PD9140A converter with Charge Wizard

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DonTom

DonTom

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The paperwork for the Charge Wizard, first line, first page reads:


"OPERATION

*The Charge Wizard automatically selects  the optimum battery charging mode--depending on your battery charge".


I started with my new 12 volt house battery in the "Storage mode" this morning because it is very charged full, from hours of driving plus being at this RV Park overnight. Very, very slow flash as expected.


But I had to disconnect the 120 VAC from this RV park this morning to move this RV to a different slot where I can stay for a few days. It took no more than two minutes from the time I unplugged to the time my 120 VAC was plugged in again, just a few feet away.


The Charge Wizard then said I was in the "Boost Mode". Green light on solid. It stayed in this mode for around two hours before going to the "fully charged" mode (the fast flash of the green light). Now, more than ten hours later, it is still in the "fully charged" mode, never went back to the storage mode.  But I assume it will by morning.


I always wondered how the converter knew the state of charge as it is supplying a charge.


But the evidence is clearly showing it's simply timers and has no idea about your real charge. Anybody here know how the thing really works?


This is not a problem, at least I don't think so. I am just curious how it really works.


-Don-  Barstow, CA
 
DonTom said:
the evidence is clearly showing it's simply timers and has no idea about your real charge. Anybody here know how the thing really works?
Click to expand...
I don't have direct knowledge of this unit but most "intelligent" chargers use a combination of terminal voltage and timers.  Since they work with a limited size and type of battery some of the charging parameters can be fixed and when certain time and voltage thresholds are crossed it will trigger the appropriate mode.  Dealing with exceptions is the challenge, like what to do if it stays in bulk mode for too long or a bad connection causes strange excursions in terminal voltage.  You gotta think all use cases are qualified in the design but there's a practical limit of how far out into the weeds you design to.

Mark B.
Albuquerque, NM
 
Mark_K5LXP said:
I don't have direct knowledge of this unit but most "intelligent" chargers use a combination of terminal voltage and timers. Albuquerque, NM
Click to expand...
But how is it going to know your terminal voltage when the boost mode is keeping the battery at above 14 volts?


Not only that, but many minutes would have to be with no charge at all to measure such a voltage.


So if it is anything other than timers, I have no clue how it works as it doesn't even seem possible to check a battery's voltage if it is being charged at above 14 volts at the same time.


73, -Don-  AA6GA/6  Barstow, CA
 
I have no clue how it works as it doesn't even seem possible to check a battery's voltage if it is being charged at above 14 volts at the same time.
Click to expand...

The charge circuitry is simply stopped for a few milliseconds every little while and a reading is taken of how low the voltage drops. It can happen so fast you'd never see it even if you had a meter on the battery and were watching it. I've triggered it on the oscilloscope but even that's difficult to catch. It's also monitoring the current draw.

We repair a lot of Xantrex so I'll use one of their charging profiles as an example:

Bulk charge is high current, whatever the charger is capable of, 75-100 amps is pretty typical of the Freedom series, it just delivers balls to the wall current until the battery reaches the preset voltage (usually around 14.5V). This can deliver up to 80% of the charge to the battery very quickly. It's important for this stage to be above 14 volts to be beyond the gassing point so the electrolyte bubbles this helps prevent the plates from being sulfated.

At this point the charger switches to Acceptance charge where the voltage is kept constant (14.4V is common - 2.4V per cell) with the voltage now held constant the current will drop as the battery charges, when the current hits a limit (10-15A is common) the acceptance mode is over and the Float Charge stage begins. NOTE: the charger will time out after an hour, if the batteries are still drawing more than 10-15A after an hour it gives up and terminates the stage. This protects you from boiling a bad set of batteries into the ground.

In Float charge the charger will not allow the battery to fall below the float voltage (13.5V is common). At first in Float Charge there is no charging at all and the batteries slowly drift down from the 14.4 that the acceptance mode charged them to to the 13.5V setpoint and then the charging starts again but at this lower voltage.
If you operate 12V appliances/lights/pumps/fans the charger will supply extra power to keep the battery above that voltage. The charger with a 100A capability can easily run all of your 12V loads at 13.5V to keep the batteries from falling below the threshold.

The charger is not smart enough to pick up where it left off so if the AC is interrupted it starts over at Bulk Charge again.

Different manufacturers will have different names for the stages and different set points etc but that's the basics of the smart charger for wet batteries.
 
