# Struggles with Tc 3.3Kw Charger



## jbman (Oct 26, 2017)

Hey folks,

I've been struggling a bit with my Tc charger. I purchased it last year, and by the time it arrived and I finally was able to test it, the return period had long expired.

Anyway, I'm using a ZEVA BMS, and the charger is CAN enabled. The BMS activates the charger when I ground the "Charge Sense" terminal.

The charger will activate properly, and everything seems fine. After a few minutes, though, it usually clicks off, kind of like an overheat. The LEDs simply indicate no CAN communication, though. The BMS also said comms to the charger have failed. I spoke with the guys at ZEVA, who said there may have been an issue with the CAN bus being overloaded, but once I found that reducing the amperage max from 15 down to 5 or less usually kept the charger running, we dismissed that. I was too busy finishing up planning for my wedding to deal with it beyond that.

Fast forward, and I'm working on the car again. I'm finding that it still won't charge properly. The higher the ambient temperature, the more quickly it fails. I added a second fan, and it still shuts off, though it will usually go a little longer. The charger barely feels warm (like maybe 5-10 degrees above ambient). It's supposed to shut off at 85C, so something seems off.

The car is basically unusable at this point, because I have to baby sit it or reduce the amperage to <2 to get it to charge semi-continuously through the night. I'm also unable to top it off between trips, so it's tough to go anywhere for an extended outing.

Do you guys have any idea what I can do? I kind of just need a lead at this point, heh.

For reference, this is the charger: Tc Charger
The BMS is from these guys: ZEVA

I'm using their current sensor, EVMS, LCD display, and the BMS modules.

Thanks for looking!


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## goingbush (Jun 20, 2017)

I have the same charger, but (now thankfully) ordered it without CAN , it just has a switch enable / disable . which I have connected to my Zeva BMS .

I did read about someone having issues with the CAN integration with that charger.

Has been faultless though Ive only had the car completed for 6 months & done 3000km now. When I first got the car completed it was in the hottest part of Summer here & we had a week of days in 40 -45c ambient & the charger didn't falter.


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## jbman (Oct 26, 2017)

I was pretty frustrated, because their page did not say that if you ordered with CAN that you couldn't use the manual activation. My plan was to order with CAN, and just use the pins if it didn't work like I wanted. Now I'm stuck trying to figure out why this stuff doesn't work. No one knows, so far.


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## goingbush (Jun 20, 2017)

Must be a different CAN protocol to what ZEVA use, If it was mine I'd cut my losses and open it up, I imagine it would be fairly simple to convert to manual control, as the risk of voiding warranty , which is hard to get honoured from China , (As Im finding with my faulty Sinopoly prismatic cells )


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## jbman (Oct 26, 2017)

goingbush said:


> Must be a different CAN protocol to what ZEVA use, If it was mine I'd cut my losses and open it up, I imagine it would be fairly simple to convert to manual control, as the risk of voiding warranty , which is hard to get honoured from China , (As Im finding with my faulty Sinopoly prismatic cells )


I just asked them to fix it. If they will, great. If not, I'm going to see what I can do. On an older charger, I'd be more confident. I know these have a lot more software than the old stuff, though.


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## jbman (Oct 26, 2017)

ZEVA told me their stuff was specifically compatible with new CAN enabled Tc chargers, and they directed me to buy from green store on aliexpress. Soooo it’s supposed to be 100% supported.


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## Coulomb (Apr 22, 2009)

goingbush said:


> I imagine it would be fairly simple to convert to manual control, ...


I don't know about these later models, but in the older models, this would be a firmware change. With the older models, all charge control is delegated to the CAN master; these older CAN models have no charge algorithm at all. But you can update the firmware on the older models yourself; details on this forum.


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## jbman (Oct 26, 2017)

Coulomb said:


> I don't know about these later models, but in the older models, this would be a firmware change. With the older models, all charge control is delegated to the CAN master; these older CAN models have no charge algorithm at all. But you can update the firmware on the older models yourself; details on this forum.


