Homemade Battery Packs

[DrkAngel]

Curious if anyone else would recommend tinkering with those 40V ryobi packs to make a larger storage pack. I'm kind of torn between the power tool hot swap convenience versus an enclosed, well weather proofed system. I would be putting this in what is essentially a toy (mx650) so not loads of real estate....

Seems like this would be a low level investment to start with potentially.

I had good success manually charging.
Recommend bypassing circuit board with jumper from last cell to negative terminal.
Lost my 19 of 20 good, in fire, but had great potential and plans as ganged bricks in oem 36V shells.

 

[john61ct]

Yes a custom enclosure could be water resistant, still have hot swap convenience.

Just not space efficient leaving them in their OEM packs, many just strip out the cells to do regular spot weld packs.

 

[DrkAngel]

Tis the perfect time and opportunity for battery building!
Sadly, have a limited inventory of basic stock. In the process of evaluating and recovering present builds, before producing more.
In need of refurbishment:
1 - 25.9V 26.4Ah Li-ion
1 - 25.9V 25.92 Lipo
1 - 33.3v 31.2Ah Li-ion
1 - 33.3V 43.2Ah Lipo
2 - 36V 13.2Ah Li-ion
5 - 36V 4.4 Ah Li-ion bricks w/ corroded BMS boards
4 - 25.9V 5Ah Lipo bricks w/corroded leads

Good new stock:
6 - 36V 5.1Ah Li-ion bricks (were securely wrapped in Saran wrap!) 2 36V 15Ah builds?
31 - 8Ah Super Lipo (durable construction!) 1 or 2 "48V" builds?)

Also need to rebuild chargers:
Lost 10s and 7s chargers and need to confirm or build new MeanWell Mega-Mod chargers.

 

[Iebiker]

Anyone tried to build a pack with these 18650 cases?

Can we find out how much current they can hold?

I used them for several years as a 4S6P and around 6-8 amp (parallel) going to a 1500 Watt motor and a 100 amp controller. I had no issues, no heating decent range and a lot of fun.

 

[john61ct]

Are you saying each cell pair wiring is OK with 6-8A continuous?

 

[bobbill]

This Noob finally got through DA's stellar list...

Thanks mountains...

Lottsa work and appreciated no end...

H.

 

[DrkAngel]

.
... Could not pass them up!



Top rated in capacity and durability!?
Bought 6 bricks, so plenty for playtime!

I will likely keep some bricks intact, can fit 2 bricks 36V 28Ah in eZip battery case.
24V 10Ah (5Ah usable) SLA @ 20LB - 120Wh ($120-$140 complete new battery)
replaced with
36V 28Ah Li-ion @ < 10lb - 1008wh = 1kWh + ($110/kWh delivered)

Turn 3 10s4p 36V 14Ah into:
2x 15s4p 54V 14Ah
or
1x 15s8p 54V 28Ah (1.5kWh) ... (Want 40mph capability from my 48V 1500w stretch frame)

 

[DrkAngel]

.
... Could not pass them up!



Top rated in capacity and durability!?
Bought 6 bricks, so plenty for playtime!

I will likely keep some bricks intact, can fit 2 bricks 36V 28Ah in eZip battery case.
24V 10Ah (5Ah usable) SLA @ 20LB - 120Wh ($120 - $140 new)
replaced with
36V 28Ah Li-ion @ < 10lb - 1008wh = 1kWh + ($110/kWh delivered)

Turn 3 10s4p 36V 14Ah into:
2x 15s4p 54V 14Ah
or
1x 15s8p 54V 28Ah (1.5kWh) ... (Want 40mph capability from my 48V 1500w stretch frame)

Received 6 batteries, 2 with equal voltaged cells @ 3.5V and 3.6V, the remaining 4 between 2.5V And 3.0V, all at equalized voltages.
Partially disassembled to bypass BMS to meter charge with 36V charger.
Great news! 1st 2 charge 14Ah+ (3500mAh per cell)
Don't need more, but how can I pass up this deal?

Received battery packs without foam! Moderate silicone only.

 

[bobbill]

My naive ? gives away my noob-ness; OK used cells. I imagine various mAmps...and voltages, how do you separate and use, as all different?

Would like to re-craft 36-volt wet cell, (3, 12V boxes) using used cells...got to be done often enough nowadays?

 

[DrkAngel]

Panasonic (LG) MJ1 3500mAh cells
3rd 10s4p EBike battery metered charged at 14,000mAh + also!
These are used batteries from rental(?) eBikes. Advertised as having failed BMS, I wonder if BMS has a power disable to deter theft or alternate reuse, enabled-disabled via the eBikes rental-tracking system? (3 extra contacts utilized between eBike and BMS) Several batteries had broken security locking brackets.

My initial use will bypass the BMS outputs but retain the balance function. All cells equal within 1/100th V immediately after quick charge, balance function is working or cells are perfectly matched, being equal voltage at empty and full! ... 8)

 

[bobbill]

Let's say some cells are 2500mv at 3.5v and some are 3500mv at 4.0v. YOu equalize voltage and can combine? Thanks.

I wonder how the former users knew BMSs were messed?

