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The "Classic" charge controller / Re: Classic 150 Won't Quick Start
« Last post by boB on Today at 12:48:43 AM »

Hi VT.  Hopefully the replacement works better.

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General Discussion / Re: Pros & Cons of DC waste Not vs AC Inverter water heater dump
« Last post by Matrix on January 16, 2018, 09:48:31 PM »


the PWM works brilliantly with DC-DC to the battery; no light flickering and it tracks the charging states. ( I did this for a year or two)

The challenge, is getting large enough DC elements, reliable DC SSR's, and of course, dealing with the wire size needed for a decent DC diversion load (4.4 KW in my set up).

I would think a large capacitor in series with my AC elements would smooth out the pulses but as a mechanical engineer I'm not supposed to speculate on such things.

Eben
Eben,  I would liked to have tried the PWM method as you did,  but for all the DC reasons you listed it was just too much trouble.  That is what actually prompted the title of this thread.    I had a enough inverter "headroom" and simply decided to go AC out of the inverter.   I know not the best given inverter inefficentcies,  but definitely the easiest a person has a large enough inverter. 

I would like to know more about the idea of a capacitor.   It would be nice on the water heater,  May even allow for the use of "Waste Not Hi (aka opportunity load) .... And I wounder ....  Would that help with smoothing out pulses from an inductive motor like a well pump? 

Any suggests would be appreciated.
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Mike,

Thanks for the reply!

All good points.

You are right about method. I copied your method using voltage points for now (w/ delay) which cycles every 20-60 seconds.

Had to make a few changes in my wiring as my Whiz Bang was not "seeing" some of my DC inputs (hydro, DC charger, 3 solar arrays with DC interconnect) but now all are on and my primary Whiz Bang can see SOC accurately again.

I'm going to go w/ what you suggest; I don't really mind if I discharge the batteries a bit at eod.

the PWM works brilliantly with DC-DC to the battery; no light flickering and it tracks the charging states. ( I did this for a year or two)

The challenge, is getting large enough DC elements, reliable DC SSR's, and of course, dealing with the wire size needed for a decent DC diversion load (4.4 KW in my set up).

I would think a large capacitor in series with my AC elements would smooth out the pulses but as a mechanical engineer I'm not supposed to speculate on such things.

I'll update back to this thread once I have it sorted out.

Thanks for doing such a nice job documents your work on this, rarely do folks return to report on progress!

best

Eben
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Lead Acid (Sealed and flooded) / Re: Not getting Full SG using my Conext SW charger
« Last post by Matrix on January 16, 2018, 07:23:45 PM »
Thanks great info that makes good sense. 

Always appreciate the feed back from the forum.  It's nice to have some folks to bounce my thoughts and issues off. 
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The "Classic" charge controller / Re: Classic 150 Won't Quick Start
« Last post by VT Fool on January 16, 2018, 03:24:36 PM »
Hey Resthome,

Thanks for birddogging the info.  My installer showed up today and we tried a few things but ended up replacing with a new unit.  I'll file this whole event in the back of my brain but at this age the long term mem is better than the short one, not sure how much will be retained.

Thanks again to all,
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The "Classic" charge controller / Re: Classic 150 Won't Quick Start
« Last post by Resthome on January 16, 2018, 02:52:03 PM »
Here is a clip from an old post by Ryan on what I think is the same issue. At least the original poster said it was stuck sending data with the same data values. The 502 made me suspect this. 502 is the Modbus Port number.

Lots of special keys to press but give it a try can't hurt.

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Owner Installed system pictures / Re: South Park, CO - Dual purpose control cabinet
« Last post by jmccallie on January 16, 2018, 02:09:11 PM »
Panels are up! Ground was only frozen for the first foot...
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The "Classic" charge controller / Re: Classic 150 Won't Quick Start
« Last post by ClassicCrazy on January 16, 2018, 12:57:12 PM »
Seems I remember one firmware update where the MNGP got stuck trying to load  like that and the only way I found to fix it was to use the jumper reset. But that was awhile ago and who knows if this is the same problem.

If I have time I will try to look it up on the forums here.
Found it - don't know if it will help but take a look .
http://midniteftp.com/forum/index.php?topic=2282.msg21422#msg21422

Larry
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The "Classic" charge controller / Re: Classic 150 Won't Quick Start
« Last post by Vic on January 16, 2018, 12:05:42 PM »
Hi VT Fool,

Thanks for the pics.

When the Classic gets stuck in "Sending Data"  (to the MNGP),   it usually occurs  from  a failed attempt to Update the Classic/MNGP Firmware.

Perhaps the installer tried to do the update,   and it failed (?)  ...   dunno.

But,   seems that someone does (probably)  need to successfully update the FW,   from scratch.

Just guessing,   good luck,  Vic
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Lead Acid (Sealed and flooded) / Re: Not getting Full SG using my Conext SW charger
« Last post by Vic on January 16, 2018, 12:01:09 PM »
Matrix,

First,   YES,  Skip Days IS Days Between Bulk in the App,   and Skip Days in the Charge>Advanced menu on the MNGP.

During a Skip Day,   the Classic begins the day in Float MPPT,   and will eventually get to Float,   if there is enough input power (usually PV),   and the loads on the system are not too great for the CC to get to the Float setpoint.

A battery that has experienced some discharge will still accept considerable charge when the charging voltage is held at a reasonable value of Float voltage.

The one thing that you should know about Skip Days,   is,   that on the day that the battery is going to get its full-charge,  it the Absorb stage is not complete, due to too little PV power available to charge the battery and supply power to the loads,  the Classic will NOT try to do a full-charge on the following day (it will just start the Day Skipping pattern again).

AND,  YES,   loads will still be supplied from your PVs,  as long as there is enough PV power available to supply those loads,   if there is too little PV available,   the CC will revert to Float MPPT,  just as it does with any other voltage-regulated stage.

In the Graph you attached earlier,   that area in the center of the Diversion area where that extra load came on,  the CC simply MJUST have reverted to Bulk,   and NOT remaining in Absorb   ...   this area shows the battery being discharged.

And,  IMO,   the part of the battery charge current (WB current) "starts" to level off,  does NOT represent the nominal EA value that should be used.   If one uses the current at the beginning of where the charge starts to level off,   the Absorb will generally NOT have been long enough.

If one chooses an EA value from where the WB current had definitely STOPPED decreasing for some period of time,   this will be a better EA value to use.   There is some Jitter in the WB current readout,   and this does make it a bit more difficult to determine  when the WB current is decreasing.

AND  I would strongly suggest that you STOP  using a Diversion Load on this system,   until you get a better handle on what Vabs and EA setting will allow for your batteries to be fully-charged on a typical day from the Classic.

YES,  previously,  you said that your concerns were when charging from the SW,  but it seems that you are also having the same trouble when charging from the Classic.

Earlier,   I mentioned the effect of large Opportunity Loads on the EA function,   and how voltage drops in the cable and breaker that connects the CC's output to the battery.   A large opportunity load (large current) reduces the charge voltage that the battery "sees",   and this voltage reduction at the battery terminals results in a lower charge current (WB current),   and can trigger an early termination of Absorb.   This CAN result in some undercharging of the battery.

This same effect could also result from using the SW to charge batts,   Again you could measure the battery terminal voltage when charging from the SW  to see what is effect on charge voltage from large opportunity loads.

IMO,   FWIW,   Vic
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