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LTO Battery Monitor
#1
Hi Everyone,

So I just picked up a SCiB Battery (1.1Kwh) for my Old Man's Camper.   These are LTO Cells so I will be breaking up the 24 cells into 6s4p setup.    Each Cell is 20Ah so the Pack will be 12V (ish) @ 80Ah 

What I am looking for is something small but nice looking to just View the 6 cells and battery voltage like I have with my Cellog 8 Meter    

That can handle each cell getting down below 1V per cell and max of 2.8V     Anyone got Idea's?
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#2
Have a look at the actual charge / storage characteristics of the cells, you will find you will likely not go below 2V and neither above 2.7V. This might simplify your choice a bit as sub 1V there are very very few BMS units...

This is a the lower end of a chart for 40Ah LTO cells... Volts left axis, cumulative discharge Wh along the bottom axis.


If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#3
Oh Quite Right. Just more of a Max min thing. And I was doing some more digging and my callog8 I think can adjust the min and max voltages for the alarm. so I'm going to try that. The Pack is supposed to be here Friday and then I have to disassemble it to reconfigure for 12V But should be fun as for BMS I am thinking of just getting one of the LTO specific Ones https://www.aliexpress.com/item/Bluetoot...a1d3133988
completelycharged likes this post
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#4
That unit looks interesting, although I notice it's in a metal case and other than the battery leads no other connectors so the range on bluetooth might be very limited as the signal can't get out the case other than the two small battery lead slots ?

Balancing current for an active balancer does not need to be above 1A, unless your pack is massive. 1A I worked out will be more than enough for my 36kWh pack....

I need to get a BMS unit sorted out, been running for a year without one and now that the pack is getting higher current loads (>100A @ 48V) the battery IR differences will start to have more of an impact on balancing - i.e. they will no longer self balance under the low currents they have seen upto now. In a year i have not had to pull any individual parallel set of cells up or down, maybe a reasonably even set of cells or just the chemistry....


Your pack will be very interesting to see..
jdeadman likes this post
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#5
Have me thinking....

Just noticed there are a few versions of that board and the case has a small hole in the side... the link you had has one of the capacitors missing on the right hand side of the board. Another version of the board :
https://www.aliexpress.com/item/1pcs-Hig...92013.html
Claims to be an updated version with the three capacitors in place and a different isolated supply arrangement in the top left.

https://www.aliexpress.com/item/eBike-Bl...73206.html
This one is using relays instead of FET's, which I may go for. Uses more power due to the relays but I had a bad experience with a different board. The failure mode was to systematically blow FET's as it thought each battery was "charged" and a failed FET shorted to the common bus..
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#6
HMM Interesting. Yea I'm still looking into these as this pack will not be always in my control so I want it to be safe and easy as possible
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#7
(04-04-2019, 12:22 AM)jdeadman Wrote: Oh Quite Right.  Just more of a Max min thing.   And I was doing some more digging and my callog8 I think can adjust the min and max voltages for the alarm.  so I'm going to try that.   The Pack is supposed to be here Friday and then I have to disassemble it to reconfigure for 12V    But should be fun  as for BMS  I am thinking of just getting one of the LTO specific Ones   https://www.aliexpress.com/item/Bluetoot...a1d3133988

I have just received the bigger brother this morning https://www.aliexpress.com/item/2A-Activ...78902.html

I plan to install it over the weekend on our 22s8p 30AH LTO pack and can report back.

We currently have this unit https://www.aliexpress.com/item/Free-shi...69857.html installed but it is basically useless for anything other than montirong on a pack of this size.

I have also ordered some basic 5 x 1s and 1 x 5s equalisers for 5s2p packs that do not require detailed monitoring and reporting:
https://www.aliexpress.com/item/1S-Lithi...53619.html
https://www.aliexpress.com/item/5S-Lithi...30720.html
jdeadman likes this post
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#8
(04-05-2019, 03:06 AM)BaronVonChickenPants Wrote:
(04-04-2019, 12:22 AM)jdeadman Wrote: Oh Quite Right.  Just more of a Max min thing.   And I was doing some more digging and my callog8 I think can adjust the min and max voltages for the alarm.  so I'm going to try that.   The Pack is supposed to be here Friday and then I have to disassemble it to reconfigure for 12V    But should be fun  as for BMS  I am thinking of just getting one of the LTO specific Ones   https://www.aliexpress.com/item/Bluetoot...a1d3133988

I have just received the bigger brother this morning https://www.aliexpress.com/item/2A-Activ...78902.html

I plan to install it over the weekend on our 22s8p 30AH LTO pack and can report back.

We currently have this unit https://www.aliexpress.com/item/Free-shi...69857.html installed but it is basically useless for anything other than montirong on a pack of this size.

I have also ordered some basic 5 x 1s and 1 x 5s equalisers for 5s2p packs that do not require detailed monitoring and reporting:
https://www.aliexpress.com/item/1S-Lithi...53619.html
https://www.aliexpress.com/item/5S-Lithi...30720.html
Hello

 I have been using the Delgreen units for over a year and did not have any fail out of 11 6s units. Going by how the some of
the questionably of the Chinese parts , I went for the higher amp units. the lower amp units heat up, these ones haven't
got much above room temperature .  If working, Hot is bad - warm ok - room temp perfect , for longest operating life .

With the one set I monitored for two weeks I use a led volt meter on it 24rs a day. The pack was 40ah 6s set. Once equalized
the volt drop was .01 volts a day. The volt drop was primarily the use of the 3 leds on 24/7
jdeadman likes this post
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#9
Thanks for the info. I just received the Battery and since the cells are glued together I have more work to reconfigure into 6s4p pack
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#10
The unit you have listed from AliExpress won't work with a 6s pack, it requires at least 40V to power up.

It does mention it towards the end of the listing but it is not very clear "Power Supply 40-100v"

In the manual it directs you to use an external power supply of your battery pack does not total more than 40V.
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