Author Topic: dry joints  (Read 263 times)

Offline Mortensen

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dry joints
« on: January 04, 2021, 12:21:49 PM »
Has anyone had a problem due to dry joints in the wiring? I have an ongoing problem getting the Tvan battery charged from the tow vehicle. After a new battery, the dealer or advice from Track, are saying it could be a dry joint in the main power box linking  the DCDC charger to the battery. The dealer said they can check this out for me. I would like to be armed with some questions to get this fixed this time. All is good on 240 and good voltage at the Anderson and pin 2 on the vehicle. Look forward to any suggestions.

Offline luke

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Re: dry joints
« Reply #1 on: January 04, 2021, 03:42:58 PM »
Has anyone had a problem due to dry joints in the wiring?
I've had all sorts of small problems with my wiring, most of which have either been poor terminations or inadequate slack in the runs. (tight leads which pull wires or plugs out)

I'd be double checking all the connections to and from the DCDC charger, including fuses.


All is good on 240 and good voltage at the Anderson and pin 2 on the vehicle.
If everything works well when charging on 240 V, then this will rule out most of the equipment and wiring, however if you haven't already, it would be worth doing a couple full charge / discharge cycles with the 240 V to really check it all out. (e.g. Charge it, and then flatten with the fridge for a couple of days, charge it back up, and check battery SOC, run times, etc are as expected.)

Although you're getting good voltage on the vehicle anderson, there could still be an issue on the vehicle side.  When there's no load (everything off) a dry joint or poor connection / termination can still show a good voltage, however this will quickly drop off under load.  When checking the 12v from the car, check it in an open circuit condition (trailer disconnected), and then under running conditions (DCDC charger running), preferably at the DCDC charger itself.  This will check from the alternator, through the dual battery isolator, vehicle wiring, Anderson plugs, and trailer wiring.

You will need to discharge the batteries a little bit so the DCDC charger will pull the full load, otherwise you can disconnect it and try plug a few 12v appliances in (the higher the load (within limits say ~30A) the better the test.)


If everything else looks good, then it's either the wiring from the DCDC charger to the battery (including fuses, etc), or it's the DCDC charger itself.
Tvan Mk IV
Prado 150

Offline Wetjala

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Re: dry joints
« Reply #2 on: January 04, 2021, 09:08:00 PM »
Dry joints occur when molten solder is cooling and the cable or component being soldered is moved which causes a high impedance (bad) joint. I do not believe there are any external (to devices like the BCDC) connections that Track need to solder, thankfully!

Check:

The “Charge Status” LED on the BCDC when charging from the car. Look at this LED when someone is “wiggling” the 7-pin connector and make sure the LED is bright and not flickering. This will check that the physical connection between the 7-pin male & female connectors (mainly pin 2) are solid and not intermittent. Do the same for the cable the feeds into the 7-pin male connector (from the T-Van) – “wiggle” the cable and “tug it” (the cable, that is!) as this will check the integrity of the wire connections into the captive screw-in receptacles within the body of the plug.

Remove the side panel where all the electrical bits and pieces are installed to check the crimp connections to the BCDC and, specifically but not limited to, the blue wire which is connected to pin 2 of the 7-pin at the car. “Tug” the wires into both sides of each crimp to make sure the wires do not pull out of the crimp.

As the 240Vac and presumably the solar inputs charge the battery(ies) through the BCDC without problem then the integrity of the charging side of the BCDC (BCDC to battery(ies)) is fine so you should also check the cable crimp connections on the cables (both 12Vdc and 0Vdc) that come from the Anderson plug through the fuse that feed into the BCDC.

As the previous post noted some of the cable looms within the panel are unnecessarily quite taut which stress connections and I too (like others who have posted elsewhere in this forum) have had problems with some of the crimp connections and male-female connectors which continue to frustrate me to this day! A bad crimp connection, just like a “dry” solder joint will result in high impedance (resistance for DC) connection that adversely affects the functions of the connected equipment.

My guess would be either a bad crimp connection or a flakey BCDC and from my own experience with some aspects of the T-Van build quality I would put money on the former!

Good luck!

Oops, almost forgot to mention: Make sure the "Charge Profile" on the BCDC is set correctly for the battery(ies) you have installed in the T-Van.
« Last Edit: January 04, 2021, 09:11:27 PM by Wetjala »

Offline TimH

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Re: dry joints
« Reply #3 on: January 05, 2021, 08:05:59 AM »
Are you getting any Tvan battery charging occurring when connected to the car or is it just partially charging?
What model Tvan is it and do you have the Victron monitor to see what current is being fed into the batteries?

I had a few electrical problems on my 2018 Mk5 Tvan.
Mainly poor crimps on the terminals and perhaps poor choice of connectors.

