3M VHB Tape

[rickst29]

Originally Posted by Hdlaut

I will be installing a 280AH lifepo4 battery and a 2000W Victron Multiplus inverter / charger. My goal is to remove the old gas range and install an induction cooktop and a microwave. For the limited cooking usage it should work out. And in the hot CA summers, the additional cooking heat will be much less.

I've already replaced the 12V battery at the front of the trailer with a 100Ah lifepo4 battery to use for the existing 12V loads.

Let me advise you to work differently with the Muliiplus product line, which I know pretty well (even though I don't have one):

The legacy version you mentioned ('2000w') does not have adequate peak power to handle the reactance of a decent size microwave oven. The current Victron 120 volts Victron '3000' model (5500 peak watts, 3000 continuous) might be OK with that. I use a 3000/600 rated inverter to run a '900 watt' microwave.
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On the current model, the battery charge capability is 70A into the "24 volt model" (up to 28.8 volts)and 120 amps into the "12 volts model" (with default voltage up to 14.4 volts).

The "12 volt" capability is roughly 6/7 as good as the "24 volt" capability, it would allow you to avoid the separate battery on the tongue. Running multiple 12v battery packs in parallel requires one additional BMS (about $130 each for the good ones), perhaps providing better redundancy at low cost. The multiplus connect DC battery wires on posts, not bare wire plugs - and 2x 2/0 cables (12v) would be adequate for running your Inverter at full power.
- - -
Although the newer '300 models' have better inverter monitor and configuration is still done by the 'legacy' VE bus connector ports (from a PC). Cellphones still cant' be used to control it directly.

[Hdlaut]

According to the Victron spec sheet, the peak power is 3500W. The continuous power is 2000W. Hopefully that will be sufficient for a 900 - 1000W microwave. But, I will do a test run before I install it permanently.

The front battery will stay independent from the battery connected to the Victron, except for a B2B charger that will only operate when the big battery is in float.

[rickst29]

Originally Posted by Hdlaut

According to the Victron spec sheet, the peak power is 3500W. The continuous power is 2000W. Hopefully that will be sufficient for a 900 - 1000W microwave. But, I will do a test run before I install it permanently.

The front battery will stay independent from the battery connected to the Victron, except for a B2B charger that will only operate when the big battery is in float.

No , a 3500w peak inverter cannot run a 900 watt microwave without burning out (fairly quickly). The REACTANCE of the microwave circuitry (it's desire to pull power out of phase, and fit it back against the sine wave pattern) will normally require that "the grid" handle waveform match problems at roughly 6x-7x that power level. In the case of your Inverter, the Inverter itself is the entire "grid" with very little wire mass or stored power to absorb the irregularities without huge suffering from large voltage changes. Those feed back through the inverter circuitry, and blow up components.

You're thinking in terms of DC power, ignroning issues of phase in AC power provided by a s "small" inverter to reactive power consuming components. The "3000/5500 watt" version stands a pretty good chance against a "900 watt microwave", although its headroom for reactance and peaking is only about 6x, not the 7x I'd prefer to see.

Please call, this is slightly complicated if you'd like to learn all the details - although your ultimate configuration can possibly be pretty simple.

[Hdlaut]

The data sheet says "Non-linear load, crest factor 3:1"

Does this apply, and if so how?

[jagizzi]

I had NO ADJUSTMENT left on the rear torsion bars. If you have some I believe that you could get away with adjusting to handle the additional load. They are a bit of a bugger to remove and install, and the new ones have threaded ends, which makes the install that much more difficult. Although upon later reflection I wondered if it would have been easier to screw them onto the lift arms that to have used force. Might have been a huge duhhh on my part ;-)

I got a full set of torsion bars figuring that it is better to have them on hand than to find out later that for some reason they are unavailable. Total cost was $1009, with $189 of that being shipping.

I did not use VHB tape as I figured that unnecessary given the use of the UV4000 which is an adhesive sealant. It is removable but that operation is certainly not easy ;-)

Also note that I did NOT seal the inside of the bolt hole of the ceiling joint on the inside of the trailer. If water leaks in from outside I WANT it to move inside quickly rather than get trapped in the foam between the aluminum skins. I would notice any leak right away as it would drop on my bed :-) i want that rather than sealing any leaked water in the ceiling.

I completely sealed the outside, under the mounting square tube, under the head of the bolt inside that mounting tube and then the uphill edge of the mounting tube.

[jagizzi]

Originally Posted by Wavery

I would highly recommend NOT drilling through the TM roof. If you decide to do that, be sure to insert 1" long crush spacers in the roof for the bolts to go through and take all of the force of the compression when tightening the bolts. If you do not use crush spacers (sleeves), The vibration of driving down the road will cause the styrofoam in the roof to crush which will result in having to tighten the nuts farther to keep the panel secure against the roof. Over time, the roof may become severely crushed.

