Cell-Log external alarm/warning

mistercrash

10 kW
Joined
Mar 9, 2011
Messages
972
Location
Guelph, Ontario, Canada eh!
I searched and found nothing on how to have an external alarm connected to a Cell-Log, or a warning light coming on as a warning of under voltage or vice versa. I found this on the net and tried it but I could not make it work for some reason. Can someone explain if it can be done and how please. Or direct me to a thread that does since I could not find it.

Thanks
Ray

tumblr_mwj48kOF6u1qa2swjo1_1280.gif
 
They don't cope very well in an electrically noisy environment - lots of false alarms.
 
Voltage checker from Hobbyking is rather not reliable ,I have 2 of them ,
Irratic readings changing I would not trust it at all
Cheap toy.
 
have you plug in one of those PC mother 2 pin speaker into the alarm port? Maybe they are loud enough for you to hear?
Or depending on how many you need you can mount the Cell log up front and run a cable to the battery so you can see the cells?
I bought a 12 conductor wire for like 4$ 50" long so I can mount 2 cell log in the front of my trike along the boom.
 
Having the Cell-Logs out in the open would not work well for me sadly, I ride no matter what the weather, even when it snows. The Cell-Logs are not water proof so I have to install them with the battery underneath the seat where they will stay dry. That would be why I want to install a louder alarm that I will be able to hear. I read about a couple that did it but they did not share how they did it. I would like to know and I'm guessing maybe a few others could use this information.
 
What about a BMS? Takes care of ODDV (over discharge detection voltage) per cell basis.

If you don’t like the idea of power interruption it seems feasible to wire a smaller, cheaper BMS in to merely control some type of warning system.
 
these work great, but remember to reblanace your pack every so often as when you leave these plugged in for a long period of time there is a slow drain of one or two of the cells even though it may be plugged into a 8s pack per say

-steveo
 
I looked for BMSs, good ones. I recently overhauled my ride, bought Leaf modules, a Kelly SIN controller and a 5kw hub motor. 2/0 awg power wires, 4 awg phase wires. All brand new. So I don't really want a cheap BMS. But the really good ones are insanely expensive. Between a cheap BMS and me being the BMS, I choose me. With the help of Cell-Logs to tell me to ease on the throttle until I get home, I will be good to go for a long time. Bulk charge all week, balance charge on the weekend to see what's happening. But with the power of the Leaf modules, I don't expect to hear the alarm ever, it's just a precaution in case a cell starts going bad.

Found an old thread about a louder alarm for the Cell-Log 8. One guy even connected his Cell-Log to a smoke detector. Can't get much louder than that. lol [strike]The problem for me is the two thin black wires going in the Cell-Log in the pics. What are they for?[/strike] Disregard, I just figured out what he did... Because he explained it. '' I wanted to be able to use this on all my packs, so instead of tapping into the Positive and Negative leads out of the battery pack, I opened up the CellLog and tapped into pins 1 which is Negative and pin 9 which is Positive. That way I can now plug this alarm unit into the balance lead coming from the pack, while the bulk charger is plugged into the bulk charger connector. ''

https://endless-sphere.com/forums/viewtopic.php?f=14&t=19955
 
You can use a Cell-Log as a BMS, and the imbalance problem is fixed by using the op-amp mod I posted ages ago. I based a BMS system on them ages ago (APBMS) - its been on a pair of LIPO batteries that have never needed balancing.

Biggest problem is finding stock - so frustrating when you need 5 of them and none available!
 
Heathyoung I looked up your APBMS and your modified Cell-Logs. It looks interesting and would be so much more interesting if I had the slightest idea of what you were talking about in those threads :D Thanks for confirming Cell-Logs are a viable option to monitor my cells. It won't be as sophisticated an elegant as what you made but it will work. I hope.
 
I need help. I am trying to make an external alarm for my Cell-Logs following the plan I linked in the post above. This schematic.

schematic.jpg


I got the first one done but something is wrong. The Piezo buzzer I have is making noise when it is supposed to but it's a faint kinda ''whirrrrrrrrr'' instead of the 94dB it is suppose to do. Can somebody please tell me if I bought the correct components. Sorry for all the links and thank you.

