Need expertise on wiring Turnigy packs?

Here is the product I am buying: http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=14617

I want to connect these 37v 5AH packs, 10 in parallel to increase to 50AH. Then connect each 50AH "string" in series 10 times for a total of 370V. I am looking at the wiring each 37v 5AH comes with, looks like 14awg. Will 14awg work or will I need to cut the wires off and replace with larger size wire? and if so what size do I need?

Thanks in advance! :lol:

I'm pretty sure they come with 10g wires, so given the short length of the pack interconnects and the current sharing that will occur between packs this should work OK for you. For the power connections I'd use some 6mm barrel connectors. HK do some with colour coded plastic shrouds that seem to be pretty good: http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=12887

You'll need to connect all the balance taps together, too, which is best done by making up some simple circuit boards with JST connectors. I've used short pieces of 0.1" stripboard to do this, it's pretty much ideal. All you then need to buy are some JST headers and solder them to the stripboard, get some 11 way JST leads and solder these to each bit of stripboard and you have an easy way of paralleling up each pack into your 50Ah sub-packs.

Sounds like an "interesting" battery pack.................

Jeremy

Jeremy,

Thank you! Can you explain this in more detail, this is my first battery pack build? Are you speaking of a BMS system here?

Jeremy Harris said:

You'll need to connect all the balance taps together, too, which is best done by making up some simple circuit boards with JST connectors. I've used short pieces of 0.1" stripboard to do this, it's pretty much ideal. All you then need to buy are some JST headers and solder them to the stripboard, get some 11 way JST leads and solder these to each bit of stripboard and you have an easy way of paralleling up each pack into your 50Ah sub-packs.

Sounds like an "interesting" battery pack.................

Jeremy

Click to expand...

EVDragRacer said:

Jeremy,

Thank you! Can you explain this in more detail, this is my first battery pack build? Are you speaking of a BMS system here?

Jeremy Harris said:

You'll need to connect all the balance taps together, too, which is best done by making up some simple circuit boards with JST connectors. I've used short pieces of 0.1" stripboard to do this, it's pretty much ideal. All you then need to buy are some JST headers and solder them to the stripboard, get some 11 way JST leads and solder these to each bit of stripboard and you have an easy way of paralleling up each pack into your 50Ah sub-packs.

Sounds like an "interesting" battery pack.................

Jeremy

Click to expand...

Click to expand...

Each of those Turnigy packs has 10 cells in it, so when you parallel 10 packs together to make your 50Ah sub-packs, you not only need to connect the pack positives together and the pack negatives together, you also need to connect each cell connection together as well. The small connectors on each pack are connected to the individual cells, so making up a connector array that these all plug into automatically connects the packs together at the cells level. It also gives you one balance tap connection point for the BMS or charger to plug into.

Whether you choose to use a BMS or not is a matter of personal preference. I'd be inclined to just balance charge (using the balance connectors hooked up to the charger in the usual way) and then just keep an eye on the overall energy pulled from the pack. If you don't drain the pack by more than about 80%, and balance charge it periodically, then there's little chance it'll get enough out of whack to risk damaging a cell.

Jeremy

Thanks again Jeremy, and Merry Christmas!

Jeremy Harris said:

EVDragRacer said:

Jeremy,

Thank you! Can you explain this in more detail, this is my first battery pack build? Are you speaking of a BMS system here?

Jeremy Harris said:

You'll need to connect all the balance taps together, too, which is best done by making up some simple circuit boards with JST connectors. I've used short pieces of 0.1" stripboard to do this, it's pretty much ideal. All you then need to buy are some JST headers and solder them to the stripboard, get some 11 way JST leads and solder these to each bit of stripboard and you have an easy way of paralleling up each pack into your 50Ah sub-packs.

Sounds like an "interesting" battery pack.................

Jeremy

Click to expand...

Click to expand...

