cell logger 8s help with operation with a relay

Hi all,

I have puirchased 2 cell logger 8s devices and 2 parallel jst 9 pin splitters.
I have got the cell loggers in the same line as the enginer bms so they are reading together.(a 4kwh kit).
I want to rig up the cell loggers with the switched output to trigger a relay. I have read up on the subject here and on prius chat about the correct wiring for the devices.

Ok, I have set up the cell loggers so that they alarm at 3.6v both cell loggers alarm port set as normally closed, so they should open when alarming.

I have the relay 12v contact supplied with a constant 12v feed from the prius 12v aux battery with a 1 amp in line fuse, the other side of the relay coil to the red + lead to the cell logger and the black -ve wire formn the cell logger to car negative. The coil energises ok, a the cel log alarm port is set to normally closed, but the relay does not close upon a cell log alarm, and the cell log alarm internal switch has opened.

The other cell logger i am sure is not working as the internal alarm swtich is always open.

I am wondering if both cell logegrs are faulty, although they are quite new, only purchased 3 months ago.

I am trying to acheive a position where my cell loggers activate a relay that in turn will activate another relay to cut out the charger at 3.6v instead of the enginers bms setting of 3.8v.

Any advice on this please.

Thanks. Anthony.

 

hi wb9k,

i didnt put a diode across and think i have damaged one cell log relay output.

Will any diode do the job? got to try and get ne somewhere.

I have got another spare cell logger i can use, got to wait until i get the diode now though.

Thanks for your input

best regards, Anthony.

 

Hi again, still having problems with the cell logger relay circuit.

Ok, can someone give some advice on my wiring, and i have reduced the fuse size to 300 milli amp.

The red wire of the cell log switch output goes to a 300ma in line fuse, and from the fuse goes to the coild of a 12v relay. The other side of the coil goes to a 12v source, powered from the enginer battery itself. Across the coil contact i have got a 1N4002 diode, with the white side of the diode connected to the 12v source, and the black wire of the diode to the in line fuse relay side.
The black wire of the cell logger relay output goes to the 12v source negative.

Is this correct?

I have tried 3 cell loggers now, 2 worked for only about 5 operations then the relay switch failed.
When the cell logger internal switch has failed, when the cell goes into alarm mode, the cell logger alarms as normal, something inside the cell log happens as at this point the cell log screen is much brighter. when the alarm mode is back to normal, the cell log screen then goes back to normal.

I am either doing something basically wrong, or the cell logger relay circuitry is very iffy, to a point where i wouldbt trust it to isolate the charger on its own. Thankfully, this circuit is working alongside my existing enginer bms, so if the cell log failed, the existing bms still protects the overcharge, albeit at 3.8v cut off and not where i would like it at 3.5v.

Many thanks for your help.

Best regards, Anthony.

 

Hi John,

Thanks for the link and schematic.

I had taken note from other schemtics around the web on various forums.

I have actually wired up the cell logger exactly as above, but with only 2 relays, one cell log and 12v relay for each rfe battery bank. These relays then operate a charher relay that can be latched off when either cell log reached high voltage alarm set point.

I cant understand why i have had 3 cell loggers fail on me. I`m either very unlucky with my purchasing or the qc on these relays are poor. Its a pain in the arse sending them back all the time for replacement under warranty.

In all fairness the store where i purchased them from have been really good, but sending them back and waiting for their return is annoying.

I am wondering now whether to ditch the simple relay method and go to a similar method to you John using a duinomite, and have a play with that. If i go down the duinomite route john will i be in the same boat as the relay method, or is it safer with the duinomite due to a signal rather than switching a voltage.

Many thanks for your help John.

Best regards, Anthony.

 

Hi John,

The output of the CellLogger8S is a transistor output with very limited current sink or source (NPN/PNP). So maybe you may have exceeded this current limit which resulted in destroying the transistor.

