bluetooth BMS?

Batteries, Chargers, and Battery Management Systems.
aethyr
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bluetooth BMS?

Post by aethyr » Jun 02, 2017 12:57 pm

Has anybody used a BMS like this: https://www.aliexpress.com/item/20S-50A ... 39362.html?

Its bluetooth enabled with an android app so you can configure everything in software, as well as monitor pack voltages.

I think I'm going to order it and try it out, but I'm curious if anyone else has seen/used a BMS like this. The only problem is that 50A is below my needs, so I'll use this just for charging. This should be fine, since my controller has LVC and I can actually monitor individual cell voltages from the phone app.

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Re: bluetooth BMS?

Post by maanebedotten » Jun 02, 2017 1:51 pm

Just remember that you have no short circuit protection if you bypass the bms for discharge.

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Re: bluetooth BMS?

Post by rojitor » Jun 02, 2017 2:04 pm

Smart bms. They are the future.
https://www.speedict.com/ This brand has been long discussed here.

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Re: bluetooth BMS?

Post by mattjrogers » Jun 03, 2017 6:06 am

I have one of these BMS units. Just installed it a week ago and working through its functionality.

I alway hate when a board has conflicting markings - such as a separate place to solder P- and C-, but they tell you to put both wires on the C- tab. Why?

I use that same phone APP and it occasionally cuts out and I have to re-connect the bluetooth, but it does not lose any data in that case. The BMS must have on board memory because it saves the number of cycles the battery has seen, fault data, and capacity info. The app asks for a lot of permissions, but it uses GPS location data to calculate your speed and distance so it can take a guess at the remaining distance your battery can go. You can pull up individual battery cell voltages in use to see voltage sag at max power and other info. It has a cool lock feature where one tap on the screen on the Lock icon turns off the output power. Nice for when you just run into a store and don't want anyone accidentally hitting your throttle. But I can imagine that you lock the BMS and then your phone dies and now you can't get it unlocked until you charge your phone. Guess I need to finish hooking up my USB port on my battery!

I have not loaded up the computer software, but it looks more powerful than the cell phone APP. You can change a lot form the phone and could save yourself by having a higher LVC and then if you really need, you can change it on the fly to a lower value to limp home. For my LiFePo4, the LVC is 2.7v. I would like it to be a little higher, but in reality it will only be at 2.7v under sag and the resting voltage will be higher. Balancing may or may not work well. I don't see any current flowing when it reaches its cell overvoltage cutoff. My charger is a standard no-name charger, but I do see 1 amp of current on other packs and BMSs when it is in balancing mode at top of charge. I can't feel any hot resistors, but they are under an AL cover plate and are small 50ma ones, so they may be working. My pack is a large 48v 45AH, so I don't expect balancing miracles. It does have a setting where I can tell it to turn on balancing at a specific voltage. I set it at a low 3.4v and when the first cells hit that voltage, a Chinese character appears next to them, so perhaps that cell resistor is turned on and reducing the current from that point until the first cell hits HVC.

Overall I really like its functions and being able to check individual cell voltages while riding really makes it a cool piece of tech. I just have to figure out how to wrap everything up so that I still get bluetooth signal but have a waterproof and protected pack. Any ideas? Also, how would you mount a USB port on a battery so that it is waterproof? I was thinking to just put the USB circuit board in with the battery and have a micro-usb cord already plugged in. Then I can run just the cord out through a waterproof grommet/caulked hole in the pack. Do they make a waterproof cover for the end of a micro-usb cable?

This is very early morning with a 1 year old, so it may not be written well, but I will update if I have any issues.

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Re: bluetooth BMS?

Post by cwah » Jun 03, 2017 6:51 am

Bluetooth bms is the way to go for cells safety
Help me find my stolen electric brompton: http://bit.ly/1a0vbBC and Bosch Sinus B3 http://bit.ly/1eV0WQz

mattjrogers
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Re: bluetooth BMS?

Post by mattjrogers » Jun 03, 2017 6:59 am

Ok, so I got the computer software up and running and it is really nice. I had no issues installing or communicating.

A few interesting features

There is a calibration function that lets you calibrate individual cell voltages and charge and discharge current. This could be useful for someone in testing.

The software even let me set the maximum discharge current above the recommended maximum. I got a 50A version, but it let me set it at 60A. Not that that may be prudent, but it is possible by software. The seller I got mine from has these in capacities up to 150A. Now I wish I got at least an 80A so I can add a mid-drive kit to my front hub cargo bike and have a dual drive. The front hub draws just over 30A and a BBSHD would draw another 30 right? I could always set the hub motor to draw only 20A.

I also could set the LVC and HVC to any value, unlike the cell APP. So this looks like it should work great for those Lipo guys wanting a BMS to charge to 4.1v.

Feel free to ask me to test something and I will try. I am not an electronics wiz, but I'll do my best, especially if you describe what you are looking for and try to limit it to things where I will not fry my BMS.

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Inwo
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Re: bluetooth BMS?

Post by Inwo » Jun 03, 2017 10:34 am

lto-bms1.gif
lto-bms1.gif (233.05 KiB) Viewed 2389 times
I've been using the 10s to 15s 30amp version. Getting the information to reset cell count was like pulling teeth.
There is also a 150a and 300a up to 32s. Optional lcd remote display. All settings can be changed from bt. Even down to LTO 1.5v to 2.75v.

