Installing a wheelchair lift - NCV3

ptheland

2013 144" low top Passgr
My Sunday began with buttoning everything back up. Put the seat back in. Attached my new cable properly to the bus bar (without a fuse) so I could close up the battery area. Yes, I'll have to get into that again once the fuse arrives, but that's the breaks. And in the mean time, the cable will be dead, so that's fine. I'll need to move the van around, so I have no choice but to get the electrics back in operating order.

But the real job of the day is to attack the flooring. The lift installation manual calls for 1/2 inch plywood under the lift base. The stock corrugated plastic flooring isn't going to be a suitable substitute. My initial plan was to cut out a bit of the floor to make room for the plywood. But that still leaves the gaping holes from the seat bases as an obstacle to navigation. I decided to do the job right and replace the floor. That way I'd get the right base under the lift and have a much better looking product at the end.

So my tie down rails have to come out. Since I lack 8 foot long arms with 3 elbows needed to do that job by myself, I call in a friend to assist. It doesn't take long to get the tracks out. Way faster than installing.

I also didn't like the way the rear track set. It tilted to the rear of the car. Getting the floor out let me see the problem. I had initially picked the track location based on aesthetics as much as function. But I missed the fact that my selected spot was right where the ripples in the floor flattened out for a cross member under the floor. Part of the rail was sitting on the flat spot in the floor, and part was on the higher ripples. I'm going to move the tie down rail about an inch toward the front of the car so that it will sit flat on top of the ripples. It's still well within my required distance range, so that's not a problem. I'll have to do something to fill the holes I made earlier. Perhaps some rubber plugs.

I took the time this time to photograph the under side of the flooring for posterity. There are some extra strips around the seat bracket holes. These sit in a low spot of the floor to support the open edge of the flooring around the bracket holes. I'll do something similar to support the flooring in the same area.

IMG_3435a.jpg

I forgot to take any photos of the next step. I laid some OSB out on the ground, then put the original floor on top so I could trace the outline of the floor onto the OSB for cutting. A bit of woodworking ensued which resulted in a wood floor.

IMG_3440a.jpg

That tongue of wood sticking out over the step is roughly where the lift will go. Once I nail down the exact spot for the lift, I'll trim the wood to fit. It will sit about 4 inches over the step. I've got an idea for support under that. But that will have to wait for the next installment. Let's just say angle iron is involved. The only hole in this part of the floor is for the d-ring tie down visible in the photo.

The floor is too big in this area for a single piece of plywood. The van is about 60 inches wide inside at the floor, and the tie down rails are about 54 inches apart. I thought ahead this time and made sure the seam between the two sheets of plywood was at a high spot in the floor ripples so that the edges of the wood were well supported. Otherwise I'd need to put some filler strips in the low spot to support the edges.

I'll still put a filler strip in the three wider and deeper strips where the seat brackets were. That's particularly important for the door side strip, as the edge of the lift will be right in the middle of that strip. The bolts for the lift will be right in line with the old seat brackets.

The next steps will be to cut about an inch off the rear of this piece so I can move the tie down rail forward a bit. Then I'll decide on the exact location for the lift and do some more drilling. The angle iron support for the front edge of the lift should be interesting. And then its on to some finishing touches - the vinyl flooring being the most obvious.
 

ptheland

2013 144" low top Passgr
Well, today's weekend update is a pretty sorry thing. Tax work has encroached on Saturdays, leaving only a bit of time on Sunday afternoon to work.

My plan was to get the whole floor done - at least in wood. Ha!! Got the front piece shortened by an inch and a half, then drilled holes to move the tie down rail appropriately. That went fine. The next step would be to remove the rear floor and recreate it in wood. And that starts by removing the 4 seat bench in the back. I'm a reasonably bright guy, but that rear bench stumped me. It looks like the latch mechanism is the same as the front two seats, but it lacks the handles to actually operate it. I spent most of my day running back and forth between the van to look at the rear bench seat and one of the seats sitting in my garage. I think I figured out how to operate the latch with a carefully placed screwdriver, but it simply isn't working.

Near as I can tell, one of the latches is likely glued shut, probably with congealed soda. (I've found evidence of either one massive soda spill, or a series of small ones, all over the van.) The latch is now soaking in WD-40. I'll re-apply daily, and perhaps I can get the seat loose by next weekend. The only alternative I can think of is to try to remove the seat bracket bolts with the seat in place. Then perhaps I can deal with the brackets one at a time and separate them from the seat. The bolts appear to be accessible, but I'd probably have to invest in the appropriate ratcheting box wrench. Can't use an open-end on those darn torx bolts, and I'd go crazy trying to move the bolts with a standard box wrench.

