AESC / LEAF Battery Modules Voltage Check

Here is a voltage check of each half module of my 3 module pack after 3 months of charge + discharge: they are still all in balance, here at the bottom at 3.59V

AESC / LEAF Battery Modules Voltage Check

After a little month of charging and discharging these 3 AESC modules wires in series, the half modules - and modules too - are perfectly in balance ...  No BMS required at all ... Like for LiFePO4 ...

Making a Charge Controller for the LEAF Battery Modules

During this week I stared building a Charge Controller for my AESC / LEAF Battery Modules
I have had this idea since last summer: build a simple, effective and safe Charge Controller for LiFePO4 cells, which is in fact a sub-system of my DIY ESS, taking care of the Battery pack charge and discharge functionality

Since the AESC Modules behave like LiFePO4, except for the voltage limits, this kind of controller ill work fine

It is composed of a Programmable Dual Relay Voltmeter, and 2 Tyco Kilovac Contactors, wires, and that's pretty much it !

I even had to read again the DIY ESS Kit documentation to see the wiring of the Voltmeter


and go through their manual to set up some additional values like the decimal point here



and I decided to set up the low voltage limit to : 3.6V x 6 half modules = 21.6V
and the high voltage limit to : 4.15V x 6 half modules = 24.9V (slightly under charge is always safer, since 4.2V is the target voltage on these Lithium Manganese cells)


Higher limit reached => the upper LED is lit and the high relay is open, which will open remove the power from the Charge Tyco Kilovac and stop the Charge .... so simple and effective


Tyco Kilovac not wired yet, but will be done later


and it should stay open until the value I entred is reached, I think it is 23.5V

DIY ESS - One Year After Voltage Check

I have been using these 8 CALB CA180FI LiFePO4 cells over the last year with No BMS and they are still perfectly in balance ! They have been Bottom Balanced once and slightly under charged. Nothing more :-)

http://www.diyesskit.com




Special thanks to Clement for filming his dad's stuff 

DIY ESS - LiFePO4 CALB CA180FI Voltage Check

As I was moving my ESS upstairs one month ago,  and split the CALB CA180FI battery pack in pairs, I shot another small video doing a cell voltage check, and as usual, they are all in balance ...



The ESS battery pack is now charged and discharged fully in winter, using the low cost electricity provided by our energy provider TOU - Time Of Use - to charge, and discharging into our home grid during peak hours, mostly for heating, cooking and lighting

Another LiFePO4 Cells Voltage Check, 6 months

After 6 months of charging and discharging almost everyday my ESS, the CALB CA180FI cells are still perfectly in balance, without any BMS ... Check out the video that prooves it, as usual ...

LiFePO4 ESS - CALB Cells Voltage Check

Here is another video of me going through the 8 CALB CA180FI cells to check their individual voltage, and it is exactly the same at 3.25V, while the ESS is on

So: no BMS, just a Bottom Balancing done once in february when I got the cells and a pack voltage kept between 3V and 3.55V times the number of cells; Now, after 4 months of use, they are still perfectly in balance at the same voltage

Watching the LiFePO4 DIY ESS Charge all day at home, from work, and back home

When my LiFePO4 DIY ESS battery pack is depleted, at 24V, the programmable voltmeter's low limit relay opens, the contactor opens, and the Grid Tie Inverter mode is shut off (low red led ON); This is what happended here

Immediately, the pack voltage goes back up and settles down around 25.4V

Now in the morning, for testing purposes, I siwthed the ESS to Forced Charge Mode, and all the chargers then are charging the battery pack

Since I can not stay all day next to it, I usually leave Karotz watch it for me and take a look remotely from time to time while away from home

08:20

At work 

10:07

11:31

16:34

it then continues and goes up pretty quickly after 27.5V to 28V where the upper limit voltage is reached and the programmable voltmeter opens its other relay, opening the charger side contactor, and terminating the charge completely

and the total Enegry used to charge fully the pack is 5kWh

Measuring my last Mottcell LiFePO4 cells

As I already wrote few weeks ago, I made a 3 LiFePO4 cells pack with them, bottom balanced them, charged, and discharged them few times by plugging in an iPhone / iPad 12V charger, which downstages voltage to 5V anyways (so it does not have to be 12V really to work, it could be 2 cells actually)

Few days ago, around diner time, I checked the voltage of each cell, because it had been more than two weeks and we had been charging our iDevices on this mostly

You can see here the benefits of bottom balancing the cells before the first pack charge: we are reaching the lower limits of the cells and they are still in balance, coming down together:

Voltage measured still under load (iPhone is plugged in as you can see)

Cell 1 = 2.94V

Cell 2 = 2.93V

Cell 3 = 2.92V

Pack  = 8.80V

=> So, no problem, and after reffilling my iPhone fully, it will be time to recharge the pack