Monday, August 27, 2012
Testing update
I've tested about one third of my cells, and all of them so far are in excess of 60Ah capacity. The cells come from CALB at about 50% charge, the PowerLab 6 takes about 6 hours to charge from half to full, discharge and recharge.
Below are some graphs that the PowerLab spits out, the raw data is also available, so I plan to look at the stats when I'm done testing the entire set.
Here you can see that the PowerLab puts in a little over 30Ahs, rests for 15 minutes, removes a little over 62Ahs, waits for 15 minutes, then puts back in a little over 63Ahs.
Here you can see the steep "knee" as the cell gets full, the plateau as the charger changes from constant current to constant voltage mode at 3.60v, the drop as the surface charge dissipates during the 15 minute cool down. Then we see the sharp drop as a 30A load is applied and the slow drop until the steep knee as the cell approaches empty, and a quick recovery as the load is removed at 2.80v for another 15 minute cool down period. In the final phase, we see a steep curve as charging starts at 30A constant current, then a long fairly flat charging curve and another steep knee as the cell gets full again, followed by the constant voltage plateau to finish.
The CALB paperwork lists this cells internal resistance as 0.44 mOhm. The PowerLab measured it at 0.5 mOhm. The other cells have been similarly off, and similarly flat on the graph. I'm not sure what that means, if anything.
Below are some graphs that the PowerLab spits out, the raw data is also available, so I plan to look at the stats when I'm done testing the entire set.
Here you can see that the PowerLab puts in a little over 30Ahs, rests for 15 minutes, removes a little over 62Ahs, waits for 15 minutes, then puts back in a little over 63Ahs.
Here you can see the steep "knee" as the cell gets full, the plateau as the charger changes from constant current to constant voltage mode at 3.60v, the drop as the surface charge dissipates during the 15 minute cool down. Then we see the sharp drop as a 30A load is applied and the slow drop until the steep knee as the cell approaches empty, and a quick recovery as the load is removed at 2.80v for another 15 minute cool down period. In the final phase, we see a steep curve as charging starts at 30A constant current, then a long fairly flat charging curve and another steep knee as the cell gets full again, followed by the constant voltage plateau to finish.
The CALB paperwork lists this cells internal resistance as 0.44 mOhm. The PowerLab measured it at 0.5 mOhm. The other cells have been similarly off, and similarly flat on the graph. I'm not sure what that means, if anything.
More Power Parts
The hardware for the cells showed up, the bolts seem to be fairly good stainless steel, as are the flat and split washers. The battery interconnects are several thin sheets of copper stacked and heat shrinked together.
I don't like split washers in things that vibrate... like motorcycles, so I ordered some Nord-Lock washers.
I also ordered a JLD404 and shunt from LightObject. I'm not sure where I'm going to mount it yet.
Thursday, August 9, 2012
Wednesday, August 8, 2012
Finally...
I've been busy, and not on fun stuff like the motorcycle. I've finally got some time to get back to work on the bike and ordered some batteries.
I really, really wanted to get Sinopoly LFP60AHA(B) cells, and got some good quotes from Sinopoly, but just couldn't get a reasonable solution to importing and shipping them to Dallas. I ended up getting the new CALB CA60FI cells from Keegan at http://www.calibpower.com/
They arrived UPS Freight in two small crates shrink-wrapped on a pallet. I removed all the extra packing material and consolidated them down to one small crate for storage while I'm working.
Unfortunately, they neglected to ship the bus bars and bolts with the batteries, so I'm waiting on those to show up in the next day or two.
I ordered 48 cells, and plan on installing the best matched 36 of those in the bike. The other 12 will be used on various other projects. I'll update on the testing soon.
According to the CALB paperwork they all tested 65Ah to 67Ah. Two were 65Ah, 25 were 66Ah and 21 were 67Ah. The "Open Circuit Voltage" listed was 3.304v or 3.305v for 45 cells with two more at 3.306v and one at 3.309v.
I really, really wanted to get Sinopoly LFP60AHA(B) cells, and got some good quotes from Sinopoly, but just couldn't get a reasonable solution to importing and shipping them to Dallas. I ended up getting the new CALB CA60FI cells from Keegan at http://www.calibpower.com/
They arrived UPS Freight in two small crates shrink-wrapped on a pallet. I removed all the extra packing material and consolidated them down to one small crate for storage while I'm working.
Unfortunately, they neglected to ship the bus bars and bolts with the batteries, so I'm waiting on those to show up in the next day or two.
I ordered 48 cells, and plan on installing the best matched 36 of those in the bike. The other 12 will be used on various other projects. I'll update on the testing soon.
According to the CALB paperwork they all tested 65Ah to 67Ah. Two were 65Ah, 25 were 66Ah and 21 were 67Ah. The "Open Circuit Voltage" listed was 3.304v or 3.305v for 45 cells with two more at 3.306v and one at 3.309v.
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