Pre charge resistor Wattage

[markz]

What value and style of fuse am I suppose to use on the positive power line?
I have the Lyen 18fet rated for 65A, but likely push it higher.
http://www.be-electronics.com/category_s/1963.htm?searching=Y&sort=1&cat=1963&show=300&page=1

I bought 150 ohm 5 watt made by NTE from same store B & E Electronics, will put it on the + line.
Where do I hook up the switch on the power + line? in series? And this will be the main power kill switch? And I should locate it on the handle bar for quick turn-offs?

Then I should also have an iginition switch, also located on handlebar, ideally close to throttle?

 

[pendragon8000]

What value and style of fuse am I suppose to use on the positive power line?
I have the Lyen 18fet rated for 65A, but likely push it higher.
http://www.be-electronics.com/category_s/1963.htm?searching=Y&sort=1&cat=1963&show=300&page=1

I bought 150 ohm 5 watt made by NTE from same store B & E Electronics, will put it on the + line.
Where do I hook up the switch on the power + line? in series? And this will be the main power kill switch? And I should locate it on the handle bar for quick turn-offs?

Then I should also have an iginition switch, also located on handlebar, ideally close to throttle?

ok, you're talking about 3 seperate things.

the power switch is just a switch, use the switch wire and the main positive on the controller, put a switch between there, yeah you can extend that to the bars, Lyen used to sell switches for that, if not check on ebay or ebikes.ca.

the fuse should be on the positive of the battery fairly close to the battery so you have minimal wire that isnt protected by a safety device. the fuse can be a high power car amp one, theres some nice fancy gold ones. or check digi key or element14 for hRC fuse, this is ideal but some would say over kill. make sure you insulate it real good with a few layers of thick heatshrink or pot it in a small box or something. other substitute is a circuit breaker. a high voltage DC is preferable but again some ppl say thats over kill and many use a high power car stereo one, eg "80 amp car stereo circuit breaker".

and the precharge, this can be wired on all the time, or with a push button and also with an led. my preferance is the put a push button on the main power connector so when you grab the controller and battery power plugs you can push the button with your thumb and watch the led light and fade, then you know the voltage is equal in the controllers capacitors and the battery and no spark will result during connection (sparks are scary!)

how to...
ill edit this post shortly with a video and diagram from an old post...
[youtube]nomBFTh3Fn8[/youtube]
where i have the 300A switch that would be a plug normally (spade lug etc) , and the mom switch is a momentary push button.

 

[gwhy!1]

A couple of months ago I fitted a couple of these onto customers bikes to see how well they hold up.. and so far so good no signs of pitting or carbon, and makes the whole thing a lot more tidy. .. I did remove the small locking lug on the plugs as these made the plugs very awkward to disconnect.
View attachment 1
http://www.hobbyking.co.uk/hobbyking/store/__61690__XT90_S_Anti_Spark_Connector_2pairs_bag_.html

HK also do these 7mm anti-spark plugs, I havent tested these yet but dont see why this will not be also a good solution..

http://www.hobbyking.co.uk/hobbyking/store/__42825__7mm_AS150_Anti_Spark_Self_Insulating_Gold_Bullet_Connector_2_Pairs_.html

 

[whatever]

what voltage will the hobbyking antispark connectors handle up to?

 

[whatever]

another question:
when using an led in series with precharge resistor, the led goes out when caps are charged, it would be nice if instead of the led going out, that it comes on when caps are charged......can anyone think of a simple way to achieve that?

 

[wesnewell]

Don't know about the XT90's, but the AS150's are worthless for spark arresting above 44V with a small 6 ohm resistor in them. They are rated for up to 200A though for the connector.

