[SOLVED] Balance Discharger... or is there anything else?

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Slipstream   10 mW

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[SOLVED] Balance Discharger... or is there anything else?

Post by Slipstream » Feb 26 2021 3:29am

Problem:
8s6p lithium diy battery
balance charger fails to bring rows to balance.

Currently using:
ToolKitRC M8 300W Charger
Does not actually manage to balance a battery ... for me anyway.

Overlander 3250 8S Battery Capacity Meter, Balance Discharger, Servo Tester
£14 ... Would this help me flatten out my rows?
https://www.ebay.co.uk/p/8008570964

What else is there?

Is there any simple cheap device I can use to quickly drain 1 row to <>3.8v?

:)
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DogDipstick   10 kW

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Re: Balance Discharger... or is there anything else?

Post by DogDipstick » Feb 26 2021 6:42am

The M8 has very little balancing current. there are chargers with much better capabilities.

Also, you cannot balance discharge on the M8, only balance charge. However if your (15Ah?) 8s6p is very out of balance the charger may terminate well before the balance is achieved. Some chargers have the option to adjust this amount of current, and the termination. The balance current on your (15~Ah) pack is only 40mA with the m8, and would take literally forever to balance a large out of balance system.



Going over the M8 info, I see no way to change balance current, nor to balance on discharge.



Do them ( the groups) one at a time. Then compare. Trying to do them all at once, the charger will stop without proper fill. Do them all one at a time, the baseline is set.

If you have access ( balance connection nodes) to the group, you can discharge ( that group, one at a time) with virtually any incandescent) light bulb slowly enough. Without overcome the design of the pack ( wire size, ect. ) .
83.1v of Ironhorse XC.. :) :bolt: by Chevy :bolt: :D Goddammn... Broke 154mph unloaded... :twisted: (Healing again... No Mom. I dont try to do it on purpose).. :? Waddyamean? You cant tell me how many amperes/Ft.^2 of the plate ?!?!? :x 1 (pound / second) Horse Power = 338.24 M^2 Kg^2 / Sec^4 ( :twisted: prove me wrong :twisted: ) :| (gottenymoem4115thangs?Yall?) :confused: Fabricator @ BSECo. Inc.

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Re: Balance Discharger... or is there anything else?

Post by john61ct » Feb 26 2021 8:01am

Light bulb, resistor, just wire, regular silicone insulated or bare nichrome, hairdryers toasters water heating elements

Basically a DIY version of this
http://store.evtv.me/proddetail.php?prod=250wresistor

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Re: Balance Discharger... or is there anything else?

Post by john61ct » Feb 26 2021 8:02am

This automates the process for up to 6S cells at a time

http://www.myrcmart.com/rcx-3in1-batter ... -4767.html

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Re: Balance Discharger... or is there anything else?

Post by john61ct » Feb 26 2021 8:04am



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Slipstream   10 mW

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Re: Balance Discharger... or is there anything else?

Post by Slipstream » Feb 26 2021 12:27pm

Many thanks guys ... will look into your suggestions.

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motomech   1.21 GW

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Re: Balance Discharger... or is there anything else?

Post by motomech » Feb 26 2021 6:44pm

Battery Medics;
I'm a LiPoly guy and have no experienced w/ round cells, but I have been using Battery Medics for 9 years and ALL the passive dischargers/balancers listed above ARE rebadged BM's.
I think what the OP wants to do balance a serial line of 8S w/ a 8S balance lead.
All the BM's listed, whether they are blue or blk (Hobbyking) are 6S! Bangood is lying about that unit, I've owned them and they are 6S.
That Overland gizmo, well, I'm suspect. They don't show the JST port, it's the same size overall as a BM and every review gives it 5 stars. BM's, by their compromised nature don't get 5 Star reviews.
This is a little off-topic, but here's the deal on BM's
The blue ones w/ the lite bulb attachment offer the finest adjustment as they allow a final balance value set at .01V increments, for example, set at 3.89 V, set at 3.90 V, set at 3.91 V, etc. They are very slow, but don't overheat. The bulb discharger is bulk discharge only and the bulbs get hotter than Hell and need some sort of safety stand constructed. But this is not what the OP wants to do anyway.
The blue ones w/out the bulbs can be set in .05V increments, 3.85V, 3.90V, 3.95V, etc and are very slow as well.
The black ones (Hobbyking) can only be set in .10V increments, 3.80V, 3.90V, 4.00V, etc., but are faster to discharge/balance. But if one tries to discharge a 4S, 5S or 6S string, they will overheat, the screen will turn blk and if left on long enough, will start to melt the housing.
Battery Medics will only "sort of" balance a cell array of 2P, as the two cells in parallel will not end-up at the exact same value. 3P and up is impossible.
In this vain, I think DogDipstick is spot-on as to why his 8S RC (toy) charger won't balance cells in more than 2P (if that).
And I'll say what DD didn't (but knows), that the OP has wired himself in a corner and needs to redo the pack w/ a BMS.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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Re: Balance Discharger... or is there anything else?

