# TCCH Elcon 1.5kw charger schematics



## kennybobby (Aug 10, 2012)

This is a project to create troubleshooting and repair schematics for the 240vdc, 5amp version 2.0 board. 

Pictures and sketches will be added as available.

Here is a quick basic overview of the electronics inside the box. The main analog power board is screwed to the heatsink. The big power semiconductors are clamped to a central standing set of plates that pass thru a big slot in the middle of the board. The control board is mounted vertically on the edge of the analog board. Left side is AC input power, rectifier, dc boost regulator to 160vdc, and the low voltage supply sections, on the right side is the H-bridge inverter, power transformer and rectifier for the 240Vdc supply,

The voltage and current range of these chargers is primarily determined by the power transformer, either a step-up or step-down, and it is mounted directly to the heatsink thru a big hole in the main board. So you can't take an 80 volt charger and add some trimpots to turn it up to 144, and vice versa.

i will just edit this first post to add and keep it updated--PM me or add a post if you find a mistake or there is something missing, and i can add it to this first post.

top level block diagram
AC input section
Low voltage supply section
High voltage DC output section
Control Board is found in post #2


EDIT: 8/5/2017 Added fresher diagrams modified with Mike's updates, see his notes for details in posts further down in this thread.


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## kennybobby (Aug 10, 2012)

*Re: TCCH Elcon 1.5kw control board*

Here is a sketch of the control board schematic drawn by paul (pdove) and mike (coulomb). There is a much larger version further down in the thread.


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## Harald Niessing (Jul 20, 2014)

Hi,
my TCCH Elcon 2.0kw charger is not working because the two of these 150 ohm resistance were burned. I replaced them but again they burned. I found the TCCH Elcon 1.5kw charger schematics but it is not the same like the 2kw schematics. Do you know somebody who has got a TCCH Elcon 2.0kw charger schematics.
To find the problem I need to have to TCCH Elcon 1.5kw charger schematics.

Thanks in advance.

Bye
Harald
[email protected]


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## Coulomb (Apr 22, 2009)

*Coulomb's schematic index*

Since I seem to be changing my versions of the schematics rather often, I thought I'd put an index here for easy reference. Many thanks to KennyBobby and PDove for the originals on which these are based.

AC Input - DC Boost Suipply (PFC stage).
High voltage DC output section.
The desaturation protection circuit.
Control board schematic as one page; as 4 pages (these have the latest updates).
Paul Dove's Eagle schematics.


====================

It could well be the bridge rectifier. I had one with burned 150R resistors and a bridge rectifier with a short AC to positive, I think.

You should also check for flashover from electrolytics to smaller capacitors. They sometimes use a cap larger than the board was designed for, and clearance can become way too small.


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## kennybobby (Aug 10, 2012)

For troubleshooting and repair please post on the other thread linked below:

TCCH Elcon troubleshooting and repair,

http://www.diyelectriccar.com/forums/showthread.php?t=90162


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## Harald Niessing (Jul 20, 2014)

As I told you both 150 ohm resistance of my 2.0kw charger were burned. This happened after the plug with the 7 pins (CAN-communication) has broken into two pieces (exactly there where the plug is sitting in the case/box of the charger) and I plugged them together but unfortunately in the wrong position then the resistance burned and I heard little noise some where. Could you help me? I like to know what could be happened? Which piece/s died and how could I localise it? As I told you I changed the resistance and they burned again. So there must be wrong something more? It would be very nice of you if you could help me.
Thanks.

Where is the difference between the 1.5kw charger schematics and the 2.0kw charger schematics?

Harald


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## billheckel (Oct 29, 2014)

This information should prove useful, thank you!

I have a 1.5 Kw 48v ElCon with hdw ver 1.5 that has stopped recognizing the attached battery pack. Flooded LA 280 Ah, 48v. Red-Green 1 second constant flashing signal after the algorithm count signal.

Doing basic troubleshooting I found that the 48v lines made it into the charger. Opening the case ( so many screws ) I find that the 2w resistor in series with the diode across the output relay has burned open. Diode is OK.