JayArr, that was probably the best explanation of how a 3 stage converter works, in laymens' terms, as I've ever read. Good job.
But your reference to an oscilloscope will probably confuse most who read this. Just saying that IMO there aren't many people left who know what an oscilloscope is. Let alone how to use one.  ;D
 
Excellent description.  One minor nit, "desulfating" isn't accomplished through gassing.  Conversion of lead sulfate back to lead is the chemical conversion that takes place as a result of charging so anytime you're charging you're "desulfating".  When describing a degraded battery due to "sulfation" is when lead sulfate crystals become too large and engrained to be converted by charging which is a consequence of leaving a battery sitting discharged for too long.  Gassing is good for a different reason and that's to stir the electrolyte.  With batteries that sit idle the electrolyte will stratify and the stronger concentration of acid that starts to accumulate at the bottom of the battery will degrade the plates, causing a reduction in capacity.  The bubbles keep things stirred up and also promote a more uniform charge across the surface area of the plates.

Now, contrast this controlled set of current, voltage and time charging parameters to not long ago when converters were just set to some predetermined voltage point and whatever currents for however long is what you ended up with.  Which is why batteries tended to be short lived, either chronically under or over charged.  The three or four stage chargers today are much kinder to batteries.  In this modern day of embedded processors I have to wonder why there isn't some form of BMS incorporated into every battery made just like most consumer lithium batteries.  It would cost pennies per battery and with closed loop control to the charging source there would be no reason to manually set, or guess, what charging parameters a given battery would need over the course of it's life.  But the 3 and 4 stage chargers get you 95% there, so probably good enough for most purposes.

Mark B.
Albuquerque, NM
 
That was great explanation from JayArr, but it still leaves me with questions.

I find it interesting that a voltage drop on a charging battery can be measured in a "few milliseconds". I would think that would be less than a microvolt difference as well as have issues with electrical noise interfering with the detection, being so low in a voltage difference in such a short period of time.


Also, it if works by checking a voltage drop, why does it have to start all over in the boost mode for hours, after being disconnected for only a few minutes?


BTW, I just now checked my Charge Wizard Status light. It's still not back to the storage mode this morning, unlike just before I disconnected yesterday morning just before I disconnected. I am still in the fast blink "battery-full charge" mode and 13.6 VDC on the house battery.


-Don-  Barstow, CA
 
Hi DonTom

I find it interesting that a voltage drop on a charging battery can be measured in a "few milliseconds". I would think that would be less than a microvolt difference as well as have issues with electrical noise interfering with the detection, being so low in a voltage difference in such a short period of time.
Click to expand...

When in a charging mode that is voltage referenced (Acceptance mode and Float Charge) even when a battery charger wants to put out 14.4 or 13.5 volts the battery will hold that down. It's the difference between the charger voltage and the battery voltage that causes the current to flow. So it's not like it's charging at 14.4 and has to drop to 12.5, It's more like it's charging at 12.51 and has to drop to 12.5

If you take a battery that is discharged to 12.5V and put a meter and a charger on it you won't read the 14.4V of the charger, you'll read the 12.5V of the battery and it will begin to rise as it charges. The voltage the microprocessor reads in the milliseconds that the charger is shut off is very very close to the voltage it was just at with the charger on, it doesn't vary that much and it's almost instantaneous. There is also very little noise on the terminals of a battery, especially a large wet cell, they are pretty rock solid.


Also, it if works by checking a voltage drop, why does it have to start all over in the boost mode for hours, after being disconnected for only a few minutes?
Click to expand...

You can't tell for sure what state a battery is in from just a voltage reading alone, the battery will be at 13.7V both on the bulk charge stage as it's charging up to 14.5 AND on the float stage as it settles down from 14.4 to 13.5. The circuitry isn't smart enough to tell how much charge is in the battery by voltage alone. Putting the battery into bulk mode as the very first stage gives the microprocessor a second data set, current, that it can use. If, when turned on the voltage is high and the current is high then it is in bulk mode and continues to supply large amounts of power. If when turned on and the voltage is set high and the current is low then it quickly drops into Acceptance mode.


BTW, I just now checked my Charge Wizard Status light. It's still not back to the storage mode this morning, unlike just before I disconnected yesterday morning just before I disconnected. I am still in the fast blink "battery-full charge" mode and 13.6 VDC on the house battery.
Click to expand...

I suspect, and don't get mad at me if I'm wrong, that you have either a bad cell in one of your batteries or the battery Wizard isn't quite as smart as the Xantrex. If your batteries are nearly full a Xantrex will bulk charge for a few minutes, switch to Acceptance charge for 5 or 10 minutes then go into float. We see that in the shop all the time when our test battery is fully charged.

