Anti Spark Connector for High Current AND High Voltage

crossbreak

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Hi,

after some friends burned their resistors in their XT90s connectors again, i'd like to try something new. XT90S are fine but they have limitations:

xts-1.jpg


:) hardwearing, you may even step on it without breaking it
:) foolproof, you cannot plug it were it does not belong
:) bend protection
:) Anti-Spark function, long service life
:( Use them below 60V, only 5.6 Ohm resistor value can be bought
:( Use them below 90A
:( Need for lots of heat shrink (only for the old XT90 version without anti spark function)
 
i like the 8mm HXT connectors
29529.jpg

:) good for 150A or even more
:) no need for heat shrink
:) bend protection
:( no anti spark function, wears out quickly
:( not really hardwearing
:( not foolproof: it's possible do connect two lipo packs 1:1 so they do great fireworks (the so called suicide trick)
 

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My idea was to build a connector that is
:) 150A, up to 100V max (non lethal voltage), variable NTC resistor. the user can solder it by himself according to system voltage and cap capacity. Some may want really (physically) large resistors so they dont burn eventually
:) hardwearing
:) foolproof, you cant plug it were it does not belong
:) self-explanatory, you directly feel the orientation it is plugged in, I tried to connect XT90S with wrong orientation several times in the dark. I always got it right in the end but this is what i think is not so user friendly.

The design uses 3 pins: Negative, positive and precharge Pin. The precharge (anti spark) pin is 4mm, the other two are 8mm gold connectors. The positive pin is recessed, so the negative and precharge pins establish contact before the positive pin does. So there are some milliseconds, maybe 100ms that can be used to charge the caps of the controller power stage. Both the positive pin and the bush are recessed 1.5mm, so in total they connect 3mm later than the negative and precharge.

I call it the HXT150S connector :p what do you think? Yet it is only an idea
 

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why only 100V? A child could touch both pins at once as there is no effective ingress protection. I for more then 100V the child may die off a ventricular fibrillation.

voltages below 120V are seen to be low risk https://en.wikipedia.org/wiki/Extra-low_voltage
 
Design spaces for seals and design for cheap injection mold tooling capable, and we can make a run of them or whatever the Ebike community most needs.
 
+4 small pins for BMS communiction. maybe they fit below the precharge pin.

i dont have any idea about how to add seals without the need for a lock clip, that i dont want. do you have an example?

HXT connectors are injection molded so i see no reason why these could not be made that way?
 
i had a look at the hall connectors from a kelly controller. the seal engages fine even if the lock clip isnt engaged. It engages radially, i always though it would engage axially which would need the clip to be engaged.

But without the outer encasement, the seal itself would not be protected when stepping on the plug though. An outer encasement like the kelly connector has, would make the hole connector significantly larger which i dont want either.

the question is: how waterproof shall it be? HXT connectors fit quite tight, there is very little room for water to get in. Yet in terms of corrosion they have worked quite well for me yet

The cable side of the connectors can be either water proofed by silicone or by rubber seal rings that are pushed onto the cables prior to soldering. For XT90S the silicone yet has worked well for me, it even provides some additional bend protection
 

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hey it can be hard to get hands on some chinese people here in Germany ;)

the positive pin cannot be plugged in till the end completely, as it is recessed by 3mm. But the last 3 mm dont carry current anyway as can be seen in the picture. contact pressure at the end is close to zero anyway... so i am confident the full potential of the bulled plug can be utilized
 

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I suspect if you put a rubber O-over the male parts of the connector it might seal when the connectors are pushed all the way together.
 
Any voltage over (48) volts can hurt you. I touched my (72) volt on my (72 volt meridian trike) and it bit the (SHISS) out of me.
 
Great Idea, could you make it with the wires on it already ?

Do the two main connectors need to be over 4 mm ?

Perhaps the main connectors 4mm and the middle 3 or 2 mm.

Or you can design/sell , different models, the under 60 volt / 30 amp ones that would be 4mm,
and for hotrodders/ high power bikes larger than 4mm.



crossbreak said:
My idea was to build a connector that is
:) 150A, up to 100V max (non lethal voltage), variable NTC resistor. the user can solder it by himself according to system voltage and cap capacity. Some may want really (physically) large resistors so they dont burn eventually
:) hardwearing
:) foolproof, you cant plug it were it does not belong
:) self-explanatory, you directly feel the orientation it is plugged in, I tried to connect XT90S with wrong orientation several times in the dark. I always got it right in the end but this is what i think is not so user friendly.

The design uses 3 pins: Negative, positive and precharge Pin. The precharge (anti spark) pin is 4mm, the other two are 8mm gold connectors. The positive pin is recessed, so the negative and precharge pins establish contact before the positive pin does. So there are some milliseconds, maybe 100ms that can be used to charge the caps of the controller power stage. Both the positive pin and the bush are recessed 1.5mm, so in total they connect 3mm later than the negative and precharge.

