bluetooth BMS?

[verdulleme]

Aliexpress has been pestering me for several years now, they always want me to login.
I found several ways around this, although they don't always work.
Coming to a product page through a search engine mostly works good.
Search on duckduckgo (or google) for: aliexpress 32963235751
It finds the exact link Flippy shared. Click on it, and no login....

Also changing the browser works, fairly. Instead of the old firefox based waterfox or palemoon I now browse ali with vivaldi. This works a lot better. Can even use the ali search again. But alas, quit often they come again with the login page.

When the search or menu items bring you to a login page, try the suggested items in the bottom of the page. Open in a new tab, and it might open normally.

Deleting cookies and cache works, but not always.

Best so far is using a vpn set to china mainland exit node. Browsing the ali site this way I have not been asked to login yet.

But to be honest, I go to ebay first for this reason. Even though there are some very good sellers and products on ali.

Oh, and the reason? They say to stop indexing bots from snooping everything on ali. But I sense its more like 'we want to know everything you do'!, log it and sell it as big data....

 

[nassal]

I have wired the BMS according to diagram and instructions but BMS got fried. It is a SP15s020 14S 60A . Any idea? I have ordered a SP15S001 14S 20A now, just don’t want to fry another one. Is it possible by looking at the photos to tell what’s gone wrong?? Thanks

 

[SilverLine]

Wrong cell order

 

[flippy]

Oh, and the reason? They say to stop indexing bots from snooping everything on ali. But I sense its more like 'we want to know everything you do'!, log it and sell it as big data....

you dont need to log in for them to do that.

 

[Fionn]

What might be useful to include for anyone concerned about idle drain would be some multipole switches on the balance leads.
This would allow you to fully package the BMS with the battery and still retain the ability to fully isolate it when not in use.
https://www.ebay.co.uk/itm/5-x-Mini-Push-Button-Latching-PCB-Switch-6PDT-30V/282668089774/

https://www.amazon.com/dp/B07P7CSFXD/

 

[john61ct]

nice concept but rating is 0.1A
https://www.e-switch.com/product-catalog/pushbutton/product-lines/pbh-series-miniature-pushbutton-switch

I'd stick to a plug/connector

 

[izeman]

No need for more current. The bleeding resistors are all that need to run current through the wires/connectors. And unfortunately they can't run more than that anyway.

 

[Fionn]

In any case here's a version rated at 200mA in case it's of interest to anyone
https://www.rapidonline.com/toneluck-pbn-s6a1-5-aag-standard-6-pole-changeover-switch-78-0501

 

[john61ct]

Aha, yes forgot where I was.

I'm looking for 5-6A in case anyone knows, want to be able to bring the per-cell pairs out, do node charging as well as use dedicated balancers.

So far plan to just use Deutsch DTM 12-wire connectors.

 

[Fionn]

One could still bring out heavy wires for that if needed and just use the switches on the BMS input.
Anyway, just a suggestion, back to the main topic

 

[john61ct]

Seems to me most reco the JBD/LLT BMSs over the ANT?

I want to be able to wire up independent battery modules, say 3P7S, then be able to put them together into 21S strings, and/or also in parallel for higher Ah capacity.

Planning to bypass the power current and drive external relays, charging HVC separately from load buss LVC so although longevity / reliability is most important to me, the FETs do not need high ampacity.

Sensor accuracy is important.

So which is better given the above?

Or in general, pro's and con's between the two features etc, would be most welcome.

 

[thunderstorm80]

Seems to me most reco the JBD/LLT BMSs over the ANT?

I want to be able to wire up independent battery modules, say 3P7S, then be able to put them together into 21S strings, and/or also in parallel for higher Ah capacity.

Planning to bypass the power current and drive external relays, charging HVC separately from load buss LVC so although longevity / reliability is most important to me, the FETs do not need high ampacity.

Sensor accuracy is important.

So which is better given the above?

Or in general, pro's and con's between the two features etc, would be most welcome.

I join the above question!
I also wonder in terms of reliability (including whether the app is still functional after major android upgrade and the bluetooth module are functional after 1 year or more)

 

[Fionn]

I'm running Android 6 & have to use the older version (2) of the Xiaoxiang app.
The newer one will install fine but doesn't operate.

 

[serious_sam]

I'm running Android 6 & have to use the older version (2) of the Xiaoxiang app.
The newer one will install fine but doesn't operate.

A couple here have noted this issue. Sounds like the new app doesn't run on older Android.