I would be nervous if my battery charger stayed in acceptance mode for ten hours, you don't want to boil them dry and ruin them. It would appear that there is no timer in your Full Charge mode to disconnect if there is a problem. Are your batteries hot right now? What is the battery voltage if you disconnect them from everything? (completely remove the wire from the battery.)

Maybe you have a defective Battery Wizard?
 
I homebrewed a manual voltage control for the 9100 series when they first came out 20 years ago.  It's not hard, the Charge Wizard pendant simply applies an analog voltage to the converter's voltage control line.

The problem I was having was the initial portion of the bulk charging mode would overpower my Honda EU1000i generator.  Raising the voltage manually over a few minutes got me past the initial surge, then I could let the Charge Wizard take over.

There are 3 wires going to the pendant, +V, ground and the voltage control line.  All it takes is a potentiometer between + V and ground with the wiper on the control line.  I used a 10k linear pot and added series resistors on each end to limit the adjustment range.  A SPDT switch on the control line will let you choose between the stock Charge Wizard and the manual control.

I don't remember which color wire corresponds to which function but it's not hard to figure out.

This is also a practical way to convert a 9100 series converter to a lithium profile.  Just raise the output voltage from 13.5 volts to 14.6 volts.
 
Not speaking to any particular model or brand of charger but other methods of charge control is watching the rate of change over some time interval of terminal voltage at a known current, or the rate of current at a known voltage.  A charger can "know" a battery is low if terminal voltage is low yet it is accepting high current.  Conversely a battery is near full if terminal voltage rises quickly at the application of nominal currents.  Same for currents, at the application of a "full" reference voltage if current is high the battery is discharged but if current is low, battery is closer to full.  This is basically inverse of how SoC meters can determine SoC during discharge.  More sophisticated SoC methods use a combination of these parameters and often others, such as the use of shaped pulses, loads and alternating currents.  Devices like the victron and trimetric also gather historical data and will apply a correction factor to the empirical data gleaned during cycling.  In terms of just the charge profile, the secret sauce - exact chemistry of the battery - plate alloys, paste formulation, diffusion rate, electrolyte density, on and on - will drive the unique charge profile that should be applied for optimum performance.  One has to trust that the manufacturer data sheet contains this data and if you follow it, you'll achieve the advertised performance.  So at the end of the day one strives to use the charge profile in the data sheet for the particular battery in use, and with any luck the charger used either emulates that automatically or is configurable enough to set the parameters manually.

Mark B.
Albuquerque, NM
 
JayArr said:
Hi DonTom

When in a charging mode that is voltage referenced (Acceptance mode and Float Charge) even when a battery charger wants to put out 14.4 or 13.5 volts the battery will hold that down. It's the difference between the charger voltage and the battery voltage that causes the current to flow. So it's not like it's charging at 14.4 and has to drop to 12.5, It's more like it's charging at 12.51 and has to drop to 12.5

If you take a battery that is discharged to 12.5V and put a meter and a charger on it you won't read the 14.4V of the charger, you'll read the 12.5V of the battery and it will begin to rise as it charges. The voltage the microprocessor reads in the milliseconds that the charger is shut off is very very close to the voltage it was just at with the charger on, it doesn't vary that much and it's almost instantaneous. There is also very little noise on the terminals of a battery, especially a large wet cell, they are pretty rock solid.


You can't tell for sure what state a battery is in from just a voltage reading alone, the battery will be at 13.7V both on the bulk charge stage as it's charging up to 14.5 AND on the float stage as it settles down from 14.4 to 13.5. The circuitry isn't smart enough to tell how much charge is in the battery by voltage alone. Putting the battery into bulk mode as the very first stage gives the microprocessor a second data set, current, that it can use. If, when turned on the voltage is high and the current is high then it is in bulk mode and continues to supply large amounts of power. If when turned on and the voltage is set high and the current is low then it quickly drops into Acceptance mode.


I suspect, and don't get mad at me if I'm wrong, that you have either a bad cell in one of your batteries or the battery Wizard isn't quite as smart as the Xantrex. If your batteries are nearly full a Xantrex will bulk charge for a few minutes, switch to Acceptance charge for 5 or 10 minutes then go into float. We see that in the shop all the time when our test battery is fully charged.

I would be nervous if my battery charger stayed in acceptance mode for ten hours, you don't want to boil them dry and ruin them. It would appear that there is no timer in your Full Charge mode to disconnect if there is a problem. Are your batteries hot right now? What is the battery voltage if you disconnect them from everything? (completely remove the wire from the battery.)

Maybe you have a defective Battery Wizard?
Click to expand...
Sorry for the late reply. I forgot to get back to this thread.


