Test bafang BBS02 not-on-bike

Batteries, Chargers, and Battery Management Systems.
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Freshblood
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Test bafang BBS02 not-on-bike

Post by Freshblood » Dec 27, 2017 2:16 pm

Hi,

Recently bought a bafang 750 bbs02 motor. Battery is a 9s6p battery . Home-built 37.3V fully charged and 25A continuous current.
I hooked up everything and the display shows low battery. How does the controller know this or should I input some settings to tell it what it is working with?
Is there a possibility I got the + and - muddled up and that is why?

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Marin
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Re: Test bafang BBS02 not-on-bike

Post by Marin » Dec 27, 2017 2:27 pm

Depending on the display you have there are settings to be entered, battery size, display battery icon type (symbol,percentage, voltage), wheel size and more

search and you will find instructions for display,

Since you have 9s and not 10S common 36 volt the symbol will always read low, set it to voltage to see your actual voltage instead of the battery symbol
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Giant Yukon bbs02
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Freshblood
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Re: Test bafang BBS02 not-on-bike

Post by Freshblood » Dec 27, 2017 2:49 pm

HI Marin

Thanks. I have the C963. I am a little limited with settings. wheel size, speed, backlight and odometer reset only. The motor however does not know whether I have a 5s 10s or 20s? It only cares about volts and continuous amps right?

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Re: Test bafang BBS02 not-on-bike

Post by Marin » Dec 27, 2017 2:56 pm

Sorry I don't have that display in the 4 I do have, here is some reading hope it helps,

https://electricbike-blog.com/bbs02-displays/
Marin ex-rental hybrid with 48v bionx...sold
Specialized hardrock with magic pie 4-5
Lunacycle with l/r mid drive coming soon
Kona Caldera with QS 30H (maybe), and phase runner
Giant Yukon bbs02
Kona Abra Cadabra bbshd
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Re: Test bafang BBS02 not-on-bike

Post by Rassy » Dec 27, 2017 3:12 pm

I don't think you would get that far if the battery polarity was wrong.

The only issue I can think of is the low voltage cut off set in the controller and the only way to reset or check it is with a programming cable. It can be set as low as 18V. The BBS02s that I have purchased were intended for 48V and the cut off was set at 41V.

EDIT: I do have a C963 on the shelf because I didn't like it's limited settings. Mainly the fact that it can only display in km and not miles. Also I think it was limited to just 5 PAS settings. Otherwise the basic little display is one of the nicest Bafang makes.
-Rassy-
One Tadpole Trike equipped with a Bafang BBS02
https://endless-sphere.com/forums/viewt ... 28&t=69419
One Delta Trike equipped with a Bafang BBS02
https://endless-sphere.com/forums/viewt ... 0#p1291260

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C963 display bbs02 low battery

Post by Freshblood » Dec 27, 2017 3:57 pm

Hi

My display keeps showing low battery even though battery is charged. Brand new battery pushing out 37.3V tested.

What is wrong here?

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Re: C963 display bbs02 low battery

Post by tomjasz » Dec 27, 2017 4:02 pm

Freshblood wrote:
Dec 27, 2017 3:57 pm
Hi

My display keeps showing low battery even though battery is charged. Brand new battery pushing out 37.3V tested.

What is wrong here?
A new 36v battery out to be fully charged to 42v.

And youre trying to run a 9s battery on a system designed for 12s, 48v, 54.6v fully charged.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Test bafang BBS02 not-on-bike

Post by tomjasz » Dec 27, 2017 4:04 pm

The proper battery would be 36v with a full charge of 42v. 10s.

I just caught on, sorry, missed it at first. A bbs02 is a 12s 48v motor. Youre all turned around!
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Test bafang BBS02 not-on-bike

Post by Freshblood » Dec 27, 2017 4:22 pm

Hi,

Sh*t I just saw it is a 48V unit. Mmm. I have a 10s BMS. Resoldering my battery to 12s would not be a problem were it not for the BMS. Any suggestions? Possible to get a 16s 60V and only use 12 balance wires? Cutoff will be to high then I think. Only reason I want to get this BMS is due to cost. 12s is almost 3 times the price
Last edited by Freshblood on Dec 27, 2017 4:30 pm, edited 1 time in total.

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Re: Test bafang BBS02 not-on-bike

Post by tomjasz » Dec 27, 2017 4:25 pm

Freshblood wrote:
Dec 27, 2017 4:22 pm
Hi,

Sh*t I just saw it is a 48V unit. Mmm. I have a 10s BMS. Resoldering my battery to 12s would not be a problem were it not for the BMS. Any suggestions?
New BMS. And 12s.
Vruzend.com can probably get one to you faster than China.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Test bafang BBS02 not-on-bike

Post by Freshblood » Dec 27, 2017 4:53 pm

thank tomjasz

Any possibility of rewiring battery to 13s and getting a 13s 48v BMS? Not sure why they have such low potential on BMS cause 13 x 4.2 is 54.6V

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Re: Test bafang BBS02 not-on-bike

Post by dustNbone » Dec 27, 2017 5:08 pm

It's the difference between max and nominal voltage. A normal 18650 cell has a 3.6-3.7V "nominal" voltage and 4.2V "full". A 10S battery therefore has a nominal voltage of 36V, 42V full. A 48V battery made of 18650s is 13S or 14S, so 46.8-50.4V nominal.

