i need is someone with an extra $300 laying around that i could use to get what is necessary to even make the prototype. all i want to do is help. fact of the matter, i won't even charge above my cost to do the first one. whoever pays for all the materials needed to make the first one gets it for cost. i'll do that for whoever is willing to help me help you.

 

[mattio79]

http://www.hobbyking.com/hobbyking/..._Fiber_and_Kevlar_29_Cloth_180g_m2_1mtr_.html the carbon fiber cloth
http://www.hobbyking.com/hobbyking/store/__9676__Turnigy_Pure_Silicone_Wire_8AWG_1mtr_BLACK.html the black wire
http://www.hobbyking.com/hobbyking/store/__9677__Turnigy_Pure_Silicone_Wire_8AWG_1mtr_RED.html the red wire.
http://www.hobbyking.com/hobbyking/store/__6580__8MM_gold_connectors_12_pack_.html the terminals
http://www.a123rc.com/goods-468-Excitingly+Powerful+A+123+20ah+PRISMATIC+CELLS.html the cells
http://www.homedepot.com/h_d1/N-25e...d=10053&langId=-1&keyword=epoxy&storeId=10051 the epoxy
http://www.homedepot.com/h_d1/N-5yc...0053&langId=-1&keyword=flexseal&storeId=10051 the sealant/waterproofer.

 

[mattio79]

oh, also a foodsaver system for the vacuum bag to squeeze the whole thing together so it can set hard.

 

[mattio79]

as i said, i will get all of these things if someone puts the money in my paypal account. i will forward ALL information to the payor so they get confirmation of the purchases of all of the products. i will take pictures and post them on this thread. as soon as it is all assembled and adhesives cured, i will package it up and include necessary hardware ( the mating terminals) to install it in your system of your jetski.

 

[mattio79]

http://www.hobbyking.com/hobbyking/..._Fiber_and_Kevlar_29_Cloth_180g_m2_1mtr_.html the carbon fiber cloth
http://www.hobbyking.com/hobbyking/store/__9676__Turnigy_Pure_Silicone_Wire_8AWG_1mtr_BLACK.html the black wire
http://www.hobbyking.com/hobbyking/store/__9677__Turnigy_Pure_Silicone_Wire_8AWG_1mtr_RED.html the red wire.
http://www.hobbyking.com/hobbyking/store/__6580__8MM_gold_connectors_12_pack_.html the terminals
http://www.a123rc.com/goods-468-Excitingly+Powerful+A+123+20ah+PRISMATIC+CELLS.html the cells
http://www.homedepot.com/h_d1/N-25e...d=10053&langId=-1&keyword=epoxy&storeId=10051 the epoxy
http://www.homedepot.com/h_d1/N-5yc...0053&langId=-1&keyword=flexseal&storeId=10051 the sealant/waterproofer.

suggest getting qty 2 of the epoxy. having too much can be cut, trimmed or sanded away, having too little will make the integrity of the shell fail.

4 cells is all that is necessary for the battery. one can of sealant is all that is necessary, and 1 meter of each of the wires is all that is necessary, and i forgot the balancing leads
http://www.hobbyking.com/hobbyking/store/__9737__JST_XH_4S_Wire_Extension_20cm_10pcs_bag_.html

 

[mattio79]

suggest getting qty 2 of the epoxy. having too much can be cut, trimmed or sanded away, having too little will make the integrity of the shell fail.

4 cells is all that is necessary for the battery. one can of sealant is all that is necessary, and 1 meter of each of the wires is all that is necessary, and i forgot the balancing leads
http://www.hobbyking.com/hobbyking/store/__9737__JST_XH_4S_Wire_Extension_20cm_10pcs_bag_.html

the cell monitor
http://www.hobbyking.com/hobbyking/...2_8S_Cell_Checker_with_Low_Voltage_Alarm.html

 

[mattio79]

the cell monitor
http://www.hobbyking.com/hobbyking/...2_8S_Cell_Checker_with_Low_Voltage_Alarm.html

http://www.youtube.com/watch?v=GrBvSST9chg&feature=g-upl the previous generation of the cell monitor. that's me in the video.