It finally went onto the storage mode several hours later. I can manually switch modes, but I just let it do its own thing. The battery is new, as one of my old 6 volt Trojans had a cell short out at the start of this trip, so I replaced both 6V batteries with a single 12 volt (114 AH) marine battery from Wally*Mart.


I wouldn't expect the battery to get hot at 13.5 volts. That's even less than when I am driving for several hours. My solar controller shows my battery voltage at all times in three large LED digits.


As far as ruining this new battery, I couldn't care less. It's mainly just to finish this trip with then I don't know what I will do with it. I am going to change the battery to a Lith-Ion as mentioned in another thread here.


The Battery Wizard appears to be working fine, I can force it to change modes, if I want, but I don't expect a charge voltage of 13.5 VDC to be a big issue unless it stays that way for weeks and boils the water out and I don't notice.


I have no idea how smart or dumb it is, that is why I am asking questions here about how it works. I will put a scope on the battery when I get home, I don't have one inside this RV. I have several small portable scopes at home.


My Onan 4K generator:
https://u.cubeupload.com/DonTom/RVGen.jpg


My Modified SQUARE (why lie?)Wave inverter:
https://u.cubeupload.com/DonTom/RVInv.jpg




-Don- Turlock, CA
 
The only time I forced a mode change on mine.. For a period I was parked at a shop. I had a limited feed from teh shop so being as the PD-9180 was a plug in type I plugged JUST it into the shop. ran the TV's. computers and such off the inverter.. This includes mu 4-cup coffee pot.

The idiots who assembled my Rig the batteries were under the steps (Front entry just behind passenger seat)
The converter all the way to the back. on the driver's side about 50 electrical feet away.

I kicked it up to BOOST before I made coffee as in Float it would not push enough current through all that (100 foot round trip) wire
 
I don't expect a charge voltage of 13.5 VDC to be a big issue unless it stays that way for weeks and boils the water out and I don't notice.
Click to expand...
The industry standard "float charge" voltage for a 12v battery is 13.6v, so if your battery exhibits any problems with 13.5v (e.g. overheating) then the problem is the battery or high-resistance wire connections at the battery terminals.
 
DonTom said:
The Battery Wizard appears to be working fine, I can force it to change modes, if I want, but I don't expect a charge voltage of 13.5 VDC to be a big issue unless it stays that way for weeks and boils the water out and I don't notice.
Click to expand...

13.5 volts won't cause a 12 volt battery to "boil" (electrolyze hydrogen and oxygen) unless it has a shorted cell that raises the voltage on the rest above 2.7 volts each.  That was a problem with older analog converters where the voltage would rise above there under no-load conditions but not with the newer electronically regulated switching converters.

Besides, the Charge Wizard reduces the converter's voltage to 13.2 volts after 34 hours with 15 minute equalizing bursts every 21 hours to further limit water loss while preventing sulfation.

https://www.progressivedyn.com/rv/charge-wizard/


 
House Husband said:
Here is Lou's Charge Wizard mod. I've been using it for several years. Works great. Thanks Lou..........
Click to expand...

Thank you, House Husband!  I misplaced my drawing of that mod and was too lazy to take my pendant apart and draw it out again.  If you don't mind, I'll file away your nice drawing for future use.
 
Lou Schneider said:
Thank you, House Husband!  I misplaced my drawing of that mod and was too lazy to take my pendant apart and draw it out again.  If you don't mind, I'll file away your nice drawing for future use.
Click to expand...
What does this mod do?


-Don- Auburn, CA
 
It's a manual voltage control for the 91xx series converters.  Lets you set the output voltage anywhere you want from about 10 volts to 16 volts instead of having the Charge Wizard to do it on it's schedule.  For example, you could change the stock 13.5 volts output to 14.6 volts and duplicate the functionality of PD's lithium specific converters.

It goes in the cord going from the socket on the converter to the Charge Wizard.  The switch on the green wire lets you choose between the manual voltage control or the Charge Wizard.
 
Lou Schneider said:
It's a manual voltage control for the 91xx series converters.  Lets you set the output voltage anywhere you want from about 10 volts to 16 volts instead of having the Charge Wizard to do it on it's schedule.  For example, you could change the stock 13.5 volts output to 14.6 volts and duplicate the functionality of PD's lithium specific converters.

It goes in the cord going from the socket on the converter to the Charge Wizard.  The switch on the green wire lets you choose between the manual voltage control or the Charge Wizard.
Click to expand...
OIC, but without the mod, how long will the boost mode last when used with a lithium battery (which I think is about 14.2 VDC)? Wouldn't you say that is enough voltage just by pressing the button to force it to "boost" to keep a lithium charged near full?


-Don-  Auburn, CA
 
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