My day was so frustrating that I had to resort to pulling weeds in the flower bed so that I could actually accomplish something today. Grrrr. :mad::yell:
 

irontent

Member
Cables. Since I'm doing everything else, I figured I may as well make my own cables. It's easy enough to find the cables and ends on Amazon. I was careful to make sure the cable I ordered was copper and not copper-clad aluminum. And that it was really 4 AWG and not 6 or 8 AWG wrapped in really think insulation to look like 4.

But that also means I'll need to crimp those ends onto the cables. Let's look at crimping tools. There's a $50 one at Harbor Freight with awful reviews. And then there's ... well ... nothing. Until you get up to $500 or $600. And then you get into the crimpers that actually work in the 4 figure price range. That's not gonna happen. What about DIY tool-less crimping? On to the interwebs.

The general consensus there is that there is no acceptable substitute for a 4 figure crimping tool.
For other forum members who are facing the job of how to attach lugs to heavy wire ...

I used a 16 Ton Hydraulic Crimping Tool with 22mm Stroke purchased from Amazon for $55.

https://www.amazon.com/gp/product/B0046D2X48/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Several of the crimps I made were for 4/0 wire, as well as 2/0, 2awg, and 4awg. The die are marked in mm rather than the more US-centric awn, so some experimenting was required to match the die to the wire.

I would not recommend it for a commercial shop doing crimps every day, but it worked out well to do the crimps in my van. My unit has a very small oil drip / leak on the cylinder, but nothing that interfered with my use of the tool.
 

Attachments

ptheland

2013 144" low top Passgr
Got a bit more of an update for today.

The WD-40 did it's job and loosened things up enough that I could finally get the back seat out. Got some help and managed to wrestle that monster seat forward onto the partially completed floor forward of my tie down rail.

The rest of the brackets all over the floor were very cooperative and came out with no difficulty. The factory floor followed uneventfully.

Here's the factory floor laid out on some OSB for tracing. My goal was to eliminate the partial cutouts for the middle row seat brackets. I also chose to skip the two bolts in the rear that only tie the floor down. The wood floor will be much more rigid than the original, and there are plenty of D rings around to keep the floor in place.
IMG_3463a.jpg

Here's some of the woodworking that I mentioned in the last update. Nothing terribly exciting here. Used a jig saw for the small curves, and a circular saw for any long, straight cuts. As always, saw horses make this kind of work a bit easier.
IMG_3465a.jpg

Lastly, here's the floor in the van. It took a bit of fiddling with some of the edge cuts to get the floor just right. The original floor has some beveled cuts around the wheel arches. Closer inspection show those were done to follow the natural shape of the wheel arches. I mostly didn't bother with this detail. The factory covers over the wheel arch cover a pretty wide area, so getting a really tight fit isn't necessary.
IMG_3467a.jpg

Unfortunately, this work was slow and tedious. I think I had the floor in and out about 5 times before I was happy with the fit. It might have gone a little quicker if I had done the marking and the cutting. I had some help today, and he traced out the floor onto the wood while I set up the saw horses and tools. The I did the cutting. Not knowing exactly where the tracing was in relation to the original floor meant I left a bit of extra material in a few places that had to slowly be identified and trimmed. But getting things right takes time.

I didn't photograph the final step of the day. I'll fix that next time with the front floor piece.

The original floor has some plastic shims to fill in the low spots on the floor in critical places, like around the seat brackets. I moved those to the wood floor, attaching them with some construction adhesive. A final sweeping of everything was the last step before putting the floor down for (hopefully) the last time.

I did have enough time to roll out the vinyl flooring and cut a piece off for the rear. But it got too dark to see well before I could trim closely around the edges plus make all of the holes for the various things that go through the floor.

I'm frustrated by my limited time to spend on this van. I only got about 4 or 5 hours in today before darkness made it too hard to see what I'm doing. I'm working 6 days a week right now and have to take part of Sunday to actually spend a bit of time with my family. And next weekend my turn into another rain out. I don't have any covered shop space to use, so I have to work outdoors. Those little things make big jobs like this much easier.
 

ptheland

2013 144" low top Passgr
Didn't have a lot of time again today, but the time was far more productive.

Started by cutting the vinyl for the rear half of the floor. We made a "sandwich" out of the vinyl. Put the old floor down, then the vinyl, then the new wood floor. Put them all upside down. The old floor lifted the vinyl up off the ground so the knife wasn't always grinding against the ground. In the photo you can also see where I reused the plastic fillers from the original floor. I used a construction adhesive to glue those down.

Here's the sandwich.
IMG_3475a.jpg

And here's my assistant (AKA my father) trying his had at some of the cutting.
IMG_3477a.jpg
 

ptheland

2013 144" low top Passgr
With the vinyl cut and trimmed, we glued it to the wood and dropped it into place in the van. Then lots of re-install work: D-ring tie downs, seat brackets, seat, and rear trim. So the back half of the floor is done!

IMG_3489a.jpg

IMG_3490a.jpg

Well, kind of done. Mostly.