I jumpered in a replacement resistor and powered up but no success. Started tracing the circuits using these schematics but with the black and yellow goop it is hard to locate components and reliably contact their leads.

The yellow goop is tenacious, any tips on removal?

Others who have had this problem, what was the root cause? Did you have success at repair?

TIA,
Bill


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## pdove (Jan 9, 2012)

The resistors are across the input not the output. They are used as a bootstrap to start the 12 volt logic which then shuts the relay bypassing the resistors.

We have seen several of these where the 12 volts goes out and opens the relay which in turn burns up those resistors because they can't take the power for that long.


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## kennybobby (Aug 10, 2012)

billheckel said:


> ...
> Doing basic troubleshooting I found that the 48v lines made it into the charger. Opening the case ( so many screws ) I find that the 2w resistor in series with the diode across the output relay has burned open. Diode is OK


i've never seen that failure on the output side, but we have repaired a few that failed on the input side. The output relay is energized from the 12V power supply but the resistor-diode is across the output contacts.

The yellow goo will crumble and come off easily after it has been heated until it turns brown. A soldering iron can do it for small spots that you want cleared, or a heat gun can be used to hit large patches.

Good luck and keep us posted on what you find. kenny


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## PStechPaul (May 1, 2012)

The resistors are 150 ohms and could see 120 VRMS if there is a short anywhere on the 160V bus (or if the charger attempts to charge at a high current level into a low voltage battery. That would be 96 watts. There should be some way to disconnect the mains supply in case of a fault like this. The resistors are there to precharge the capacitors. For 1000 uF the two resistors in parallel (75 ohms) have a time constant of 75 mSec and full charge will be applied in 5 TC or 375 mSec. If you replace them with two 1000 ohm 20 watt resistors they will dissipate at most 14 watts each, and the TC will be 500 mSec, with full charge in 2.5 seconds. Seems reasonable to me.


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## Coulomb (Apr 22, 2009)

PStechPaul said:


> The resistors are 150 ohms and ...


I think the original poster was talking about another resistor, one associated with the output relay, not the mains relay.

Also, increasing the pre-charge reististors presumably won't change how fast the relay closes. In fact, it seems to me it closes as fast as the 12 V supply comes up. Slowing the pre-charge will delay that a little, but will leave a longer time when the DC-DC is operating, yet the capacitors are not yet at full charge (i.e., if I'm right, it may well defeat most of the pre-charge process).

However, I'll be the first to defer to you guys' superior knowledge of the charger hardware.


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## pdove (Jan 9, 2012)

Coulomb said:


> I think the original poster was talking about another resistor, one associated with the output relay, not the mains relay.
> 
> However, I'll be the first to defer to you guys' superior knowledge of the charger hardware.


Oh, ok you guys are right. I forgot about that big resistor on the output. I don't believe we have seen that failure. It would be nice to see what the software is outputting. Did you recognize the flash sequence Mike.


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## PStechPaul (May 1, 2012)

I'm not familiar with this charger, but I found the specs:
http://www.elconchargers.com/catalog/item/7344653/7638003.htm

It seems to have PFC so the PF is better than 98%. It also claims to have output short circuit protection, but I'm not sure how that is implemented. I don't understand the function of and reason for some of the circuit elements, and in general it seems way too complex for what it does. 

It looks like the precharge relay does pull in when the 12V supply comes up. If that supply depends on the DC voltage for the raw output supply, then it would stay deenergized until that voltage rose to a nominal level, and would drop out eventually if the output were shorted while in operation or during start-up. A larger precharge resistance would probably also delay the rise of the 12V supply and extend the timing of the relay operation, but it really should be done by the processor or a simple analog circuit that senses the voltage across the relay (and resistors) and pulls it in only when it drops to a safe level. And the power supply should really be ahead of the precharge and rectifier/filter section, so that it powers the processor and other circuitry as soon as the unit is plugged in (or possibly controlled by a small switch).

It looks like the Viper 20A switching supply is configured differently from the recommended circuit:
http://www.st.com/web/en/resource/technical/document/datasheet/CD00070223.pdf


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## Coulomb (Apr 22, 2009)

pdove said:


> Did you recognize the flash sequence Mike?


Red-green flash (no gap) is just "battery disconnected".