The simple relay method with two CellLoggers is OK. Dan Lander is still currently using this method with an Enginer kit (Probably a good idea to send Dan Lander (Dan21 on Priuschat)) a PM for advice). So it must be OK. The benefit is that you can set the HVC/LVC value to whatever value you want. Thus setting the HVC for your Enginer kit to 3.5volts may be a good idea.

I am using a 300mA fuse in line to the cell logger and the fuse is still ok, from my knowledge the circuitry in the cell log can take max 500mA, so i am well within spec and the fuse hasnt blown.


Once you have this setup up and running it may be a good idea to setup your BMS16D to balance. Where are you up to with this, last I heard you were getting the latest firmware for BMS16D from Sushp to lower HVC.[/quote]

I have pm`d shushp for info on a firmware update for the bms16d, he hasnt got back to me yet.

Thanks John.

Hi wb9k,

the spec on the coil is 85ma load. I did read the cell log manual too to make sure i was doing it correctly.
I am not experienced with electronics, and the spec of them, i`d rather stick with this method if i can nail it down to work reliably as its in essence so simple (but to frustrating)
I shall pm dan to see what he can advise too, i have hod very good advice off him on the enginer forum, i`ll drop him a line.
Thanks wb9k.

 

Hello again,

I contacted Dan and he also has experienced issues with the internal transistors blowing, although the correct wiring is being followed. he suggested using an opto interruptor in line to the relay coil.
I have read alittle on the opto interruptor, and other cicuits using an additional NPN transistor with a resistor before the transistor. I am coming to the conclusion that i have to do either of those mothods.
Its a shame really that hobbyists follow the manufacturers own diagram as printed in the installation manual and we can still damage the products.

OK, as i have no real idea of electronics, c an someone suggest a transistor part and an appropriate resistor to place in line to the relay coil, as i have no real idea on specifying parts like this.

Many thanks, Anthony.

 

Hi wb9k,

I am mechanically biased and dont have any knowledge in electronics, so my mechnical mind is telling me that if i place an additional part in line to protect original part, the protection part must be rated lower to protect the original part.
So what now protects the additional transistor, what stops that from blowing? Would the use of a resistor before and after the additional transistor protect that transistor.
I have searched google for a 12v 300ma transistor, would this be ok to use, and if so, what size resistors would you recommend for this application.
The data for the cell logger shows voltage to be less than 50v, and less than 500ma, but the transistor inthe cell log has blown although i have a 300ma fuse in the line, I cant understand that bit
I am not sure if you have any experience is electronics, but thought i`d ask.

Many thanks Anthony.

 

Thanks John and wb9k.

My replacement cell lg cam back this morning but i`m not going to fit any more until i get this small moe made up.

I`ll post back when i get it sorted out correctly and working reliably and shall include details of what will be done.

Thanks for your support. Anthony.

 

small update,

i had purchased the relays, they are rated 5A 30vDC, with a coil resistance of 160 ohms. " relays, one for each battery bank.

I checked the coil resistance with a multimeter, relay 1 was reading 70 ohms and relay 2 was reading 8 ohms. Problem.

relay 1 I=V/R 12/70 = 171mA. ok but too high.

relay 2 I=V/R, 12v/8ohms = 1.5 amps, hence the blowing of the small open collector in the cell logger.

I had also purchased other relays at the same time for the 240v AC power switching. Checked these, both relay resistance was 160 ohms,

therefore, the amps required to switch the coils is 75mA.

So, i have changed to these relays as i now know the load on the open collector is only 75 milli amps.

Additionally, i have purchased 2 2n5551 NPN transistors rated at 600mA, and 2 1k 1/4watt resistors, i shall connect these in the line to the cell logger open collector relay port, this additinal transistor will / should operate the relay and protect the cell logger transistor.

It is very late now in the uk, i intend to wire these items into circuit tomorrow, I shall report back with how it goes.

Thanks for all your help and suppport.

best regards, Anthony.