Post by motomech » Feb 26 2021 7:00pm

To further elaborate on what I've learned to do w/ LiPoly is to never go w/ more than 1P. There is no reason to, I simply use a pouch capacity to get me to a pack capacity I want. On my bike, that is usually 14S/1P for 54 V/10,000 mAh (two bricks).
Since each brick is 7S, I wired it w/ two balance leads, one 4S and the other 3S. That way I can use Battery Medics (4 of them :roll: ) when I bulk charge w/ my Mean Well HLG.
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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Re: Balance Discharger... or is there anything else?

Post by john61ct » Feb 27 2021 3:45am


motomech wrote:Battery Medics…

ALL the passive dischargers/balancers listed above ARE rebadged BM's.
That's very interesting

and valuable insight if true.

But I posted lots of powered units, and came across hundreds of others googling

just in case some readers do not realise the distinction.

So long as the "terminate discharge" point is accurate enough

couldn't a 6S battery medic be used on an 8S pack?

First stage do cells 1-6, second round do 3-8 ?

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Re: Balance Discharger... or is there anything else?

Post by Slipstream » Feb 27 2021 4:25am

:) Wired myself into a corner hehe

In defence the 4x 8s6p design was trial and error --- simply kept adding rows and batteries until performance was acceptable.

The m8 charger was the cheapest out there (a year ago) that managed 8 cells in series.
The fans wore out in month 13 ... pretty noisy now.
Balance Discharge = fail ... does have a discharge function but intent on doing all rows at once so never gets there in a 8S6P battery. Operating at 65w ... <2A eg. not overworked as specs say 300w max.
Takes a loooong time (12hrs+) to recharge (80%) all four batteries, one after the other. Sigh.
Safety first ... mixed cells etc so the slow charge is probably sensible.

As for the Overlander thing ... I also suspect the flash box with the sci-fi graphics.

What I need is to be able to flatten a single row (second hand 18650 cells no need for any accuracy).
Is there a 3v-> 12v converter circuit than can deliver 1-2A at 12v to a bulb or such devices I have handy?

Based in the UK.

EBAY is easier for me.... eg... what do you think about this one?

https://www.ebay.co.uk/itm/5A-DC-DC-ste ... 3827553643

Specification:
1.Module feature:XL6019 step up module
2.Module type:Non-isolated boost
3.Rectification method:Non-synchonous rectfication
4.Input voltage:3V-35V
5.Output voltage:5V-40V(notes can not step down voltage)
6.Input current:3A(maximum 5A)
7.Transfer efficiency:94%(The highest)Normal efficiency for 85%
8.Switching frequency:220KHz
9.Output ripple:<100mV
10.Load regulation:+-0.5%
11.Voltage regulation:+-0.5%
12.Operating temperature:-20℃~+85℃
13.Size:5cmx2.8cmx1.2cm(2.28"x1.10"x0.47")
Package include:
1Pcs 5A DC-DC Step Up Power Module
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motomech   1.21 GW

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Re: Balance Discharger... or is there anything else?

Post by motomech » Feb 27 2021 9:31am

john61ct wrote:
Feb 27 2021 3:45am
motomech wrote:Battery Medics…

ALL the passive dischargers/balancers listed above ARE rebadged BM's.
That's very interesting

and valuable insight if true.

But I posted lots of powered units, and came across hundreds of others googling

just in case some readers do not realise the distinction.

So long as the "terminate discharge" point is accurate enough

couldn't a 6S battery medic be used on an 8S pack?

First stage do cells 1-6, second round do 3-8 ?
You would have to wire the 8S w/ 2 balance leads, so 4S and 4S. To balance ck/discharge w/ one BM successively would take way too long. But, on the other hand, buying a bunch of BM's suck. After quite a few years, I just replaced mine, $100 for basicly 4 plastic POS :roll:
'11 Motobecane Fathom team, Bafang SWX02-13T, 14S (54V) LiPoly, 9-FET 17A controller. Schwalbe Marathon's, 24 to 25 MPH.
Hobie Passport Kayak w/ Watersnake 18# motor, 12S LiPoly (46V) to golf cart 12V converter, 4 mph

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Re: Balance Discharger... or is there anything else?

