Custom Battery Packs? INTERESTED?

[torqueboards]

If I'm understanding this correctly, having the bms built in means that all you do to charge is plug in your pos/neg wires to the charger. Without a bms means you need to plug in the balance cable AND the pos/neg wires.

Aha. That's what I'm finding. Is charging solely through the balance wires slow and how would u do it if making a pack would include about 24 batteries and more Balance leads than the charger recognizes for one pack?

Yes, that's correct. The BMS will balance the cells individually through your charging wires. It's like having your "bulk lipo charger's balance feature" built into the battery pack. Charging through balance wires only is slow which can be done on the "RC lipo chargers" the small ones. Under 3S you can charge through balance wires only any series higher you wouldn't want too.

You don't need a balance lead for every single battery. Only the amount of batteries that you have in series. If they are in parallel they are considered a single series. I think.

Good luck guys I'll be waiting to see your custom made packs

 

[Silenthunter]

by torqueboards » Sat Nov 01, 2014 4:35 pm

@Silenthunter - Yeah, we are actually waiting to do test units and will do a bigger batch once we get closer.

Wow! 30 miles a day! lol Are you swapping packs? 30 miles is a ton.

My Mountain Board has a 24 amps battery (I get about 24 + miles - 0.75 amps per amps) and when it gets drained I switch to my longboard 10 amps which gives me another 10-12 miles...

 

[BShady]

U cant use typicsl laptop cells. They wont discharge enough amps. There are a couple companies selling high discharge li-ion cells. High c rating or amp current is what you need and u can add to the amps produced at one time by adding to the size of the total pack. A 10ah pack will give more than a 5ah. I forget the formula but thats the gist of it. I forget how many amps people get to on a skateboard and wish i knew. If the batteries cant supply the power..you wont get the power and will also be damaging your batteries

If I'm going with 12s than I should be ok even with lower discharge batteries. At least that's what we said before. More voltage less amps.

Is there any 12s BMS for li-ion?

@torqueboards the website you posted to buy li-ion cells, it doesn't say what the capacity is?

Is there any other websites to buy batteries from?

Regarding the laptop batteries could someone explain it to me. How can 6s only equal 10.8v? I though each one is 3.6v?
http://m.ebay.com/itm/181354377584?nav=SEARCH

 

[chuttney1]

@BShady, the battery pack is actually 3S2P. 3 cells x 3.6V= 10.8V Total. Interesting thing is, I got a HP laptop using these MU06 battery packs.

 

[onloop]

I am a DIY'er as well.... so ES'ers please don't take this the wrong way....

unless you have lots of time & money to waste trying making your own pack using 'random' 18650 its probably not worth it!

SOME THINGS ARE BETTER LEFT TO EXPERTS...

Not many people buy individual lipo pouches to make there own LIPO batteries, 18650 cells are not really any different.

Just like the sentence in my signature, about the false economy... this is a perfect example.

AT WORST BATTERIES CAN BE VERY DANGEROUS IF MADE INCORRECTLY. THEY CAN EASILY RUIN ALL OF YOUR EXPENSIVE MOTORS & CONTROLLER TOO>

What Torque & I are trying to do is offer something that is missing from the DIY eboard community that is a; high quality, pre made, reliable, safe, easy to use batteries that will perform really well for the specific task at hand... something that will deliver unprecedented range & energy efficiency with at least double, or more life span.... when compared to LIPO. The overall result outweighs the benefits of LIPO... the cost is not necessarily more. I would say PER Wh it is about the same.

And TORQUE if thats not what you're trying to do.. sorry to put words in your mouth....

 

[Silenthunter]

Well, I don't agree with you statement Onloop...

I have tested cheap unbranded (fake Chinese cells) and all of them performed well enough. The only difference is that ICR or Panasonic cells give you more range with less weight. Anyone can do it....this is how you learn!

I am still using these unbranded cells for my flashlights and after 1.5-2 years they are still running strong. Some people buy used dead laptop batteries and put them together for their electric cars.

My advice is do a good research and give it a try!

 

[torqueboards]

@onloop - that's fine. I'm sure that's what we all are trying to do. While some people do want to make it themselves. Others do not.

I do like how everyone wants to do it themselves just to learn. But as you've everyone should already know.. at times you'll end up spending 2 to 3 times more just to do it yourself. LOL

I just hope whoever does make their own pack they release it on ES. Would be nice for everyone else who do want to learn and do it themselves.

