Better than the Stark Varg? 76v 90Ah 35kw Dirtbike Build

[Blacksheep Engineering]

My thinnest path of a series connection on this battery is about 6.25" (160mm). So yeah .3mm is probably fine. 48mm^2 I believe. I would still be concerned about soldering my leads to that thin of material though. They could also get deformed fairly easy I would think. Are these concerns valid? I'm thinking .5mm would be a happy medium. Not that I need 80mm^2, but making them too thin just sounds like a pain to deal with.

 

[Blacksheep Engineering]

BMS suggestions? I have new cells from a reliable source so I don't think I need active balancing. I am open to the suggestion though.

ANT BMS 21S-30S 170A-380A 400A 420A Smart 112V Lifepo4 li-ion LTO Battery Protection Board – ANT BMS

antbms.vip

I'm planning on getting this BMS. The 400 amp continuous version is 2cm shorter than the 420 amp one so I will probably go with that one but its still about 3.5cm longer than my battery is wide.

My original BMS I bought is the 17-24s version of this one. Guess I'll have to build another bike

 

[thebes]

Your only real option (unless you want to spend exorbitant amounts of money on industrial solutions) would be ant. Do note that the .vip site is illegitimate/a scam, they will take your money and run as they did with me and as I later found out a couple other users, thankfully paypal has half decent buyer protections...

I ended up buying a 30s 380a cont one (which has now been replaced by the 400a one) from icgogogo on aliexpress and havent had any issues.

 

[Blacksheep Engineering]

Ah, good to know. I placed my first order through them successfully but I made sure to stay in communication which might have made them actually follow through. I will look it up on alibaba just in case. Thank you.

 

[Dui ni shuo de dui]

I do not know if the QS 138 70H V3 can really make use of voltages like the ND108 series can handle.
It is a motor designed for 72V, with 108V you can get more than twice the power out of the motor, but the motor needs to handle the additional generated heat. I would go for a ND96 series.
The stress on the motor is nearly the same when you use higher battery voltage.
The big advantage is when you need to apply field weakening because you do not have a high enough voltage to get higher rpm.

Heat is current dependant. So at equal power a higher voltage system will typically heat less.

 

[dominik h]

Heat is current dependant. So at equal power a higher voltage system will typically heat less.

Yes , I now this.
The motor has a fiexd kV value. and to make use from lower currents the gearing has to be lowered.
Otherwhise the motor needs the same voltage and current for the same speed and power requirements, as in 72V system.

 

[Blacksheep Engineering]

What are you guys doing for chargers? Is there a good off the shelf option for a 28s battery?

 

[gustavo88py]

aliexpress.com/item/1005007207816312.html

 

[dominik h]

Or the modified Huawei R4871G1, they have a much better efficiency.
I measured on mine 97% efficiency at 3kW charging power.
They are available from 42-170V in different steps and currents , prices vary between 190-400€

 

[Blacksheep Engineering]

Can I adjust the voltage on the Huawei? It has a note to tell them your voltage and desired current so they can modify it. I'm willing to spend a bit extra for reliability and efficiency if I can adjust it to work on any bike I have.

Also, I can only find R4875G1 chargers. Is that the same thing? Does anyone have a link to a specific one?

 

[Blacksheep Engineering]

Has anyone tried this one?

https://www.aliexpress.us/item/3256806248126207.html?spm=a2g0o.detail.0.0.59ef7N7P7N7PkV&mp=1&_gl=1*3f7k9i*_gcl_aw*R0NMLjE3MzE2MjUwNzQuQ2p3S0NBaUEzTmE1QmhBWkVpd0F6cmZhZ0gzalZvXzlCWlk0Ri1VTk1YOFhWZW9Vb1FlTFdNZWpHd3NCam9fMFNpaWN5eHVHUzVUZWtSb0NTLU1RQXZEX0J3RQ..*_gcl_dc*R0NMLjE3MzE2MjUwNzQuQ2p3S0NBaUEzTmE1QmhBWkVpd0F6cmZhZ0gzalZvXzlCWlk0Ri1VTk1YOFhWZW9Vb1FlTFdNZWpHd3NCam9fMFNpaWN5eHVHUzVUZWtSb0NTLU1RQXZEX0J3RQ..*_gcl_au*MjA3MTQ4NzY0MS4xNzI5NzE1NzM4*_ga*MTQyNjQyMTU5NS4xNzI5NzE1NzM4*_ga_VED1YSGNC7*MTczMTcxMzkwMi4xMi4xLjE3MzE3MTU1NzAuNjAuMC4w&gatewayAdapt=glo2usa

It looks like the one Electro and Co uses. I would guess they're just rebranding it. This is the one on their site:

E&C Lightning Charger

Recharge at Lightning Speed with the E&C Lightning Charger! This High Quality, All Aluminum Body, Fully Adjustable Charger is the perfect upgrade for your YZ-EMX, EMX14, EMX17 or any E-Bike. This charger is incredibly compact and is easy to transport with you on the go. Variable Charging Output...

electroandcompany.com

 

[dominik h]

Sorry for the typo. R4875G1. Mine has a Bluetooth connection to the phone and can be adjusted from 72-103V. They also make a version that goes up to 120V.
there also exist versions with manual adjusting.
They are not intended to use as an onbpard charger.

 

[dominik h]

Do not buy a hiawei that can go from 0-120V. They are heavy modified inside.
The others only have changed the output transformer, output condensator and a few resistors and do the voltage and current adjustment via Can-Bus inside.
As it is done in the original ones.