I haven't checked, and I'm quite rusty now, but I think that this corresponds to "state zero" before the output relay is connected.


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## Coulomb (Apr 22, 2009)

PStechPaul said:


> It looks like the Viper 20A switching supply is configured differently from the recommended circuit:
> http://www.st.com/web/en/resource/technical/document/datasheet/CD00070223.pdf


It looks pretty close to me, except that the snubber capacitor, with a designator of C16 (suggesting a capacitor, but drawn as a diode) on the circuit diagram in the first post, is actually another diode (possibly a zener diode) in real life. I'd say they followed the suggested circuit at first, and found that the diode worked better in the end. Snubber design is a bit of a black art.

I've had one of those diodes fail, however. I can't remember which one.


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## PStechPaul (May 1, 2012)

There is also something weird with the PNP transistor in the COMP circuit. It looks similar to the slope compensation or current limit connections, but they use NPN transistors. The three diodes in series (D12 and dual D9) also seems odd.

I'm not sure that D1, R1, and C3 in the ST schematic constitute a proper snubber, and the circuit as drawn in the unit schematic is different, even if the diode would be a capacitor. Th values of the resistors (240k) are a lot higher than typical snubbers. Usually a snubber is a capacitor and a fairly low value resistor (10-500 ohms) in series.


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## Coulomb (Apr 22, 2009)

*DC Output Section*



PStechPaul said:


> There is also something weird with the PNP transistor in the COMP circuit. It looks similar to the slope compensation or current limit connections, but they use NPN transistors. The three diodes in series (D12 and dual D9) also seems odd.


Agreed with the oddities, including the snubber on the DC/DC. Perhaps for another day.

I'm going to post my updates to the DC output section, since I'm trying to sort out the snubber for the main MOSFETs. I think PDove was going to do a nice schematic in Eagle, but it may have stalled for time. KennyBobby, perhaps you would like to include this one in the post with the others near the start of this thread. I'd keep the original, in case I've stuffed up or inadvertently made something worse to read.

I'll also attach my desaturation protection partial schematic (see below for PDF version), since all schematics belong in this thread.

[ Edit: here is a partial list of updates: swapped Q1 and Q2, added 1R0 gate resistors, added capacitors C2, C46, C43, C15, and the 0.022uF, CB28 is not connected, asterisked many parts that vary with voltage and power options, and reworked the output relay contact part of the circuit. Added the MOV or whatever it is after the rectifiers D1/D4/D5/D6. Moved R29 to before the final common mode choke. ]

[ Edit Mar/01: Designators for C38, D17; value for C46 ]
[ Edit Mar/01 (2): fixed output relay contacts, shorted inductor. Thanks, PStechPaul! ]
[ Edit Mar/03: A few more designators (R2? -> R2, added L4, L9, large output inductor is definitely L(?) ). Added CB13 and CB20. ]
[ Edit Mar/04: C46 goes to ground, not to transformer B. ]
[ Edit Mar/09: Had Q1/R32/CB21 swapped with Q2/R31/CB18 (had swapped the wrong parts, making it worse than original) ]
[ Edit Mar/11: CB28 is indeed the connection from battery minus to DGND! ]
[ Edit Mar/11 (2): R25 and C43 are after the DC rectifiers (had them after the AC bridge rectifier). ]
[ Edit 2017/Apr/14: One of the C43s -> C34; values and designators for more capacitors. ]
[ Edit 2017/Sep/23: Corrected CB28; R22 range. ]
[ Edit 2017/Sep/24: R22 now 1-20 mΩ. ]

The snubber appears to be just RD (Resistor Diode) with no C (Capacitor), which is a bit unusual, but perhaps not unheard of. Perhaps C46 is part of the snubber arrangement, or perhaps it is attempting to make a resonant circuit, but I somehow doubt that.[ Edit: more likely it's to limit dV/dt, so the MOSFETs don't turn themselves on through Miller (drain to gate or reverse transfer) capacitance when switching off with high dV/dt. ]

The decoupling capacitors seem to be the 220 uF electrolytic C38, which would presumably be pretty useless at high frequencies, and C2, which is just a very small ceramic capacitor. That all seems a little light for suppressing ringing to me, but I'll be the first to admit I'm no expert in this area.

