LLT SmartBMS questions

[frame]

I suggest u check p5, 11,14 and 15. It’s not normal when bms reporting them higher than rest, but it goes back down that fastand in line with the rest when charger is off

[GnomeMeansNo]

Hmm I ran the pack down to 25% but llt still reports 100%.

[me_ashman]

I manually set my voltage percentages and that fixed the 100% charge always showing

[tech.shit]

If your BMS isn’t wired into the discharge the reported percentage will almost always be incorrect unless charging, at least in my experience with a half dozen LLTs

[fessyfoo]

lil cross linking

@vegr0

Cant get an answer from LLT. i got their 10-17s bms. first time using it and i can’t get the settings to write anything other than 13s… You can see the extra cell group. its a 12s pack.

I followed the harness wiring correctly, stopping after the first 13 wires.
Any idea?

@ShutterShock

You did not follow the diagrams, you have to solder together a number of the leads to make it 12s. You should be able to get the diagram from the product page in a pdf

@vegr0

yea thats the issue, There is no diagram for this unit.

https://www.lithiumbatterypcb.com/product/little-size-36v-48v-60v-li-ion-or-lifepo4-smart-bluetooth-bms-with-40a-60a-80a-constant-current-for-10s-to-17s-battery/

Normally the first black wire is for battery -

then the first white wire hits the positive of battery -

then each wire hits the next positive terminal of every group. - I used a total of 13 wires for this 12 pack.

Which part did i mess up for this unit as it obviously isn’t wired the same as their standard 12s bms.

edit - i see now theres a text link hidden on the page that shows the diagram…

@ShutterShock

There is a diagram for it, you just posted it

It doesn’t have a 12s one, but it’s a reasonable assumption since all the others are like this, to think that 12 should be the last connection on the end (17)

Then 11 should combine 16, 15, 14, 13, 12, 11.

@glyphiks

It does have a 12s one

Search terms LLT diagram 10-17s bms wiring

[fessyfoo]

Troubleshooting “fluctuating balance readings”

LLT BMS cell values fluctuating

Hey everyone, I’m mid way through swapping an original Lacroix nazare over to 18s using the internals I bought second hand from someone parting a supersport. The battery is in, powers up without issue, but the BMS is constantly fluctuating the voltage on a few cells from 1-2V up to 6V. Anyone seen something similar or have any ideas? [Screenshot_20231105_165857_XiaoXiangElectric] [Screenshot_20231105_165903_XiaoXiangElectric] [Screenshot_20231105_165907_XiaoXiangElectric] [20231105_171049] …

[fessyfoo]

reference

@AlexB

Hi all, finished building my 18s6p P45B pack and did my BMS wiring yesterday. I am using a JBD SP22S003 BMS and everything seemingly went fine except for my final readout. The diagram shows leads BC16-17-18-19-20 as getting combined, however on my connector there is no lead for where BC20 would be - it skips and has the last 2 leads. I combined the 4 wires 16-19 and finished it off per the diagram, however I am getting an odd readout on the Xiaoxang app. Not sure if I should add a lead where there is one missing, and add it to the other combined leads? Even though the BMS model number is SP22, it’s listed as a 21S BMS (and the missing wire would confirm that also).

Any thoughts? Thanks in advance and happy holidays all.

@Skyart

What i normally do is remove the black plastic cover on the back of the BMS and solder those pins together at that location.

@AlexB

I just ran all 4 leads to the 16th P group since it wasn’t a long run. Do you have any idea what might be up with the funky reading? I haven’t used this BMS in particular before, only the 10-17S one before.

@Skyart

The weird reading comes from the missing lead messing up the way the BMS reads voltage. You could just solder that one to the reatbof the group, but i recomend soldering all of them together at the back of the BMS and removing all but one of those leads that go to your group 16.

After that you should be able to plug everything in and it will read lile it should. If it doesnt you will need to go into the settings menu and charge the BMS from 21s to 18s

@AlexB

Thanks, ended up jumping them on the back of the BMS and all is reading well now Now need to ride it!

[fessyfoo]

@glyphiks

JBD is the manufacturer. LLT is a reseller. They are the same bms.

[fessyfoo]

LLT (JBD) appear to sell different BMS for LifePo4 vs Lion.

do you think these are the same hardware with differnt software configs? Could I reconfigure a LION BMS I have for LIfePo4 ?

[cherryflavouredpez]

I find making a ‘dummy’ change, eg turn balance while charging only on, then off again updates the static battery percentage to the correct value. But it doesn’t update after, so becomes wrong again .Wondering if it’s limitation of the app?

[hatman]

Yes. U do it in the app

[Jagden]

Does this BMS , specifically this one has some sort of on/off button / circuit ? Or is it always on connected to the battery.
Do I need to control on it via dedicated button on my enclosure or I can be satisfied with my VESC on/off switch and that’s it ?

[AlexB]

It’s always on & transmitting bluetooth signal.

[Jagden]

Doesn’t this kill the battery ?

[glyphiks]

No.

And you wouldn’t want your board set up to discharge through the bms anyway.

Relying on the vesc switch is safer than using a switching bms.

If you must discharge through the bms, you’ll likely want one rated to a lot higher discharge current than you linked.

Most of the JBD bms have an e-switch where you can turn discharge on or off through a button on the app. A lot of them used to have a physical switch capability, i’m unsure if that’s still the case.

[fessyfoo]

@Jagden

Doesn’t this kill the battery ?

yes over a very long period of time. Depending on size of battery. 6 months to 2 years kinda time. Some versions may do better. But if storing a small battery for a long time. Best to check on it. Better to use it and not store it.

[tech.shit]

So I’m unable to turn my discharge onf, using a combined port llt.

Discharge is on when charging though, it’s hooked up to a light.

Any idea how I should fix it? It worked last week.

Edit: fixed it’s self in a day idk how

[blaz.ferlic]

Did anybody try this BMS? https://www.aliexpress.com/item/1005006347440227.html?fbclid=IwY2xjawEZyHNleHRuA2FlbQIxMAABHVpAfuZmA5m6I3IbITgh6r2YExkehx5dBaMP_NGSt1zONRTjpHJ4OtW9Ww_aem_Qhx5B8bwTgJk8jdXjy6DzQ

[AlexB]

Yes, lots of people running these JBD BMS’ (myself included). Built in Bluetooth and smaller footprint makes them the preferred option.

[massy]

Actually ordered one of these for the size as my big one (also JBD) was at risk not fitting. It was even smaller than I expected. BT built in which means I can probably connect the UART elsewhere. Happily surprised it was even smaller than I thought.

But I haven’t been able to test it yet. I trust it as long as it’s from the same brand (JBD) as people have been using for years.