Blown relay

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hguido1
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Joined: 09/16/2009
Points: 216

I hooked the relay pictured below from my dc converter to give it 12v then I grounded it on the last battery in my series pack. I put 72v on one of the poles to be transfered to my aftermarket controller turn on wire. That way I can still turn the controller on from the keyswitch. It worked running on the stand then I took it for a ride got to around 30mph and the relay blew. I also blew the fuse I installed from the 60v tap to the dc converter. I was wondering if anyone could tell me why? It said it could handle 125vdc unless I read the package wrong.

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hguido1
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Joined: 09/16/2009
Points: 216
Re: Blown relay

Could it have anything to do with me using the last battery neg in the series pack. I ask because that is where it appears black and blown on the case. I looked this relay up on tyco website it is model pclh-202d1s. Far as I can tell this relay is identical to the relay zerogas used except it uses 12v for the coil voltage.

marylandbob
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Joined: 06/22/2009
Points: 520
Re: Blown relay

I am not sure just how you had the total relay wiring configured. I do see that your relay has a 10 ampere rating, but that applies for only up to 24 volts D.C.-Relays will not reliably switch as much power at D.C. as they will on A.C., due to the fact that D.C. voltage tends to SUSTAIN an arc more readily, and such an arc can quickly vaporize the contacts. Special relays, and/or circuitry to suppress arcing are often required when switching high D.C. voltage and/or amperage.-Bob

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Robert M. Curry

hguido1
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Points: 216
Re: Blown relay

The turn on wire to the controller only draws 65ma but I am switching 72v. I can't figure this out it is almost identical to relay that zerogas used to switch 48v from battery to his dc converter. Why would it work until I put a load on it by driving the bike. It even worked til I hit top spead of 30mph.

sixpax2k9
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Points: 285
Re: Blown relay

did u ever use a meter to measure the voltage from first battery positive to 5th batter negative???? If I were u i would wire the negative to the controllers negative. Or at least keep checking voltages. What in the relay is now bad??? the switching coil? the transfer point? You need to find out what blew on the relay. Although there is only a small amperage for the SWITCH in the relay, there may be a lot more in the transfer area. perhaps connect it to a 5V lead instead of a 12V. Without knowing WHAT failed it is impossible to know WHY it failed without a complete diagram.

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Dave ; Tennessee
XB-600.

hguido1
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Points: 216
Re: Blown relay

The coil part is what has shorted I think. I connected the relay power to the red wire with the 10amp fuse. I think that is the dc converter out which should be 12v. I used the 6th battery negative as ground. I check the red wire with the fuse but I couldn't get it to read anymore than 2v. I used the same 6th battery as ground with my voltmeter.

hguido1
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Points: 216
Re: Blown relay

My meter wasn't working correctly. I rechecked that wire this morning and it has 65v on it. So that is why I fried the coil section of the relay. My next question is why does the red wire with the 10 amp fuse have 65v on it? I thought that wire came from the dc converter. It should have 12v correct? Once I figure this out I can install a new 12v relay and fix this problem. Maybe my bike doesn't have a dc converter? I have 12v bulbs in my brake and turn signals though.

marylandbob
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Joined: 06/22/2009
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Re: Blown relay

TWO reasons your red wire from the converter may indicate 65 volts: 1-it could be the INPUT wire. 2:it could be the OUTPUT wire, but you may be using the incorrect source for your GROUND. You must use the CONVERTER ground!-Bob

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Robert M. Curry

hguido1
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Points: 216
Re: Blown relay

ok, so what I don't understand is the converter hooks into the main ground from the battery pack. The wiring diagram I am using show the dc converter as having the input from key switch which would be 65v,the ground would be the battery pack ground and the output shows a wire with has a 10amp fuse. I assume that is the 12v output. I did use the last batteries ground in the series pack as the ground for my voltmeter. Wouldn't that be the same though as using the main ground or is the dc converters ground different even though it hooks back into the main ground. All the lighting circuits hook back to the main batteries ground not directly to the dc converter.