The charger I'm repairing at the moment, despite having tested it switching at 48 V and with 365 V on the DC bus (but not switching), ended up blowing one pair of MOSFETs immediately that it started charging for real. So I'm highly suspicious of the snubber circuit, at least on this charger. I'll test for ringing at 48 V on the DC bus once I replace the chain of parts that died (likely 2 x MOSFET, 1 x driver, possibly 1 x NOR gate, likely 2 x 1R0 gate resistor, will replace the diodes across the 10R gate resistors since they're very hard to test in place).


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## PStechPaul (May 1, 2012)

The first common mode choke (L3?) seems to have the lower winding shorted. Also I don't see how the charging current connects to the output. The relay seems to just switch a capacitor from the green connector to one of two points in the circuit.

The diodes and low value resistors on one leg of the H-bridge seem to dump any high voltage transients back to the DC supply. And I'm not sure of the purpose of the inductor on the low side of the output circuit.


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## Coulomb (Apr 22, 2009)

PStechPaul said:


> The first common mode choke (L3?) seems to have the lower winding shorted. Also I don't see how the charging current connects to the output. The relay seems to just switch a capacitor from the green connector to one of two points in the circuit.


My bad! Thanks for the pointers. Fixed now. KennyBobby, could you please copy the corrected schematic to the first page.



> The diodes and low value resistors on one leg of the H-bridge seem to dump any high voltage transients back to the DC supply.


Yes, where the massive 0.0022 uF capacitor absorbs them!  Edit: But in fact, the resistors would be doing the absorbing. I can't see that the 0.0022 uF capacitor does anything, really. Even at 1 MHz the impedance is 72 ohms. [ Edit: I now believe that C38 absorbs all but the sharpest of the switching transients. ]



> And I'm not sure of the purpose of the inductor on the low side of the output circuit.


It's the big donut shaped one with the voltage and power rating for the whole charger is usually written on it. I think it's just the L part of an LC filter to get rid of the switching noise. It's equivalent to being in the positive side, where it would seem more natural. But the transformer output is floating, so it doesn't matter (except for capacitance to ground).

[ Edit: I now believe that it's essentially part of a buck converter. When the IGBTs are on, the charge current ramps up; when the MOSFETs are off, the battery current ramps down through the battery and the rectifier diodes (D1, D4-6). ]


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## Coulomb (Apr 22, 2009)

*Control Board Schematic*

While I procrastinate over this charger (I can't find anything wrong with the capacitors), I thought I'd post my accumulated changes to the daughter board schematic. I had to save it at 75% size to get it under the 2.38 MB file size limit.

[ Edit: a big thanks to KennyBobby and PDove for the original schematic; despite the changes I made, the original was remarkably good; without it, fault finding on these chargers would not have been possible. ]

The main changes:
* Updates to the desaturation protection circuit, already published, but included for completeness.
* Added some designators, such as D4, D7, U12.
* Corrected some component values, mainly around U13 pin 5; R60 10R -> 100k; R73 3 kR -> 499 kR.
* Added some calculated voltages, mainly around U13 pin 5.
* Corrected some CON32S connections, e.g. 13 and 20 don't go to GND, but to the full bridge outputs.
* Added a few missing components, such as C58 (near Q7, upper left).
* Renamed 12VDC_Aux to 15VDC_Aux, reflecting the actual voltage better.
* Redrew several transistors as dual diodes.
* Made connections to the 7-pin round and 5-pin rectangular connectors more obvious.
* Added some text suggesting function, e.g. what the jumpers are for, when the comparator outputs are high, and so on.
* Added some missing connections, e.g. to the SYNC and VC pins of U14. Pin 13 of U13 connects to pin 12.
* Moved C50 from across R63 (U2 pin 13, near top left) to pin 19.
* Added a few test points, e.g. T44, T45, T33, T34.

Edit Mar/06:
* R107 goes to CON32S pin 5 now, for current sensing.
* Updated some resistor values: R107, R108, R110, R101.