 

[DrkAngel]

Let's say some cells are 2500mv (= 2.5V) at 3.5v and some are 3500mv (=3.5V) at 4.0v. YOu equalize voltage and can combine? Thanks. ... ?

I wonder how the former users knew BMSs were messed? Seller advertised "Most of these modules were salvaged due to a defective BMS "

 

[DrkAngel]

Panasonic (LG) MJ1 3500mAh cells
3rd 10s4p EBike battery metered charged at 14,000mAh + also!
These are used batteries from rental(?) eBikes. Advertised as having failed BMS, I wonder if BMS has a power disable to deter theft or alternate reuse, enabled-disabled via the eBikes rental-tracking system? (3 extra contacts utilized between eBike and BMS) Several batteries had broken security locking brackets.

My initial use will bypass the BMS outputs but retain the balance function. All cells equal within 1/100th V immediately after quick charge, balance function is working or cells are perfectly matched, being equal voltage at empty and full! ... 8)

4th battery (32V) metered 13.8Ah charge
5th battery (35V) metered 10.2Ah charge
6th battery (36V) metered 9.8Ah charge
It appears all batteries might still be within the specs for new 3500mAh cells!
Even better, Fluke meter shows charge voltage at 41.63V, which indicates slightly higher capacity for "full charge".
On the other hand, I highly recommend against the 3.0V as a static discharged voltage, even the 3.2V seems harsh and to be avoided - IMO.

I, personally, would avoid discharging below a static ... ~3.40V?
Discharge voltage and discharged voltage are very different!
Under a moderate load a battery might discharge to 3.0V but with throttle released will demonstrate the battery discharged to 3.4V.
Note the voltage recovery when discharge discontinued, most notable on the 10A and 15A discharge curves!

 

[john61ct]

AKA resting voltage, the only proxy for SoC% both easy and reliable.

Good rule of thumb, leave an extra 10% in there compared to the data sheet minimum.

Going to 20% instead can greatly increase cycle lifespan, for low C-rate usage maybe triple it.

 

[docw009]

I came across this guy, Battery Clearing House. He's selling this metal enclosed 40 cell 10S-4P for 57 dollars. Taken out of scooters. Thing is, it's got a BMS that needs a Can-bus to run, and he sells an Arduino circuit to do that, Wow.

https://jag35.com/collections/jehus-deals/products/copy-of-40-cell-ncr18650bd-18650-lithium-scooter-battery-pack-w-case?fbclid=IwAR2tFWrrRQDm8D8yv79TnVh3KI_MOiHzA1oDv9W8CNVx-5qjlycKThzV_50

https://www.youtube.com/watch?v=-XPgsOdK8Zc

I had an interest in Arduino a while and I bought a starter CPU kit. This would be a good way to get me back into it, but I'm passing. Ought to be a pretty fire proof battery though,

He's also selling 26" front wheel/bafang G20 motor for 45 bucks plus shipping, taken out of rentals. I bit on one of them. Also has a mezmerizing assortment of surplus packs,

https://www.batteryclearinghouse.com/products/26-bafang-dc36v-sturmey-archer-rx-rd3-electric-bike-wheel-with-tire-brake?fbclid=IwAR3w-5uPP52UostXoluCROpNt09WQxdboGDF2dLjGlNPMSYN8uukMXr8yGU

 

[amberwolf]

BCH and Jag35 are different companies. Jag35 apparently communicates, packs well, etc., while BCH...leaves much to be desired. I only have direct experience with BCH (but wish I didn't).

Here's a thread about the motor wheel
https://endless-sphere.com/forums/viewtopic.php?f=2&t=110408
and one about the original BCH deal for a pair of sets:
https://endless-sphere.com/forums/viewtopic.php?f=9&t=106233

 

[bobbill]

Amber Wolf scolded me for doing same thing (mentioning rippers) re Vruzend...Tsk-Tsk!
ironies do abide.

 

[docw009]

Thanks for the info about BCH/JAG. I think I bought them from BCH, but there's paypal to cover it. What can you do to a wheel except scratch it up and maybe bend a few spokes.

 

[bobbill]

I have 30 18650 cells @ 3.5 all same mAmps, (NCR) and 30 at 4.2v all same mAmps (30Qs)

Also plan to acquire 10 more of one or other cells to have one 10s3p pac (NESE modules), and one 10s4p pack both 36v to powerbikes.

Prefer 36v limits.

Simple, I know!

I am Right Track?

 

[DrkAngel]

9Ah battery should be OK for a 36V 250w motor ... barely.

 

[bobbill]

Thanks, DA; Was informed the added cells should match the others in the pack, mAmp-wyz.

 

[DrkAngel]

Thanks, DA; Was informed the added cells should match the others in the pack, mAmp-wyz.

Matching cell mAh is not so important as matching the low end of their discharge profiles!

 

[bobbill]

Thank you for the observation. Will add to a jillion perameters and ask one question:

How is that cell-status determined if theses cells, to be added, are not already acquired?

 

[DrkAngel]

Cell comparator
Chose your 2 cell types and compare voltage of "cliff" point ... where voltage drops steeply.

 

[bobbill]

How to do prior to acquistion? Might buy new?