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Discussion Starter · #1 ·
I need some help. I know I have seen a diagram of the circuit needed to connect multiple CellLog8s devices to a common relay to interface with the charger on LVC and the vehicle controller on HVC. I have searched, but even the post I think might have had it, the photo link no longer works. I also used google and endless sphere searches to no avail.

Please help.

major
 

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Discussion Starter · #2 ·
I need some help. I know I have seen a diagram of the circuit needed to connect multiple CellLog8s devices to a common relay to interface with the charger on LVC and the vehicle controller on HVC. I have searched, but even the post I think might have had it, the photo link no longer works. I also used google and endless sphere searches to no avail.
O.K. I found these.





Has anybody tried these? Any other comments or help appreciated :)
 

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O.K. I found these.
Has anybody tried these? Any other comments or help appreciated :)
The bottom wiring diagram is from my old post. Here is the updated wiring diagram for 44 cells. I have been using it about 6 months. It's very reliable. Just plug in to charge and forget about it. No worries about overcharging on any cells. The same way as for driving, the LVC will kick in when any one of the cells hits a set low voltage limit. It reduces the power to 50% throttle. Here is a link to my car in the garage
http://www.diyelectriccar.com/garage/cars/281

Here is another post http://www.diyelectriccar.com/forums/showthread.php/bms-not-bms-53768p7.html
 

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Discussion Starter · #4 ·
The bottom wiring diagram is from my old post. Here is the updated wiring diagram for 44 cells. I have been using it about 6 months. It's very reliable. Just plug in to charge and forget about it. No worries about overcharging on any cells. The same way as for driving, the LVC will kick in when any one of the cells hits a set low voltage limit. It reduces the power to 50% throttle. Here is a link to my car in the garage
http://www.diyelectriccar.com/garage/cars/281
Thanks, honn.
 

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Major, did you ever build one? I am looking to build/get someone to build one for me. Honn any updates or comments on your design?
thanks
Francis
 

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Major,

We are using a modified version of Honn's circuit on our pulling tractor.

We do not use the HVC protection circuit because our charging system is unable to charge any individual cell stack above 3.5 volts. For the LVC we decided to go with complete shutdown rather than a partial throttle signal he used. We may change that to something other then 50% first we need to see if we will get any cells pulled down to under 2.1 volts during a pull. If we start seeing LVC we plan to try various percentage cutbacks.

This setup, now that we have it working, is wonderful. We can see at a glance how all 50 cell stacks of the battery are doing while charging and know when all 50 cell stack charger boards have reached 3.5 volts. It also shows us any cell stack imbalance after a pull which might indicate a weak cell in a stack. Another unintended benefit has been the ability to spot a bad charger board (the DC to DC boards we are using are incredibly moisture sensitive and go bad often) before it damages a cell stack.

The system was a bit of a pain to get up and running because of our (my) design/material choices. I used a male/female SCSI cable to wire the Cell Logs to our battery. The cable was cut in half and the ends plugged together. One end of each wire (by color code) went to the individual battery parallel stack, the other went to the mapped Cell Log pin. The system is turned on and off by simply unplugging the male/female cable connectors.

The two difficulties with this set up was my choice to build up the Cell Log plugs myself. The 26 gauge wire used in the SCSI cable is just not tough enough to stand much flexing so even using the correct crimping tools I was having problems with wire breakage when handling the plugs. The other problem was bad (high resistance) in some of the SCSI cable circuits that required replacing some wires.

We will be rewiring the tractor over the winter and we plan to clean up the installation using perfboard, phoenix connectors and some pre made connectors for the Cell Logs I found on eBay.

Hope this info helps
Jim
 

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Discussion Starter · #7 ·
Major, did you ever build one? I am looking to build/get someone to build one for me. Honn any updates or comments on your design?
Believe it or not, we're still working on it. We have tested the circuit boards on charge and discharge and they look good. Hopefully next week we can actually test with them turning off the charger.
 

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Discussion Starter · #8 ·
We will be rewiring the tractor over the winter and we plan to clean up the installation using perfboard, phoenix connectors and some pre made connectors for the Cell Logs I found on eBay.
Hi Jim,

I used #22 wire and MiniFit Jr connectors. Maybe a bit bulky, but durable and I hate working with real small stuff. So eBay beat my connector deal?

Regards,

major
 

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Hi Jim,

I used #22 wire and MiniFit Jr connectors. Maybe a bit bulky, but durable and I hate working with real small stuff. So eBay beat my connector deal?

Regards,

major
Major,

Yah I agree making up those connectors was a MAJOR (pun intended) pain. :p I'm in my late 60s so my eyes and dexterity aren't what they used to be.