Edit Mar/11: CB28 is indeed the connection from battery - to DGND! (Later changed to CB27.)

Edit Mar/18:
* Fixed R69, R75 go to source, not ground.
* Added part number for D5,D6 (also used in power supply)
* Tentative value for C40, C43: 3.3 nF

Edit Mar/28:
* Fixed PFC OVP threshold to 425 V

Edit 2017/Feb/23
* Added TP29; C38 and C46 definitely 100nF; D4, D7 LGE -> BR6.

Edit 2017/Sep/23
* CON32S pin 28 is a no-connect
* R23, R10 vary with voltage and/or power
* Added note re shunt across R10 via R20.

Edit 2018/Mar/13
* U2 powered by 15VDC_Aux (thanks, KennyBobby!)

Edit 2018/May/24
* Added R103, moved R98, C58; values for C56, C58.


Edit 2020/Jun/20
* See also the schematic on four pages, more up to date than the attached.


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## kennybobby (Aug 10, 2012)

Thanks for checking all this Mike and making corrections. On U2 there are shown two connections to gnd on the left side of the chip shown in the diagram. Those actually go to either end of the sense resistor bus wire soldered on the bottom of the main board, and are used to measure current for the PFC controller. i made this discovery and redlined a drawing but the updated diagram didn't get finished.


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## Coulomb (Apr 22, 2009)

kennybobby said:


> Thanks for checking all this Mike and making corrections.


Thanks for the originals.



> On U2 there are shown two connections to gnd on the left side of the chip shown in the diagram...


Great pickup! I didn't totally follow what you said, so I traced it myself.

I've modified the control board diagram to suit, and include a modified AC input diagram showing R13.

How does that compare with what you came up with?

Edit: added PFC MOSFET gate resistors, designators for L12 and R25.
Edit: added R15, C10, C3, CON32S 11, fixed designators for R5, C37.
Edit: Removed R25, C34 (on DC output schematic now).
Edit Mar/29: Input relay returns to DC-, not neutral.
Edit Apr/06: Added designators for the two large polypropylene capacitors (C8 and C26)
Edit Aug/04: Added designator for C7, one of the main filter capacitors.
Edit Dec/21: Added part number for Q7, Q8 (PFC MOSFETs).
Edit 2017/Apr/06: Corrected C37, values for C3, C9, C10, C11. R3 seems too big for 2W; marked as "3W?". C37 connects to other side of R13.
Edit 2017/Apr/07: C8, C26 are X2, not X1. Tidied up.
Edit 2017/Apr/25: values for _three_ snubber capacitors were wrong! (C11, C37, C10)
Edit 2017/May/01: C5 -> C100


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## Coulomb (Apr 22, 2009)

I had somehow convinced myself that the connection from battery negative to digital ground (DGND) was somewhat tenuous, about 3kR comes to mind. While tidying up one of the diagrams, I decided to check where CB27 and CB28 actually connected to on the main board, even though I had in mind that there was no connection on the control (daughter) board. But I found that indeed it was to pack negative via CB27, and indeed CB27 and connect to the digital ground plane of the daughter board (DGND), which indeed connects to the 5-pin connector and elsewhere.

Sigh.

My apologies if I led anyone astray by that. I've updated the schematics (the two relevant ones are a page back now).


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## crackerjackz (Jun 26, 2009)

when I read your posts is when I realize. even if I have an electronics degree and am an electrician who debuggs multi million dollar machines that I don't know shit lol ... 


my charger has had a very bad end concerning water  .... water got into the trunk some how and the charger wasn't charging ... lights would go on ect ... realized I was getting an error checked properly and saw water was about 1/3 the height of the charger  .... cleaned out the water toke out the charger opened it up and dried it with air and then next to my fire place about 3 feet away for 1 hour .... 

plugged everything back in except the bms enable cable .... turned it on nothing .... realized my mistake and plugged in the cable .... still nothing .... its in worse condition than when I even opened it up to dry lol .... I should hopefully get time Friday to open it up again and fully check the schematics ... im guessing ive got a blown control power supply  ... plug it in now and although I hear some electric noises like humming ect .... nothing turns on ... no lights whatsoever and no raised output voltage ...


