Enginer PHEV automatic over/under voltage protection

Was going to ask the same thing. The lock-washer is clearly not compressed fully.

 

For those of you that are using the CellLog you might want to make sure that you have a 1A-2A fuse on the battery end of the CellLog wires. I just finished watching the latest Jack Rickard Friday show and his CellLog shorted and burned some wires. The simple solution is to put fuses on the battery end of the wires. Of course Jack Rickard suggests just not to use the CellLog at all since its really not needed.

Just thought I would let everyone know because I dont want to see on the news that another PHEV Prius burned to the ground.

 

I was concerned about that as well. Technically you need a fuse on each wire to the battery; but that is asking too much. I convinced myself that the wire is so small, effectively a fuse. Since the cellog draws very little current, I could use even lower wire gage and preferably teflon insulation.

 

He is not using a BMS. He just charges to a set voltage and he never lets the batteries discharge below a certain point. He uses an MetricMind E-Vision instrument that lets him see the amp hours in and out of the battery. He also watches that as a fuel gauge.

He also has his battery pack split in half and has an LED array that tells him if the pack is out of balance. Dont ask me how it works because I'm not to sure. I just know that if the light stays in the center of the array the pack is balanced. If the light goes to the left or the right from the middle the pack is out of balance or there is a bad cell in one half of the pack.

 

Jack Rickard showed the wire and it was bare. He said it was glowing red when he popped the hood. The wire wont act like a fuse but more like a heater and fire starter. I suggest using fuses. Their cheap and should be easy to install.

The CellLog does draw very little current but if two wire short you basically shorted the battery. Try putting the same gauge wire across the terminals on just one of those batteries. That wire will go up in smoke in no time and will be a fire hazard. It wont burn its self out quickly like a fuse will.

 

What is he using for cell overvoltage protection? Does the LED array switch off the charger when it is out of balance due to a high volt cell or a low volt cell?

 

I just bought two of the same one on Ebay. Has USB connection.

See link.

Cell Voltage Monitor & Logger 2

Specifications:

1. Small size with multiple functions, backlight 128*64 lattices LCD and Buzzer Tone Reminder;
the interface can be operated smoothly.
2. CellLog 8S can not only measure 2-8S Li battery individual voltage,
but also measure NiMH, NiCd, Pb battery pack voltage.
It can be set Individual Voltage Alarm and Pack Voltage Alarm, Overvoltage Alarm,
Low Voltage Alarm, Differential Voltage Alarm and Time Over Alarm. What’s more,
the extra alarm output can be linkage controlled by the users.
3. It has 8 sets default monitor alarm settings, which can be selected for different battery packs.
4. CellLog 8S has been 100% calibrated before it enters to the market, at the same time,
it supports the calibration by users themselves.
5. CellLog 8S has a 16Mbit flash storage, which can log offline data in 36 hours.
6. Support upgrading the hardware program by USB port. The CellLog 8S also supports the “logview”
software and can display, plot and analyze the charge and discharge data by it.

 

Hi John,
I use CellLogs on several of my older Enginer systems. One of those systems has been running for almost a year with no balancers.

So You need to know some of the problems.
1. The CellLogs are for 8 cells. You need to label them lower and upper. Then you will have L1-8=1-8 and U1-8=9-16. you will have two data files instead of one. I copy the data from those two files into one combined file so that I can chart all 16 cells on one chart.
2. The CellLogs as shipped do not draw power evenly from all cells. They will leave cells cells 7 and 8 high and cause your system to go out of balance unless you mod them with a jumper inside each one.
3. After the mod they will not come alive from the USB cable. Then you must take your computer out to the car to download the data.
4. The ground for the USB is the negative terminal of Cell#1 so the ground for the two CellLogs is 24v apart. Never plug in 2 USB cables at the same time or you will fry something. Black smoke leaking out is not good.

Thanks,
Dan

 

Hi Dan,

I found out about the last two cells not drawing power by adding a six volt battery across each cell pair connections, one at a time. I did not know that you could do a jumper modification inside the Cell logger so it would draw even power from all cell connections.

Thanks for the tip,

John

 

Hi Dan,

I found instructions on a ebike forum about the modification. I have applied 8 volts DC between pin -1 and +(7 or 8) to verify it works. It all went according to plan.

Thanks,

John

 

I have some that I have been able to bring back from the dead. Others are way too far gone. Any time I am not using the kit for a while I disconnect the batteries from the rest of the system. This keeps the draining to a minimum.

 

Can you share how you test for capacity?
I'm sure others may want to test their cells at some time.