I asked about that, and they said that there is a physical wire that needs to be soldered in, and that they can't do it once the unit is sealed. I find that hard to believe, unless the unit is literally sealed with some kind of glue on the inside. I'm still waiting on their response at the moment.


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## Coulomb (Apr 22, 2009)

jbman said:


> I asked about that, and they said that there is a physical wire that needs to be soldered in, and that they can't do it once the unit is sealed.


Oh. Maybe there is the equivalent of the attached in there (the photo is from a ~ 2014 model, definitely not a 3.3 kW model). I wonder what the voltage and current settings would be when enabled; I can only imagine that it's flat out with no voltage limit, and it's up to the BMS to tell the charger to turn off. They never documented whether these models still have voltage proportional control, where a voltage between 2 and 5 volts (with respect to the pin marked ground, which is NOT ISOLATED from the pack) gives you 0-100% of rated current.

Did you tell them how many cells etc, so that there is an end voltage built-in to the firmware supplied for your particular charger? I thought that they no longer wanted the hassle of customising the firmware for each customer. I wonder if Elcon in Sacramento can program in a limit and a proper "curve", and whether it can also be a CAN model at the same time (presumably ignoring the internal curve settings when CAN messages are detected).

WARNING: I don't have a traced schematic for any post-2013 TC charger models, so attempt shorting these pins at your own risk. I suggest using a 1 kΩ resistor instead of a dead short, at least to start with, in case 12 V would damage the TEMP input (I'm assuming that this is for the optional external temperature sensor, which uses the same ENABLE input).


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## Coulomb (Apr 22, 2009)

jbman said:


> I find that hard to believe, unless the unit is literally sealed with some kind of glue on the inside.


I've just realized that it could be completely potted. Depending on the type of potting, it might be completely impractical to make this sort of change. If that was the case, you'd think that they'd bring the pin out to some externally accessible connector.


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## jbman (Oct 26, 2017)

Well, I took the cover off and was disappointed...











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## jbman (Oct 26, 2017)

Well, chalk this up to an expensive lesson learned. I'm going to salvage this for parts, later. Does anyone have a recommendation on a cheap charger? The battery pack is 200v, only about 10KwH.


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## kennybobby (Aug 10, 2012)

Is the potting hard and rigid like epoxy, or soft and flexible like a rubber material?

The flexible stuff can be removed, here's a before/after example of digging a board out.


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## jbman (Oct 26, 2017)

It's the soft stuff. I figured I could dig it out, so I got started. I was hoping to hide my shame, but I damaged some surface mount components. Normally I'd give it a try, but they're far too small for my skill level and iron!


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## kennybobby (Aug 10, 2012)

Use a bamboo chop stick whittled on one end to a flat screwdriver blade for scraping the bulk out, then use a pencil sharpener on the other end to make a point for getting into the tiny areas. 
Dont use metal tools unless you can see clearly.

That little resistor can be re-soldered.


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## jbman (Oct 26, 2017)

I’ll deal with it when I’m a little less frustrated. Everything works except this charger, and everyone is blaming everyone else for it.

EDIT: I considered getting something less annoying or oem, but the most economical thing is to try to fix this, first. I’ve set the resistor aside and taken pictures of it’s location. I’ll proceed with wooden tools. Thanks for the advice!

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## Coulomb (Apr 22, 2009)

jbman said:


> Well, I took the cover off and was disappointed...


I must be strange then. I was excited 

Those two large circles poking out of the potting look like film capacitors. Maybe TC have gotten a bit more sophisticated. I've heard bad things about the connectors though.

Thanks for being the guinea pig that documents what's inside those new models. For whatever reason, we've seen nothing about what's inside, and they've been around for years.


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## Coulomb (Apr 22, 2009)

jbman said:


> Does anyone have a recommendation on a cheap charger? The battery pack is 200v, only about 10KwH.