Here is a link to bike wiring http://www.markmilley.com/ev/xb600wiring.png

Could I use the ac version of the relay I used. It has a coil section that accepts 110v ac and is activated by at least 30 % of that so around 33v ac. Would it turn on and work with 65v dc hook to it?

hguido1
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Re: Blown relay

I tested the red wire coming out of the dc converter using the dc converter black ground wire it shows 65v. I then tested the yellow wire from the dc converter using the same dc converter ground wire and it reads 11.7 volts. So I guess the yellow wire is the output but if the red wire that has the 10 amp fuse located by the controller is the input for dc converter then the wiring diagram is wrong. That would be why when I tested the red wire with the fuse yestarday it showed 65v. I used the my 6th battery ground to do that test but it didn't make a difference which ground I used because it has 65v at the dc converter as well. Must be the input I guess.

sixpax2k9
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Points: 285
Re: Blown relay

that red wire is the converter INPUT !!!!!!!!! IE supposed to be the 48V input that is THEN converted into 12V!!!!
If you want a 12V wire that is switch live when the key is turned you need to actually go to the front of the bike and find a 12V wire on the OUTPUT of the converter, then run a wire off that back to under the seat for the relay. The dc converter is actually mounted with the one screw in the front of the bike right behind where the headlights are. The whole front cover comes off, 1 screw in the front, about 4 on the sides of the black kick panel. The dc converter should have several 12V outputs as well as some 5V, find a 12V output and use it!!!!! GO GO Gadget multi-meter!!!!!!

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Dave ; Tennessee
XB-600.

hguido1
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Points: 216
Re: Blown relay

Thanks Sixpax, I am doing what you stated as we speak. The wiring diagram shows the dc converter output having a 10 amp fuse so that is what I used yestarday. Turn out that is the input I guess. Like you said. The yellow wire is the output up front. I will tap that and hook a new relay under the seat should then work. I should have tested that red wire yestarday instead of believing the wiring diagram.

marylandbob
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Re: Blown relay

I also add: Do NOT attempt to use any battery ground other than that of the LAST battery! (You will have severe "groung loop" problems)--Tapping the battery chain for reduced voltage is also a BAD idea, as it will destroy cell balance. If your converter will not tolerate the total voltage, REPLACE IT, use one that will!-Bob

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Robert M. Curry

hguido1
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Re: Blown relay

Your totally right Bob, I am tapping only 5 of the batteries right now. I am going to convert a laptop power supply as the dc converter as someone did here earlier. I have several around the house to use. So no cost. Hooray

I wonder also how hard it would be to convert the stock one to take 72v input?

marylandbob
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Points: 520
Re: Blown relay

As far as the DC/DC converter goes, you could open the lead to its high voltage input, and measure the current with an ammeter, to see how much amperage it takes while operating all lights, etc. Afterwards, you could insert a suitable power resistor, to drop the input voltage. Example: previous voltage was 60 volts, new voltage is 72 volts, current drawn was 1.5 amperes at 60 volts--use a 10 ohm, 25 watt wirewound resistor, it will reduce the voltage by 15 volts, in the example given, putting the voltage back into the "safe" range. (Note: as described, the resistor will dissapate over 20 watts, and will become HOT, this is normal, but it must be mounted so as not to damage other components.)- If your input current is lower than this, the resistor value in ohms, will be higher--for 3/4 amp, use a 20 ohm resistor, for 1/2 amp resistor would be 30 ohms, etc.--Bob
PS:resistor will be cooler at lower current!