Each of those Turnigy packs has 10 cells in it, so when you parallel 10 packs together to make your 50Ah sub-packs, you not only need to connect the pack positives together and the pack negatives together, you also need to connect each cell connection together as well. The small connectors on each pack are connected to the individual cells, so making up a connector array that these all plug into automatically connects the packs together at the cells level. It also gives you one balance tap connection point for the BMS or charger to plug into.

Whether you choose to use a BMS or not is a matter of personal preference. I'd be inclined to just balance charge (using the balance connectors hooked up to the charger in the usual way) and then just keep an eye on the overall energy pulled from the pack. If you don't drain the pack by more than about 80%, and balance charge it periodically, then there's little chance it'll get enough out of whack to risk damaging a cell.

Jeremy

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Looking at some of the sticky threads at the top of battery section should help. Care and feeding, and lipo noob links.

The wire size may depend on the c rate, I bought some 30c that had 8 guage wires, while 20c had 10 guage. Personally, I was planning on 45 amps max, so I added 12 guage wires to mine to match a 45 amp connector I wanted to use.

You are planning a HUGE pack though, so you will need to connect the existing wire from the packs to something large enough to carry the kind of current you plan on. So you will no doubt be doing some kind of connecting the packs discharge wires to much larger wire, or buss bars or something. The size of the wire or copper strip or whatever you use will depend on the voltage and amperage of current that will flow through it. Obviously this is not for a bicycle, so you will have to get that advice from the electric car experts. But I can say, the wire that is on the packs will be adequate for connecting each pack to the much larger wire, that will actually be carrying all the current. The pack wiring will be adequate for the current flowing from each individual pack.

Permanently paralelled packs will need to be connected at both discharge wires and at balance wires, as said above. No harm in upgrading that wire to something that is a bit larger, simply to make it easier to handle.

Jeremy Harris said:

I'm pretty sure they come with 10g wires

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IIRC from LFP's reviews of the 45/90 nano's, they come with 8g hookups.

Hello Guys,

I have contacted a few battery pack builders and they have pointed out more "trouble" to look for, the battery tabs? These 37V 5AH packs may not have sufficient tabs connecting the batteries together for the addition voltage and AH, what is your thoughts on the tabs? :|

Lukes going to have kittens when he reads someones connecting this many nano tech lipos up "I want to connect these 37v 5AH packs, 10 in parallel to increase to 50AH. Then connect each 50AH "string" in series 10 times for a total of 370V" LoL... i wanna see what these batteries are going in EVDragRacer ....then see it run the 1/4 mile...best of luck...

KiM

Your making me nervous, is that a good thing or am I in for a disaster? Here is the Camaro dragster the pack is going in:
http://www.lithiumaniacsracing.com/

AussieJester said:

Lukes going to have kittens when he reads someones connecting this many nano tech lipos up "I want to connect these 37v 5AH packs, 10 in parallel to increase to 50AH. Then connect each 50AH "string" in series 10 times for a total of 370V" LoL... i wanna see what these batteries are going in EVDragRacer ....then see it run the 1/4 mile...best of luck...

KiM

Click to expand...

EVDragRacer said:

Your making me nervous, is that a good thing or am I in for a disaster? Here is the Camaro dragster the pack is going in:
http://www.lithiumaniacsracing.com/

AussieJester said:

Lukes going to have kittens when he reads someones connecting this many nano tech lipos up "I want to connect these 37v 5AH packs, 10 in parallel to increase to 50AH. Then connect each 50AH "string" in series 10 times for a total of 370V" LoL... i wanna see what these batteries are going in EVDragRacer ....then see it run the 1/4 mile...best of luck...

KiM

Click to expand...

Click to expand...

