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Discussion Starter · #1 ·
Hello,
I have a question about contactors. I am connecting the above setup on my truck and am unsure of the correct number of contactors required and their configuration. Has anyone put there installed such a dual motor/dual controller setup?
Thanks,
John
 

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I assume that the plan is for two motors (in one case as the AC-35x2), each with their own controller. I can see how this causes confusion... does one contactor supply both controllers, or should each controller manage its own contactor? If you use one contactor, be sure that both controllers are ready before closing it, and that either controller can open it.

By the way, the 1239E controllers are from Curtis (not HPEVS), and the AC35 motors are from HPEVS (not Curtis) - just a typo, I assume.
 

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By default Curtis controllers supplied with HPEVS motors are programmed to have a contactor controlled by the controller, and won't function without one. It is also the recommendation of Curtis to have the contactor controlled by the controller as a failsafe, though it's not super clear to me which failure modes they're trying to address - maybe MOSFET short circuit ?

Either way, sticking to the recommended way you will have one contactor per controller, with each controller wired to enable the contactor when key switch is turned on.

Second option is to disable main contactor in each controller, and have one contactor keyed externally (like by the BMS, for example) to supply power to both controllers. I have a machine setup that way at the moment... mainly because I don't have a contactor suitable for Curtis :D
 

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Some basics:
-one main contactor per controller, wired directly to controller (no bms cutoff in the coil circuit or anything else that will affect it.)
-no enconomizers on contactors. No flyback diodes.
-48v contactor coil or higher suggested.
-ensure contactor driver PWM pull in voltages and hold voltages programmed correctly
-make sure the relay or switch turning on KSI pin is rated for batt voltage and at least 30A to be safe.

That stuff for starters.

Please do share more info on your components and connections.
 

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Discussion Starter · #7 ·
Thanks everyone for responses. I am embarrassed that the very title of my post is bassackwards 😬
I have Gigavac contactors (GV200PA-1) as supplied by HPEVS, the recommended resistors and pre charge relays also supplied by them and their very well done instructions. I also have purchased 12 Tesla module S modules and Dilithium BMSC and BMSS for a system with about 144V and around 500 amp-hours to power my 1953 Dodge military power wagon.
My confusion around contactors came when I saw EVWest’s diagram showing two contactors connected to a single 1239e. HPEVS shows only one per controller. Should I in fact be wiring 4 contactors into my system (2per controller)?
 

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My confusion around contactors came when I saw EVWest’s diagram showing two contactors connected to a single 1239e. HPEVS shows only one per controller. Should I in fact be wiring 4 contactors into my system (2per controller)?
There is an extra contactor in that EV West diagram (which is for one controller running one motor) just to control power to the DC-to-DC converter - it has nothing to do with motor control. So no, not two per controller as far as the Curtis controllers are concerned.
 

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-ensure contactor driver PWM pull in voltages and hold voltages programmed correctly
-make sure the relay or switch turning on KSI pin is rated for batt voltage and at least 30A to be safe.
Oh sheesh... I was giving misleading info here that applies to the 123X controllers that handled their own precharge. I did not put 2 and 2 together that the 144V (with 12V logic that does not reference B- ) does not precharge itself as you only feed 12V to pin 1 (KSI).
Also:
-no enconomizers on contactors. No flyback diodes.
For anyone else building off this info I am not sure if these suggestions apply. The controller already may have the lower hold voltage as an option (so probably still no economizers?), and it appears the coil flyback voltage suppression is still built in to the controller as they show no other device across the coil.

Out of curiosity do you happen to have pics of your supplied precharge resistors and relays? I have a 144V 1239 that I will need to wire up soon and had not arrived at your predicament yet. I did not buy it as part of a package, it was at auction with one AC35. This thread has been helpful to me as I was going to get pretty confused when I went to build the harness from memory of 1238 96V. I already left a skid in my pants when I first went to power it up with a 96V supply (assuming it would still turn on at a lower than 144 voltage) and supply negative to B- post and I got nothing. I then learned of the 12V KSI and was sure I had fried it, but I guess the isolation from logic to battery circuit is pretty good, as it was ok. This suggests a much more reliable controller than those that reference B- for CAN, serial, logic etc as most of the broken 1238's I have worked on suffered from failures caused by big V spikes or major current events, cooking the logic circuit in some way.

Thanks, Brian! That makes sense. So, I’ll need 3 contactors right?
A contactor for the DCDC might be the easiest way, but as a cheaper option I set up my little truck's DCDC with a manual precharge and overnight park switch. The system was all wired with the DCDC getting constant power from the traction battery which meant the DCDC was on for probably a good part of 12 years (from previous owner design) and had died, also with the parasitic draw on the battery pack being undesirable. I put a momentary 15A switch from battery + to a chassis mount resistor in parallel with an LED, and all that in parallel with a larger lockable disconnect switch. My DCDC has pretty sparky inrush when connected to the battery so the precharge idea was to save the disconnect/overnight/storage switch contacts from pitting.
 

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Discussion Starter · #12 ·
DMPstar,
I’ll post the resistor and relay pictures tomorrow. They’re temporarily mounted in the truck while I make a mounting box for them. Thanks for the clarification. I’m finding that there aren’t many folks out there with this combination of motors and controllers - heavier truck than most conversions.
John
 

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Discussion Starter · #16 ·
Good catch, Remus. Thats the relay that came with my “kit” from EVAmerica a little over a year ago and I just assumed it was right for this setup. I’ll order the correct ones from EVWest.
Thank you,
John
 

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You should not be using an AC-rated contacts relay to switch DC.
Remus, your abrupt statement may be interpreted that there are only relays for switching DC or relays for switching AC. As you know, they will sometimes have a rating for both, but with the DC voltage contact rating being lower than that of the AC rating. As for this one the datasheet only briefly mentions DC contact rating at 28V, so it is not rated for this application. Likely it can handle it, but using it is not best practice. I would risk it with a manual override switch in case of failure, but that's just my budget and comfort level with relays.
Just wanted to clarify that as you weren't around to scrutinize your own statement ;)
 
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