After everything else was in and buttoned down, I set the tie down rail in place to store it until next weeked. That's when I noticed that part of the floor is not lying flat. I'm almost certain a piece of plastic filler strip got jostled out of place and is holding a corner of the wood floor off of the van's floor. Fixing that will require removing everything to get that repositioned.

And if I'm going to do that, I also need to do some trimming around on of the d-ring holes. It's slightly out of position, where I can't get all of the pieces to line up correctly. I got it's bolt in, but the aluminum filler piece under the cup doesn't line up with it's hole in the cup. You can't tell when it's assembled, but I know it's wrong. And that will bug me no end until I fix it.
 

NevadaBlue

Member
Nice work. Thanks for the pictures.

So, after seeing the original floor and making a new one, what do you think of this? I want to leave the back row in place like you did. I don't want to replace the floor. I do want to put vinyl over the existing floor. Do you think that removing the first two rows of seat mounts from the existing floors, making inserts to replace them and make the floor flat, then installing the new vinyl over it would work?
 

ptheland

2013 144" low top Passgr
Nice work. Thanks for the pictures.
Pictures do a good job of hiding the shoddy, amateur workmanship. :shhh:

Do you think that removing the first two rows of seat mounts from the existing floors, making inserts to replace them and make the floor flat, then installing the new vinyl over it would work?
Yes, except for where the wheelchair lift will mount. The factory floor is not adequate to support the lift. It will crush under the forces the lift exerts. So you'd need to cut out the floor where the lift will be installed and use 1/2" plywood under that. And you probably don't want the vinyl flooring under the lift, either.

So now you've got six patches from the seat brackets, and one patch under the lift. Those patches for the seat brackets are some depth that I didn't take the time to figure out. The steel floor of the van is rippled or corrugated for strength. But there are deeper spots where the seat brackets go. I'm sure you could manage to shim those up to match the existing floor. And using surface mounted L-track for the tie downs would allow you to put that on top of the factory floor instead of cutting out the floor to accommodate the track.

It would certainly speed up the installation. No question. My concern was aesthetics. I was afraid the patches would show through the vinyl, and I really didn't want the L-Track on top of the flooring, adding a trip hazard and making a large bump for wheelchairs to navigate. So I'm taking the longer route. I'm not sure yet that this longer route is worth the effort.
 

NevadaBlue

Member
Thanks for that. An installer will be doing the work and we will be using a Qstraint docking station, the kind with the peg under the chair that locks into a 'fifth wheel hitch' on the floor. I will be discussing all this with the installer and probably camping at his shop while the installation is done. Sigh...
sorry for the diversion...
 

NevadaBlue

Member
Peter, have you decided where you will tap the electrical system for power for the lift? The manual says it needs a 90 amp service!

Edited to say I did find your electrical work... again, I forgot. So, what size fuse did you decide on?
 
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ptheland

2013 144" low top Passgr
I've got a 120 or 125 amp fuse for the bus bar at the battery, and the circuit breaker is 100 amps. I went with a larger amp fuse at the bus bar because I didn't want that blowing before the circuit breaker tripped. That fuse is only to protect the wire between the bus bar and the circuit breaker - about 2 feet or so. The circuit breaker protects the rest of the wiring, from the breaker to the lift and on to ground. The lift is designed to be grounded through it's bolts to the body of the vehicle. I may run a more proper ground back to the passenger seat base to make sure it's grounded.
 

220629

Well-known member
... I went with a larger amp fuse at the bus bar because I didn't want that blowing before the circuit breaker tripped.
...
Coordinating fuses with circuit breakers can be challenging when amperage ratings are close. Given the mechanics of common circuit breakers there is a lag in response as compared to the response of a common fuse.

Depending upon the fuse design you may need 50% larger or even higher rated fuses before a circuit breaker will trip first. That is especially true if the fuse is designed/intended to protect solid state components.

:2cents: vic
 

ptheland

2013 144" low top Passgr
Coordinating fuses with circuit breakers can be challenging when amperage ratings are close. Given the mechanics of common circuit breakers there is a lag in response as compared to the response of a common fuse.

Depending upon the fuse design you may need 50% larger or even higher rated fuses before a circuit breaker will trip first. That is especially true if the fuse is designed/intended to protect solid state components.

:2cents: vic
No solid state components on this particular circuit. The big draw will be an electric motor driving a hydraulic pump that operates the lift. The lift itself incorporates a couple of relays and circuit breakers. The controls are all low current manual switches which would connect the higher power motor via those relays. About the biggest risk to the fuse and circuit breaker I've added is that of a dead short in the cable going to the lift. For that kind of problem, I don't care which one trips first, as long as one of them trips quickly. Right?