You should still be able to run that battery, the battery meter might not work correctly but if you reprogram the controllers LVC (Low Volt Cutoff) to something like 24 or 25V it should work fine. AFAIK you'll need a programming cable and the Bafang software to do this.

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Re: Test bafang BBS02 not-on-bike

Post by tomjasz » Dec 27, 2017 11:14 pm

Freshblood wrote:
Dec 27, 2017 4:53 pm
thank tomjasz

Any possibility of rewiring battery to 13s and getting a 13s 48v BMS? Not sure why they have such low potential on BMS cause 13 x 4.2 is 54.6V
I’m sorry and embarassed...
Me matin* a really dumb mistake. 13s is correct for a 48v nominal, 14s for. 50-52v(v value depends on vendor)
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Test bafang BBS02 not-on-bike

Post by Freshblood » Dec 28, 2017 3:47 am

Thanks all,

I am between rock and hard place. Redo entire bloody battery from scratch and purchase new 13s BMS OR get one of those reprogramming cables and reduce cut-off voltage. I am limited with space so I have to go from 6p to 4p battery reducing my potential distance by 30% without real power gains. Anybody got one of those cables lying around I could purchase as I really only need this thing once. :D

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Re: Test bafang BBS02 not-on-bike

Post by dogman dan » Dec 28, 2017 9:01 am

Actually, 13s or 14s for a 48v system. You need a 13s bms and charger.

Same number of cells, so your distance did not get less, but,, you may have a battery so low capacity ( as a 48v pack) that running it will ruin it quickly, unless you severely limit your speed and continuous draw..

I'm assuming you have 5 levels to choose from,, for now, forget levels 3,4 and 5.

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Re: Test bafang BBS02 not-on-bike

Post by Freshblood » Dec 28, 2017 9:58 am

Okay I rewired for a 13s, 54V 9Ah battery pack.

I have the following charger I bought for the previous setup:

36V 37V 42V 45V 5A Battery Charger For 10s 10x 3.6V/3.7V Lithium Li-ion Battery

It's a 240W unit. I don't want to invest in another bulky charger. Would this one not work? My electronic experience is limited but my common sense tells me that it would just take longer to charge as the charger can only push 5A at a max of 45V
The BMS on the battery will protect the circuit as it is suppose to do
charger.PNG

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Re: Test bafang BBS02 not-on-bike

Post by dustNbone » Dec 28, 2017 11:41 am

It depends on the maximum voltage of the charger. If you're going 13s you'll want a charger that can output 54.6V in order to fully charge the battery (4.2V x 13 = 54.6V) and allow the BMS to balance the cells.

A charger that outputs 45V max will only get the cells up to 3.46V (45V / 13 = 3.46V) which is not even going to charge them half way.

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Re: Test bafang BBS02 not-on-bike

Post by amberwolf » Dec 28, 2017 2:07 pm

You're going to have to match the parts for the battery, the charger, and the controller, so that they are all designed to work with the same voltages, if you want to avoid problems and workarounds.

If you use a battery that's 13s of a particular chemistry, you need ot use a charger that's setup for the full-voltage of that size and chemistry pack. In your case that's 13 x 4.2v if you're fully charging typical non-LiFePO4 lithium cells.

Otherwise, as noted, you won't get much of a charge, and you're still stuck with the same "low battery" problems, limited range, etc.


Also note that if you use a charger that is too high a voltage, then if anything goes wrong with the BMS it will overcharge the pack (and if it's badly unbalanced it could be enough overcharge to start a fire). So you want ot make sure you get one that's set for your pack's actual full-charged voltage.


Note that you could use your existing charger and BMS for charging, as long as you configure the pack for 10s to charge, but then you have to reconfigure it for 13s to use it on the bike. Doing that kind of reconfiguring on a regular basis can lead to a mistake at some point that leads to damage to battery or charger or BMS, and potentially fire. (people do this with some modular batteries, and some are successful and some aren't--accidents happen, usually when people are in a hurry or tired). It's also a PITA to have to do every time, even if nothing ever goes wrong. :(

The 10s BMS won't work for use on the bike during discharge, though, so you'd either have to monitor manually or get a 13s BMS for that.




Some chargers can be adjusted, but probably not as far as you need to on this one. If you want to adjust it, you'll be doing exploratory experimentation that risks damaging or destroying the charger, unless you can get the info from the manufacturer on how to do it (probably not available). Some chargers have threads on adjusting them here on ES, but I don't know that yours is one of them. Some possible threads
https://endless-sphere.com/forums/searc ... mit=Search

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Re: Test bafang BBS02 not-on-bike

Post by tomjasz » Dec 28, 2017 4:32 pm

Where do you live? Maybe we can work something out on the cheap.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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