SURRON DIY 80V / 29kW BATTERY BUILD – HOW-TO

SURRON DIY 80V / 29kW BATTERY PACK BUILD – HOW-TO

0:00 - Introduction
0:29 - Organization of This Video
1:48 - Pros - Why DIY Build a Sur-Ron Battery Pack?
3:48 - Cons - Why Not DIY Build a Sur-Ron Battery Pack?
8:44 - Nickel Strips vs. Bus Plates
10:52 - Cost Example for DIY 72V Pack
14:04 - Brief History Of The Surron Pack
19:37 - Why use 21700 cells, if the Surron is not designed for them?
20:55 - Figuring out cell layout
22:40 - Why you shouldn't glue cells together
25:50 - Finding a case - Huge problems
29:04 - Cell Holders/Spacers for 20S / 22S 9P
30:03 - Cells & Copper Bus Bars - Choosing & Finding
31:50 - Searching for Copper/Nickel Bus Bars
35:00 - Paper Insulators - Needed?
35:00 - Build Process Photos
41:30 - 45 Second How-To Build a Sur-Ron Pack
42:17 - The Actual Build Process Video!
44:55 - Best 21700 Cells to Use for a Surron Battery Pack
46:45 - Is the cost savings worth the work?
47:13 - After all the Work, $1000-$1400 For Labor Is Not Too High!
48:35 - Solving the Bus Bar Problem
53:00 - Links In Description to Buy Components
56:07 - Parts Start to Arrive, Cells Held in Customs
57:38 - Copper/Nickel Bus Bars Arrive
58:39 - V1 Metal Cases Arrive
59:00 - And, Get Ready for the Big Letdown..
1:00:30 - Next Problem... 575A BMS Doesn't Fit
1:01:50 - Finally ready to weld!
1:06:00 - 3D-Printed Case Arrives
1:08:50 - Starting to Weld
1:13:12 - Connecting the 2 Bottom Bus Plates
1:16:36 - Connecting the BMS wires
1:20:30 - Fiberglass Sheets
1:23:15 - How the Case Fits in the Bike
1:24:50 - Soldering B+ and B- wires
1:26:20 - Important Notes About ANT BMS Setup
1:28:10 - Finishing Details & Tips
1:32:52 - The Finished Battery Pack

First: Sorry this video, again, is (just a bit) long! Tried to make it as brief as possible but it covers a very involved 4-month research and build process. And, some things I repeated, sorry about that.

This covers the process of researching, finding components, and DIY building my 29kW, 80v nominal (92.4v fully charged) 22S9P high-power Surron battery pack. (Note - same steps apply if you're building a 60v, 72v, or 80v battery pack - and for the Surron or Talaria.)

There wasn't a whole lot of info about DIY Sur-Ron pack builds online, so I thought I'd document the process. The Surron pack requires some specialized parts, and is super-compacted into the available space, so it's been the most difficult pack to build of the 15 I have done since 2015. Yes, you can save over $1000 by building the pack yourself, and yes, it's satisfying to complete, but I do NOT recommend building the Surron pack as your first battery build. Do some simple packs, and study battery theory, first before trying this.

Pack Specs:
22S9P / Samsung 40T / 21700
80V Nominal / 92.4V fully charged
36Ah, 2880 watt-hours
Max 315A, 29.1 kW

COMPONENTS USED FOR BATTERY PACK:
Cells - Samsung 40T 21700:

BMS - Ant BMS 8-22S 130A Continuous / 325A Peak:

Bus Bars/Plates - Custom Copper/Nickel Bus Bars (22S9P/20S9P):

Cell Spacers - Custom 21700 Offset Spacers for 20S/22S 9P Configuration:

Case - Metal 160x139x420mm (Fits Talaria):

Case - Metal 160x139x420mm, Diagonal Cut Corners (Fits Surron):

Case - 3D Printed 158.5 x 136 x 422mm, Fits Surron - Free .STL Files:

Welder I Used - MinderRC DH30 MAX V2:

COMPONENTS FOR MY 29kW FRAME-UP SURRON BUILD:
**Coming Soon

I'm adding chapters to make the video easier to navigate. If you want to skip ahead to the building process clips, feel free, I know it's long.

