Bamboo GT AT 50km Range Project

I was thinking, why to build a single 4s10P pack if I can keep 5 completely separate 4s2p with 5.5 bullet connectors between and 5 separate balance plugs going via 5 to 1 adapter?
Benefits could be:
1. As it will be 5 separate small packs may make air-travel possible? Each pack will be 88.8Wh (7.4V x 12Ah)
2. Easier to diagnose/fix in case of issues with cells
3. No issues with flex

Li-Ion batteries air-travel rules:

Devices containing lithium ion batteries over 160Wh are not permitted as passenger baggage and must be sent as freight.

NOTE: Watt hours (Wh) are determined by multiplying the voltage (V) by the amp hours (Ah). ie. 12V x 5Ah = 60Wh

 

Enclosure arrived from USA today
looks good -mock of of cells
need to trim overall lenght from 630 mm to 580mm to fit under board-width is 205
Will leave approx 140mm for VESC and BMS which should be ample
Enclosure is an ABS material with a sparkling gloss finish -looks fairly rad

 

Nickel Strip night tonight
first cut some 63mm long .15mm thick 10mm wide strips(for positive parelleling of four cells ) with slightly rounded ends
then spot weld two togther then some cross sharing strips (these should see virturally no current) and then put solder blobs at ends of cross strips
There will be 2 bare copper braids in parellell for each series connection and each copper braid will have three solder points. This should provide optimum low series volt drop and good current sharing through each bank of four cells in the 8P cell pack.

Same thing for negative series connections - only a slightly longer main strip

last photo shows how it will finish up on +v of cells.

 

Eugene

Great idea but pretty sure that they will take your total Ah as the criteria !

Cheers

 

Hi mate,
Yes, they will if it is still inside the device. But I meant to say if I'm taking 5 x packs out in fire proof bags in a hand luggage or split them between different luggage bags including hand luggage.
Please correct me if I'm wrong.
Cheers

 

How to carry batteries safely
Watch the CASA safety video - travelling safely with lithium batteries, to learn how to carry everyday batteries safely.

Batteries under 100Wh rating

• The batteries that power your phone, laptop and camera are usually under the 100 watt-hour (Wh) rating.
• If you're carrying a spare battery that's not in one of these devices, it must be in your carry-on baggage only.
• Spare batteries, regardless of their size are not to be carried in checked luggage.
• Spares Limited to carrying a reasonable amount needed for personal use only.
  

Lithium Ion batteries 100-160Wh rating

• These are more powerful batteries, and can be found in industrial equipment such as power tools and mobility aids between 100 and 160Wh.
• You must have approval from your airline before flying.
• If the battery is installed in a device, it can be carried in either checked or carry-on baggage.
• If the battery is a spare - that is, the battery is by itself and not contained in equipment - it must be in your carry-on baggage only.
• Spare batteries, regardless of their size are not to be carried in checked luggage.
• There is a limit of two spare batteries per person. These batteries must only be packed in carry-on luggage and should have their terminals individually protected to minimise the risk of contact other metal objects in your luggage.

How to protect your battery from short circuits
Short-circuiting batteries have been responsible for numerous on-board fires, so it’s important that all spare batteries have their terminals protected properly.

You can do this by:

• Keeping batteries in original retail packaging or
• Insulating the battery terminals by taping over exposed terminals or
• Placing each battery in a separate plastic bag or protective pouch.

We also demonstrate these techniques in our safety video above.

 

I ordered the same plug online and now im going to rewire the old battery and new battery with those wires using the 2.0mm pitch and cutting it off the battery and using the male connector that came with the 1.5mm pitch wire

 

I was going to do the same but going size up (2.54mm pitch) and even made adapters 2mm to 2.54mm pitch as those connectors are much stronger than 1.5..

 

Eugene
Do you have a link for the correct BMS plug
Thanks

 

making battery backs tonight

first hot glue 4 cells in a template then another 4 cells in a row then glue the two rows together to make an 8 cell pack then tape the pack up.

Repeat process for all ten packs

Them make two complete rows with 5 packs in each and tape up each to create a 10S 8P battery pack.

I am leaving spot welding on cells until last and after all series braid and balance wire soldering is complete to avoid any heat damage to cells

the foam between cell packs is for flexibility and also insulation between cell packs casings

I am waiting on flexible braid and more nickel strip to arrive for further progress .

total time to make the 10 cells-around two hours

Cheers

 

Looks good mate!

 

That's the closest I've found: haven't received it yet, but it's should be 2.0mm size not 1.5 that's 100%



Look at this on eBay
2.0mm PH 11-Pin Male Female Connector with wire Length : 300mm x 10 Sets

 

I've decided to keep mine packs separate. I've used bulett connectors from xt90 plugs and pushed them in to 5.5mm tubes.
XT90 are rated to 90a so should be good.
Still waiting for heat wraps to make it look pretty and for balancing plugs and should be good to go!

 

yeah finally arrived and works OK
only charges at 1.5A so good for a top up while driving
Cheers

 

Check you nickel strips are pure by scratching/buffing and placing in saline solution for 48 hours

nickel plated steel strip on right (no good)
pure nickel strip on left

 

Bit more progress on making the power packs.
Nickel strips spot welded to cells and a trial series connection completed with copper braid. Am using two braid for series connections for flexability and high ampacity
The two power packs are taking shape







View attachment 2330

 

Eugene
Has this arrived yet and is it the right one for Evolve BMS
Cheers

 

No, still hasn't arrived yet. It's very frustrating as that is the only thing left to do to complete my project.

 

One of the two power packs nearly complete
Glad to get some tape over the series braid to avoid potential accidental shorts.
BMS wires are high temp 18awg flexible with silicon insulation.
Two fuseholders on +42 V -one 40A main supply to BMS and the other 5A for auxiliary things such as USB charging port ,lights and 12V bell/horn
Waiting on more braid to complete other pack.
Going to put some liquid tape on braid series connection for middle of pack and then a 10mm foam strip for further insulation.
A lot of power exists between the opposite middle series braids so need to extra sure no potential for shorts
No potential for shorts on outside braid series connections do just tape willl be OK
Each of two power packs will finally be individually wrapped in 2mm foam sheet then an overall heatshrink over the two power packs will finish it off