As an aside, I've decided that I must run a dedicated ground for the lift. The lift will be mounted on the wood flooring. Under the van, the nuts and washers will be contacting mainly the undercoating under the van. If the bolts contact the steel floor as they go through it, that will be a happy accident and a very small connection point not conducive to carrying the loads the lift can draw. The only way to ensure a good ground is to do so deliberately.

Is there a standard grounding point under the passenger seat?
 

220629

Well-known member
No solid state components on this particular circuit.
...
That doesn't mean that the fuse rating isn't designed for solid state = quick reaction.

For that kind of problem, I don't care which one trips first, as long as one of them trips quickly. Right? ...
I suppose. As long as you have the spare fuse(s) and the tools/ability to change them. One purpose of a circuit breaker is to allow easy reset.

With properly run cable a short is unlikely anyway.

... That fuse is only to protect the wire between the bus bar and the circuit breaker - about 2 feet or so. ...
Why bother with a fuse at all?

In AC power distribution there is a "10 ft tap rule". That rule allows undersized conductors (as to the main protection rating) of less than 10 feet in length to feed a dedicated load (switch or breaker) that has proper overcurrent protection. The concept is that the 10 feet of small conductor will not be subject to long time overcurrent. It will withstand a short circuit.

Your 2 feet of bus bar could be unprotected (no fuse). It will never see overload because that is prevented by the downstream breaker.

...

Is there a standard grounding point under the passenger seat?
I'm not aware of any OEM.

If your ground cable is eventually going back to the van body steel why not just use a short(er) ground cable to the body steel? Where you connect to the body isn't critical. Losses are not an issue.

vic
 
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ptheland

2013 144" low top Passgr
That doesn't mean that the fuse rating isn't designed for solid state = quick reaction.
I see. I was mis-understanding. I thought you were talking about what was on the circuit, not how the fuse is designed.

I suppose. As long as you have the spare fuse(s) and the tools/ability to change them. One purpose of a circuit breaker is to allow easy reset.
That gets back to why I picked a larger fuse than the circuit breaker. My goal was to try to keep the fuse from blowing before the circuit breaker tripped.

On the other side of the coin, the lift is capable of manual operation. Pump the hydraulics like a bottle jack, release the pressure with a twist valve. So an electric failure isn't the end of the world, it just means I get some exercise.

With properly run cable a short is unlikely anyway.
I hope I've accomplished that. I'm not going to claim my cable is up to OEM standards, but it should be adequate (it's a decent quality welding cable). And I'm following the same path as some of the OEM cables from the battery to under the driver's seat. So I would hope that the path itself is adequately designed to protect against shorts.

Why bother with a fuse at all?
Mercedes decided to put a fuse on their cables, so I figured I should do the same. Besides, it's either a fuse or a piece of copper. I've got to use something to fill in the gap and complete the circuit. (There's a photo up-thread where I talk about the wiring I did.) This is at the OEM bus bar attached to the chassis battery.


If your ground cable is eventually going back to the van body steel why not just use a short(er) ground cable to the body steel? Where you connect to the body isn't critical. Losses are not an issue.
The electronics for the lift are only a few inches behind the passenger seat base. It would be very easy to run a ground connection those few inches back to a grounding point under the seat. It's about the closest convenient place to connect to ground. I may still run a ground cable there (under the passenger seat), and just use one of the seat base bolts for the ground. Another easy alternative would be anywhere in the B pillar.
 

220629

Well-known member
When the tap conductor size is large enough to withstand the short circuit, there is no need to include a fuse. The main battery cable and the electric starter cable are not fused.

...
Mercedes decided to put a fuse on their cables, so I figured I should do the same. ...
I'll fix that for you.

"Mercedes decided to put a fuse on their NAS aka NAFTA model cables"

The Euro models don't necessarily have a fuse block right at the battery. They apply some standard similar to the "10 ft. Tap Rule" I described earlier.

Here is what the T1N Euro model battery looks like. No fuse block as is found on the NAS aka NAFTA models.

BatteryConnectionEuro.jpg

vs

NAS aka NAFTA T1N

011MIDIfusesOffBattery.jpg


... Besides, it's either a fuse or a piece of copper. I've got to use something to fill in the gap and complete the circuit. ...
That's fine. Just be aware that the fuse will likely open before the circuit breaker can react.



This is all just discussion. What you have should be/is fine.

:cheers: vic
 

ptheland

2013 144" low top Passgr
This is all just discussion. What you have should be/is fine.
But it's still an interesting discussion, for which I thank you. And thank you also for the perspective from outside my little corner of the world. It's sometimes quite easy to think that what is in your own circle of experience is all that there is.

PS - Power Distribution Center. I'll have to remember that. That drawing from the T1N looks just like the one I have in my NCV3. In North America. :)
 

NevadaBlue

Member
Thanks for the discussion. I got to talk with my installer this week and will be sure to update my thread when the work gets done. He will be taking pictures for me.
 

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