I think he meant Luke'll be excited to see such a large pack application. I'm also very interested to see how this works out. I second the use of busbars for paralleling the cells, btw...big busbars. Speaking of which, I notice on the page you linked that you're using a Zilla 2K. Have you done calculations and whatnot to figure out what kind of current you're expecting the motor to be able to draw? With a 11" WarP I think you should be able to sufficiently blow away the 2kA limit of the Zilla 2K. And the batteries will easily blow away 2kA. Just staying within the spec limitations, a 50Ah pack of these will hit 4.5kA burst, and in his testing I think Luke said he could consistently hit 200C burst, which would push a 50Ah pack to a max of 10kA burst! ..granted, at 200C they would drain in 18 seconds, but for a 1/4 mile with these batteries and that 11" WarP, I doubt that would be a problem.

I would say save yourself some extreme frustration, money, and time, and buy larger cells, instead of stringing together a buttload of these cells.

At the bottom of the charge, lipos like to get unbalanced.
If you drain these batteries anywhere below i dunno.. 15% remaining, you will need to individually balance charge each pack.

You can have an LVC set to prevent this, but voltages will vary widely at the bottom of the charge, so you'll end up wasting some amount of capacity.

I am not sure about the nano-tech cells, but this is a huge issue with other lipo in general. The Cells are just not professional grade, with 100% matched capacity, internal resistance, etc.

I too will love seeing the vid of this thing draining 50 ah of 374v in 1/4 mile. Yeah baby!

With all that power and yet so little weight, you gonna need a way sticky tire. Sounds like good clean fun!

Live for physics is the man for you to start a dialoge with. He knows how to connect up best for some high power uses. But the packs themselves are built to take pretty hefty discharge rates, so I think the pack wiring will ok. It's the wires to carry 100s that will need to be mondo. I'm getting this pic in my head of copper bars the size of leaf springs. 100s lipo. Holy crap! Hobby King is going to love you. And whatever you buy, we won't be able to get any of for a year. :lol:

I am learning the same thing in a race situation, I really want to carry enough battery to have a lot left at the end, just so I don't get slow. But upsizing any more will sure get pricy.

Okay thanks!

x88x said:

EVDragRacer said:

Your making me nervous, is that a good thing or am I in for a disaster? Here is the Camaro dragster the pack is going in:
http://www.lithiumaniacsracing.com/

AussieJester said:

Lukes going to have kittens when he reads someones connecting this many nano tech lipos up "I want to connect these 37v 5AH packs, 10 in parallel to increase to 50AH. Then connect each 50AH "string" in series 10 times for a total of 370V" LoL... i wanna see what these batteries are going in EVDragRacer ....then see it run the 1/4 mile...best of luck...

KiM

Click to expand...

Click to expand...

I think he meant Luke'll be excited to see such a large pack application. I'm also very interested to see how this works out. I second the use of busbars for paralleling the cells, btw...big busbars. Speaking of which, I notice on the page you linked that you're using a Zilla 2K. Have you done calculations and whatnot to figure out what kind of current you're expecting the motor to be able to draw? With a 11" WarP I think you should be able to sufficiently blow away the 2kA limit of the Zilla 2K. And the batteries will easily blow away 2kA. Just staying within the spec limitations, a 50Ah pack of these will hit 4.5kA burst, and in his testing I think Luke said he could consistently hit 200C burst, which would push a 50Ah pack to a max of 10kA burst! ..granted, at 200C they would drain in 18 seconds, but for a 1/4 mile with these batteries and that 11" WarP, I doubt that would be a problem.

Click to expand...

The reason I am buying these cell packs is the very high C-Ratings I need for racing. Larger batteries (like Headways) have lower C-ratings and are very heavy and bulky.

neptronix said:

I would say save yourself some extreme frustration, money, and time, and buy larger cells, instead of stringing together a buttload of these cells.

At the bottom of the charge, lipos like to get unbalanced.
If you drain these batteries anywhere below i dunno.. 15% remaining, you will need to individually balance charge each pack.

You can have an LVC set to prevent this, but voltages will vary widely at the bottom of the charge, so you'll end up wasting some amount of capacity.

I am not sure about the nano-tech cells, but this is a huge issue with other lipo in general. The Cells are just not professional grade, with 100% matched capacity, internal resistance, etc.

Click to expand...