 

[john61ct]

Older Android devices can easily be bought for less than a fast-food meal, so NBD

 

[serious_sam]

Older Android devices can easily be bought for less than a fast-food meal, so NBD

Did you even read the post? The new app doesn't run on older android. SMH.

 

[john61ct]

I didn't mean **that** old, just second-hand from a couple years back, 8/Oreo or Pie/9

 

[qwerkus]

I have a 60a jbd smart bms plugged onto a 14s7p cell samsung 35e cell pack. Unfortunately, the battery keeps shutting down (cuts power) even though its 50% charged. Here is a screenshot of the configuration:

One of the issues might be regen. The motor is a rh212 DD hub driven by a kt controller with regen enabled. Braking for a long time (2min+) for sure shuts down the bms. Anyone succeeded using one of those jbd bms with regen ?

The other issue is shutdown during load. Right now the bms shuts of just past 800w which is way to low for this config. Something must be wrong with my config. I'm going to try an change Pack UVp to a lower value - see if that helps. Anything else I should change ?

Thank you for your help,

 

[serious_sam]

Thank you for your help,

Looks like there have been a couple of under-voltage incidents?

What are your cell group voltages? How old are the cells? How well is the pack assembled? Are you confident there isn't a problem with any cells?

Another thing to check is the shunt resistor value. One quick way to confirm that the set value is in the ball park: you can plug in your charger, and check the current flow on the phone app or pc software. If the current on the app matches the actual current, then it's set correctly.

If it reads high, then the BMS might be cutting out due to incorrectly thinking that you're running over the current limit.

 

[serious_sam]

Braking for a long time (2min+) for sure shuts down the bms. Anyone succeeded using one of those jbd bms with regen ?

I run regen, and I have no problem with my jbd BMS.

However, regen does create a lot of heat in my motor (MXUS3K). Especially when going slowly down steep hills. Basically DD hub motors are terribly inefficient at low speeds, so power in or out creates a lot of heat at low speeds.

I'm running a Nucular 12F, and it is programmed to throttle power when my motor hits 130c, which does happen under heavy regen.

Do you have motor temp connected to your controller? Could it be the controller that is cutting power due to motor temp?

 

[qwerkus]

What are your cell group voltages? How old are the cells? How well is the pack assembled? Are you confident there isn't a problem with any cells?

Another thing to check is the shunt resistor value. One quick way to confirm that the set value is in the ball park: you can plug in your charger, and check the current flow on the phone app or pc software. If the current on the app matches the actual current, then it's set correctly.

If it reads high, then the BMS might be cutting out due to incorrectly thinking that you're running over the current limit.

Nice spotting! I didn't know the bms was keeping track of failures. Cells are brand new samsung 35e cells - don't think tey are the problem. Pack is spot welded with large serial connections should be ok. Here the cell monitoring page.



Same shunt is used for charge and discharge ?

 

[qwerkus]

Do you have motor temp connected to your controller? Could it be the controller that is cutting power due to motor temp?

Good point - thanks for the input. Controller is kt 12s and the motor has a built in temp sensor. Unfortunately I did not find any infos on where to solder that temp sensor wire so right now it's not connected, can't be overheating issue.

The sellers tells me I should disable overcurrent protection by setting it to 70a. Not sure if this is a good idea - I'm never going to hit those value anyway. The motor is rated for 1000w. Even if I pump 2000w into it, that's 40A max.

 

[serious_sam]

Here the cell monitoring page.
...
Same shunt is used for charge and discharge ?

Cells look well balanced.

Yes, same shunt for in and out.

Temp is 6.9c. Cold at your place!

 

[qwerkus]

Here the cell monitoring page.
...
Same shunt is used for charge and discharge ?

Cells look well balanced.

Yes, same shunt for in and out.

Temp is 6.9c. Cold at your place!

Yes, still winter. Pack was in the garage overnight and takes quite some time for 5kg to warm up. So I see 2 tests to do:

1. charge current test: compare serial dmm value with bms value to calibrate shunt. need the pc for that as i don't have the bt dongle.
2. cell under voltage test: plug battery to a load (somewhere) and check each individual parallel group - see if one drops too much.

 

[serious_sam]

So I see 2 tests to do

Also:
3. Bypass the BMS completely, just to be 100% certain that it is the BMS causing problems.
4. Change the limits to far outside normal parameters (for example, cell ovp=4.4v, uvp=2.0v etc), and try and figure out if/which one of the limits is being tripped.