The connectors I found use 20 AWG silicone wire with about 1 foot of wire lead. At $4.50 each they are hard to beat.

http://www.ebay.com/itm/130419112764?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

<EDIT>

There are also these with 24AWG PVC wire at $3.79 each

http://www.ebay.com/itm/150608613045?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

<End EDIT>

They come from China so there is a long lead time.

I plan to use the plugs and leads from the Cell Logs to one side of a barrier strip and the SCSI cable leads to the other side or I might use Phoenix connectors with both wires under the screw.

I could swear that I sent you a post about them.
 

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Major, did you ever build one? I am looking to build/get someone to build one for me. Honn any updates or comments on your design?
thanks
Francis
Here is my updated wiring diagram. I added a solid state relay to completely turn off the charger, especially the cooling fans that run off the AC. My battery monitoring system using celllogs has been reliable. Currently I have 26,500 electric miles. I never overcharge any of my cells. Just plug in and walk away. I used a small ac-dc converter connected to the charger's AC wires to automatically power my celllogs and the charger external relays. I used two direction diodes to isolate the +12V aux source (from key switch) and +12V ac-dc source for powering the celllogs. See pictures in my diygarage.

Brian has designed a PCB for the celllog to make the wiring less headaches. Check out his blog for more info. http://s2kev.blogspot.com/
 

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those long wires won't allow accurate voltage readings....

[edit]
I know lead length doesn't effect the measurement, but some people have had issues with accurate readings on these cell-logs....whether that was noise, capacitance, etc, I'm not sure, but it should be considered.
 

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those long wires won't allow accurate voltage readings....
I was getting things together to make this cellog setup. So 6' runs of 26 gauge wire (25pr telephone wire) will throw off the reading enough to make the setup not worth it?

francis
 

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those long wires won't allow accurate voltage readings....
Why not? There is very little current flows through those celllogs wires. What causes the celllog voltage reading appears to be lowered than usual is the external resistance in the high power connections like 2/O gauge wire. For example, during high current load if a 2/O gauge wire connected between two cells is too long, you will notice the voltage reading on one cell is slightly lower. I found this out by swapping the cells. The voltage reading varies depending on the current draw under load.

Honn
 

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No, it's low current I know that, but I know people on ES have issues with long cables and inaccurate readings. Maybe has something to do with some noise?

can someone test this? I mean, compare his reading at the cell to the reading back at his cell-log?
 

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I haven't used them with leads longer than about 12" but they always agreed with my Extech 830 dvm - they only read to 2 decimal places though.
 

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As mentioned by others in a couple of posts we also had some trouble at first with inaccurate readings. In the end it appears that the problems were the harness wires themselves. We used a six foot 68 pin (34 pairs) SCSI cable with a male and female plug. We plugged the two ends together and cut the cable into the lengths we needed. One half was affixed to the battery and the other to the tractor, cellog8s and control relay. Since the battery was made to be removable we use the plugs as a means to turn the cellog8s off and to allow battery removal without major wire rework.

At the battery end we connected each wire to a dedicated phoenix connector on the charger boards and noted the color code of the wire and the battery stack number (one through fifty), At the other end I initially built plugs for the cellog8s using plugs and terminals. Although I did have the correct crimping tool it still became a real problem because the wires themselves were not able to withstand all of the mechanical stress while building and installing the plugs. I later found the pre made plugs I noted in a previous post and used them to replace the plugs I built. We still had a few problems that were corrected by switching to a different wire. Since we finally got all of the cellog8s up and reading we find them to be quite accurate within +- 0.002 volts compared to two very accurate VOMs.

So yes, you may get some funny readings at first, but with a bit of care and detailed diagnosis you should be able to get good accurate results. We still don't know why some wires would give an erroneous reading and others would be OK. I'll do some checking this winter when we take everything apart for painting and rewiring.
 

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Does anyone have the link to the modifiction to the cell log 8 to make it power off all 8 cells rather than the first 6 cells? We are using 2 loggers on a 24v pack in a motorhome, one for LVC and the other for HVC, suprising just how much they put the pack out of balance. We have resorted to readding 4 cells from each logger and not having an LVC till we can get it sorted.

Thanks
T1 Terry
 

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Good morning all. Ok I am starting to build it. I have the cellogs and pre-made cellog wiring connectors and have ordered the alarm relays. But what is the part number for the three on/off DPDT cellog relays? Is this it:

http://www.ebay.com/itm/Tyco-V23079...913?pt=LH_DefaultDomain_0&hash=item256782afe9

And everything else I can get at Radio shack or should I ebay for more of the components?

thanks
francis
Francis,

Yep, that is the same relay brand and part number I used to turn ON/OFf the celllogs.
 
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