MNWBJR feedback

[cybermaus]

So, I installed the MNWBJR today. Can't say anything yet on long term SOC% correctness. But I do have some feedback:

It seems that not connecting it directly on the shunt but on some twisted pair shielded wire is not without risk of problems. It gave me a persistent difference of -14 Amps with reality. So if my Mastervolt CSCP was saying 0 Amp, WB claimed -14. If my Mastervolt claimed -20 Amp, WB claimed -34. Actually, it wildly fluctuated from -9 to -19, but the fluctuation centered around -14 Amp

The shielded twisted pair was not a single run, there were two RJ45's in there. I suspect some electrolytic offset caused by the contacts on those RJ45 are to blame. So I went with direct mounting on the shunt, despite the tight and impossible spot where the shunt was mounted. After I mounted direct, the WB and the CSCP were very much in agreement on current out and in. (I do not have actual SOC% comparison yet)

So feedback 1: take care with wired remote mounting.

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Item two: the idea to directly mount the WB and its form factor are very creative and as proved above also very good for stability and precision. But really, the device is horribly flimsy, showing a bare back, and those separate spacer rings are horribly difficult to mount when you do not have good access to the shunt.

I feel it should really have been completely enclosed (not bare back) and in proper strike-proof PVC or something, not in a flimsy (polycarbonate? Acrylic?) half-cover with bare back and clips that break of even easier. And those spacer rings should be held in place by said encasing, even if only by temporary friction, so you don not have to hold 4 rings and two screws and some washers at the same time because it is impossible to do one and then place the second screw's spacers later.

So feedback 2: for future revisions, a better encasing please.

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Do not misunderstand me: I suspect I will be very happy with the WB and SOC% based Aux1. It's what I missed on the Classic even before I bought it (yes, I read the entire manual before I bought the Classic). And I did manage to mount it without damaging anything, not even a single clip. But really, compare the WB to the case of the Classic itself. No contest.

Thanks

[boB]

Thank you Cybermaus...

No, you cannot get good accuracy with the shunt placed very far off of the shunt because there is
some current going through the wires that power the WB Jr....  That is probably why you have the
difference.  It might work better though if you were to use larger diameter wire going to the WB Jr.
to the shunt.

Can't say that we will be changing the packaging but feedback is very appreciated.

We did think of making the cover a screw capture arrangement but it doesn't work very
well especially if you need to add another pair of wires for another shunt monitor in
parallel with the WB Jr....   You cannot reliably add another pair on the shunt side of
the WB Jr.  Only the outside of the WB. Jr.

boB

[zoneblue]

To put your wiring into perspective remember that their is only 10ths of a millivolt across that shunt.

I cant see it being much fun to try to attach the WBjr while the deltec is mounted. You really have to remove the shunt, and mount the WB on the bench.

Kinda agree that it seems vulnerable. I wrapped a bunch of tape around mine before mounting it. But once in place and with good cable managment its not going anywhere.

[dgd]

I cant see it being much fun to try to attach the WBjr while the deltec is mounted. You really have to remove the shunt, and mount the WB on the bench.

Nah! that didn't work for me 'cos the WBjr when mounted on the Deltec means you cannot get at one of the mounting bolts for the shunt into place. The WBjr case covers it over 
As my shunt was also nearer the bottom of my MNDC box I could not easily get at the small brass bolts that hold the WBjr to the shunt. After lots or swearing and balancing just the bolt on finger tip and gently rotating to try and just grip the thread I eventually had to resort to not using washers and a right angle bent small flathead screwdriver.
I fiddled and faffed with this for over an hour, and when completed the double single malt was well deserved.
Of course SOD's law (aka Murphy's law) applied and I had the main connections to the shunt the wrong way around and  the app reported -ve current when it was really positive. Alt least that was easy to correct even though I had to cut a cable and recrimp a 70mm (wire size mm2) lug. Getting the large crimp tool up to the MNDC was a real contortion act and needed more double single malts to aid recovery.
dgd

[zoneblue]

Ha! For a wee thing a fair bit of assembly

Yeah i must have put the deltec mounting screw in first, then fitted WB, then just tightened it from the rear, and called it good. The back plate comes out of that cabinet at least.

[boB]

Gee.  Sorry it's such a hassle to install that thing !

We went through this here quite a bit.  Just saw (at work) the screw underneath the
PCB and for some reason, we didn't think it was going to be a problem in most cases.
Can't remember why now.

boB

[cybermaus]

@boB : current through those wires? Not just high impedance measurement? Oh wait, you feed only through one wire (with some one wire protocol to boot) so it needs to sinc through the shunt. Tricky.

@dgd : That is your shunt? I don't want to sound belligerent, but man, that is *oceans* of space compared to what I was doing yesterday, even if you do have to use angled screwdrivers.  I'll see if I can take/post a picture later today.


Anyway : at least though my shunt had metric screws in them, the screw position and distance was identical to the US one the manual referred to. Imagine also having to deal with that.

[TomW]

Gee.  Sorry it's such a hassle to install that thing !

We went through this here quite a bit.  Just saw (at work) the screw underneath the
PCB and for some reason, we didn't think it was going to be a problem in most cases.
Can't remember why now.

boB

And here I thought it was just me and my install. 

