Custom Battery Packs? INTERESTED?

[an7h0ny]

Wondering why no one mentions the lifepo4 chemistry. Its suppose to be safer with its iron cathode, have a high cycle life and easier to charge because they stay balanced longer. Its also expensive. I bought lipos for my first setup, I went (2) 4s1p to run in series for 8s. They have 60c and 20c options and come in a hard case. I'm just gonna double side tape them to the bottom of the board. I choose 8s over 6s because I fly rc planes, and other guys I fly with are saying their escs, motors and batteries are running cooler since the jump in voltage. Do to less resistance and energy being turned in to heat.

 

[Hummina Shadeeba]

Interested, but confused.
Pleae tell me if I have this right.
With this or any BMS you need the correct power supply to feed the BMS, this would maybe be 30v dc at some low amperage. Then from the BMS to the batteries. The BMS limits the incoming charge and outgoing. Please tell me what I'm missing but it seems no charger is needed and just an appropriate power supply

How fast will this charge?

 

[torqueboards]

I believe, the voltage drops out way too soon which will affect your riding. Cycle life is nice but if your voltage drops tremendously is it worth it? Anyone with experience with the lifepo4 packs? I may buy a few for testing.

The power density is also greater with Lithium Ion. LiFePO4 is also much heavier. You would get less power + capacity versus Lithium Ion. Tesla also uses Lithium Ion 18650 cells and/or (use too). Their cars had something like 7000 cells or something.

18650 are also more heavily used then any other cells which helps as well.

@Hummina - Yes, you will still need a power supply/charger same thing IMO. You won't need a lipo battery balancer charge as the BMS supplements it on-board.

Traditionally, you need your power supply/charger + lipo battery balancer charger which will keep the cells balanced. It's all the same except the lipo battery balancer is the BMS and the BMS is on-board. You then use a smaller battery charger that has one purpose is to charge a specific battery pack at a specific rate. Other lipo balancer power supply's have more features/options. Ex. Ability to power (2) lipo balancer chargers.

Typically, you want to only charge at 2A and 5A with a BMS.

 

[an7h0ny]

Torque- lifepo4 is a lithium ion battery with a constant 3.2 volt per cell they actually are less affected by voltage drop because they deliver 3.2 from start to finish. Its heavier and that's why we don't use it for rc planes but for a an eboard it wouldn't matter. Its like a person who weighs 150 instead of 145. I think I read somewhere that this the go to chemistry for car makers who make hybrids now.

 

[torqueboards]

Torque- lifepo4 is a lithium ion battery with a constant 3.2 volt per cell they actually are less affected by voltage drop because they deliver 3.2 from start to finish. Its heavier and that's why we don't use it for rc planes but for a an eboard it wouldn't matter. Its like a person who weighs 150 instead of 145. I think I read somewhere that this the go to chemistry for car makers who make hybrids now.

Thanks for the insight an7h0ny. I'll definitely think about it and do a bit more research. I was comparing the two and the 18650's seemed to trump the LiFePO4. Will have to scrutinize it more closely now

I do like the 2000 life cycles almost double...

 

[an7h0ny]

Torque- I was considering making a pack of my own and after looking at both the 18650 were the better price option because you need more lifepo4 cells to get the same voltage. then I gave up on the idea and bought some lipos.

 

[onloop]

game changer

 

[torqueboards]

Nice setup! Lipo or Lithium Ion?

 

[onloop]

LG 18650HE2 2500mAh HYBRID HIGH DISCHARGE CELL

10S3P (7.5AH) 80A BMS + 2A MAINS CHARGER = charge time of 3.75hrs (or 2hrs with fast charger)

Chemistry: Li[NiMnCo]O2 (H-NMC) / Graphite + SiO
Official Max Continuous Discharge Current: 20 amps
Nominal Voltage: 3.6
Max Charge Current: 4 amps

Please note: test data from LG has shown this 18650 cell handling a continuous 35 amp discharge load. this pack could output burst of over 100 amps but will be limited to 80A by BMS

 

[torqueboards]

Nice..

I thought you said 60A Continuous JK. Should have my packs soon. Was suppose to get delivered today but couldn't pick it up.

 

[onloop]

each cell can do 20A

but this custom made pack is 3P so 60A

 

[BShady]

Can you post a link to te 80amp BMS?

