Thanks for the kind words. I note that I didn't have much to do with finding and fixing the premature float bug. That was coulomb. But I am responsibile for the changes to current reporting that you are having a problem with.
Thank you for such a detailed report. So that's Wh in and out of the battery? Particularly with a lead-acid battery, I'd expect Wh in to be 5% to 15% greater than Wh out. Also, the resolution of current measurement by the PIP is only 1 amp. Not really good enough for coulomb counting. How much do they differ, and in what direction?I'd like to report a bug/regression :
From version 72.70c beta, you've "improved the accuracy of the battery charge and discharge current readings, particularly for low currents, as displayed on the LCD, and as given in response to the QPIGS and QPGS serial commands"
I've built a small data logger / coulomb counter that runs on raspberry pi. And since the upgrade, my "total wh in" don't match "total wh out" any more (within reasonable margins).
That is correct. And when the battery is not being charged, we've also increased the amount of amps reported by the inverter for battery discharging current by 1 amp.It looks like you've reduced the amount of amps reported by the inverter for battery charging current by 1 amp?
From the Dynamic Current Control manual:
"The inverter does not have a current shunt, or any other means of measuring battery current. The standard inverter firmware estimates battery current by measuring AC power and applying a simple efficiency scale factor for inverting (100/108), and another for AC charging (119/128). It completely ignores the no-load and no-charge losses."
"We improve the accuracy of low readings by the simple expedient of subtracting 1 amp from the charge current reading if it wasn't already zero, otherwise adding 1 amp to the discharge current reading."
Thanks for confirming that.At first glance it seems reasonable to do that because the new figure becomes finally the real battery current, in most cases (see below).
Right.The previous battery current reported (before the upgrade) was actually "battery charge or discharge current" + "self consumption".
This is why the inverter would always report 1 amp even when the battery was in float and full.
I think we tested it with AC charging and found approximately 50 W losses there too. But we will check this.I don't know exactly why, but there's an exception to this case, when in bypass mode and charging with AC.
In this state, the battery charging current doesn't include self consumption (or maybe more logically the self consumption is much less than the average 50W in solar charging mode with inverter on).
I can see that would be a problem. We will investigate, and we may produce a version 73.00b to fix the problem.This has two unintended consequences with the new firmware :
1. The charging/discharging current reported is wrong (which is why my raspberry pi program is wrong)
2. The charger quits charging way too early when charging with 2amps, and quits slightly too early when charging with 10amps.
You should be able to replicate the problem by putting the inverter in bypass mode, AC charging at 2 amps, absorb time 180min. It never stays in absorb mode that long. (see attached picture - last night charging at 10 amps, absorb should be 180min - top red is AC charging)
As I've got a small system (4x 100Ah gel batteries) this is a bit of a problem for me.