EVDragRacer said:

The reason I am buying these cell packs is the very high C-Ratings I need for racing. Larger batteries (like Headways) have lower C-ratings and are very heavy and bulky.

Click to expand...

I do understand that. For drag racing, lifepo4 is kind of a joke.
I wish i had a better recommendation for you. Getting cozy with A123 or another industrial battery manufacturer is what most other drag racing teams do.

Using busbars is one option, but I might use a larger wire with a quick disconnect. The reason for this is quick fix and replace if one 5AH 37V pack gives me problems, I want to have spares ready for a quick on track fix. Later I can fix the bad cell or two and reweld, but on the track I will need a quick fix. So, I must find what size wiring I will need and what type of connector, along with a BMS system. Does anyone have addition technical info on Turnigy products? and any past builds of paralleling these packs?

I read one guy from Facebook (John Metric) who is building the same type of battery box, but he is using Enerland (A123), that is where I received the idea. I decided to go with Turnigy over Enerland because of pack voltage 37V. Here are his pictures:

Indeed, a very " interesting" pack

50Ah x 200c burst = 10.000 A x 370 V = 3700 KW x 1,35 = 4995 Horsepower

It would be great to build a dragerace with Hobbyking and Turnigy stuff !

The wiring is not more complicated than a simple E-bike, it's only a bit more and every 5,5mm connector should be fine.

My 90c Nano Lipo came with 10 AWG wires but that is a 6s 5ah pack, but I don't think you will use the 200c or 90c burst so 10 AWG is also no problem.

Finally someone with a real drag car and yes i think Luke will be most
pleased with copious amounts of nano techs piled high in the car, all the
best look forward to seeing it run

KiM

I agree with the idea of quick in the pits battery replacement. I definietly made the same decision for my much smaller scale racing effort.

http://endless-sphere.com/forums/viewtopic.php?f=6&t=22573

My race bike battery box is designed specifically for quick change to a fresh pack for the next heat, and all of it can be swapped out if I get a problem with an individual pack.

One thing I did learn, was that with dozens of anderson connectors in the system, I wanted to tape all of them to prevent accidental unplugging during the race.

Other connectors might not have a problem, but with my rats nest of andersons, I could easily lose a connection while riding. A larger size cell of some kind might be easier to make all the connections, but you won't get the c rates in the larger size pouches. I think you are on the right track.

You might want to have spares for entire paralell pack sections trackside, so you can just swap out a whole group of paralelled cells if you discover one puffing up or smoking. Then fix it later in the shop.

Charging in the pits is the other biggie. You may have to rent a huge generator to charge in the pits with a pack that powerfull. I doubt they will have the kind of plug you'd need.

This is the right way to do it.

Right chassis.
Right rearend.
Right battery.
Right motor.

This will be the quickest electric car.

As far as the battery goes, paralleled small cells (like you're doing) are the only method to get the c-rates you need.
A123 has nothing that can come close to the nanotechs. You will have a massive battery advantage over all EVs before you.
Nanotechs tabs are huge, about 3x normal lipo tabs. No worries there.

Being limited to 2000amps on a 50ah pack is going to mean your cells never get warm or be taxed. This is a good thing to ensure years of trouble free racing.

Use no BMS. BMS in a racecar is an extremely bad idea. You want to be able to disconnect your pack and park your car for the winter and not have the BMS wreck your pack. Parallel all balance taps, use an RC charger to manually balance should the need ever arrive, which is doubtful if you're smart and only use the top half of the pack capacity.

I thank you for your insight. I am still confused in regards to balancing these packs? Each 5AH 37V pack comes with two large wires on top (pos & neg) then smaller wires with a connector. My plan is to connect the larger wires in parallel (ten times) to create a row that will be 50AH 37V, then connect that same row in series to another 50AH row, and continue untill I reach 370V. Is this possible? If so how would I balance the cells if I decide not to use a BMS? how would I charge such a large pack? and because of the additional volts and AH do I need to change the large wires (pos & Neg) to a thicker wire? How about the smaller wires in the connectors, do they need to be enlarged?

