Lux ac battery controller

1961Nick

philologus said:

I've had a look at that inverter terminal Nick and it looks OK.

How would I to connect it to the battery cable?

The cable I have has the usual snap-on connector to the battery terminal and there's enough cable to cut the damaged part off at the inverter end.

You would need to take the cover off the inverter to see how the terminal is wired on the inside… my guess is that it’s connected with a bolt.

The sparky wanting to replace the inverter rather than taking the cover off doesn’t really make sense. If you change the inverter, the old one gets binned so the warranty is irrelevant.

If you power the inverter down, you may be able to undo the 4 screws that secure the panel mounted connector & view the underside? 

philologus

Thank you for the Offer Paul,

I'm in Redcar on the NE coast.

 Nick: The terminal is held on with 4 screws. I've removed them and the cable is attached by bolt as you said. 

1961Nick

A pair of Pylontech cables & a new panel mount connector should sort it out for arounf £50. The only thing you'll need to source are some nuts, bolts & split washers.

https://www.ebay.co.uk/itm/234969311682?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=nexdv5ietfu&sssrc=2047675&ssuid=QukZql4xSby&widget_ver=artemis&media=COPY

https://www.amazon.co.uk/All-copper-Lithium-Connector-Terminal-High-current/dp/B0B4QZG7WP?th=1

Just need to check the screw centres are the same at 23mm.

It might be worth getting 2 & doing the negative as well?

A couple of these would make a really tidy job https://polevolt.co.uk/acatalog/Battery_Terminal_Covers.html

(I trust you've screwed the original back in place so the conductor isn't touching the case?)

philologus

I have screwed it back. There would be sparks flying if I hadn't. :-)

I thought that the connection to the battery lead had to be water/moisture tight?

Am I right in saying that the problem I have has been caused by someone not making the crimp properly and allowing air between the wires, and that produced moisture inside the fitting?

There was definitely a lot of moisture in there when I took it apart. I thought there must have been some sort of gel in there - but the Leccy today said definitely not.

1961Nick

philologus said:

I have screwed it back. There would be sparks flying if I hadn't. :-)

I thought that the connection to the battery lead had to be water/moisture tight?

Am I right in saying that the problem I have has been caused by someone not making the crimp properly and allowing air between the wires, and that produced moisture inside the fitting?

There was definitely a lot of moisture in there when I took it apart. I thought there must have been some sort of gel in there - but the Leccy today said definitely not.

Is the inverter situated outside?

Heedtheadvice

Water in the unit is a definite concern.

Moisture in itself should not have caused a problem at the connector as the circuit at that point is a) very low voltage and b) very low resistance compared to any conduction resistance of plain water.

One possible problem is if the water has affected the inverter electronics. The inverter needs to be thoroughly dried out, inspected and tested if that is the case as it may have started some corrosion within the unit ( even if still working) that my manifest itself given time!

However as far as the connector overheating is concerned it could be the water has caused corrosion at the positive terminal connections inside the unit or at the battery cable conection lug or cable crimp connector/cable. All need to be examined for that.

It is just or more likely that the connections between battery cable and inverter positive have been a problem of poor connection either the crimp or the bolted parts.

In either of the two connector over heating potential causes they both are due to higher than acceptable resistance at the connections and the resistance acting as a heater with the high power passing through it. You would be well advised to find the cause to ensure no repeat and ensure all connections are properly made with any upcoming work you intend to do.

1961Nick

Heedtheadvice said:

Water in the unit is a definite concern.

Moisture in itself should not have caused a problem at the connector as the circuit at that point is a) very low voltage and b) very low resistance compared to any conduction resistance of plain water.

One possible problem is if the water has affected the inverter electronics. The inverter needs to be thoroughly dried out, inspected and tested if that is the case as it may have started some corrosion within the unit ( even if still working) that my manifest itself given time!

However as far as the connector overheating is concerned it could be the water has caused corrosion at the positive terminal connections inside the unit or at the battery cable conection lug or cable crimp connector/cable. All need to be examined for that.

It is just or more likely that the connections between battery cable and inverter positive have been a problem of poor connection either the crimp or the bolted parts.

In either of the two connector over heating potential causes they both are due to higher than acceptable resistance at the connections and the resistance acting as a heater with the high power passing through it. You would be well advised to find the cause to ensure no repeat and ensure all connections are properly made with any upcoming work you intend to do.

Good advice.

Using a bolted connection both sides of the panel fit terminal should provide a stable connection & would be better than the OE Surlok type connector. If this inverter is situated outside, the possibility of water ingress requires investigation. Water & electronics are poor bedfellows in my experience. 

philologus

The inverter and batteries are in the airing cupboard upstairs so are at a more or less even temperature. There have been no water leaks in there.

This what the cable looks like so I'm convinced that the problem is with the crimp.

Heedtheadvice

I would tend to agree that the heat emanated from the lug/crimp area. Everything points to that area.

It will have nothing to do with air in  the crimp. It is usual that the voids in the cable and cable to crimp are air filled unless specially filled with compounds. The supplied cables for Lux to Pylons DC power cables are not such special cables.

What would concern me is your mention of moisture. Where that is coming from (airing cupboard drying things?) and where it has got to and potential resulting damage. If there is moisture inside the inverter has it dripped down into the connector/ crimp, corroded and caused that heat....

It could just be  a poor crimp. Usually shown up by a pull test at manufacturing time! It is rare to get a poor electrically conducting crimp if mechanically sound unless other problems exist prior to or after crimping.

philologus

The airing cupboard is not used for anything other than storing towels, bedding, etc. The inverter and batteries are in there as is the combi boiler. (Gas - new one installed five years ago.) the door is always half open so there's plenty of air circulation.

Using a torch and a mirror, I've had a good look and there's no signs of moisture anywhere in the inverter.

I've been offered a pair of  2 metre Pylontech cables with both ends already fitted for £28 delivered. Unless I get a better offer from the installers I think I'll be accepting the offer and getting the terminal that Nick recommended.

I'll wait until Monday to decide.

Thank you all for the very good advice I've been given. My wife and I are in our late 70's and have our share of disabilities, my wife has dementia and doesn't fully understand what's going on but worries about it and gets stressed so I have to do things as low-key as possible to avoid this. In years gone by I'd have been kicking some butt by now!