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## pdove (Jan 9, 2012)

That sounds bad. What sort of help do you want? Can you remove the cover and take some photos?


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## crackerjackz (Jun 26, 2009)

No lights whatsoever come on so im guessing i dont have control voltage present .... toke some pics ... visually nothing looks horrible :s friday i should get time to start testing a few things .... no fuses blown or obvious resistances blown as ive checked everything easy .... i think


Envoyé de mon iPhone en utilisant Tapatalk


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## crackerjackz (Jun 26, 2009)

Envoyé de mon iPhone en utilisant Tapatalk


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## PStechPaul (May 1, 2012)

For a device that has been immersed in water, it is a good idea to scrub everything using hot water and detergent, followed by a rinse with hot (preferably distilled) water, and finally a thorough drying using a heat gun. It may be good to remove all connectors to make sure they can be dried out. What is the black coating on the bottom? 

Good luck. 

Did you ever get your charger back from Valery?


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## crackerjackz (Jun 26, 2009)

PStechPaul said:


> For a device that has been immersed in water, it is a good idea to scrub everything using hot water and detergent, followed by a rinse with hot (preferably distilled) water, and finally a thorough drying using a heat gun. It may be good to remove all connectors to make sure they can be dried out. What is the black coating on the bottom?
> 
> Good luck.
> 
> Did you ever get your charger back from Valery?




Iwater in the trunk was 1/3 of the charger ... this thing is sealed pretty well when i opened it up only a few ml came out and the only traces i could see were on the horizontal control board specifically were the little button is to change programs .... 

I have the emw charger back .... i just had so many issues with emw plans being wrong i wouldnt trust the charger even if i got it to work and my time is limited :s ( 3 kids and 36 horses to take care of lol ) .... if you would still be interested in me shipping it to you send me your address in pm ill get a quote and see if it could be worth me sending it to you .... obviosly i would take care of return shipping ... 


Envoyé de mon iPhone en utilisant Tapatalk


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## Coulomb (Apr 22, 2009)

Reply moved to the TCCH Elcon charger troubleshooting and repair thread here. It would be nice to keep this thread for schematic updates and discussions if possible.


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## Coulomb (Apr 22, 2009)

Ick! I had the values of _three_ snubber capacitors wrong. Corrected now in this post.


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## Coulomb (Apr 22, 2009)

Here's another thing that took me a long time to get straight in my head.

Several posts back I noted that DGND on the daughter board was connected almost directly to battery negative, only via half of L4 and the shunt resistor R22. The latter is only 1-10 mΩ.

This means that the negative input of the shunt amplifier op-amp (first half of U6) is connected to DGND via a 100Ω resistor. Since the shunt has negligible resistance compared to the shunt amplifier circuit, it also means that R10, which has a value from 3 kΩ to 6.2 kΩ depending on the model, is shunted by R20, another 100 Ω resistor! They go to a lot of trouble to make the positive and negative inputs have the same resistance to DGND, so how does this work?

It turns out that the op-amp isn't particularly bothered. Yes, there is only 2-3 mV at the op-amp inputs, but it amplifies these by the gain to place the output at about 100-200 mV above DGND (about twice as high as it would be if CON32S pins 24 and 27 weren't connected together, it seems).

It's something to keep in mind if you're checking the shunt op-amp. A moderately common failure mode is for battery voltage to end up at the current shunt, sometimes burning PCB traces, and often one or both of the 100 Ω resistors (R20 and R21), so one might get caught up with this unusual arrangement.


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## Coulomb (Apr 22, 2009)

After years of working with these chargers I've finally figured out what the resistor and diode are for, across the output relay.

Before the output relay is energized, there can be a substantial difference in voltage between the battery voltage and the DC bus (charger output) and its capacitors. They prefer to use a cheap AC rated relay, and besides it's just hard on the contacts and the capacitors to connect uncharged capacitors across an EV sized battery. So before they close the relay, they make sure that the MOSFETs are off for half a second, so that R2 can approximately equalize the capacitor and battery voltages.

But then, when you first connect the battery, there will be this capacitor charging current, which would still cause an unpleasant, though modest, spark when connecting the battery. So they put in diode D12 to prevent this. But now the charger output has to be higher than the battery voltage before the output capacitors discharge _down to_ the battery voltage.

