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Old 15-06-2013, 14:27   #2716
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Quote:
Originally Posted by Lagoon4us View Post
Terry can you draw the correct junsi diagram for four cells please?
cheers Frank
I'll have a crack at it a bit later Frank, drawing circuit diagrams on a computer don't come naturally to me... actually, nothing on a computer comes naturally to me :lol:

T1 Terry
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Old 15-06-2013, 16:18   #2717
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by T1 Terry View Post

.......
That first log file is over 60hrs, not 14hrs, each 4 vertical bars represents 22hrs 13 mins and 20 sec so I'm assuming the logging was every 20 secs? The drain down is in steps, hard to tell accurately but the load was off for approx 4hrs, then on for approx 1hr, then off again fir 4hrs and so on, these are not the usual patterns for a cell logger load as it would be constant draw down.

......
[/FONT]


T1 Terry
I only ran the logger over night. This was the first time I hooked up the logger from brand new. I had not done anything with the batteries except check te voltage with a multi meter.

There must be something wrong with the LogView program and the time scale. The time scale makes no sense. The total time should be in the 12-hour range as this is the first file I recorded and that was over night.

There was nothing attached but the logger. All the other equipment you see in the pictures was not there yet. First I though it might be temperature drift, but excluded that when I did a second test during the day with rising temperatures and the result was the same.
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Old 15-06-2013, 17:11   #2718
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

What was the sampling rate you set? If you go into the log view screen with the graph there is also a table screen I think it's called, that will give you the sample by sample readings, that will verify how many samples were recorded and how long between each sample. how many tests have you conducted all together?

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Old 15-06-2013, 18:27   #2719
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by T1 Terry View Post
What was the sampling rate you set? If you go into the log view screen with the graph there is also a table screen I think it's called, that will give you the sample by sample readings, that will verify how many samples were recorded and how long between each sample. how many tests have you conducted all together?

T1 Terry
I have done 5 tests all together. Three with no load.

I looked up the table data for the no load graph I uploaded the picture from. It says 60 seconds between data points, which would mean 67 hours. That would mean I started logging before the batteries arrived here, and also before I started the previous logs which ended before this one started. Makes no sense. I played around with different settings for the log interval before this run, started a log, changed my mind and erased the log file and started again with a different interval. I must have run into a bug in the CellLog, where you change the log interval but it records it as if it was not changed. I probably started a log with a 60 second interval, stopped it, changed it to 10 seconds, maybe without erasing the file, and then started again. Now it logs every 10 seconds but records it as 60 seconds. That would mean the the log is about 11 hours long, which would make sense.

I ran another load test last night recording the long term voltage recovery. The tests consisted of:
1 minute 4A
1 minute 46A
1 minute 76A
6 minutes 126A

The voltage dropped from about 13.35 to 12.45 (to be exact by 0.89V) at the end of the load test. I then let the batteries recover over night for 10.5 hours. The pack voltage recovered to within 1mV. That is 0.001V. I am not sure if the Celllog is this accurate though.It took me a while to zoom into the graphs at the start and end and put the measurement lines on them.
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Old 15-06-2013, 18:30   #2720
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

I am showing in the top right of the picture the arrangement the alarm setup inside the Junsi should look. Let me know if you think that is correct.

Click image for larger version

Name:	Junsi <a title=Alarm corrected.png Views: 121 Size: 84.5 KB ID: 62603" style="margin: 2px" />
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Old 15-06-2013, 18:55   #2721
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

I looked up a Winston discharge diagram - this one is for 160Ah - but it should be very similar to the 250Ah or all LiFePo (from Winston at least) in general.

These curves should scale well as long as we are talking about discharge values with respect to capacity (i.e. 0.5C, 1C, 2C) for our large prismatic cells.

Looking at the dV for the curves at different SOC one sees that the largest voltage drop between the 0.3C - 0.5C - 1C curves is at about 90% SOC. Before and after that the dV gets somewhat smaller.

Looking at the resting voltages my cells had when they arrived (3.45V sounds like 100% SOC) they would now be at about 90% SOC. That could explain the large voltage drop under load and the recovery with no load for 10 hours.

Actually, I doubt the correctness of the diagram at the left end. Those curves should not come to one point, and they should not come from 4.25V (which would be the charge voltage, not the resting voltage).