Feel free to leave comments and questions; I'll try to answer any questions.

Thanks for watching!

My old channel, with 72v BBSHD and Tangent Ascent videos:
CALIFORNIA ELECTROBIKE UKRAINE
@californiaelectrobikeukrai5074

[TheGTIman]

Nice vid! Some remarks/suggestions for other builders:
- if you are building for max power (amps * volts) instead of range, you could opt for Samsung 30T instead of 40T. The 30T can handle more amps; up to 50A is possible during acceleration bursts whereas 40T can provide up to some 40A or 30A without too much voltage drop. At these high current levels per cell, the 30T actually has more capacity/higher volts than the 40T (look at test curves >30A). This way, you can create very powerful very lightweight batteries!
- you should always design for off-design situations (contradictio in terminis..) where the battery is failing due to overheating. So indeed cover the places where you run the bms wires (also small ones) with fire resistant paper, and cover each wire with its own layer of kapton tape. Preferably use heat resistant silicone wire for all wires, also the small ones. Always install temperature cutoff sensors (ant bms has them as well). These measures buy you a little more time when things start to overheat.
- if you are using simple rows with parallel cells, you don’t need spacers or glue at all. Just wrap each row in a layer of kapton tape, and then wrap all rows together using kapton tape as well. The spot welding and/or soldering will keep everything firmly together, and if a cell ever fails, it is much easier to remove and replace this cell when everything is not glued or clicked together with spacers.
- the bus bars look like a nice and easy solution, but if you are planning on running 50a through each 30T cell like me, I think the resistance is still too high. I would suggest soldering copper braided wire in series on top of each cell like I do. If you solder very quickly with a large powerful soldering ion + cool the solder with a wet towel immediately after soldering, the cells don’t overheat and are not damaged. I have built all packs in this way and all rows have full capacity and have lasted for years already. But be very careful not to melt a short; please know what you are doing and use heat resistant paper spacers for the plus side of the cells.
- if possible, please always install an active balancer (based on capacitors) in addition to the bms. The bms is very slow and bad at balancing rows, and only balances at the highest voltage level. A balancer always balances also at the bottom. To this extent, attach an extra set of ‘thin bms wires’ for the active balancer. If you attach an on/off switch to the active balancer, you can prevent it from draining the battery when it is stored for a prolonged period of time.

These are just my experiences; your vid is already very helpful to others!

[jameshamilton]

Just wanted to say thank you so much for your super hard work on this video, people like you make our hobby possible.

[dlyer]

This is a great video. Thank you so much! I own a Talaria Sting R and have been looking into upgrading the battery. I have built a few packs before and I'm seriously considering building my own for the Talaria as well. I have been looking for this exact video to push me over the edge and get going 😅 And I totally agree with you, the worst part of buildning a battery pack is to solder thoose thick wires!

[ElectricBikeLaboratory]

Major props! This is a tremendous resource you're sharing! Well done!!

[QBN]

Bro, I don't have a Surron, or any e-bike... (right now i don't even have a bicycle), I've never built a battery-pack and yet i find this video very interesting, with lots of information. You apologized many times for the long form of this ... tutorial, but seriously, this is a very detailed video, and it's not that long, considering you are sharing the knowledge acquired through months of research...

[christianwagner]

Was thinking of doing the exact same and Iam really happy to see that somebody else went this route and provides the parts for DIYers :)
Still, I´ll purchase a battery from a known builder here in Germany, as he manages to fit 22s12p with bms in only 38cm!! Ofcourse, no spacers but you get so much more energy in that I couldn´t care less.

[imho]

First of all, this is such an amazing video. Definitely something personal should watch before making a high power pack.

@1:27:00 there are two different ANT boot up wire type:
2 black wires are just connected to a momentary on switch, normally accessible on the outside of the battery case.
Red and black wire needs a 3v-5v source. Worthless in most cases. Lol

I have both versions.

Since you installed your ANT correctly, not cutting off 3 of the 4 power cables that ensure current is distributed correctly across the mosfets, you might be able to get longer times at higher amps.


As you can see in settings, there are 3 discharge current zones, each with its own time limit.

