Blown relay
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.
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
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.
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
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!!!!!!
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
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!
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
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.
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.
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.