 

[mattio79]

i really wish i could afford to buy all of this stuff to help you guys, but i am honestly strapped for cash.

 

[Idok]

step away from the reply button! ...oh my lord

 

[WFO Speedracer]

He is quite excitable isn't he !

 

[mattio79]

 

[jMike]

That's funny I was also looking at those prismatic cells after a guy at my LHS was showing them to me online.. Coming up with a way to mount them in the ski will be interesting being roughly 6" x 8.5" x in size

 

[mattio79]

That's funny I was also looking at those prismatic cells after a guy at my LHS was showing them to me online.. Coming up with a way to mount them in the ski will be interesting being roughly 6" x 8.5" x in size

6 35/64 x 8 15/16 x 1 7/64 total internal pack dimensions. with the kevlar/carbon fiber shell, figure on adding about 3/16 to each dimension. it will be a solid design that i have decided needs to be serviceable so that if a cell dies, it can be pulled out an replaced. the problem with that, however, is that you would have to then suddenly remember how many cycles you put the original pack through and make the replacement cell have the same amount of cycles. the reason for that is because each pack will be resistance-approximate matched and when a battery is cycled, that resistance increases, taking the pack farther away from when it was new. introducing a new cell would make it discharge faster than the rest of the cells, if its resistance happened to be lower than the other cells in the pack. the way i would make the pack's shell serviceable is by measuring the pack very carefully and carving/ cutting a block of wood to match the size of the pack (inlcuding a barrier layer ( for ease of assembly, the parts can't be too close together in size. the extra space can be taken up by silicone for shock absorption) and forming the shell around that block ( leads (discharge/charge and balance) will be part of the block, so that they will make their impression.) so that the force of a vacuum bag won't squish the cells during the curing time of the epoxy resin infused within the kevlar/cf cloth. then after curing, i would take each half of the shell out of their bags, trim and fit them to each other and the cells, then i would put some silicone caulking around the assembled pack of cells ( they would be attached to each other with double-sided tape and the cell tabs would already be insulated by either flex-seal ( found it at walmart) or plastidip spray-on insulating rubber. i would then glue the halves together with some sort of reversible adhesive that is durable enough not to let go during service. anyway, just putting that out there.

 

[Superjetjim]

Mine has had the cells break away internally as well - there only held in place with a few dabs of silicone so no wonder it came apart after a few flips, the cells move and the spot welds break off:

My Ballistic charger power adapter blew up the first time I plugged it in as well (wasn't even connected to a battery!) - stuff is poor quality..

 

[mattio79]

i would do such a better job. and besides, the prismatic cells better lend themselves to series AND parallel connections. their tabs are on the same end. i'm tellin' ya folks, all i need is one person with $300 burning a hole in their wallet (i have already shown you my costs, i would have to fork out for a Foodsaver vacuum system) and then i can proceed. also, a carbon-fiber/kevlar casing is going to be many times stronger than what looks to me to be either HDPE or ABS. maybe even polycarbonate. i will also use round cable to attach 8mm bullets to it. i would let you choose the configuration of the discharge leads: long, external or short, at-the-case, as is similar to what ballistic has here. i would put them at the same end as the tabs on the cells. no crappy copper plating very chincily spot-welded to a cell. i would use solder and make sure that it was as thin as possible ( meaning that i would lay the stripped discharge cable along the cell tab and solder it to that. thanks for the pictures by the way.

 

[mattio79]

That's funny I was also looking at those prismatic cells after a guy at my LHS was showing them to me online.. Coming up with a way to mount them in the ski will be interesting being roughly 6" x 8.5" x in size

speaking of mounting, i could make a flat box with 5 sides that is slightly larger than the pack so it is like a tray. i would then put several pieces of carbon rod into the sides and install velcro straps going long and wide so the pack is Very secure. you could mount the tray in any orientation ( make it convenient to access, say on the underside of your seat, or maybe alongside the pump housing ( jet?) or just on the sidewall. many options, i'm sure.