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Re: EV car conversion hardware
Posted: Mon May 04, 2020 6:55 pm
by mdrobnak
Kevin Sharpe wrote: ↑Mon May 04, 2020 6:30 pm
mdrobnak wrote: ↑Mon May 04, 2020 5:58 pm
Re: ISABELLENHÜTTE 1000A CAN Shunts could someone tell me what they are being used for? Are they required to get the DC current info in the web interface for the VCUs? It's just unclear why I'd want to buy it.
It measures pack voltage at three locations, current, has a coulomb counter, is a BMS, and has lots more functions (see datasheet). It's a standard feature of Damien's conversions today and going forward. If you don't want to reinvent the wheel then invest the 160 euros
We'll document many of the features in the wiki;
https://openinverter.org/wiki/Isabellen ... te_Heusler
So the part that confuses me is - OK great, pack voltage measurement (in multiple places)..but no balancing. So it doesn't really replace a BMS in that respect. Coulomb counter / kWh used definitely useful. I guess multiple datapoints is not necessarily bad, so maybe I'll buy it anyway.
Re: EV car conversion hardware
Posted: Mon May 04, 2020 7:20 pm
by johu
Could you please move this discussion to a bespoke thread, thanks
Re: EV car conversion hardware
Posted: Mon May 04, 2020 7:31 pm
by arber333
Well you need your voltage and amp counter in your ev. But from them you get your power and energy left in battery.
If I didn't have one EVdisplay left to use I would definitely buy one of those sensors.
Re: EV car conversion hardware
Posted: Mon May 04, 2020 8:06 pm
by Kevin Sharpe
mdrobnak wrote: ↑Mon May 04, 2020 6:55 pm
So the part that confuses me is - OK great, pack voltage measurement (in multiple places)..but no balancing. So it doesn't really replace a BMS in that respect. Coulomb counter / kWh used definitely useful. I guess multiple datapoints is not necessarily bad, so maybe I'll buy it anyway.
It's very simple, you follow Damien's lead or choose your own path
Re: EV car conversion hardware
Posted: Fri May 22, 2020 5:59 am
by konstantin8818
Are this contactor assemblys from Toyota HV battery of any good use?
Two contactors at both positive and negative lines, precharge relay with resistor and as far as I can say - with built in current sensor.
Why I'm asking? There is a guy, who sell toyota HV cells, and those assemblys are "leftovers no one needs"
and he sell them for ~30 euro, and as he says, he have got "many of those".
I've bought one and tested - it works.
Re: EV car conversion hardware
Posted: Fri May 22, 2020 9:15 am
by Kevin Sharpe
konstantin8818 wrote: ↑Fri May 22, 2020 5:59 am
I've bought one and tested - it works.
How long did you run the contactors for? You need to run them for an hour or so at ~14V and measure the temperature rise to ensure they will work long term.
Great find even if they need external economizers
Re: EV car conversion hardware
Posted: Fri May 22, 2020 5:37 pm
by konstantin8818
Kevin Sharpe wrote: ↑Fri May 22, 2020 9:15 am
How long did you run the contactors for? You need to run them for an hour or so at ~14V and measure the temperature rise to ensure they will work long term.
Great find even if they need external economizers
Will do. Just need to wait until summer refreshes in it's memory it is time to show up
My garage is opened to every winds. I've just detached economizers from kilovac contactors, because they were jumping like crazy. So I need to attache them back?
Re: EV car conversion hardware
Posted: Fri May 22, 2020 6:32 pm
by Kevin Sharpe
konstantin8818 wrote: ↑Fri May 22, 2020 5:37 pm
So I need to attache them back?
If you run a contactor that requires an economizer without one then you'll burn out the coil.
Re: EV car conversion hardware
Posted: Fri May 22, 2020 9:04 pm
by xp677
You can also just send a PWM signal to them (this is essentially what the economiser does). Start at 100% and then drop it to whatever keeps it closed.