Post by Bobw » Feb 28 2021 12:17pm

This is what I use to do a pre-charge pack balance on my bike. There is a 6 cell limit to the balancer, in my case I configured my 12S8P pack to allow separation into two 6S8P packs.
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Re: Balance Discharger... or is there anything else?

Post by Slipstream » Mar 01 2021 5:07am

Nice solution Bob ... thanks. So these little gizmo boxes can balance larger batteries!

I was hoping that someone here was using the Overlander (8s) box ^^ above and could tell me how well it was.

On that note ... anyone using one of these below?
Cellpro PL8 PL6 308/3010/4010 2~8S Battery Charger Balance Board
https://www.ebay.co.uk/itm/172481392694

Have asked the supplier on ebay ... they were polite but not able to answer.
Is there a manual (no)
Is there a balance board on this adaptor? or straight through?
What exactly am I looking at here???!
:oops:
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Re: Balance Discharger... or is there anything else?

Post by john61ct » Mar 01 2021 2:52pm

That FMA PL8 is a fine balancing charger, very accurate and robust, better than newer models.

Balance boards in this context means

rather than actually doing any balancing themselves

allowing multiple identical packs to be safely parallel charged at once, speeding things up out flying in the field.

Not good for precise balancing, which requires one pack at a time

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Re: Balance Discharger... or is there anything else?

Post by john61ct » Mar 01 2021 2:53pm

CellLog 8S would be a useful tool here

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Re: Balance Discharger... or is there anything else?

Post by DogDipstick » Mar 01 2021 6:06pm

Slipstream wrote:
Mar 01 2021 5:07am


On that note ... anyone using one of these below?
Cellpro PL8 PL6 308/3010/4010 2~8S Battery Charger Balance Board
https://www.ebay.co.uk/itm/172481392694


Is there a balance board on this adaptor? or straight through?
What exactly am I looking at here???!
:oops:
It it's called a safe parallel board it allows you to charge a few lipos in parallel on one channel on your charger. just straight through sometimes they have polyfusions that do not allow excess current through the balance lines from the node points on the board to create large current in Russians when you plug them in and they are unbalanced to each other like a typical hobbyist would..

I have a few and have used them for a while for RC hobby stuff. Usually for not over 30 amps they come with 10 gauge wire and some of them you can daisy chain train along... No they don't balance anything they just distribute current amongst four parallel batteries or however many of the board is designed for.

Usually around 30 amps they get really hot around 25. Melt plastic hot. Lol. I used one to gang up for five amp hour batteries for a 20 amp hour build or at least half of that 20 amp hour there were eight batteries in total , 4 on another parallel harness ... One of the harnesses smoked it's plastic and desoldered it's connectors.
83.1v of Ironhorse XC.. :) :bolt: by Chevy :bolt: :D Goddammn... Broke 154mph unloaded... :twisted: (Healing again... No Mom. I dont try to do it on purpose).. :? Waddyamean? You cant tell me how many amperes/Ft.^2 of the plate ?!?!? :x 1 (pound / second) Horse Power = 338.24 M^2 Kg^2 / Sec^4 ( :twisted: prove me wrong :twisted: ) :| (gottenymoem4115thangs?Yall?) :confused: Fabricator @ BSECo. Inc.

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Re: Balance Discharger... or is there anything else?

Post by Slipstream » Mar 02 2021 3:52pm

Thanks for the comment D.

12 hour charge time here currently. Will probably buy one and try it.

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Re: Balance Discharger... or is there anything else?

Post by john61ct » Mar 02 2021 3:57pm

Parallel charging is inherently much more dangerous than one at a time.

To the point that many experienced hobbyists have sworn off ever doing it anymore after big fires.

Others say it's OK, so long as

cells are all in good condition, certainly not worn or secondhand, ideally newish packs

well balanced

avoiding the top voltage area

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Re: Balance Discharger... or is there anything else?

Post by Slipstream » Mar 03 2021 1:56am

I never leave the packs charging un-attended, and do not charge >75%.

Also an alarm clock set on 1/2 or 1/4 hr intervals so I regularly check the thing manually.

Also a fire blankey.

Also charge area is on a metallic sink. Problems? Push it into the sink, cover in fire blankey, extractor on, and evacuate.