To get your build going while you deal with the charger, consider an older model TC or Elcon charger, possibly second hand. If it's one with a 7-pin round connector, then it's one that can be serviced and firmware altered by users, with assistance from people like Kenny, Pdove, and myself. Perhaps you can get one about the right voltage second hand, and we can convert it to a "CAN" model (possibly serial interface, bypassing the external CAN box). The Zeva BMS might support it directly. Otherwise, get one about the right voltage, and we can adjust it to suit your pack properly.

However, it's a lot of work changing firmware. Also, the relevant posts have been affected by the missing posts problem on this forum. I'm busy recovering the Elcon/TC related posts now.

[ Edit: duh, OP told us he has a Zeva BMS in the first post. ]


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## jbman (Oct 26, 2017)

Thanks for your help and advice. I started digging in over lunch today. Here’s where I’m at...













































Where should I continue digging for now, and should I look for anything in particular?


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## Coulomb (Apr 22, 2009)

> Where should I continue digging for now, and should I look for anything in particular?


I'd say look for the temperature sensor; that should be near the processor. My guess is that the pocessor is on the daughter board nearest the connectors. In the older models, the temperature sensor is an LM20, as shown in the attached. They may well still be using the same sensor, so look for an SOT23-5 device near the processor with a U designation (Uxx, where xx likely won't be 11 any more). You can see it it's outputting sensible readings (it's just an analog voltage), to see if that's why the charging stops too early. But to do that, you'll need to feed power to the processor.


The processor will look different, but it will have many fine leads, probably a lot more than the 28 leads of the old models. [ Edit: my guess is that the processor is near the bottom left of the first photo, if the red and black wires are the CAN wires. ]


So I'd also look for power the power supply; there will probably be at least 2 because a charger naturally divides into a power section before the isolating transformer, and a control section after the transformer. The transformer appears to be the large thing in the middle with the 4 hex-socket bolts. My first wild guess is the silvery rectangle near the top right of the first photo. Try to get some numbers from that/them, so we can look up the specifications and see how to drive it or bypass it. You might also look for pads near the processor with "12 V" on them; they could be a way to power the processor. Finally, look for a voltage regulator near the processor; photo of the old models attached. It could well be a similar 3-leaded device with a bit of a heat-sink. In the old models, it's an SPX1117M3, marked with 1117M3.


Edit 2: Another place to dig is around that resistor you accidentally chipped off. It would be good to see a close-up magnified vew of any markings on the resistor. Or just measure its resistance with a multimeter.


Edit 3: The power supplies might not be separate bricks with part numbers; they might be a bunch of components, likely associated with the bright yellow transformers / multi-winding inductors. For whatever reason, transformer tape is very often that bright yellow color.


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## kennybobby (Aug 10, 2012)

i agree with coulomb about the yellow tape and transformers/inductors.

here is my guess of what we are seeing in your first picture. The micro controller is likely on the board near the header on the lower right corner.

What are the dimensions of this box--it looks kinda tiny compared to the old versions?

i'd say keep digging down on the side walls and maybe the entire center could be removed (after unscrewing the jam nuts on the connectors).

Are there any screws or bolts protruding on the sides or bottom? Maybe something bolted to an internal heatsink?


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## Coulomb (Apr 22, 2009)

kennybobby said:


> What are the dimensions of this box--it looks kinda tiny compared to the old versions?


Mounting holes are 222 x 109 mm. Same height (including fan), about half the footprint, for 1.5x the power. See middle of this page.

That's why I suspect high band-gap switches, running at high frequency (several hundred kilohertz).


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## jbman (Oct 26, 2017)

I haven't had time to dig into the charger more, and I managed to get a very cheap ($185 shipped) Elcon PFC 2500 that's just a year old. It's on its way to California to be reprogrammed now. That'll keep everything running for now while I dig into this charger. When I get some more time I'll tear it apart a bit and post some pics.


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