I use this code to achieve this:
Code: Select all
#define CONT_MAXPWM 2550 //start pwm value
#define CONT_MINPWM 1280 //end pwm value
#define CONT_PWMRATE 1 //rate of change
//setup
int c_pos_pwm = CONT_MAXPWM;
//contactor function, called from loop
if (contactor[C_POS])
{
if (c_pos_pwm > CONT_MINPWM) c_pos_pwm -= CONT_PWMRATE;
analogWrite(CONT_POS, (int)c_pos_pwm / 10);
}
else
{
analogWrite(CONT_POS, 0);
c_pos_pwm = CONT_MAXPWM;
}
//same again for negative contactor, etc
Of course you need a suitable circuit to drive the coil. Best to keep the economiser. I run Kilovac contactors (with economiser), with a 10A relay to trigger them. The code above is used as an economiser for the 10A relay.
Re: EV car conversion hardware
Posted: Sat May 23, 2020 10:37 am
by konstantin8818
xp677 wrote: ↑Fri May 22, 2020 9:04 pm
You can also just send a PWM signal to them (this is essentially what the economiser does). Start at 100% and then drop it to whatever keeps it closed.
Of course you need a suitable circuit to drive the coil. Best to keep the economiser. I run Kilovac contactors (with economiser), with a 10A relay to trigger them. The code above is used as an economiser for the 10A relay.
I'm barely understand this programming thing. Also contactor in this board activates true BTS117. Are they capable of handling PWM signal? Won't they overheat? I'll better solder those economisers back.
Re: EV car conversion hardware
Posted: Sat May 23, 2020 11:08 am
by Kevin Sharpe
konstantin8818 wrote: ↑Sat May 23, 2020 10:37 am
xp677 wrote: ↑Fri May 22, 2020 9:04 pm
You can also just send a PWM signal to them (this is essentially what the economiser does). Start at 100% and then drop it to whatever keeps it closed.
Of course you need a suitable circuit to drive the coil. Best to keep the economiser. I run Kilovac contactors (with economiser), with a 10A relay to trigger them. The code above is used as an economiser for the 10A relay.
I'm barely understand this programming thing. Also contactor in this board activates true BTS117. Are they capable of handling PWM signal? Won't they overheat? I'll better solder those economisers back.
Most contactors require economizer functionality to minimise power consumption in the coil. This can be built into the contactor, an external circuit, or via software/hardware in the controller.
AFAIK none of the Open Inverter boards support software/hardware economizer functionality directly (they're just simple switched outputs) and therefore you need to implement this yourself with an external board or use a contactor that has the functionality built in.
Re: EV car conversion hardware
Posted: Sat May 23, 2020 11:34 am
by konstantin8818
Kevin Sharpe wrote: ↑Sat May 23, 2020 11:08 am
AFAIK none of the Open Inverter boards support software/hardware economizer functionality directly (they're just simple switched outputs) and therefore you need to implement this yourself with an external board or use a contactor that has the functionality built in.
I used to program Curtis inverter and that guy wasn't happy about economiser. There are parameters as pull in and hold voltages, it also detects any failure within any circuit. Really bullet-proof design as it turns out=)
Re: EV car conversion hardware
Posted: Sat May 23, 2020 11:38 am
by Kevin Sharpe
konstantin8818 wrote: ↑Sat May 23, 2020 11:34 am
Kevin Sharpe wrote: ↑Sat May 23, 2020 11:08 am
AFAIK none of the Open Inverter boards support software/hardware economizer functionality directly (they're just simple switched outputs) and therefore you need to implement this yourself with an external board or use a contactor that has the functionality built in.
