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Topic: Parallax Power Supply Issue - Need Advice (Read 498 times) previous topic - next topic
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Parallax Power Supply Issue - Need Advice
My shore power line in neutral wire is fried at the busbar (and in the transfer switch).  With it it took out the busbar plastic insulator and a good inch of every other neutral wire that was connected to it.  According to the interwebs this is usually caused by lugs that need to be tightened periodically (and have never been in 17 yrs as far as I know).

I'm about to do the first phase of a solar array install this summer (starting with the LifePo, Victron inverter/charger, line distributor and followed by the solar panels and mppt soon thereafter) so the parallax power supply/converter will be used only as a 120v and 12v distributor panel/fuse holder and the converter will be turned off permanently.

Questions

- Would it be wise to replace the parallax at this time and upgrade to a larger (55amp) for battery charging when plugged into shore/on generator?

- I have a 12v refrigerator cooling unit that I need to run until the replacement busbar assembly arrives so I've trimmed off the charred wire/insulation and connected the 120v shore line directly to the converter neutral w/ a wire nut so I can at least have 12v (I also had to extend the wire a bit using a butt splice).  Is this an ill conceived temporary setup?  Seems to be working.
Re: Parallax Power Supply Issue - Need Advice
Reply #1 –
Wow, that is a mess, the reason why we have recommended tightening all the connections in the Power Center every two years or so.
The temporary fix should be OK until the parts arrive.

If installing a lithium battery, install the largest lithium-specific converter that will fit. lithium batteries can safely absorb a  large amount of current, up to 50% of battery capacity

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Parallax Power Supply Issue - Need Advice
Reply #2 –
Quote from: Larry W  - 
Wow, that is a mess, the reason why we have recommended tightening all the connections in the Power Center every two years or so.
The temporary fix should be OK until the parts arrive.

If installing a lithium battery, install the largest lithium-specific converter that will fit. lithium batteries can safely absorb a  large amount of current, up to 50% of battery capacity

Larry

Thanks Larry.  Could this have also been cause by a drop in shore power voltage?
Re: Parallax Power Supply Issue - Need Advice
Reply #3 –
Quote from: Howard A  - 
Thanks Larry.  Could this have also been caused by a drop inshore power voltage?

That might have polished it off but never tightening the terminal screws is the underlying issue. Copper wire is soft and changes shape under pressure and vibration.
Every LD owner needs this performed periodically, done by a qualified tech.
This is a common issue.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Parallax Power Supply Issue - Need Advice
Reply #4 –
Which is why my boating friends (and ABYC guidelines for boat builders) say that solid wire should never be used in a mobile installation. I know this is a lost cause as far as RVs are concerned--every manufacturer I know of does it. But when I replaced AC wiring in my last three rigs, I used stranded marine wire (Ancor brand with fine, tinned strands), because I know it's much less likely to fail at the connection points.

The other thing that helps (and again, most RV makers don't do this) is instead of bare wire going into set-screw terminals, to use crimped-on ring terminals (FTZ Crimp'n'Seal) with gas-tight heat-shrinkable coatings. These are much less likely to come loose, and they won't allow the wire to oxidize. But to do this, your gear must have the appropriate screw (not set-screw) posts that will accept ring terminals, and most factory-installed gear, such as the widely used Parallax power centers, doesn't.

I know these suggestions won't help most people, because replacing electrical gear is a big job. But if you're undertaking any serious electrical upgrades, it's a good idea to use stranded wire, and to look for gear that accepts ring terminals, such as Blue Sea breakers and panels.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Parallax Power Supply Issue - Need Advice
Reply #5 –
When we replaced our 12V circuit board, it had one connection on the backside.  And it was loose!   I felt lucky to find it before we had any trouble.  The replacement has all the connections on the front.   WAY BETTER!
Re: Parallax Power Supply Issue - Need Advice
Reply #6 –
Quote from: Andy Baird  - 
Which is why my boating friends (and ABYC guidelines for boat builders) say that solid wire should never be used in a mobile installation. I know this is a lost cause as far as RVs are concerned--every manufacturer I know of does it. But when I replaced AC wiring in my last three rigs, I used stranded marine wire (Ancor brand with fine, tinned strands), because I know it's much less likely to fail at the connection points.