The only thing Mine does not do is input current limitation. I know the Huawei can do this as I have programmed it already on 30 modules or more. But on the modified ones they must have programmed it wrong.

 

[gustavo88py]

https://pt.aliexpress.com/item/1005...DXhiU3&gps-id=platformRecommendH5&scm=1007.18 499.315613.0&scm_id=1007.18499.315613.0&scm-url=1007.18499.315613.0&pvid=9039e7cc-2dad-42d2-aaa1-412cf5271d76&_t=gps-idlatformRecomme ndH5,scm-url:1007.18499.315613.0,pvid:9039e7cc-2dad-42d2-aaa1-412cf5271d76,tpp_buckets:668%232846%238110%231995&isseo=y&pdp_npi=4%40di s%21PYG%211105346%21983719%21%21%21141.50%21125.93%21%402101ead817317411751272614e7801%2112000030637787036%21rec%21PY%211917886262%21XZ

 

[dominik h]

Can't get a link from aliexpress, it always opens the app on the phone.

I would go for something like this, as they still use the normal controll and protections from the Huawei pcb.

 

[dominik h]

The normal Huawei control voltage is 58.5-42V.
58/42=1.4
118/84=1.4
So they use the original voltage setting commands via CAN-BUS and have not done big changes.
I had a modified R4850G2 before [0-100V] they had cut a lot on the pcb and hat over 10 wires going to a separate controll Board. It lasted a few cycles. The modifikation was so big that I did not even tried to put that controll board in one of my unmodified new Huawei PSU.

 

[dominik h]

I also have a modif ied Delta PSU as mentioned above (and a lot of unmodified Delta, Vertiv, Eltek, Huawei and Meanwell PSUs in the 1-4.3kw range). The modified Delta is bigger and louder than the R4875G1.
Efficieny from the Delta is 90% and below on lower voltages. The Huawei has nearly 97% from 1-3kw output power on 230V mains.

I test every psu I buy with an electronic load and other nice Equipment.

 

[dominik h]

With 28s can also use two unmodified telecom rectifiers in series.
I had used two Eltek Flatpack S and two Eltek Flatpack 2 He, also Vertiv R48-2000E3 and two Huawi R4875G5 with good experiences, i have used them Single phase, two phase and 3-phase , up to 10kw charging power.

 

[Blacksheep Engineering]

Ok, I think this is the one you said you'd recommend @dominik h . It looks like it will work for me. Thanks for the feedback, before you responded I almost ordered the 120v option not knowing about the modification differences.

https://www.aliexpress.us/item/3256807803075818.html?spm=a2g0o.productlist.main.5.3c8089efyLt2Bt&algo_pvid=2780dddb-5c51-4c7d-8956-d913115f0176&algo_exp_id=2780dddb-5c51-4c7d-8956-d913115f0176-2&pdp_npi=4%40dis%21USD%21202.00%21202.00%21%21%21202.00%21202.00%21%402101c59817317758267855056e8d16%2112000043175027119%21sea%21US%216194823290%21ABX&curPageLogUid=geqJV7nm77IY&utparam-url=scene%3Asearch%7Cquery_from%3A

Im going to place my order for this, the 420 amp continuous 20s-30s BMS from IC GOGOGO, and a ND961800 controller from SiAECOSYS.
The controller ad says it may have issues clearing customs depending on the country and they arent willing to help at all or take a return if it doesnt work. I messaged them and they had no insight as to if I would have trouble. I havent had to deal with that on anything else. Does anyone have insight on what I might be up against here?

 

[dominik h]

That is the one I had seen for 28s.
I do not know if it also has the possibility with App control via Bluetooth. But you can ask them.
And ask them if they made a proper connection of the small heat sinks and not with cable ties.

Mine was bought from Tonifishi Store on Aliexpress, maybe they can also offer a 28s modification.

 

[Blacksheep Engineering]

Ok I placed the order. Sketchiest order I've placed so far. Didn't even give me any sort of confirmation that the order placed other than seeing the huge charge on my card. Guess I'm not getting any sleep for the rest of the month.
Threw in a super cheap throttle too. We'll see if it works lol.
I honestly hope that charger doesnt need an app. I already need a couple apps to run this bike, seems a bit silly.

 

[dominik h]

Mine can be used with or without an App.

 

[Blacksheep Engineering]

Ok, Im figuring out wiring, I made a crude model of the BMS and some beautiful mouse drawn wires to help visualize.

Im thinking I'll use 3 separate wires to carry all the current in the battery. This works well with the post set up on the BMS and would reduce the overall thickness since they can lay next to each other.
If I use 8 gauge wires, that gives me a total of 25mm2.
The wires on the motor say 20mm2 which I think is about 4 gauge, and I'll probably run 4 gauge for everything else outside of the battery, but I definitely want the battery to be the last thing to build any heat.
What do you guys think? 8 gauge or 6 gauge? (25mm2 vs 40mm2)

 

[bananu7]

I went with 1AWG for battery-controller, and I'm planning for equivalent inside of the battery. My positive side has 6 copper strips directly soldered onto three terminals, and I think the equivalent would be 3x7AWG (3x12mm2) for the negative side.

Also worth considering the fuse if you're planning for one. Megaval fuses use M6 bolts. That's perhaps a bit concerning given that one would need 3x7AWG connected to those poor nuts on both sides just to reasonably reach 500A current rating of the fuse itself.

 

[dominik h]

In my scooter with 400bA peak I have used 35mm² (AWG2) from the fuse to the controller and from the battery to the fuse two 16mm² in parallel.
My wires are very short. I think in total less then half a meter.