I used to program Curtis inverter and that guy wasn't happy about economiser. There are parameters as pull in and hold voltages, it also detects any failure within any circuit. Really bullet-proof design as it turns out=)
The great thing about open source is that you can change anything you want. Indeed, Damien and Johannes are using different contactor driver chips iirc. My approach is to use contactors with built in economizers and that's something we recommend on our courses
Re: EV car conversion hardware
Posted: Sat May 23, 2020 12:18 pm
by xp677
BTS117 contains a load of extra components for the various protection measures, not sure how it would handle PWM, I imagine it would depend on your switching frequency.
The economisers which come with the Kilovac contactors are best suited for the job.
I was advised (probably in another thread on this forum) not to use transistor-based switching for the power input to the economisers on these contactors. Which is why I used a small relay.
The PWM code above is just there to reduce the power consumption of that relay. It reduced the relays coil power by about 1W, which is a good result for just a few lines of code.
Re: EV car conversion hardware
Posted: Sat May 23, 2020 1:14 pm
by Kevin Sharpe
xp677 wrote: ↑Sat May 23, 2020 12:18 pm
The PWM code above is just there to reduce the power consumption of that relay. It reduced the relays coil power by about 1W, which is a good result for just a few lines of code.
Just to be clear, was that code tested on non modified open inverter hardware and if so which boards?
Re: EV car conversion hardware
Posted: Wed May 27, 2020 12:27 pm
by bobby_come_lately
I'm struggling to find one of the commonly used Panasonic relays from the Leaf or Ampera for the precharge on my project - at least at what feels like a sensible price. Mostly £30-40 used from China. Is there any reason I couldn't use something like this? Not much more and it has the advantage of being new:
https://uk.rs-online.com/web/p/solid-st ... s/0352496/
Re: EV car conversion hardware
Posted: Wed May 27, 2020 9:17 pm
by xp677
Those are only suitable for AC. The nature of these units is that once triggered, they remain on until the current falls to zero. in a DC application, this would make them impossible to turn off. This is what they mean by "zero crossing", they turn off as the AC waveform crosses zero.
One example of use for these SSRs is for intensity control (dimming) of high powered resistive lamps. If you trigger them with a pulse, they will remain on for the remainder of the AC half-cycle. Thus the power transferred is the area under the curve.
I used the EV200 contactors for my precharge - overkill for the application, but they are available second hand at reasonable cost.
DC-rated switchgear will always be more complex and expensive compared to that designed for AC, as any arc created during an opening event will not self-extinguish. Features such as arc chutes, vacuum chambers, plated contacts, magnets, etc are added to higher voltage DC rated contactors to help extinguish this arc. Also remember when installing them that they are often polarity-sensitive.
Re: EV car conversion hardware
Posted: Thu May 28, 2020 7:29 am
by jnsaff
I have a bunch of the 800VDC/100A rated small contactors up for sale here:
viewtopic.php?f=12&t=712 if you can switch off after pre-charge is complete you don't even need an economiser.
Re: EV car conversion hardware
Posted: Thu May 28, 2020 3:53 pm
by bobby_come_lately
xp677 wrote: ↑Wed May 27, 2020 9:17 pm
Those are only suitable for AC. The nature of these units is that once triggered, they remain on until the current falls to zero. in a DC application, this would make them impossible to turn off. This is what they mean by "zero crossing", they turn off as the AC waveform crosses zero.
One example of use for these SSRs is for intensity control (dimming) of high powered resistive lamps. If you trigger them with a pulse, they will remain on for the remainder of the AC half-cycle. Thus the power transferred is the area under the curve.
I used the EV200 contactors for my precharge - overkill for the application, but they are available second hand at reasonable cost.
DC-rated switchgear will always be more complex and expensive compared to that designed for AC, as any arc created during an opening event will not self-extinguish. Features such as arc chutes, vacuum chambers, plated contacts, magnets, etc are added to higher voltage DC rated contactors to help extinguish this arc. Also remember when installing them that they are often polarity-sensitive.
Thank you. Really useful answer. Learning a lot here!