Glad to see it was not just me. Not really but I just don't have the fine motor skills I once had so it was a fumble fingered ballet getting mine in and now I don't feel so klutzy knowing it was a bit of a chore for others. My Epanel is pretty busy inside cable wise.

Well worth it in the end, however.

Tom

[toothy]

I really like my wbjr!

I thought I would install it without taking too much stuff apart... An hour later after the spacers had made it to the floor many times and wound up behind wires and wedged in nasty spots, I admitted defeat.

I had every screwdriver I own under 12" involved in this project.

At that point I took stuff apart, and was done in 5 minutes, which is where I should have started.

Wade

[TomW]

An hour later after the spacers had made it to the floor many times and wound up behind wires and wedged in nasty spots, I admitted defeat.

I had every screwdriver I own under 12" involved in this project.

At that point I took stuff apart, and was done in 5 minutes, which is where I should have started.

Wade

Sound advice there. One of those "short cut" gone long scenarios.

I definitely think it was worth the effort but if I had to do it again I would take it apart further to get it done.

I really need to get to bed.

Tom

[Vic]

Many/most of the early WBjr applications  will be retrofits into existing,  and sometimes  installations working while the WB is being installed -- the case here.   Retrofits will always be more difficult.

But,  stepping back a bit,  and trying to think of all that the mechanical designer is faced with ...   there are SO MANY different configurations in service,  and some differing ones still to come.  There are not too many ways to make the WB petite,  enclosed,  and still attach to a Shunt  in a workable way. 

Believe that the WBjr is a perfectly adequate solution for many,   many of us,   it is very cost-effective,  and did not take five or more years of design/redesign for MN to bring this great addition to many of our systems (am guessing on the design time).

I was quite happy that the WBjr fit a 10 year-old Xantrex DC Conduit Box  with about 3/16"  from the side wall of that box to spare.  Will admit that I was concerned that some of the spacers might just sling themselves into an abyss and never again be found,  but,  so far,  all has gone well with installations.

Had been thinking about a small plastic sheet thingie that might help retain the lower spacers/standoffs,  and still be removable after the screws have begun to mate with the Shunt's threads.   Bit there are still so many variables in different installations that even that is not a simple 'solution".

THANKS  MidNite for another useful,   great product,  that just gets better and better with FW additions to the original functionality.

Opinions,  Vic

[dgd]

@dgd : That is your shunt? I don't want to sound belligerent, but man, that is *oceans* of space compared to what I was doing yesterday, even if you do have to use angled screwdrivers.  I'll see if I can take/post a picture later today.

ok, so one person's puddle is another person's ocean... 
With the limited real estate in the MNDC box, I had no choice but to mount the shunt/WHjr combination so that the WBjr was underneath the shunt.  It was the need to hold up the WBjr and still manipulate the brass bolts in the 'puddular' space  below the shunt, with back bent, neck contorted, spit trying to steady the bolt balancing on pinkie finger and eyes losing focus in the confined space that made the task so exciting...
Anyway it was worth the effort finally seeing some SOC% stuff the next day. If this business was easy then everyone would be doing it 
dgd

PS
I had already decided the MNDC was too cramped and bought an Epanel, aluminum, the exact same size as the MNDC by just taller. It has the shunt already mounted and some wiring done and it looks as if the WBjr will just fit on top of the shunt. Should be easier to do.
Pity is that to get this larger box I had to pay for all the unwanted AC switches and wiring for genny inputs, etc.  I wish it were possible to get epanals without all this AC paraphernalia but I suppose thats a whole nuther thread subject

[Vic]

Hi dgd,

Was not trying to argue or similar ...  The first installation of the WBjr here was not a slam-dunk  either,   but some of the issue here was that I had placed one toroid choke kind of in the way,  and there were numerous CC + and  return cables run at the back edge of the Conduit box very near the Shunt.

Successive installations seemed to come easier,  and easier.

Was just trying to make the somewhat obvious point that retrofits are often going to be considerably more protracted vs a new installation,  from scratch.   And the implied thing,   that usually,  once installed,  the WB will just sit there and work quite well.

I am one who was BEGGING and begging MN to ship the WBjr sooner rather than later.   It just keeps getting better,  and all,  for a very,  very reasonable price.  Given all of the variables in Shunt location,  and cable dress of systems in the field,  doubt that much more engineering time would have made the WBjr very much easier to install on existing systems.      Again,  just opinions ...      Vic

[dgd]

hi Vic,

I agree that its the retrofitting of devices such as the WBjr, that makes life complicated.  When I look at the MNDC layout I would have done it differently if the shunt and WBjr were there at the planning stage. 20/20 hindsight is just wonderful but all experience is good.
As you say it gets easier as you do more of these installations.

I also realise if I hadn't been such a cheapskate in thinking the MNDC was sufficient instead of doing the job properly in the first place with an Epanel, then I would not have had these problems.

As the pilot in Mad Max said 'No matter where you go, there you are'  - so I mostly brought these issues on myself 

dgd

[zoneblue]

Aw dgd, where would you be without a little excitement once in a while