Click image for larger version

Name:	Winston LiFePo160Ah under discharge load.png
Views:	169
Size:	238.8 KB
ID:	62607

Does anybody know of diagrams that explain better what happens under various discharge conditions?

I guess Balqon top-balanced the cells because I asked them to put them together in two individual 4-cell packs. Then they shipped, without a partial discharge.

I try to get an answer from them on Monday.
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Old 15-06-2013, 20:40   #2722
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Are you near Balqon ?

If the cells got to you in less than a day, then possibly Balqon took them directly off a charger and shipped them.
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Old 15-06-2013, 22:58   #2723
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by T1 Terry View Post
I'll have a crack at it a bit later Frank, drawing circuit diagrams on a computer don't come naturally to me... actually, nothing on a computer comes naturally to me :lol:

T1 Terry
Would really appreciate it Terry, i have a MacBook Pro and couldn't load the mini-disc, by comments here i believe my Junsie is not working correctly, maybe a talk through wire by wire for four cells rather than a sketch?

Cheers Frank
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Old 15-06-2013, 23:26   #2724
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by roetter View Post
I looked up a Winston discharge diagram - this one is for 160Ah - but it should be very similar to the 250Ah or all LiFePo (from Winston at least) in general.

These curves should scale well as long as we are talking about discharge values with respect to capacity (i.e. 0.5C, 1C, 2C) for our large prismatic cells.

Looking at the dV for the curves at different SOC one sees that the largest voltage drop between the 0.3C - 0.5C - 1C curves is at about 90% SOC. Before and after that the dV gets somewhat smaller.

Looking at the resting voltages my cells had when they arrived (3.45V sounds like 100% SOC) they would now be at about 90% SOC. That could explain the large voltage drop under load and the recovery with no load for 10 hours.

Actually, I doubt the correctness of the diagram at the left end. Those curves should not come to one point, and they should not come from 4.25V (which would be the charge voltage, not the resting voltage).

Attachment 62607

Does anybody know of diagrams that explain better what happens under various discharge conditions?

I guess Balqon top-balanced the cells because I asked them to put them together in two individual 4-cell packs. Then they shipped, without a partial discharge.

I try to get an answer from them on Monday.
That is a graph for a very long time ago, back in the early LFP days, they don't charge the cells near that hard these days.
Hopefully this up loaded showing just how flat the newer LYP cell discharge curve is.
As far as the diagrams for the alarm port, don't let the + sign mislead you, that is to mark that this cable is more positive than the other, not battery positive, does that make sense? When the alarm port is set to the N/O state, when there is no alarm function occuring the red wire has no voltage, it is floating, when an alarm function occurs, the red wire is pulled down to battery negative. The black wire is always tied to battery negative.

T1 Terry
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Old 15-06-2013, 23:29   #2725
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by Lagoon4us View Post
Would really appreciate it Terry, i have a MacBook Pro and couldn't load the mini-disc, by comments here i believe my Junsie is not working correctly, maybe a talk through wire by wire for four cells rather than a sketch?

Cheers Frank
I will take a photo of a junsi cell logger witrh all the plugs attached and label where each wire goes, will that help?

T1 Terry
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Old 15-06-2013, 23:38   #2726
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Yep the outlets are misleading, once connected mine goes to an overvoltage reading and doesn't read individual cells, our voltage sits below 14.1 from memory the Junsie was reading 21 or so.
Cheers
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Old 16-06-2013, 00:10   #2727
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by NahanniV View Post
Are you near Balqon ?

If the cells got to you in less than a day, then possibly Balqon took them directly off a charger and shipped them.

No, I am in Canada. But they shipped really fast after my order, and they where here in 5 days.
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Old 16-06-2013, 00:30   #2728
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by Lagoon4us View Post
Yep the outlets are misleading, once connected mine goes to an overvoltage reading and doesn't read individual cells, our voltage sits below 14.1 from memory the Junsie was reading 21 or so.
Cheers
Here is a marked up diagram from the Junsi manual. Does this help?
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Old 16-06-2013, 01:11   #2729
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Cheers Rolf i'm on it now ....
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Old 16-06-2013, 01:16   #2730
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Does this mean I'm off the hook for the detailed photo?

T1 Terry
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