electrical connector question

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paulga

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DD
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Marine Trader Sundeck 40'
there are situations where I need to manually jump a pump, either the fuel lift pump on a westerbeke 6.0, or a small metering pump on a CDH. what cable and connectors do you usually use to clip to a house battery or a distribution panel?
 
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I have never jump started a pump (what kind?) and don’t understand why you would need to do it.

But use a cable, heavy enough to carry the pump motor starting current, roughly 3 times running current, and big enough to keep the voltage drop below 1 volt at that current. Then put alligator clips on both ends big enough to get over the terminals.

David
 
I have never jump started a pump (what kind?) and don’t understand why you would need to do it.

But use a cable, heavy enough to carry the pump motor starting current, roughly 3 times running current, and big enough to keep the voltage drop below 1 volt at that current. Then put alligator clips on both ends big enough to get over the terminals.

David
I agree with the above. But would be cautious in this. That's why my answer was short. You could back feed the whole boat. I would disconnect any other wires attached to the pump.
 
I agree with the above. But would be cautious in this. That's why my answer was short. You could back feed the whole boat. I would disconnect any other wires attached to the pump.
yes. i got the wires need to be disconnected first
 
I don’t fully understand the question as well. If we are taking something light duty I would use alligator clips, just like jumper cables.
 
I have never jump started a pump (what kind?) and don’t understand why you would need to do it.

But use a cable, heavy enough to carry the pump motor starting current, roughly 3 times running current, and big enough to keep the voltage drop below 1 volt at that current. Then put alligator clips on both ends big enough to get over the terminals.

David
is "heavy enough" to say the wire gauge? what specification of the wire does "big enough" refer to?
 
Greetings,
Ms. p. The question has been asked: What are you attempting to do? I'm curious, as well.
 
With what little info you have provided so far I would say 10 gauge wire with heavy alligator clips on both ends.

David
 
With what little info you have provided so far I would say 10 gauge wire with heavy alligator clips on both ends.

David

I found 22-14g alligator clip online, but it may be too small for a battery post?

I need to make the jumper cable myself, because the electrical port on the CHD metering pump requires a 2-pin harness connector. I need to get such a harness and splice to the cables using some butt connectors

Image_20240503144937.jpg
 
I added a fuel lift pump to a fueling system before the filters on it’s own 12 volt switch and breaker with a 3 way valve. No chance of back feeding fuel or voltage. The small pump you pictured, you could do the same thing.
 
I added a fuel lift pump to a fueling system before the filters on it’s own 12 volt switch and breaker with a 3 way valve. No chance of back feeding fuel or voltage. The small pump you pictured, you could do the same thing.
Thanks for the idea.
but this work is very low frequency. it's only needed at every filter change on the gen. racor, and is really a one time thing at the mounting of the CDH metering pump. so I'd save the effort of installing a lift pump and consider making a manual jumper tool.
 
I agree with the above. But would be cautious in this. That's why my answer was short. You could back feed the whole boat. I would disconnect any other wires attached to the pump.

i didn't think it through how the back feed could happen when the existing wires are not disconnected. Here is an diagram of the gen. battery and the fuel lift pump. the curved wires are the jumper cables, the arrows are the alligator clips. The existing circuit remains open when the generator is not running. Even if I do not disconnect the existing positive wire from the pump, how is voltage back feed a risk?

Screenshot 2024-05-05 232341.png
 
It is not a risk in the circuit you’ve drawn.
 
This was not mentioned or I didn't catch it in the first few post "The existing circuit remains open when the generator is not running."
 
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