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Re: bluetooth BMS?

Post by kocetoMR » Jun 03, 2017 2:12 pm

bms.jpg
BMS-panasonic
(193.63 KiB) Downloaded 28 times
http://www.smart-bms.com/English/Produc ... ent%20BMS/

banjaxxed
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Re: bluetooth BMS?

Post by banjaxxed » Jun 03, 2017 2:19 pm


mark.curry3
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Re: bluetooth BMS?

Post by mark.curry3 » Jun 03, 2017 5:09 pm

I just hooked up a Bluetooth BMS and it shows 30 cells when there should be 20. I checked all of my connections and they look right. I'll be hooking it up to my computer to see if it's any different than what's broadcast.

on another note is it possible a BMS could cause one cell to charge lower than the rest of the cells

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Inwo
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Re: bluetooth BMS?

Post by Inwo » Jun 03, 2017 9:36 pm

You can only change cell count in computer sw. Not with bt. At least for my cheap ones.

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Re: bluetooth BMS?

Post by mark.curry3 » Jun 03, 2017 9:38 pm

Thanks. I will give it a shot

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Inwo
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Re: bluetooth BMS?

Post by Inwo » Jun 04, 2017 10:21 am

14s bt cell count.png
14s bt cell count.png (76.84 KiB) Viewed 409 times

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methods
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Re: bluetooth BMS?

Post by methods » Jun 04, 2017 4:53 pm

????
"One test is worth a thousand opinions"

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crossbreak
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Re: bluetooth BMS?

Post by crossbreak » Jun 07, 2017 7:10 am

Any Info on what ICs where used? What is that microchip in the upper right corner?
Attachments
lto-bms1.gif

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Inwo
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Re: bluetooth BMS?

Post by Inwo » Jun 07, 2017 8:50 am

I'll let you know. I've done some repairs on these and I think chips are marked.
What are you plans?
Be glad to do any testing within my capability to help out. I have a couple extra of these and the 15s smart bms.

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Inwo
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Re: bluetooth BMS?

Post by Inwo » Jun 07, 2017 9:08 am

Can't seem to get a clear picture.

It's a STM8L151
MVC-010F.JPG
MVC-010F.JPG (103.13 KiB) Viewed 2175 times

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methods
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Re: bluetooth BMS?

Post by methods » Jun 08, 2017 1:46 am

Damn that thing looks simple....

Where does the smoke usually come out?

-methods
"One test is worth a thousand opinions"

vipster76
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Re: bluetooth BMS?

Post by vipster76 » Jun 08, 2017 6:09 am

where can i get one posted to the uk 8)

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Inwo
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Re: bluetooth BMS?

Post by Inwo » Jun 08, 2017 11:31 am

The one with lcd display?

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Re: bluetooth BMS?

Post by keyne » Jul 02, 2017 5:12 am

Yeah, where did you get the one with the LCD display from?

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Inwo
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Re: bluetooth BMS?

Post by Inwo » Jul 02, 2017 8:43 am

From alibaba. Looking for a link. Only find my emails.
Seems they were about $150- $300.
I got a few of them before hooking up with Chargery.
All functions can be set. Not just to defaults for battery type. Anything from aboutn1.5v to 5v.

aethyr
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Re: bluetooth BMS?

Post by aethyr » Jul 06, 2017 1:40 pm

Update, I received the bluetooth BMS and wired it up just for charging. Bluetooth works great. Here are some screenshots from my phone:

This is the dashboard page:
Image

Overview page: There are 4 short temperature probes. Realistically only 2 or so are useful because a 20s pack is going to be larger than the temp probe wires can reach.
Image

Individual balance voltages: These update in real time during charge/discharge. My pack is 20s, the display scrolls so you can see the rest.
Image

Parameter settings: I'm not entire sure what all of these settings are for, but the seller is very responsive to questions. You can set the final end voltage if you want to charge to 4.1 or less for increased pack longevity, and various other settings, such as when to start balancing, etc.
Image

All in all, I'm quite happy with this BMS. It charges well and provides me with the monitoring features I need, as well as setting parameters, all from my phone. There is a "lock" feature, but I haven't felt the need to use it since the chances of someone nearby with this BMS/app is very slim. The phone app is android only, however, no iphone. They do have a PC app (again no mac/apple), which has more features, such as the ability to calibrate balance voltages, but its also heavily peppered with Chinese characters, and I haven't felt the need to use it. The BMS comes with 2 communication modules - a bluetooth module and serial module (for PC link). You can only use one or the other since there is only 1 comm port on the BMS, which the communication module plugs into.

The BMS is always "on" - the balance wires power it, so it does draw some small current. According to the seller, it draws 200uA during sleep mode and 20mA when active/communicating via bluetooth.

Steu851
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Re: bluetooth BMS?

Post by Steu851 » Jul 06, 2017 2:58 pm

It looks like you have a better translated app than mine. I have some parameters in chinese. Do you have a link where download the app? Thanks

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Re: bluetooth BMS?

Post by vipster76 » Jul 06, 2017 6:29 pm

where did you buy the bms from :) i wouldnt mind getting my hands on one!

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