So in RELAY_SET, they spend the first 1.5 seconds asking for one fortieth (2.5%) of the maximum charge current, which will ramp the output capacitors from zero to somewhere near the maximum charger voltage. From 1.5 to 2.0 seconds after calling RELAY_SET, they set the charge current to a small negative current that guarantees that the MOSFETs will be off. This allows the capacitor voltage to "free wheel", allowing D12 and R2 to discharge the capacitors to approximately the battery voltage. At 2.0 seconds, the relay is energized, shorting D12 and R2 so that the full charge current can go to the battery.

When disconnecting the output relay, the output current is ramped to zero so that the MOSFETs are again turned off before de-energizing the relay. When the contacts open, they will be switching essentially zero current.

All these long delays mean that some of the main loop code as to be replicated in the various RELAY_SET loops. So they've gone to a bit of trouble to get this right.

It's a quite neat system. The only problem is that you might receive a mild shock through D12 and R2 if you touch the charger output when the relay is supposed to be "off". But even that should never happen, because the output voltage won't ramp up if no battery is detected. With no battery detected, it stays in "stage zero", blinking the LEDs in warning, and doesn't call RELAY_ON at all.

The value of R2 in the schematic, is shown as 100K*. The asterisk means that the actual value will depend on the exact model of charger. 100K is for a quite high voltage charger (around 300 V), and lower voltage models will come with lower valued resistors so that the larger valued capacitors can still equalize voltage in the given half second.


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## Coulomb (Apr 22, 2009)

I decided that I needed a new print of the control board schematic. The last one I printed on 4 pages, and cut and taped them together into something like an A2 sheet.

To avoid that work, I've split the control board into 4 parts, so I can just print the 4 pieces and staple together. The four parts are attached. Depending on feedback, I may decide not to update either the large schematic or the 4 page version in future.

This version incorporates some changes around the PFC MOSFET driver transistors (Q6, Q7 of the control board; note that one of the PFC MOSFETs on the main board is also designated Q7). I ended up replacing Q6 and Q7 on the control board when not necessary, because it looked like they were both low resistance base to emitter. With the corrected schematic, you can see that you expect 44 Ω from each base to each emitter. To test the transistors, you have to remove R98 first, or test with at least about 20 mA of current.

I hope I have it right now; it seems odd to have the two identical networks R103/C58 and R99/C56 in parallel.

Edit 2018/Aug/09: Added test point T17; moved C14 to the other side of R16 (page 2).
Edit 2020/Jun/20: Added several capacitor values from this post (thanks, reedb!)
Edit 2021/Jun/22: Added C39, C42; Clarity.
Edit 2021/Jul/11: C64 → 4.7 μF
Edit 2022/Jul/12: Added desaturation protection links page 3 to page 2.
Edit 2022/Aug/26: Added C51 to page 1; moved U13 pin 8 to page 1 and redrew


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## pdove (Jan 9, 2012)

I finally got around to putting the daughter board in Eagle. You can't build it from this because I didn't get all the packages right but it should be right electrically. You all can scrutinize it and see if I made any mistakes. I did find at least one part that wsn't on the prvious versions. It's a power supply supervisor on the reset line.


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## Coulomb (Apr 22, 2009)

Here are Paul's three schematics as portable network graphics (PNG) images.


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## Boulder Hybrids (Jan 30, 2013)

*Re: 20 Free Broken Elcon Chargers !!*

\March 10, 2020 : all the chargers are spoken for and GONE!

______________________________________________________

March 2, 2020. I have approx 20 of these chargers, all broken!

Free if you pick them up in Boulder Colorado or pay for freight shipping (must take all, on a single pallet sent to a USA commercial address for me to ship them). 

If anyone wants to try their repair skills send me a pmail and we'll work it out.


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## Coulomb (Apr 22, 2009)

I just unnecessarily replaced U14, the UC3836N PWM chip, because I thought it can't be right that one output had 57% duty cycle, and the other 11%. But after painstakingly pulling out all those pins to replace the chip, I found the same behavior with a new chip. This was with only the 15VDC_Aux connected, to power up the control board on its own, nothing at AC-in or on the DC bus.