Piezo buzzer
https://www.digikey.ca/product-search/en?keywords=458-1209-nd

optoisolator
https://www.digikey.ca/product-search/en?keywords=751-1271-5-nd

resistor
https://www.digikey.ca/product-search/en?keywords=cf14jt4k70ct-nd

fuse
https://www.digikey.ca/product-search/en?keywords=f4655-nd

No need to link the fuse holder or the project board.
 
The opto coupler and mechanical relay are both doing essentially the same thing. It should work with the mechanical relay as shown in the first post if you use the right relay. It's also fair game to tap the pack midway to supply a lower voltage to the relay coil. The relay needs to operate with a fairly low current.
 
mistercrash said:
Anyone? No one in here knows how to have an external alarm go off when the Cell-Log detects A low or high cell?

The 4.7KΩ resistor limits input current to the opto to about 5mA. Spec sheet says 60mA. Perhaps the opto isn't turning on fully. Try a lower R to get 60mA.
 
major said:
The 4.7KΩ resistor limits input current to the opto to about 5mA. Spec sheet says 60mA. Perhaps the opto isn't turning on fully. Try a lower R to get 60mA.

I was told the same thing by someone else in another forum. Since I will be plugging these Cell-Logs on 5S packs, I ordered some 2k resistors and I will try those.
 
mistercrash said:
major said:
The 4.7KΩ resistor limits input current to the opto to about 5mA. Spec sheet says 60mA. Perhaps the opto isn't turning on fully. Try a lower R to get 60mA.

I was told the same thing by someone else in another forum. Since I will be plugging these Cell-Logs on 5S packs, I ordered some 2k resistors and I will try those.

A 2K resistor may not be enough. If you can hook up a test circuit to the opto input which will vary the current, test and determine the minimum current needed to fully turn on the output and buzzer. Then with the pack voltage at LVC, you can calculate the value for the resistor.
 
fechter said:
The opto coupler and mechanical relay are both doing essentially the same thing. It should work with the mechanical relay as shown in the first post if you use the right relay.

Do you know which relay? I don't know how to figure out which one to get.

major said:
A 2K resistor may not be enough. If you can hook up a test circuit to the opto input which will vary the current, test and determine the minimum current needed to fully turn on the output and buzzer. Then with the pack voltage at LVC, you can calculate the value for the resistor.

You're right, the 2k resistor did not work. As for the rest of what you said, I know where the input of the opto is, I don't know how to do the rest of what you said.

Thank you for trying but I have spent enough money and wasted enough of my time trying to figure this out. Until someone can show me a video of their Cell-Log 8M with external alarm actually working, followed by detailed instructions on how to put the system together and a materials lists with part numbers so I can find the exact parts needed on Digikey or Mouser, I will assume that Cell-Logs 8M with external alarms do not exist. Without a video, it never happened. :lol:
Plus the OP of the old thread I found in here was using Cell-Log 8Ss which is very different from my 8Ms.

Thanks guys
Ray
 
mistercrash said:
You're right, the 2k resistor did not work. As for the rest of what you said, I know where the input of the opto is, I don't know how to do the rest of what you said.

Hi Ray,

O.K. You must have had to buy more than just one 2KΩ resistor. So give it one more try. Twist 5 of the 2KΩ resistors together at both ends. This makes 5 resistors in parallel for an equivalent 400 Ω which would yield about 60 mA to the input of the opto. Just treat the bundle of 5 like a single resistor in your circuit. If that doesn't work, you have more problems than I can see.

good luck,

major
 
Well my dear major, thank you for your persistence. I twisted five 2 KΩ resistors together. The first try did not work. Then I decided to switch the Cell-Log for another one. Not working again. I'm thinking that I will try for the very last time with a third Cell-Log. And it works! The Piezo nearly broke my eardrums as soon as one cell hit 3.6V like I set it in the Cell-Log. I tried the last Cell-Log I have and it worked again. So it looks like I have two Cell-Logs with busted alarm outputs for some reason. :roll:

Will these resistors do? I am trying to find a Canadian distributor this time. I got burned with taxes and custom fees with Digikey and Mouser.
https://www.dipmicro.com/store/R2F47-4

Thanks
Ray
 
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