renix ballast resistor amperage?

How many amps run to the ballast resistor?How many amps after the ballast resistor?I'm working on a kill switch.....
I'd test it with my DVM but the amp rating on it is real low and I dont want to take a chance on blowing my meter.

Where you at ecomike or 5-90?

Check the amp rating on the fuse that protects the pump and there's your answer! You don't want the switch to be rated under the fuse's amperage rating. Sorry I can't be more exact. :dunno:

:cheers:

"Check the amp rating on the fuse that protects the pump and there's your answer!"

I wish it was that easy......

outlander said:

I wish it was that easy......

Click to expand...

It is.

The fuse needs to be the weakest link of the circuit so it will blow/open during an overload.

If the fuse is a 10 amp, then your switch needs to be rated above 10 amps.

While I don't claim to know everything, I've been doing the hobbiest electronics thing for about 35 years and a amateur radio operator for about 15.

:cheers:

the amperage will not change before and adter the resistor, but the voltage will. place your dvm across the resistor (one probe on each side) and have someone in the jeep turn the vehicle from off to on, and then start it. watch the voltmeter, and keep track of the highest reading it gives (probably just after the fuel pump finishes its first charge). do this a few times to make sure you get the highest voltage.
after disconnecting at least one end, measure the resistance. divide your max voltage by this resistance, and double the result to be safe. this is what you want your switch rated for.

Cant you just use Ohms law to get the voltage drop knowing the resistor is 1.1ohms

crystalship1 said:

It is.

The fuse needs to be the weakest link of the circuit so it will blow/open during an overload.

If the fuse is a 10 amp, then your switch needs to be rated above 10 amps.

While I don't claim to know everything, I've been doing the hobbiest electronics thing for about 35 years and a amateur radio operator for about 15.

:cheers:

Click to expand...

what I am saying is the renix motor doesn't have a fuel pump fuse.It has a fusible link.Your 97 is probably different....
I fully understand the part about the switch rating....

Should I add an inline fuse to the wire comming off the ballast and into the cab to my switch or is the ballast wiring already protected?Anytime I have hot wires running into the cab without a fuse inline I get nervous

outlander said:

what I am saying is the renix motor doesn't have a fuel pump fuse.It has a fusible link.Your 97 is probably different....
I fully understand the part about the switch rating...

Click to expand...

Ahhhhh.... OK. I got 'ya now!! :doh: :thumbup:

:cheers:

If I were to wire a kill switch in the Renix system I'd do it directly to the +12VDC feed to the ECU. That wire will be under your dash and quite hard to get to (making it less likely somebody will find it) and pretty small amperage.

I don't have any wiring diagrams handy or I'd give you more information.

I can tell you from experiance that if that circuit is blown there is *no* starting the XJ (had that fuse link die on me a long time ago).

Sequoia

Muad'Dib said:

Cant you just use Ohms law to get the voltage drop knowing the resistor is 1.1ohms

Click to expand...

simply put, yes. put being a pump (inductive laod), there will be a moderately large transient voltage and current, and just using the steady 12-14v may not provide for enough safety. personally, i would put the kill switch on the starter relay signal wire, which provides +12v to the relay in the PDC with minimal current (less than 500 mA)