Re: EV car conversion hardware
Posted: Thu May 28, 2020 3:55 pm
by bobby_come_lately
jnsaff wrote: ↑Thu May 28, 2020 7:29 am
I have a bunch of the 800VDC/100A rated small contactors up for sale here:
viewtopic.php?f=12&t=712 if you can switch off after pre-charge is complete you don't even need an economiser.
Thank you. Already have a couple of contactors on their way from you! Will let you know on these.
Re: EV car conversion hardware
Posted: Thu May 28, 2020 5:11 pm
by SciroccoEV
xp677 wrote: ↑Wed May 27, 2020 9:17 pm
Those are only suitable for AC. The nature of these units is that once triggered, they remain on until the current falls to zero. in a DC application, this would make them impossible to turn off.
In a precharge application, the current would drop to zero once the main contactor closed. However the leakage current can be a problem.
I've used SCRs in series with relays. The relay contacts are closed under zero current conditions and then the SCR is triggered.
Re: EV car conversion hardware
Posted: Thu May 28, 2020 9:47 pm
by xp677
SciroccoEV wrote: ↑Thu May 28, 2020 5:11 pm
xp677 wrote: ↑Wed May 27, 2020 9:17 pm
Those are only suitable for AC. The nature of these units is that once triggered, they remain on until the current falls to zero. in a DC application, this would make them impossible to turn off.
In a precharge application, the current would drop to zero once the main contactor closed. However the leakage current can be a problem.
I've used SCRs in series with relays. The relay contacts are closed under zero current conditions and then the SCR is triggered.
In an ideal world, yes. However this would rely on the leakage being low enough to allow the SCR to open, and would necessitate the precharge completing with the "main" contactor closing (imagine if you turned the ignition key to "OFF" mid-precharge, for example).
Such events could perhaps be solved with logic (for example, opening a separate contactor elsewhere in the chain) and component choice, but the fact remains that components would have been chosen which are unsuited to the task at hand.
Re: EV car conversion hardware
Posted: Fri May 29, 2020 6:50 am
by arber333
bobby_come_lately wrote: ↑Wed May 27, 2020 12:27 pm
I'm struggling to find one of the commonly used Panasonic relays from the Leaf or Ampera for the precharge on my project - at least at what feels like a sensible price. Mostly £30-40 used from China. Is there any reason I couldn't use something like this? Not much more and it has the advantage of being new:
https://uk.rs-online.com/web/p/solid-st ... s/0352496/
I have used AEV52012 from Nissan Leaf in a lot of applications. It is really a good small relay for HV. Dont make a mistake, it is not a contactor. It can release up to 20A. As i presented it in the beginning of this thread you can get it for like $40 or so with shipping. I consider this a fair price.
https://www.ebay.co.uk/itm/FedEx-DHL-ON ... SwnhFeeaCP
It has two magnets under silver contacts which pull down arc discharge before it fully forms.
Also i tried to use it for heater control and it worked ok. You need to keep the amps low though and use PWM so it doesnt release under full power.
I tried to use SSRs, even the mosfet version and they failed miserably when releasing under power. Dont reccomend them above 120Vdc.
Re: EV car conversion hardware
Posted: Fri May 29, 2020 7:49 am
by bobby_come_lately
I've gone ahead and ordered an AEV52012 but only place I could find one at that price was from China so it's going to take a few weeks to arrive. Surprised no UK breakers seemed to be selling them. Might have to get friendly with a local scrap yard. Miss the old days when you could just roam around and pay on the way out. If anyone knows of a yard like that in Manchester... Guessing health and safety might rule it out though.
Re: EV car conversion hardware
Posted: Thu Jun 04, 2020 6:24 pm
by Hank
Hi,
I'm not super happy with the stock HV cables for the LDU from Tesla, and am considering building my own bespoke cables, but there are some bit's I don't know how to source, or even what they are called. They are the connectors/Shielding terminators in the attached photos.
Any help would be appreciated.