I call it the HXT150S connector :p what do you think? Yet it is only an idea
 
Not a reinvent, because doing a 4mm version of your HXT150s , would be smaller than the XT90 big fat yellow housing, .. and 4mm version one , should be able to carry enough amps for mid voltage bikes. , 4mm version would fit into tight battery cases, and wire harness better.
Many people now use Turnigy batteries, and the 4mm bullet connectors, I would like them better because ,
My next build I want all the connections to be hidden as much as possible, to make the bike look like a regular bike as much as I can, Hide all the wires.
I am sure many people want to hide as much of the wiring as possible.

and the HXT150s that you are designing would be used for the Higher Amperage / Faster Hot Rod Bikes.

Just saying two sizes could be a good thing. one for low-mid range Amperage's/Voltages, and one for Higher Amperage's / Voltages .
With corresponding wire sizes .

crossbreak said:
Why reinvent the xt90s?
 
you only need one of these connectors in your vehicle... so i dont get why you are concerned about size?

If you want to connect multiple lipos this is not the right plug. go for HXT instead. Lipo wiring will always be a mess...another reason to go 18650 ;)
 
Oh, So you are only making this for plugging the charger into the battery pack ?

I was thinking of smaller ones so I could take my battery pack off my bike for charging, when going into a store for quite a while, and for using the same battery on 2 different bikes.

So also between the battery and controller as well.


crossbreak said:
you only need one of these connectors in your vehicle... so i dont get why you are concerned about size?

If you want to connect multiple lipos this is not the right plug. go for HXT instead. Lipo wiring will always be a mess...another reason to go 18650 ;)
 
sure it's the same plug for charge and discharge. if you carry your charger with you then - sure - you have 3 connectors with you in total.

As said, i use Xt90s for a while now and i'm quite happy with them, aside from being limited in power. I'd really like to go higher power but yet there is no off the shelf connector solution
 
BLUESTREAK said:
Any voltage over (48) volts can hurt you. I touched my (72) volt on my (72 volt meridian trike) and it bit the (SHISS) out of me.

you are right. 60V is the limit for so called "Extra Low Voltage". Only then no ingress protection is necessary. All builds here that use XT90 or HXT plugs with more than 60V violate IEC in this manner.
One could argument that the XT90s battery side is ingress proof. Sure it is. But the controller/charger side is not. The controller still has charged caps after disconnecting the battery. If you put your finger in the connector, it bites you. I dont like black fingers, but an ingress protection is really hard to archive in this kind of connector.

Would be nice to have it, but would also be nice if it wouldn't become that bulky :? If there was the 4 additional pins for data connection, the battery voltage could be turned off by the BMS as soon as the plug is pulled. This way the big bullet pins would not need any ingress protection as they would only have voltage when the connector is engaged. I think the SAE J1772 works that way

When not mated, J1772 connectors have no voltage at the pins
https://en.wikipedia.org/wiki/SAE_J1772

SAE J1772 connector
220px-SAE_J1772_7058855567.jpg
 
They are called AS150 connector. Nice, but doesnt meet the specs. A friend told me that precharge resistors dont last at higher voltages, he gave up on them and is back to XT90S. Personally I would never use them as battery connector since there is no protection against reverse polarity. For cell series connection these are too expensive, Anti-spark is not needed for this anyway. Maybe OK for experimentation but not for every day use.

I'm trying to implement 4pole data connection and seals ATM. Data connection can be UART, USB, I²C or any other that uses 4 pins. +5V is provided to power some logic on the other side, or a galvanic Isolator

Pins are :
  • +5V
    Data- or Data
    Data+ or Clock
    logic ground

Same pinout as USB
 
doh!

as i know you are a professionel expert, can you explain what resistor i need for 20s (84v) and 150A Battery Current for a few seconds on accelerate....

(how someone can calculate it for himself)


i would do it this way till your build is ready ;D

https://endless-sphere.com/forums/viewtopic.php?p=1133371#p1133371
 
you can calculate using this calculator: http://scriptasylum.com/rc_speed/nospark.html

i think a 5W resistor with 10 Ohms should match your needs. An NTC resistor would be even better, as it speeds things up: At the beginning, current is high but resistance is also high, saving the charge pin due lower current flow (still high like 500A in the chart, still lower than a constant resistance). Some milliseconds later, the resistor warmed up and has lower resistance, thus the much lower currents that flow then are enhanced a bit.
But i think this 5W 10 Ohms resistor will do just fine for your setup

https://www.reichelt.de/5-Watt-axial/5W-AXIAL-10/3/index.html?&ACTION=3&LA=2&ARTICLE=2595&GROUPID=3117&artnr=5W+AXIAL+10
 

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