I guess it must be an artefact of the desaturation protection circuit, or some such. I don't think that there are many of these left in service, but this might prevent someone else from wasting time replacing a good PWM chip.


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## Coulomb (Apr 22, 2009)

*The Desaturation Protection*

I'll briefly describe how I think this works here. I was sure I described it elsewhere, but I can't find it now. Schematic trace in PDF: https://www.diyelectriccar.com/attachments/elcon-desat-schematic-pdf.131310/










The upper diodes (Q14 and Q19, these aren't transistors) ensure that the circuit only has an effect when the lower transistors are conducting, so the gate signals are near +15 V. R59 and the left half of "Q14" charges C40 to the highest voltage across the MOSFET drain to source voltage, plus one diode drop. The bottom of R59 is one diode drop higher, and the common between the two sides falls back to one diode drop above the drain-source voltage. Obviously, if the Q1 (right hand) side has a higher voltage, that takes precedence.

If the lower MOSFETs aren't saturating properly, this voltage will be higher than normal, which will pull up the CS+ voltage (current sense input of the PWM chip). The chip thinks that too much current is being drawn (it probably is), and throttles back its pulse width. The various resistor values are carefully chosen to hopefully bring the transistors inside their working area, preventing catastrophic failure. At least, that's the theory; I've seen enough blown MOSFETs to know that it doesn't always work. Who knows how many failures it does prevent.

The reasons for the sync pulses and the ramp current injection via Q5 and R50 is a mystery to me. Maybe Q5 simulates a proper current shunt signal, to "keep the PWM chip happy", and Q4 simulates the dead time when neither transistor is conducting. If that's really what it's for, it seems it would have been easier to provide the actual measured current. Maybe that's too noisy to get it to work reliably.

[ Edit: Following Paul's post, corrected "D6 charges C40. ]


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## pdove (Jan 9, 2012)

Coulomb said:


> The upper diodes (Q14 and Q19, these aren't transistors) ensure that the circuit only has an effect when the lower transistors are conducting, so the gate signals are near +15 V. D6 charges C40 to the highest voltage across the MOSFET drain to source voltage, plus one diode drop. The bottom of R59 is one diode drop higher, and the common between the two sides back to one diode drop above the drain-source voltage. Obviously, if the Q1 (right hand) side has a higher voltage, that takes precedence.


Hey, nice to hear from you again. See you are still playing with these chargers.

I think you meant "D5 charges C40".


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## Coulomb (Apr 22, 2009)

pdove said:


> Hey, nice to hear from you again.


Likewise!



> See you are still playing with these chargers.


They find me! I can't hide! 



> I think you meant "D5 charges C40".


Huh, I screwed it up pretty bad. Edited now. Thanks for pointing that out.

I've updated the control board schematic page 1, moving a piece of the circuit from page 2, and redrawing it. I needed to make more sense of the connection to the Vfeed input of the PFC chip recently. Schematics are here.


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## Coulomb (Apr 22, 2009)

The resistor arrays in series with diodes D3 and D2 are hard to see under the black rubbery goo, but I'm finding that they are often damaged, so it's good to know what is supposed to be there.

In the more recent 2 kW models, each seems to be 3S of 5 resistors in parallel: three 8.2Ω on the bottom row, and two 22.0Ω on top of them. That comes to 2.19Ω per 5P block, so with three of these in series, the result should be 6.56Ω. Each of these are M3216 size (1206 imperial). I'm guessing that they use individual resistors like this to increase the effective power dissipation. They put the higher values (lower power dissipation) on top, which is good because they will be heated by the ones underneath.

It gets really confusing when you only see the top layer of resistors.

I note that the original schematic, for 1500 W models, showed different values for these resistors (8.2Ω and 12.3Ω); these seem to have a single plane of all 8.2Ω resistors, one 3S3P resulting in 8.2Ω, and one 3S2P, resulting in 13.2Ω (4.4 x 3). I have no idea why the 1500 W model needs different value snubber resistors.

The below represents both arrays in the 2 kW model:


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