 

[Silenthunter]

Just for curiosity connect the charger and draw 20 amps on one cell and see what is going to happen. The question is if you have a charger that is capable to withdraw 20 amps ))

 

[Hummina Shadeeba]

Just for curiosity connect the charger and draw 20 amps on one cell and see what is going to happen. The question is if you have a charger that is capable to withdraw 20 amps ))

Yea how bout doing a battery test for us.
Seems there's questions about how much these cells can take verse advertised claims. It'd be nice to see

Maybe add a temp sensor

And expansion test

 

[CFRP]

onloop,
That is a very nice looking battery pack. Great job. Would you tell us a little bit about the expected cycle life of this pack.

 

[torqueboards]

Here are some photos for a pack with Panasonic NCR18650PF cells 2900mah. This particular pack is 8S3P. 30A Cont. 10" long, 5.75" width, 1" tall.

I'm leaning more towards a 6" length x 5.75" width x 1.85" height. 1.85" height isn't that tall. Allows you to still use a much smaller deck w/ a shorter wheelbase.

We could use 3400mah cells. Samsung cells are also much cheaper than Panasonic.

 

[BShady]

How much did this pack cost?

 

[okp]

congrats, how much does it weight ?

 

[chuttney1]

The Battery pack are very well made, for sure. Please do tests to confirm the stated amperage is what can be drawn and performance over 300 cycles. My thoughts are 3 cells in parallel, with continuous 10 amps discharge rate each, is able to deliver 30 amps from the understanding of the number of cell in parallel as opposed to being in series. For what it is worth, the performance of the 18650s may meet or exceed lipos in the long run using the same configuration. The price is a hard one for anyone new to building an eboard and would choose lipos instead since its cheaper at face value. From the perspective of the makers of the pack, its easy to see why the cost of so many cell can add up to the entire pack. I still buy the pack because it's done professionally. What's the time scale looking for availability? The DIY route kind of wins if you have access to a battery spot welder to make to make your own.

To those interested in using LiFePO4 as the battery chemistry. Given each cell is 3.0V for a nomial charge level, its kind of hard to beat lipo/NMC 3.6V--3.7V voltage. LiFePO4 do beat other lithium battery chemistry for being really safe when damage and not have thermal run away. We all probably heard the stories of Tesla Model S catching fire after the battery pack was puncture with big metal shrapnel, but the car is really awesome. LiFePO4 cells are best bought from A123.

 

[torqueboards]

How much did this pack cost?

This pack is about $300. It's a bit more expensive since I used the Panasonic cells and didn't purchase in bulk so shipping adds to the cost. Samsung cells should be much cheaper. I'm hoping for a $200-250 pack for 7S 8.8ah or so.

congrats, how much does it weight ?

Weight is about 3 lbs.

@chuttney1

Yeah, pack was well done. I think a better test would be to check the actual amperage we are pulling from our systems. From what it seems our peaks are about 60-80amps for about 2-3 seconds if not less. Our cont seems to be about 10-15amps if not less. For us to really use 60-80amps continous. I would think we would need some sorta foot straps on our boards. lol Correct me if I'm wrong.

Voodoo
Currently has 7S2P packs which are 20A cont and he says they are pretty much normal compared to the Lipo packs. At first, I thought we needed more but I don't think we do.

 

[drmacgyver]

This Anker external battery pack apparently uses 4x4000mah "Premium" LG cells. Didn't know 4000mah existed, but for the $30 sale price that's a steal.
http://www.amazon.com/16000mAh-External-Battery-Technology-Portable/dp/B00N2T7U90/ref=gb1h_tit_c-2_7622_085da242?s=wireless&ie=UTF8&qid=1416271761&sr=1-1&keywords=B00N2T7U90&smid=A294P4X9EWVXLJ&pf_rd_m=ATVPDKIKX0DER&pf_rd_t=101&pf_rd_s=center-2&pf_rd_r=0YKDVMSKHTRN3QSHCPQ7&pf_rd_i=384082011&pf_rd_p=1959117622

 

[BShady]

You think they are real? Sounds a little good to be true? :/

 

[beto_pty]

Separating the cells and replugging in series that would be 3s at 4000 mah...

Hobbiking has 4s 5000 mah at about 24 bucks or so... (1.6 x this one)

 

[onloop]

Maybe it has 6x 2700mah

 

[beto_pty]

I should get commisions from Hobbyking...



Also Im only replying to the dirt cheap part of the original comment.. after looking at the parts diagram this looks super advanced compared to your typical lipo sandwich..

but I think we are hijacking torque`s thread.. this is about his new technology batts... sorry Torque...