 

[thepronghorn]

I don't understand the desire for higher voltage beyond ~25V. It just adds complexity and cost in the form of more channels on your bms/charger. Higher voltage is not necessarily more efficient! Wiring can be smaller at higher voltages, but that is about it. The reason ebikes use higher voltages is because hub motors are usually wound with very low kV's that make higher volt batteries necessary in order to get the speed people want. For longboard motors, we have a large variety of motor winds to choose from, allowing us to select a motor with the appropriate kV for the motor rpm's we want and the battery voltage we want.

For example, instead of going from 6S (22.2 V) to 10S (37 V), why don't you just increase motor kV by 67% while keeping battery voltage the same? Your motor rpm will increase 67% just like with the voltage increase and motor torque will be unaffected; it will just take more amps to make the same torque. Fortunately the motor's resistance has dropped exactly proportional to the increase in amps so that the motor's torque rating is unchanged.

Since this is a thread about battery packs... I think an 18650 pack would be awesome. Perhaps 6S4P of Samsung 25R's or 29E's or maybe Panasonic NCR18650PD.

 

[torqueboards]

@thepronghorn - Basically, IMO the cost for lipo isn't that far away from having your own Lithium Ion pack with even more voltage.

I've also been enjoying higher voltage than the typical 25V in which I don't want to go back to 25V either.

Higher voltage would give us a higher gearing ratio for more torque while still having the option to keep our top speed. This will also result in being able to climb hills much faster. The higher voltage will also allow us to drop the cont amperage when in use.

You can increase the motor KV by 67% which I've done but the start up torque is just horrible. Sure, once you get it going you can go faster but there isn't any torque.

I would prefer this setup but am still interested in what you would have to say.

 

[drmacgyver]

Perhaps 6S4P of Samsung 25R's or 29E's or maybe Panasonic NCR18650PD.

Those are exactly the specs I want for my pack: 4 x 6s2600mah in parallel, so that I won't need to buy a new ESC and charger. It's the same voltage I'm using now but with double the range. I'm plan on using the highest mah Panasonic cells they make, and not the generic "fakes". There's other brands that claim to have 5ah, but in fine print say "max 1800" - wtf - so I've become weary of the high mah claims. I'm still reading about the process, so if anyone can post some pics of their packs and the wiring that would be very helpful. In regards to soldering, DrkAngel provided me with this helpful link: http://endless-sphere.com/forums/viewtopic.php?f=14&t=26383#p392172

The added cost of making mistakes and whatever makes DIY more expensive is a fair price to pay for learning something new. This whole eboard build has been like that, but it's been worth it. I don't necessarily feel like I'm venturing into territory that's out of reach. Although, it's nice to know that there will be pre-assembled options too.

 

[torqueboards]

@drmacgyver - checkout the flashlight forums as well. They have quite a bit of research on these 18650 cells and where to purchase them as they actually test them out.

You can get the complete knock offs on eBay but I wouldn't use those on these boards as they wouldn't be that reliable. They are fine for a flashlight.

There are some great chinese made 18650s.

 

[drmacgyver]

I've been reading around candlepowerforums. I'm definitely sticking with the real 18650's. Don't want to cut corners especially because I'm just learning. Are you going to build your own, Torque?

@onloop: I'm reading mixed information regarding whether it's a safe hobby or not. I feel like I've already taken a risk by using lipo's without much of any knowledge about them. I like to think it is possible to safely build a 18650 pack if done with care, responsibility, and the right instruction. What I gather is that taking apart laptop batteries and mixing cells is a bad idea with no knowledge. Starting fresh with new, name brand cells seems like a controlled approach to getting started though.

 

[thepronghorn]

Double the volts or double the amps, you're still getting double the power.

For the same torque from the motor, a higher gear ratio will give you more torque.

If you double the kV and double the amps, torque will be the same.

If you double the volts and double the ratio, you will get double the torque and the same top speed.

Generally power is limited by the batteries since our controllers don't really do any current limiting. So if you're going to double the kV and want to double the amps to keep the motor torque the same, a higher amp controller to handle the power as well as more batteries in parallel will be necessary.

You complain about a lack of torque when you increased motor kV, but did you get a higher amp controller as well as more batteries in parallel? Basically if you want to go the high kV, high amps, same voltage route, you have to change stuff around just like you would for a high voltage setup.

What is your current battery, controller, motor, and gearing setup?

Perhaps 6S4P of Samsung 25R's or 29E's or maybe Panasonic NCR18650PD.