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Robert M. Curry

hguido1
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Points: 216
Re: Blown relay

Relay installed today with proper 12v to relay coil coming from dc converter. It is transfering 72v from batteries to turn on aftermarket controller. Seems to be working fine.

hguido1
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Points: 216
Re: Blown relay

The resistor you mentio Bob, would it be wired inline with the power lead to the dc converter? If that is the case could I use a pot to limit the voltage if I didn't know what resistor value to use?

marylandbob
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Points: 520
Re: Blown relay

Yes, the resistor would be added "Inline" with the + high voltage lead to the converter. You COULD use a potentiometer, or rheostat, to adjust the input, but you would need high-power, low resistance unit, which would be large and expensive! (50 ohms at 50 watts, perhaps)-if you have such a device, be sure to set it to maximum series resistance at the start. A series wired ZENER DIODE, rated at 12 to 15 volts, and 50 watts or more, would also work, but the diode would require a fairlyc large heatsink.--Overall, the BEST solution, and the one that reduces drain on your battery, is to REPLACE the converter with a unit designed to operate on the available voltage, without any additional equipment or modifications. (Ideal output voltage is 13.8 volts, D.C. as 12.0 gives dim lights, over 14 volts gives short bulb life.-Bob

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Robert M. Curry

sixpax2k9
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Re: Blown relay

Yes, a resistor wired in line will drop the voltage with respect to the amount of current running through it. V=IR so if current is .5 amp and resistor is 20, thats a 10V drop, so from ~72V to ~62V. Your best bet probably is the computer power supply. That guy running the XM-3000 seems to have set it up great and it can handle the ~84V dc just fine as it seems. However, I kind of like your setup using the 5x 20ah to converter and 1x 18ah 6th battery. I think that keeps them almost in perfect sync. If you go the comp supply route I would look into getting another 20ah battery.

When I blew up my pack I actually replaced them with 22ah batteries at the same or lower cost....
http://www.batteryplex.com/universal.cfm/m/UB12220
Just an idea, they also have 20ah UBs as well.

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Dave ; Tennessee
XB-600.

hguido1
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Points: 216
Re: Blown relay

sixpax2k9 wrote:

Yes, a resistor wired in line will drop the voltage with respect to the amount of current running through it. V=IR so if current is .5 amp and resistor is 20, thats a 10V drop, so from ~72V to ~62V. Your best bet probably is the computer power supply. That guy running the XM-3000 seems to have set it up great and it can handle the ~84V dc just fine as it seems. However, I kind of like your setup using the 5x 20ah to converter and 1x 18ah 6th battery. I think that keeps them almost in perfect sync. If you go the comp supply route I would look into getting another 20ah battery.

When I blew up my pack I actually replaced them with 22ah batteries at the same or lower cost....
http://www.batteryplex.com/universal.cfm/m/UB12220
Just an idea, they also have 20ah UBs as well.

If I understand what that guy with the computer power supply did is he just wired the positive of the computer power supply to the main dc converter red wire and wired the black ground from the dc converter to the ground on the computer powere supply? Then he connected the computer supply output to the yellow wire on the bike. Does that sound right?

sixpax2k9
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Points: 285
Re: Blown relay

I have not studied what he did at all, but if it indeed can handle 110v dc, wiring it the to same + and - that goes to the converter works.(as long as the + is from all batteries) I dont remember which of the lines is the fused one. The red wire 10A fused I am pretty sure is the + supply to the converter. The - is not fused nor goes through the ignition. The circuit is only closed when the ignition is on. I would need to do more analysis, but basically the ignition wire loops from the last battery's + through the ignition back to the converter. As far as the output, once again, I am not sure. I would have to research it again, I am sure u can do the same. If you really need me to let me know and I will check into it.

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Dave ; Tennessee
XB-600.

hguido1
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Points: 216
Re: Blown relay

Sixpax2k9, I think I have it figured out. The red wire at the dc converter is the + from keyswitch. The ground is the black wire and the yellow wire is the output from DC converter. All the wires are there right under the front headlamp. I read the post from the gentlemen that used the laptop power supply. What I read made me believe it is positive to the red wire, Neg to the black wire and the output from the laptop supply to the yellow wire. From what I read online most switching power supplies can be used with straight dc voltage as long as it is high enough. Have you ever heard that before?

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