Just in case it's relevant to your situation, here are a few details.
I upgraded to the 40Amp version of the BCDC as I wanted to charge batteries up as fast as I could between camps.
However my batteries never received the full 40Amps and they were only getting to about 70% charged before the BCDC would wind back to float charging so I would never get fully charged batteries.
Charging with 240V via the Project charger was fine.

After much testing and investigating I found that there were poor connections in the wiring leading into the BCDC and between the BCDC and the batteries.
When being charged from the car I was getting a drop of more that 1 volt between the car Anderson plug and the BCDC input. I was also losing around half a volt between the BCDC output and the batteries.
While doing this testing I found that several of the wiring connectors were very hot. Most were too hot to hold for long, with one of them getting to 117C (one terminal on the main fuse) and starting to melt the insulation!
I assumed poor crimps so replaced the terminals and while I was there I replaced the blade style connectors with Anderson plugs.
I also replaced the main 50A blade fuse with a midi fuse just to prevent future problems.
I also replaced some of the cabling with thicker cable but that maybe that was overkill (but while I was there...).

What I think was happening was that the losses caused by the poor connections was limiting the current that could be supplied.
I also think that the losses between the BCDC and the batteries was confusing the BCDC into thinking the batteries were fully charged when they weren't.
The 240V Projecta charger is probably too dumb to care so just charges away regardless and being only 20A charger wouldn't be so affected by voltage drops.

Either way the fixes worked and I get a full 40A up till the batteries are about 95% charged before going to float.
In my case the batteries are lithiums so they are supposed to charge that way. With AGMs the charging would be a bit more stepped.

So while the Tvans are great mechanically there is still some room for improvement on the electrical side.
This is very common in the industry. My previous two campers were far worse electrically (Cubs).

Good luck with it.
Tim
 
« Last Edit: January 05, 2021, 08:56:43 AM by TimH »
Tim & Julie
Tvan (Mk5 Murranji)
Prado 150 GXL

Offline Mortensen

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Re: dry joints
« Reply #4 on: January 05, 2021, 09:49:10 AM »
Thanks for all the feed back. This will give me something to check myself and if I do go back to the dealer put these facts to them. The Tvan is a Scout Mk5. Thanks again.

Offline Harry Lissimore

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Re: dry joints
« Reply #5 on: January 06, 2021, 05:20:04 PM »
Mortensen,

I had a similar problem with my new LC200.  Voltage at the anderson was about 13.5, but when charging the Topaz batteries, all I could get (with batteries down to about 80% charge) was about 100W.  In my previous Isuzu MUX it would be about 450W.  Checked it with a friends LandCruiser 200 Series and it was about 300W

Where to start?  I noticed that the anderson plug wires were not wired as I would have liked.  The active Red wire came direct from the cars start battery (via a protection switch for the start battery) to the anderson plug, however the anderson earth was just bolted to the chassis about 100 mm from the anderson plug.  Using a multimeter, I discovered that there was very little earth at the anderson.  I disconnected the earth from the chassis to find that the paint hadn't even been ground off the chassis prior to bolting the earth wire to it.  In fact, the only earth being used was the thin earth wire in the trailer 7 pin plug and perhaps a little from the anderson earth.  It's a wonder that wire wasn't burnt out!

To fix the problem, I made a good connection between the anderson earth wire and the chassis and I now have 450W streaming in as I expect.

Harry
Formerly 2002 TVAN, now a 2015 Topaz Savannah and 2014 Isuzu MU-X LST. Now towing with a 2019 Toyota LC200 GXL.

Offline peter_mcc

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Re: dry joints
« Reply #6 on: January 08, 2021, 09:41:20 AM »
A friend had a problem with their Mk5 not charging from solar or the car (240V was ok). Their batteries went flat every time they went away for the weekend. The dealer checked it out and blamed their fridge for high power consumption - something that was unrelated to the real issue (not charging from the car or solar).

I spent hours looking at it. It would charge for 30 seconds from the car (according to the Victron) then the charge current would drop to zero and the charger would say the battery was full.

The problem turned out to be a faulty circuit breaker between the DC-DC charger and the battery - after a few seconds of charging it would go high-resistance (not open circuit) and drop about 1.5V. This lead the charger to think the battery was full and stop charging.

People have given other suggestions - follow them up as well. If you have the same problem as my friends you will see the DC-DC charger charging for a few seconds before it thinks the battery is full and it stops. I can't remember which circuit breaker it was in the panel - Track Trailer could probably help out - but you could check the voltage drop across it when it should be charging (ie across the terminals). The voltage drop should be close to zero.

I'm happy to chat or take a look if that helps - I'm on the lower north shore in Sydney.