Those are exactly the specs I want for my pack: 4 x 6s2600mah in parallel, so that I won't need to buy a new ESC and charger. It's the same voltage I'm using now but with double the range. I'm plan on using the highest mah Panasonic cells they make, and not the generic "fakes". There's other brands that claim to have 5ah, but in fine print say "max 1800" - wtf - so I've become weary of the high mah claims. I'm still reading about the process, so if anyone can post some pics of their packs and the wiring that would be very helpful. In regards to soldering, DrkAngel provided me with this helpful link: http://endless-sphere.com/forums/viewtopic.php?f=14&t=26383#p392172

The added cost of making mistakes and whatever makes DIY more expensive is a fair price to pay for learning something new. This whole eboard build has been like that, but it's been worth it. I don't necessarily feel like I'm venturing into territory that's out of reach. Although, it's nice to know that there will be pre-assembled options too.

Careful with high capacity cells, often their internal resistance is high enough that you will get more watt hours from a cell with lower capacity and lower internal resistance.

 

[torqueboards]

@drmacgyver - No, not building my own unfortunately. Will be getting custom packs made. Have enough to do already. I'm interested in learning more about your build though.

Taking apart laptop packs isn't that difficult. I'm sure you are more then capable of getting it done once you research.

I think it's more of the 90% who don't do prior research before implementing in which it would be a bad idea. Nothing is a bad idea with prior research.

@thepronghorn

That's one of my main issues for going higher voltage as I cannot double the amount of amp output.

I want to double the volts and double the ratio (almost) to get nearly the same top speed but double the torque (the goal).

I assume - doubling the amps isn't what you would want to do. You would want to get the same output at lesser amps to keep things lower, cooler?

Also a higher amp controller would end up costing more.

I would go higher kv but your start from a stop is almost non existent. Even worse. Once you get up there you'll have your speed. I agree, I would have to change things around as well.

However, if I add up the cost for all things. The simplest thing would be to go higher voltage. I would probably go with higher KV if more speed was what I wanted to achieve but since my main goal is to have more torque I would prefer higher voltage sooner than more speed later.

To add higher voltage doesn't really do much for increasing price either. Not much more than a typical lipo setup IMO. My 2 cents.

 

[drmacgyver]

Is there someone here that's definitely making packs for eboards? I'm not making any purchases yet, still learning and weighing pros/cons of making vs buying. My biggest problem is my ESC and charger are limited to 6s, and it seems more people are focused on higher voltages, so making one to my own specs is a big reason for me to DIY. My motor is 280kv also, so higher voltages don't seem necessary for that reason. If I had an 8s+ esc/charger from the start, I could partake in the conversation of pre-assembled.

2600mah is fine with me too. I can't see going much lower that that though. Do you know how much the life span would decrease as a result of using higher capacity cells?

 

[torqueboards]

voodoojar, onloop and I will probably all have packs which will be very similar but slightly different. Most of these packs will all have a BMS and a charger already included though.

Voodoojar already has packs available at 7S/8S.

You'll have to get one of the Single 8S 120A or Dual 8S 120A ESCs and/or wait until Vedder comes out with his 40V and 60V ESCs.

We could make packs for 6S but there's no point when 7S/8S is more fun + isn't that much more even 10S/12S. Isn't far off in price.

As for battery life, it's better to charge at 90% versus 100%. Also to not discharge amp rating quickly or charge quickly would stress the pack. At least that's what I think. Higher capacity cells shouldn't affect it much. However, 18650 cells are the most popular and most sold. They have been tested for years now and are still the most popular even though 26650 is still being sold. Either or is better than none.

Probably will stick to Lithium Ion or LiNCM versus LiFePO4 as the drop off in voltage is pretty significant with LiFePO4.

 

[drmacgyver]

How much more speed and other factors would I get from moving up to 7s, or more? I don't think I need any more than 25mph. I plan on switching permanently to pneumatics also, so I know that factors in.

 

[torqueboards]

How much more speed and other factors would I get from moving up to 7s, or more? I don't think I need any more than 25mph. I plan on switching permanently to pneumatics also, so I know that factors in.

Probably not much from 7S. 8S is a nice bump in power. Allows you to get up to speed quicker and allow for a little more range for top end. I'd say it's about 25% better or so riding. You can tell you have much more speed and power. 10S is a nice too. 12S/13S might be a bit overkill.