Please excuse my ignorance, I have never built a pack this way.

liveforphysics said:

This is the right way to do it.

Right chassis.
Right rearend.
Right battery.
Right motor.

This will be the quickest electric car.

As far as the battery goes, paralleled small cells (like you're doing) are the only method to get the c-rates you need.
A123 has nothing that can come close to the nanotechs. You will have a massive battery advantage over all EVs before you.
Nanotechs tabs are huge, about 3x normal lipo tabs. No worries there.

Being limited to 2000amps on a 50ah pack is going to mean your cells never get warm or be taxed. This is a good thing to ensure years of trouble free racing.

Use no BMS. BMS in a racecar is an extremely bad idea. You want to be able to disconnect your pack and park your car for the winter and not have the BMS wreck your pack. Parallel all balance taps, use an RC charger to manually balance should the need ever arrive, which is doubtful if you're smart and only use the top half of the pack capacity.

Click to expand...

You would be connecting all the big discharge wires paralell in each 10p block of batteries. Then you would also be connecting all the smaller balance tap wires paralell.

Paralelling all those little wires won't do anything for you on the discharging side, but it will when charging. Through the little balance wires, each pouch in each pack will be connected paralell to each other. So pouch one in pack one, is connected to pouch one in pack two. All the way through the pack. This way, when you charge, you have in effect, one big 50 ah cell. It would then be possible to balance the entire 50 ah 37v pack when needed. Quite a few methods could be used, such as a single cell charger bringing up the low cells, or a light bulb or hotplate bringing down the high cells individually.

If you dig in the forum here, you should be able to find examples of how others did this connecting on bikes with smaller packs.

It would be a really good idea, for you to do some small scale experimenting before finalizing your design. Perhaps build an electric go cart? Or bike?

You will definitely want to break in your individual packs with a few cycles before building up the 50 ah blocks, and then individually test each block for a few cycles to weed out the inevitable pack that puffs. Gotta discharge em somehow, may as well be on something kinda fun like a pitbike.

The more I think about it, you really should build the entire thing in somewhat smaller modules, perhaps 25 ah blocks? That would make having at least one spare block in the pits a lot more affordable in case trouble develops between runs. 25 ah 36v is small enough to put on a bike or scooter, and not so expensive if a few mistakes get made on the experimental stages of the build. It would, I think, have more manageable wire size for connecting to the final bussbar, and be a more manageable size for balancing too.

In my mind, I'm picturing a design that has 5 5ah 5s packs with both balance leads and discharge leads paralelled. That would be series connected to an identical pack at the discharge leads. To charge, you could use a 36v power supply, but it would be just small enough to balance charge by disconnecting the series connection, and use RC chargers to balance charge each 18v pack seperately. You could have all the connections at that level, 5s 25 ah made with solid soldered connectors, and consider that size to be the smallest quickly replaceable pack. You'd save a few bucks on connectors, and never have one little 5 ah pack getting disconnected while the car bumps down the road to the track.

To troubleshoot a 36v 25 ah block, you'd only have to replace half of it, A 25 ah 18v block of five batteries. Even if you did build the entire car with 36v 50 ah packs, you could still do some experimenting on the design starting with just a few packs and simulate the load on the batteries with a smaller EV.

All you need for a bms, is a way to balance on the charging side. Then on the discharging side, just monitor voltage. you could do that with one volt meter for the whole pack, or banks of voltmeters for each 36v block, or even use 5s low voltage alarms on each 18v section. But that would be a ton of those alarms to do it that way, and a ton of switches to turn each alarm on on and off between uses.

Okay thanks! I am not sure what size the "large wires" are, the packs are not here yet. What size wires will hold all the 50AH and 370V safely? I know when building large packs for EV's they use large welding wire, do I need to change to that large size?

dogman said:

You would be connecting all the big discharge wires paralell in each 10p block of batteries. quote]

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