 

[gwhy!1]

the xt90's i have used are on 48v (lifepo4 )systems so hot of around 55v and have been fine as antispark , the xt90 plugs will be safe to use upto around 80-90v , I dont know what the resistance is on the xt90's but I expect it not to be a lot .. I will check and report back but I expect they are going to about the same as the AS150's, as long as when the controller caps are charged the plug is inserted fully asap they are fine , which is one fluid movement. The faster the caps charge the less time the resistor has to heat up , with the xt90's @55v you dont have to think about waiting for the caps to charge you plug it in in one fluid movement thats another reason i removed the small tag because it you stay to long on the precharge part of the plug it will get hot and possibly cause problems due to the current used by the controller lv circuits.. on some of my bikes I use a 180ohm 2W resistor and if I unlink the direct connection the resistor gets hot just because of the lv current in the controller.. dont forget that the anitspark resistor is only there for the very,very initial current flow which only last less than a fraction of a second ( with a small value of R ) of course this depends on the value of your R , if its to big in value then the inrush of current will take much longer to charge up the caps maybe 1-2 sec.

 

[pendragon8000]

another question:
when using an led in series with precharge resistor, the led goes out when caps are charged, it would be nice if instead of the led going out, that it comes on when caps are charged......can anyone think of a simple way to achieve that?

the indicator led can be done with a push button as i mentioned but conect the leds resistor and negative to the controller power pos and neg. this will light full brighnes when the controller has full voltage. it shouldnt be conected without a switch because the resistor will be working pretty hard, but for just a second while connecting the plug its okay.

I have thought about using a bi coulor LED so it fades from red to green, or use 2 leds.

peace
Ken

 

[gwhy!1]

just measured the xt90's resistor value and its 6ohms so the same as the AS150's

 

[wesnewell]

Well, they may work on some low voltage controllers that have really small caps, but I think they would be worthless on large controllers with large caps. A 6 ohm resistor just won't stop the spark enough for many ebike controllers. I started with a 570 ohm resistor and it only had a small voltage difference, so there was still a big spark when plugging in the mains. I found a 150 ohm 10W was perfect for 48V and higher controllers. The voltage came up to about 10V under the the battery voltage. I run 100V with 1000mF caps in the controller. I bought some AS150's a long time ago and never even tried them when I found they only had 6 ohm resistors since I knew what would happen with them. Someone else had already reported they gave a big spark on his controller and blew the resistor iirc.

 

[gwhy!1]

I tested the xt90's on one of my 6kw 48v controllers without issue and as I have said 3 customers 48v bikes 6 months ago and he plug are as good as the day they were fitted.

 

[whatever]

some interesting info/views,
I think it might be possible to have an led that lights up, but might require matching a resistor/led combo to a given voltage
battery, there might also be a way to do it with zener diodes?

 

[pendragon8000]

yeah my opinion is basically look at the video i posted at the top of this page and see a moderately big controller being charger with 100v in a second or two, through 100 ohm resistor.

Its all good.

 

[whatever]

its interesting how quickly the caps loose their charge also, I wonder if that is just normal internal discharge of the caps,
or some other reason? Seems to me some controllers hold the precharge and others it disappears quickly.
Anyone know the reason for quick discharging of the caps?

 

[TheBeastie]

its interesting how quickly the caps loose their charge also, I wonder if that is just normal internal discharge of the caps,
or some other reason? Seems to me some controllers hold the precharge and others it disappears quickly.
Anyone know the reason for quick discharging of the caps?

Digging to the limits of my knowledge it could have something to do with the size of the motor or just stuff like the CA, 5000uf of capacitors isn't a lot of energy at the end of the day. It could be that if plugged in longer the stored energy in the motor in the form of inductance could help hold on to more charge in the controller but as far as I know inductance energy takes longer to build up because with inductance comes impedance.

 

[pendragon8000]

its interesting how quickly the caps loose their charge also, I wonder if that is just normal internal discharge of the caps,
or some other reason? Seems to me some controllers hold the precharge and others it disappears quickly.
Anyone know the reason for quick discharging of the caps?

Digging to the limits of my knowledge it could have something to do with the size of the motor or just stuff like the CA, 5000uf of capacitors isn't a lot of energy at the end of the day. It could be that if plugged in longer the stored energy in the motor in the form of inductance could help hold on to more charge in the controller but as far as I know inductance energy takes longer to build up because with inductance comes impedance.

Aabove a certain voltage, it's a saftey rule to have a discharge resistor that reduces the stored voltage to under a certain voltage within a set time.
although some controllers dont have a discharge resistor i think.