Zone 1, 0a to max continuous, no time limit. As long as the MOS temp doesn’t get hot you can bump this up some.
Zone 2. Max continues to peak. This has a time limit. You can set it to several minutes if you want.
Zone 3: peak discharge to short circuit protection. This can be set for a few seconds just to cover a minor surge from the controller.
Zone 4: short circuit cutoff, normally set in microseconds. Should be set as low as possible that doesn’t hinder zone 3, but high enough to allow pre charge of the capacitors in the controller.

Just monitor your app for temperature and test it when doing the current limit, but the ANT normally under rates the values.

It does have thermal protection that will shut down the BMS but it’s important to limit current to something that takes several seconds to reach overtemp so the BMS can shut down before frying.

Of course you have to juggle between the BMS and the controller settings so there is no conflict. I use fardriver with boost (which also has a timer) so my normal line current is set within the ANT continuous amps zone and the boost current is in the peak current zone (2), with a time limit shorter than that set in the ANT.

I think if you monitor the app you will see the ANT stays cool as a cucumber in normal operation.

To limit heat in the battery and BMS, after the first top balance, you can set balance current to 20 milliamps and it will still do its job and not make much heat.

[bhendy]

Dude.. your the man! So appreciated all of this.. motivated me to do it!

[Calthecool]

For the connection on the bottom of the pack, could you lay the bottom of both sides end to end, weld a double length copper/nickel plate, then fold the two halves together? I've done something similar with nickel strips, it could negate the need for the soldered connection.

[mario_on_e-odin.]

Excelent video !!! I have different bike and battery and does not need to build a battery but your video is so great that I had to watch it till the end :) Do not appologize for the length of the video, you shared a ton of useful informations and that takes time, it is much better this way that a short video. Plus this is a perfect example how to make an instructional video, I have to learn a lot :) Great job, keep on ! Subscribed.

[Hunter-]

My man...this is 1 very sexy pack! Well built, great job!

[ianmangham]

You did a gradeA job, absolutely fantastic 👏 🇬🇧👍🙏

[instarServis]

Do video about 50s im very interested because everybody is using them im usingthem i dont get overheat 20 amps !!

[Gersberms]

Super impressive, those bus bars are pieces of art! The longer I look, the more impressed I am by your knowledge and design choices.

One thing that surprises me is the sizes of the conductors. Have you calculated the conductor cross section area across the pack, BMS, and wires? The wires to the plug seem to be 6 gauge, which is apparently around 13.3 mm2. Is that really enough for 325 A? I suppose it's fine at peak load but not sustained. Anyway, point being, I think the cross section area differs wildly from place to place so have you not been overthinking the bus bars? Another edit: so they are overkill, 0.3 mm x 140 mm = 42 mm2, that's way bigger than your 6 gauge wire. But they're super beautiful.

[TobiL-mv]

Great content! Do you already have experience with cell imbalance due to the passive balancing ANT BMS? I started having issues with imbalance in my 20s10p pack after discharging it to 2.8V per cell (yep… I always have to learn the hard way 😅) and was only able to fix it by using an active balancing JK BMS with a 2A balancing capability. Unfortunately, it’s slightly too big for any housing. I’m definitely planning to build your 22s pack next year and would love to find a BMS that supports 200A continuous / 350A peak with active balancing like the JK, but fits a Sur-Ron pack..

[kevind]

Great job on the video! Very good information presented and covering safety was a big plus. For some reason none of the cool watts links are working for me. Thanks!

[jonlad]

Great video even for others building a Battery! I am planning to build a 13s4p pack with the 50s. Max Current will be limited to 50Amps (12, 5A/ Cell). Do you think I can use the 50S for this case?

[boardinrider]

Nice Job man! I Designed a case that is made for me from Sendcutsend out of aluminum that holds a JBD colour display

[PizzaCologne]

bruh, life saver thank you, you got a sub

[kekebmx]

Hi, thanks for the video, so much knowledge you share! How come alot of battery manufacturers use samsung 50s here in europe? I'm waiting for a 72v50ah battery with 50s and I'm quite scared now 😅. Is it still ok for 15kw ? Cheers