 

[drmacgyver]

Hmm, I have had a small itch for a little more speed, but I might get that just from the increased wheel size. My gearing is 3:1 now and will be the same with the pneumatics. Even with extra speed available, I'm not sure I would use much more than what's already available to me. My biggest priority is getting more range. Having to charge every other day is a PITA, which is why I'm making 10ah a minimum requirement for my 18650 pack.

 

[torqueboards]

Hmm, I have had a small itch for a little more speed, but I might get that just from the increased wheel size. My gearing is 3:1 now and will be the same with the pneumatics. Even with extra speed available, I'm not sure I would use much more than what's already available to me. My biggest priority is getting more range. Having to charge every other day is a PITA, which is why I'm making 10ah a minimum requirement for my 18650 pack.

To me it's more of a need for power rather than speed. I don't care too much for top speed past 25mph. I do want my speed to 25mph to be quick and fast but not too fast where it's uncontrollable.

But yeah 10ah is a nice number. Definitely, adds to weight though. 8ah is still a bit less. I've kind of been wondering about that too as well.

 

[onloop]

this is the pack that i am planning on running with, it is completely custom made to my specifications using high discharge cells from korea, if testing works out well it will become available for purchase. It will also be the battery i use for all future ready made eboards & DIY power kits.

this is a photo of the sample being made, and what it looks like finished, it has just been made & is in transit to me.

the cost inc charger for the KOREA cells battery pack is about 20% more than custom made lipos that i currently use, i will try to absorb this cost into my kit prices so that my customers get a superior battery system, I believe this type of battery is the future for eboard builders.

if i went with chinese brand 18650 cells it would actually be much cheaper than lipo but i have doubts about the quality & longevity. I may eventually test some chinese cells, but they don't have any high discharge rate 18650 available so would need to go 10S4P which would be much larger in weight/size.... however slightly more capacity with 325Wh (which is equal to 6S 15AH LIPO) that pack would offer peak discharge of about 60A... which would be good.. but it has 10 more cells.

this is the cost breakdown per Wh when comparing the cost increase from the cheapest option
chinese 18650 cost 100%
chinese LIPo cost 149%
Korean LG 18650 cost 191%

So I am going with a premium option because i really think battery performance is critical..I believe that the cheaper option will have too much voltage sag and won't be able to deliver the capacity i expect.. Im the guy that puts the high octane fuel in my car, not the cheap shit.

the specs of custom made LG18650 eboard battery:
> it is 10S3P
> 277.5Wh (this is greater power capacity than what you get from a 6S 12000Mah LIPO)
> Professionally built with spot welding of tabs to ensure reliability in high vibration environment
> pack made using LG He2 imported from KOREA, they are high discharge cells DATA SHEET
> does 60 amp continuous discharge
> 80Amp BMS integrated.
> Built using 18650 battery holders to allow good heat dissipation & allow room for battery size fluctuations when temperature changes
> has panel mounted DC charge port
> Has common XT60 Plug for connecting to ESC.

 

[BShady]

Looks really good! How much you think it will cost?

A problem I would have is fitting your pack into my existed battery case. As I am MTB I have my batteries top mounted so thicker pack like 50mm is ok for me.

Can you link the website you bought the cells at? Thanks

 

[drmacgyver]

I'm not sure if they're to the exact specs or more expensive than Onloop's, but an ebay search came up with these:
http://www.ebay.com/itm/2-PCS-LG-HE2-18650-35-AMP-High-Drain-2500mah-Rechargeable-Battery-Flat-Top-/191258425474?pt=US_Rechargeable_Batteries&hash=item2c87e3f882

I wish someone would make a 6s10ah pack. *wink wink*

 

[okp]

10S3P is 30 pieces of LG18650 HE2 2500mAh cells right ?

one cell is 48g so 30x48 = 1440 grams so that's good !

one cell cost 9 USD average not discounted = 9 x 30 = 270 USD without shipping to Europe without the BMS

here are some specs for one cell I found

18650 LG 18650HE2 2500mAh High Discharge Flat Top
Nominal Capacity: 2500 mAh
Nominal Voltage: 3.6V
Discharge End Voltage: 2.5V
Standard Charging Current: 1.25A
Charging Voltage: 4.20+-0.05V
Max. Continuous Discharging Current: 20A
Internal Resistance: <20 milli-ohms
Dimensions:
65.00mm (L) x 18.30 mm (D)
Weight: 48.0g

 

[torqueboards]

No need for 6S 10ah if we can go higher Who knows.. maybe I'll check up on a 6S 10ah option. Is a nice option.