The square tube spacers are an excellent idea for raising the panel off the roof. However, instead of bolting the double tubes together, I would (again) recommend the VHB tape. If you double up those spacers and make them 6" long, you'd end up with 12 sq inches of surface contact with the roof (per leg). that would result in 48sq inches of VHB tape which would result in 3,360# of shear strength and 4,080# of tensile strength. That means that you could lift the entire TrailManor off the ground by the solar panel before that tape would separate.

I agree with you about the bolts crushing the roof if they were the principal means of attachment. They are merely back up to the UV4000 Adhesive Sealant. If the sealant fails I won't have the panel go sailing away on the freeway, and I will get a failure indication when it rains as the leak will end up on the bed.

In regards to doubling up the square tubes to increase surface area I am in complete agreement. So much so that if you look at the photo closely you'll notice just that. I doubled up to increase the surface area ;-) for the adhesive.

[jagizzi]

I have a lot of faith in VHB tape but I also understand that things fail, over time, with weather, sun and heat exposure. I chose an adhesive with a mechanical backup based on those thoughts and some personal experience.

I have always had rain guards on each of my three Ford F-150's. Ford parts with preinstalled VHB tape on the guards. Each truck had 4 guards for a total of 12 over the years. One of them came off of the truck going down the highway. The tape was on the truck but the guard had come away from the tape and left the vehicle. Poor surface prep on the part of a factory I am sure.

My techs used VHB tape for simple window handle installs in my service department for Yachts and boats. Almost always we had no problems, customers were happy and we never saw them again once the handles were reinstalled but...there were several times that the handles came away from the tape and we had to do the job over. Poor install conditions most certainly in one case and bad surface prep in another that i can remember.

A factory install failure and several failures on a low stress part convinced me that I would prefer to have a mechanical fastener as a safety backup. My choice, based on my experience. Was something done incorrectly with regards to surface prep or install conditions (temp, humidity etc) with the VHB tape, most certainly. This makes any spec for bonding strength invalid.

This was my thought process for my install.

[jagizzi]

And I wholeheartedly agree that this is one of the best forums on the web. i would not have been able to get through my 2005 2720 refit without it, and those that participate in it. Thanks to all of you for your thoughts, discussions and comments. I am still learning tons ;-)

[rickst29]

Originally Posted by Hdlaut

The data sheet says "Non-linear load, crest factor 3:1"
Does this apply, and if so how?

I don't know what they mean by that, and whether it would be applied to the peak value (3500 o the old model, 5500 on the new) or the continuous power rating. 2000 on the, 5500 on the new models).

If it is applied as a maximum in comparison to the continuous rating, you'd have 6000 watts after applying the the factor 300% times 2000 watts is insufficient for most "1000 watt" microwave ovens, with reactance of about 7x (700%). I suspect that is is their method in providing in 300% "crest factor". 900 watts times the 7x typical reactance is only 6300 watts, and the 6000 watt "crest rating" would be short by only 5%.

These have been good questions on a complex subject. My own inverter (3000/6000) is rated for is rated for slightly more peak power than even the new Victron units, it has run a 900w microwave pretty hard (for two years, multiple trips totalling multiple weeks) with no damage so far. I know that it can exceed it's 3000w continuous rating for many minutes, but I never created a configuration to asses it's "peak" rating.

Most "peak ratings" are defined for 1/10 second as a continuous high AC power load. That kind of power demand is quite a bit different than reactance: Reactance occurs in conflict with each AC cycle (USA is 60 hz per second), a much shorter period in which a decent inverter design can handle a bit more abuse. But it all depends on the capacitor and transistor characteristics of the Inverter design - push them too hard, and they die young.

[Wavery]

Originally Posted by jagizzi

Also note that I did NOT seal the inside of the bolt hole of the ceiling joint on the inside of the trailer. If water leaks in from outside I WANT it to move inside quickly rather than get trapped in the foam between the aluminum skins. I would notice any leak right away as it would drop on my bed :-) i want that rather than sealing any leaked water in the ceiling.

My main concern about the through bolting is that your solar panel is fairly heavy and mounted behind the trailer axle. When the TrailManor goes down the road, everything behind the axle has upward AND downward thrust, like a whip. The pressure of the downward thrust will be lessened by the 3M4200 sealant that you used. However, the upward thrust will pull the bolt and backing plate up against the roof panel. The combination of the 2 will most certainly cause the styrofoam between the inner and outer skin to compress if you do not have a crush sleeve in there.