Author Topic: Calculation error?  (Read 5290 times)

3rdStng

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Calculation error?
« on: March 06, 2013, 11:36:43 PM »
I utility rates changed on 1/1/13 but I didn't get the new rates into my TED until 1/30/13.  I realize that my data prior to the update would be skewed.  But I was surprised to see that my February dollar amount was way off.  Comparing my actual Feb bill to TED, the dollar total is way out of kilter.  My usage is nearly spot on though.

TED reported a NET of 111 kWh's used at a total of $63.46.  My prior month was 206 kWh at $22.46.  I am on a TOU rate plan and Tier 1 only went up less than a cent per kWh.  Tier 2 went up on average 3-4 cents per kWh.  Why the large difference?

On my actual bill, it shows a NET of 116 kWh at a total of $8.86.  I have solar, so I expect some generation credits during the peak daylight times.  But again, why the huge difference?  Can I edit the history file some how to reflect the total closer to my bill?  How can I verify this doesn't happen again in the future?  I triple checked my utility rates and found they were only off by a hundredth of a penny.

matt1001

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Re: Calculation error?
« Reply #1 on: March 07, 2013, 01:14:35 AM »
I noticed that too. If you make any changes then the monthly totals get screwed up. You may have to way until your billing cycle restarts before the monthly totals make sense again. This seems to be a nasty bug rather than just a simple failure to take into account that you had two rates during the month because the numbers go way off into the weeds.

If the fix is too complicated then it would be better if at least it said it wasn't going to apply the changes to the utlity rates until the next billing cycle started.

DanS26

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Re: Calculation error?
« Reply #2 on: March 07, 2013, 08:09:26 PM »
Try doing a export of your daily data.  It may show you what you want to see, maybe not depending on the type of mid month change you made.

The screen accumulators do get screwed up.  I always make any changes to TED 5 minutes after midnight on the first day of billing cycle.  This will keep the accumulators correct on the screen.

3rdStng

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Re: Calculation error?
« Reply #3 on: March 08, 2013, 01:25:24 AM »
WOW!  I exported my Daily history and did a SUM just on the cost column for February.  The total came out to $10.29.  Pretty close seeing as I had the costs off by a couple hundredths.

Good to know this appears to be a bug.  Am I correct in thinking that my March monthly total will be more accurate?  Anyone running the latest firmware and still seeing this issue?  I am running 483/262 still.  Nothing compelling in the new 499 to make me upgrade, unless this bug is squashed in there.

DanS26

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Re: Calculation error?
« Reply #4 on: March 08, 2013, 02:22:41 AM »
Well, I would not call this a bug.  This is just how the system was designed.

A bug would be an anomaly to system design.

Glad you got the data you needed.

DanS26

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Re: Calculation error?
« Reply #5 on: March 08, 2013, 02:27:59 AM »
WOW!  I exported my Daily history and did a SUM just on the cost column for February.  The total came out to $10.29.  Pretty close seeing as I had the costs off by a couple hundredths.

Good to know this appears to be a bug.  Am I correct in thinking that my March monthly total will be more accurate?  Anyone running the latest firmware and still seeing this issue?  I am running 483/262 still.  Nothing compelling in the new 499 to make me upgrade, unless this bug is squashed in there.

Your March accumulators will be fine, as long as you do not fiddle with the setup during the month.

I'm on the latest and greatest 499, but only because I use the PeoplePower app.

matt1001

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Re: Calculation error?
« Reply #6 on: March 08, 2013, 02:53:19 AM »
Well, I would not call this a bug.  This is just how the system was designed.

I would call it a bug if it unintentionally generates erroneous data.

I would agree that it's not a bug if it did one of the following...
a) used the previous rate for the period before you changed the rate, then the new rate from then on
b) ignored the new rate until the next billing cycle
c) recalculated from the start of current billing cycle using the new rate

...but it doesn't seem to do any of those.

DanS26

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Re: Calculation error?
« Reply #7 on: March 08, 2013, 04:03:48 AM »
Well, I would not call this a bug.  This is just how the system was designed.

I would call it a bug if it unintentionally generates erroneous data.

I would agree that it's not a bug if it did one of the following...
a) used the previous rate for the period before you changed the rate, then the new rate from then on
b) ignored the new rate until the next billing cycle
c) recalculated from the start of current billing cycle using the new rate

...but it doesn't seem to do any of those.

Well, I stand by my statement:  The system is operating EXACTLY as designed.  I agree it is poorly designed in this area.  Not a bug just poor design.

matt1001

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Re: Calculation error?
« Reply #8 on: March 08, 2013, 05:57:15 AM »
Can you explain what it's doing in this situation then? The number seems random to me.

DanS26

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Re: Calculation error?
« Reply #9 on: March 08, 2013, 07:54:23 PM »
Well, I installed TED in 2009 and have added solar in the meantime.  I do not know the design details of TED but I have a pretty good guess based on my experience with the system.  This is my take on how the system was designed to operate.  I could be wrong so I hope a TED support person will come along and clarify things.

1. The system was designed to use PLC (power line communications).  Some would say this is the biggest design flaw in TED.  PLC is subject to erratic or missing data.  So to get around corrupted or lost data packs TED has algorithms that fill in the missing or corrupted data.

2.  Most of the time the algorithms work well, but as we all know corrupted data can slip through.  Read all the treads about people trying to fix or replace erroneous history information.

3.  The algorithms work using "constants" some of which are the system and utility setups along with the "variable" data from the MTUs.  When you change the constants in mid-month the on screen accumulators are screwed up.  Everyone's constants are different, so asking to recreate the crazy numbers people see is impossible.

4. So, the system was designed to sort of self correct for bad or missing data and in doing so has created a host of other problems that are design related.

So if I'm wrong, TED people please enlighten me.