Fire station 3 minutes around the corner.

Neighbours are pretty horrible so if the lot burns down will be entertaining.

Emergency living stuff on the boat 6 miles away.

: )

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Re: Balance Discharger... or is there anything else?

Post by john61ct » Mar 03 2021 2:09am

Great, but the gear and knowledge to ensure

> cells are all in good condition

is a good goal to focus on.

Replace proactively, or at least charge the weaker packs as singles.

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Re: Balance Discharger... or is there anything else?

Post by Slipstream » Mar 03 2021 2:48am

+1 ... wish I knew more. DIY ebikes are a steep learning curve - beyond my initial skill set by some margin.

Initially ... as the motor was 48v I went for 2x6s6p, with a pair of chinese BMS 6s.

The result was so bad it only went out once.

Removed the bms... went to 7s... still fairly poor.

2x8s provided the performance I imagined.

2x2x8s was enough to get me to the boat and back.


The current battery build is literally as cheap as I could make it.
batteries-IMG_20200609_001735.jpg
batteries-IMG_20200609_001735.jpg (162.41 KiB) Viewed 529 times
Each cell consists of;
1x empty 4L milk container (free!) cut so handle folds nicely
48 used cells (<>£30 @ ebay)
5m solder (£5)
2x xt60 connectors (£1)
1x 8s (9 lines) balance lead (£2)
10m black insulation tape (£1)
2m mains cable (stripped for busbars) £2
= about £42 and at least 8 hours making 96+ perfect solder connections.

HINT: DO NOT TRY AND SOLDER FULLY CHARGED CELLS!!!

The next battery I build is going to be a little different.
No drawing but basically plastic dinner trays cut, holed, and compressed together, sandwiching cells and bars.

96 Copper compression fittings ? thinking domed copper rivets
96 Copper roves ? thinking drilled 1/2 penny pieces!
Mouse pad high density foam £1
Plastic trays x4-6 £1 each
Hole saw 20mm £5
Threaded bar 1.5m
10x Nuts
2x xt60 connectors (£1)
1x 8s (9 lines) balance lead (£2)
10m black insulation tape (£1)
2m mains cable (stripped for busbars)
... and some cells! Probably 48 ebay cells @£30+ UK import duties etc!

Notice ... no solder. Idea being I can simply replace a row if it annoys me!

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Re: Balance Discharger... or is there anything else?

Post by Slipstream » Mar 17 2021 3:36am

ToolkitRC M8 charger blew up (tiny pop noise then no function) yesterday.

Am now using the XL6019 board ^^ above + diode + voltmeter to charge the batteries.

Oddly quicker than charging with the now dead M8 ... approx 1/2 the time to 70% ish which brings me to about 4-5 hours for a charge for all 4 batteries. Muuuuch better.

But ... it's very "Blue Peter" looks awful ... lots of wires, bare board and tape... and worries the Mrs.

I need a good 8s balance charger, used is fine, for around £10-30. Roughly.

Will avoid the M8 which cost just over £30 about 18 months ago.

UK.

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Re: Balance Discharger... or is there anything else?

Post by Slipstream » Mar 28 2021 8:13am

Here is the replacement:
isdt-q8.jpg
isdt-q8.jpg (65.87 KiB) Viewed 346 times
ISTD 8Q

https://www.isdt.co/qseries.html?lang=en

Input voltage: 10-34V - DC voltage
Input current max: 20A
Output voltage: 1-34V
Charging power: 500W (from 27V input voltage)
Discharge power: 15W
Charging current: 0.1-20A
Discharge current : 0.1-1.5A
Balancer current: 1500mA / cell
adjustable final charge voltage: up to 4.35V for LiHV
number of cells - battery type: 1-8 LiXX, 1-7 LiHV, 1-16 NiXX, 1-12 Pb

Will let you know if it skrews the pooch or actually works!

: )

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Re: Balance Discharger... or is there anything else?

Post by john61ct » Mar 28 2021 3:33pm

Make sure if using for DIScharging to stay well below the rated max current level.

Doing so reduces charger reliability and lifespan.

Bigger multi-channel ("Duo" style) that let you discharge into an external resistance or depleted battery (regenerative) across channels.

e.g. iCharger 4010 Duo, can handle only 130 watts per channel or 200 watts total with internal dissipation (not advised, stay well below!)

but up to 1000W if 17+V input, in cross-channel external mode.


But really, if you frequently need high power discharging, get hardware purpose designed dedicated to that function, do not stress a charger so much.

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