The other thing that helps (and again, most RV makers don't do this) is instead of bare wire going into set-screw terminals, to use crimped-on ring terminals (FTZ Crimp'n'Seal) with gas-tight heat-shrinkable coatings. These are much less likely to come loose, and they won't allow the wire to oxidize. But to do this, your gear must have the appropriate screw (not set-screw) posts that will accept ring terminals, and most factory-installed gear, such as the widely used Parallax power centers, doesn't.

I know these suggestions won't help most people, because replacing electrical gear is a big job. But if you're undertaking any serious electrical upgrades, it's a good idea to use stranded wire, and to look for gear that accepts ring terminals, such as Blue Sea breakers and panels.

I'm considering this.  I love the Blue Sea hardware although it's pricey.
Re: Parallax Power Supply Issue - Need Advice
Reply #7 –
Quote from: Larry W  - 
That might have polished it off but never tightening the terminal screws is the underlying issue. Copper wire is soft and changes shape under pressure and vibration.
Every LD owner needs this performed periodically, done by a qualified tech.
This is a common issue.

Larry


Larry, what type of specialist would check the torque on an RV power supply?  Regular electrician?

The new busbar arrives tomorrow but in the meantime I'm using the newer 10AWG Wago 5 port.  Seems to be working okay.  Wonder why not just use this permanently? 
Re: Parallax Power Supply Issue - Need Advice
Reply #8 –
wow we're suppose to tighten what exactly and how often?

using wago as a busbar might not be a good idea based on how many amps it's meant to handle. a buss bar can usually handle an outrageous amount of amps which is needed when things go bad as far as I know
1995 23.5 Rear Lounge
Re: Parallax Power Supply Issue - Need Advice
Reply #9 –
Quote from: majortom  - 
wow we're suppose to tighten what exactly and how often?

using wago as a busbar might not be a good idea based on how many amps it's meant to handle. a buss bar can usually handle an outrageous amount of amps which is needed when things go bad as far as I know

One of the things they never tell you in the manual😂

The wago is rated for 41 Amps but you’re probably right that the standard busbar can handle a lot more.  Fortunately it arrives today and now just need to find the right sized blind rivets to mount.
Re: Parallax Power Supply Issue - Need Advice
Reply #10 –
I think if it were me, I'd use self tapping screws and snug them down good. As bad as your wires are burnt, make sure you strip into clean copper again. Now you know where that smell was coming from. Solid wires are notorious for vibrating loose, we never used solid wire in our refrigeration systems and as preventative maintaince would check all the high current connections even though they were all stranded wires


1994 MB
Final Results
Reply #11 –
So the busbar came today which meant I needed to locate the appropriate sized pop rivet to mount the new insulation plate since the old one was toast.

The pop rivet is a 5/32 diam and the grab should be around 1/4-1/2”.  Had to take a trip to a far away Home Depot but found them.

Next was a plan for the required 35 in.lb. of torque requires on the neutral bar.  Found an in. lb. torque wrench from Harbor Freight for $20.  That place is insane.  Anyways even if I only use the wrench once and never do the required periodic calibration on it again, it’s worth it.

Drilled out the old rivets and mounted with new, placed and torqued each wire and then crossed my fingers that all would work.  Seems to be going well so far.

FYI the wago 5 port seemed to work quite well as a short term fix.  I ran the A/C with it but made sure not to run multiple high voltage/amp devices simultaneously.

Side Note: I also checked the torques on the ground busbar while I was there.
Re: Parallax Power Supply Issue - Need Advice
Reply #12 –
Quote from: Howard A  - 
Larry, what type of specialist would check the torque on an RV power supply?   

Anyone who is comfortable and experienced working high voltage can tighten the screws on the bus bars and circuit breakers. I don’t want anyone to get hurt.
I use a regular screwdriver to tighten the screws as tight as I can, no need for a torque wrench.
The important thing to do it periodically .
Solid wire has no place in any vehicle and you always see stranded wire use in cars, trucks, boats, aircraft and any other high vibration application. Switching a LD’s solid, 120-volt wiring to stranded would be a needlessly huge job and would provide few, if any benefits as long as the busbars are tightened often.
Any electrical add-on should use stranded, marine-grade wire.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
 
Re: Parallax Power Supply Issue - Need Advice
Reply #13 –
Since this would be done with the batteries disconnected, the solar fuse(s) pulled, and AC power disconnected, what are the possible hazards? 

I believe I saw some solid grounding wire near my converter.  Is this an issue?
Greg & Victoria
2017 Mid-Bath  “Nocona” towing a manual 2015 Forester
Previously a 1985 TK
SKP #61264