Capacity Testing and 20 HR Rating
I'm thinking about doing a capacity test on my four GC2's. They have a 20hr rating of 215Ah. One thing I'm curious about is how the 20hr rating would have been determined. Being 6v, would they h...
Forum Discussion
I noticed a few things when doing the 'after capacity test' charge Thursday evening. This pm4b-45 brings the 215Ah strings to about 83% soc, before amps begin tapering. So, on the full 430Ah bank I would expect amps to taper somewhere over that 83%. And I have seen each string, and full bank, accept around 8a/100Ah at 90% soc, at 14.8v. So let's say 32-34a acceptance at 90% soc. So, amps should have tapered somewhere between 83 and 90%. However, according to the Trimetric's Ah counter, amps did not begin to taper until well over the 90% soc mark.
I took readings every 20 minutes, and there was a lower reading than what Amps X Time would produce; apparently in keeping with the meter's allowance for losses. But amps didn't start tapering until about +177Ah were replaced (actual meter reading). 216Ah (removed) - 177Ah (replaced) = 39Ah to go. But 39Ah is less than 10% of 430Ah, so it appears amps didn't taper until after 90% soc? By 90%, amps should have been lower than 45a... like ~33a; at least according to previous observations. So, I will be keeping an eye on this, next charge cycle.
Another thing I noticed, Amp Hours replaced (according to Trimetric) were at 216 at the very same time Vbatt (plus Voltage Drop) rose to and equaled 14.8v.
11:00pm ... 22.8a @ 14.7 Vbatt + 0.07 Vdrop ... 206Ah replaced
11:20pm ... 17.5a @ 14.73 Vbatt + 0.06 Vdrop ... 211Ah replaced
*** 11:40pm ... 14a @ 14.74 Vbatt + 0.06 Vdrop ... 216Ah replaced ***
12:00am ... 12.2a @ 14.76 Vbatt + 0.04 Vdrop ... 220Ah replaced
The PM4b has been topping out at .04v lower than my original Vabs setting, which was at 14.84v... so 14.8v. I'm pretty sure that's no co-ink-ee-dink.
By 2am, Trimetric said 8.8a @ 14.78v, 238Ah replaced, and it still had a ways to go. 216 plus 4% (for losses) = 225Ah.
I took readings every 20 minutes, and there was a lower reading than what Amps X Time would produce; apparently in keeping with the meter's allowance for losses. But amps didn't start tapering until about +177Ah were replaced (actual meter reading). 216Ah (removed) - 177Ah (replaced) = 39Ah to go. But 39Ah is less than 10% of 430Ah, so it appears amps didn't taper until after 90% soc? By 90%, amps should have been lower than 45a... like ~33a; at least according to previous observations. So, I will be keeping an eye on this, next charge cycle.
Another thing I noticed, Amp Hours replaced (according to Trimetric) were at 216 at the very same time Vbatt (plus Voltage Drop) rose to and equaled 14.8v.
11:00pm ... 22.8a @ 14.7 Vbatt + 0.07 Vdrop ... 206Ah replaced
11:20pm ... 17.5a @ 14.73 Vbatt + 0.06 Vdrop ... 211Ah replaced
*** 11:40pm ... 14a @ 14.74 Vbatt + 0.06 Vdrop ... 216Ah replaced ***
12:00am ... 12.2a @ 14.76 Vbatt + 0.04 Vdrop ... 220Ah replaced
The PM4b has been topping out at .04v lower than my original Vabs setting, which was at 14.84v... so 14.8v. I'm pretty sure that's no co-ink-ee-dink.
By 2am, Trimetric said 8.8a @ 14.78v, 238Ah replaced, and it still had a ways to go. 216 plus 4% (for losses) = 225Ah.
