Should controller pv and batt inputs be fully sealed up?

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Should controller pv and batt inputs be fully sealed up?

Postby Jman » Mon Nov 12, 2018 7:30 pm

Hello,
The part of the exposed copper cable after being stripped of insulation and slided into screw terminal opening just looks open and exposed to air and moisture. If we are suppose to heatshrink all cable terminations againts oxidation, should this area of the controller be sealed up with some temporary sealant?

Thanks.
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Re: Should controller pv and batt inputs be fully sealed up?

Postby jules » Tue Nov 13, 2018 12:40 pm

You could solder the tips of the wires that you're going to insert in the screw in connectors of your CC. Stopping oxygen and moisture from finding their way into stripped wires is next to impossible. I'm presuming that the amount of insulation you've stripped off the wire allows you to insert the wire into the screw in connector so that there's no bare wire showing.
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Re: Should controller pv and batt inputs be fully sealed up?

Postby Jman » Tue Nov 13, 2018 5:43 pm

jules wrote:I'm presuming that the amount of insulation you've stripped off the wire allows you to insert the wire into the screw in connector so that there's no bare wire showing.


Yes, but the air & moisture will readily get in as the terminal is far from airtight. I read how soldered tips will soften & cause the connection to loosen. Is there some kind of sealant that won't harm the copper & I can just cover the whole area up that can be broken off easily at a later date?
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Re: Should controller pv and batt inputs be fully sealed up?

Postby jules » Tue Nov 13, 2018 7:04 pm

Yes, they do compress slightly over time, though they will never fall out. It's not all that tricky to just tweak the screws every now and then and they do seem to settle down. Even with bare wire it's a good idea to check the screws occasionally as the wires seem to deform slightly

Most CCs generate a small amount of warmth, so while the oxygen is there, the moisture is kept at bay. You certainly wouldn't want to use a sealant that could wick into a joint and reduce conductivity. In theory you might be able to use neutral cure silicon but it would be very hard to get a complete seal, messy and of little or no advantage to the integrity of the connection.
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Re: Should controller pv and batt inputs be fully sealed up?

Postby davidg » Wed Nov 14, 2018 4:19 am

if you really want to seal against corrosion, the best and really only way/s are

1. use crimped ferules with electrical conductive paste (copper version for copper)
2. electrical conductive paste without ferrules

The fact is copper will go dull quite quickly however the conduction of properly tightened copper connections should not cause any issues normally.

If you are in the tropics then use a conductive grease, silicone and the like will NOT stop moisture.
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Re: Should controller pv and batt inputs be fully sealed up?

Postby australsolarier » Wed Nov 14, 2018 12:34 pm

never solder the copper wire ends for screw terminals. this is a big nono except for very low power applications. ( you will look for trouble. used to do this and a screw terminal burned out.)
and yes, i am using bootlace ferrules for all my wire connections. and i do not worry about air getting into the connection area. unless they are in the open and rain and dust and things can corrode everything. where the copper wire makes contact with the terminal, that is were the electricity is conducted, not the bit of wire you can see.
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Re: Should controller pv and batt inputs be fully sealed up?

Postby Jman » Wed Nov 14, 2018 5:51 pm

Thanks to jules, davidg & australsolarier for the help. :)
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Re: Should controller pv and batt inputs be fully sealed up?

Postby Jman » Sun Dec 09, 2018 10:19 pm

Hello again

Just another quick question about ferrules. How strong is the crimp join suppose to be?

On all mine using a self adjusting square crimper with 6mm2 & 13mm2, I can pull the ferulles off the cable end with my bare hands with enough force. Is this normal? Or the sign of a bad crimp tool?
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Re: Should controller pv and batt inputs be fully sealed up?

Postby australsolarier » Mon Dec 10, 2018 5:03 am

no, you should not be able to pull the ferrule off.
you are using the wrong size ferrule for the wire diameter.
the ferrules have nominated sizes, so have the wires.
so say for a 4mm wire, you use the 4mm ferrule.
easy
i found when the wire comes off, using really thin wire, for which i have no ferrules, crimping twice does the trick. but i don' recommend it.
naturally if you use a 16mm crimper on a 1mm wire it will also remain lose
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Re: Should controller pv and batt inputs be fully sealed up?

Postby davidg » Mon Dec 10, 2018 9:59 pm

Jman wrote:On all mine using a self adjusting square crimper with 6mm2 & 13mm2, I can pull the ferulles off the cable end with my bare hands with enough force. Is this normal? Or the sign of a bad crimp tool?

you should NOT be able to pull them off period, that is a sign of insufficient crimping force.

13mm2 where does that come from ?

STD wire sizes in AUS are

1mm2, 1.5mm2, 2.5mm2, 4.0mm2, 6.0mm2, 10mm2, 16mm2, 25mm2, 50mm2, 70mm2, 95mm2

There's more of course.
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