Another Inverter Selection Question

[Glider]

Originally Posted by JWA

Option 1 all the way. There would be nothing else ever plugged into this inverter.

I have spent some time researching inverters during the past year. One of the criteria I use for evaluating technical products is the quality of the technical data they publish, and another is the depth of knowledge of their technical support people.

I was very impressed with the quality and depth of the white papers published by Samlex and by Magnum Power (now Sensata Technologies). I called both companies, and the Sensata techs had excellent, thoughtful answers for everything that I could throw at them. The Samlex tech I spoke with, on the other hand, was rude, and gave me an incorrect answer to a very basic question about the functionality required in a UL 458 inverter. That put Sensata on my list, and took Samlex off.

I also had a particularly excellent conversation with the tech guys who design and repair AIMS inverters. This is a smaller company, located in Reno, NV. I was quite impressed with their helpfulness and the depth of their knowledge. AIMS is on my list.

AIMS inverters use somewhat different technology than the Sensata or the Samlex units. Two of the benefits of the AIMS design is that it is less expensive to build, and it generates considerably less heat. The installation instructions for both Sensata and Samlex emphasize mounting on fireproof material as well as specific cfm flows for cooling air. The AIMS units have much more flexibility regarding where and how they can be mounted, as they run much cooler.

Without getting into detail, there is one drawback to the AIMS approach, but it only affects inverter/chargers--which is not what you are looking for--that are being hard-wired into a 110v panel--which is not what you are doing. So we don't need to get into that bit.

Xantrex used to be the manufacturer of choice for SMB; I don't know much about Xantrex, but my impression is that they may be somewhat lower quality than other options. From poking around at the SMB Austin facility, it looks like they have now dropped Xantrex, and have switched pretty much to Sensata.

To summarize, then: my two companies of choice, at present, are Sensata and AIMS. The two inverters I would suggest, given your use case, are:

1. AIMS Power 600 Watt Pure Sine Inverter. $129.00
https://theinverterstore.com/product...lt-to-120-vac/

2. Magnum CSW412 400 Watt Pure Sine Inverter (Sensata Technologies). $219.60.
https://www.amazon.com/Magnum-CSW412.../dp/B01D8ROHNM

Let me know what you decide to do, and how you like it. I'll be interested to hear.

[arctictraveller]

Glider, that was an excellent analysis of inverter technology. Its a pleasure to be able to talk with knowledgeable tech reps on the phone isn't it? I am considering replacing my Xantrex unit only due to the higher standby wattage, and I was not aware of AIMS, I'll give them a look

[BrianW]

I’d be interested in hearing about the drawback to hard-wiring an AIMS inverter...

[Glider]

Originally Posted by BrianW

I’d be interested in hearing about the drawback to hard-wiring an AIMS inverter...

Summary: Most inverters that are designed to be hard-wired have a "pass-through" option. The AIMS inverter handles the pass-through differently than a Sensata or a Samlex.

1. Hard-Wire Setup
In a hard-wire setup, the inverter is wired directly to a 110v circuit breaker panel, located in the van. Power outlets and appliances are wired into the breaker panel. The inverter powers the panel; the panel powers the outlets and appliances.

2. Other Forms of 110v Power
Many vans are set up to accept 110v input from either an outside source (shore power) or a generator. This means that you potentially have three different sources of 110v power: inverter, shore power, and generator. All three of these sources are wired to the van's 110v circuit breaker panel (this typically requires a transfer switch). The power source powers the panel; the panel powers the outlets and appliances.

3. Panels and Sub-Panels
If you have an inverter, the proper way to set this up is with two 110v panels--a main panel and a sub-panel. The main panel is powered by the generator or shore power, and it powers things that suck a lot of juice--that you would not want the inverter to power--such as the air conditioning system. The sub-panel powers just the things that you want the inverter to supply electricity to, such as lights and a few outlets.

The sub-panel is not wired directly to the main panel. Instead, the main panel has a 30 amp breaker (typical) which sends 110v power to input studs on the inverter. The inverter is hard-wired to the sub-panel, so it powers the sub-panel.

4. Running on the Inverter
When the inverter is powering the van's 110v systems, 12v DC power runs from the batteries through the inverter, where it becomes 110v AC power, and from there it powers the van's sub-panel. Only the items that are connected to the sub-panel receive 110v power.

5. Running on Shore Power or Generator
When external 110v power is being supplied to the van, things are a little different. The shore power connection or the generator supply 110v power to the main panel. The main panel sends 110v power to the inverter (via the aforementioned 30 amp breaker); and the inverter simply passes that power through to the sub-panel, without otherwise messing with it. This is known as a "Pass-Through" function.

6. Finally: The Difference Between AIMS and Sensata/Samlex
In the case of the Sensata or Samlex inverters, the pass-through function works without turning the inverter on. That's nice, because there is no noise from the inverter's fan in this case.

In the case of the AIMS inverters, the pass-through function only works if the inverter is turned on. If you are sensitive to fan noise, this might be a point to consider. I haven't owned an AIMS inverter, so I don't know how much noise their fans make. Given the advantages of the AIMS units and how rarely I need 110v power, I would be inclined to not worry about it, and just go with the AIMS unit. But everyone has their own tradeoffs, and I would be remiss to ignore the difference.

[1der]

The #3 setup makes sense for setups that have loads beyond what would be supported by the Inverter. If there are no such loads, why would there be a need for this second panel?

[Glider]

Originally Posted by 1der

The #3 setup makes sense for setups that have loads beyond what would be supported by the Inverter. If there are no such loads, why would there be a need for this second panel?

Well, you know I'm just a hack, so I'm perfectly willing to be wrong...that said, here are my thoughts:

[EDIT: I was thinking sideways when I originally wrote this post...thanks to gentle prodding from 1der, I've attempted to redeem myself in #19, below. In order to avoid confusion, I've deleted the remainder of this post.]

[arctictraveller]

Originally Posted by Glider

6. Finally: The Difference Between AIMS and Sensata/Samlex In the case of the Sensata or Samlex inverters, the pass-through function works without turning the inverter on. That's nice, because there is no noise from the inverter's fan in this case.In the case of the AIMS inverters, the pass-through function only works if the inverter is turned on.

I have a 3000W Xantrex inverter / charger that requires 12vdc in order to energize the pass through relay. When my batterys went dead, I was unable to get shore power to any outlets or to get the charger started until I connected a different battery charger to the batterys. Having the ability to energize the pass through without having the inverter on is a good feature.

[1der]

I guess I am thinking about an inverter/charger with the integral transfer switch. Those type of units act as the automatic switch depending on source., What is nice is the switch over is super fast and transparent to the load.

[Glider]

Originally Posted by 1der

I guess I am thinking about an inverter/charger with the integral transfer switch. Those type of units act as the automatic switch depending on source., What is nice is the switch over is super fast and transparent to the load.

And that brings up a couple of interesting details:

1. There are two different things that people call "transfer switches" in inverter/chargers.

a. Many inverters claim to have automatic transfer switches. What most manufacturers mean by this is that the inverter/charger will automatically switch modes (from charging to inverting, or vice-versa) when external 110v power becomes available, or when it goes away.

b. Samlex does something rather special with their inverters. Samlex offers not only the type of transfer switch noted above, but they also build in a transfer switch that allows the inverter to manage the selection between shore power and generator.

The vast majority of inverter/chargers out there--at least the ones up to 2000 watts--do not have this second type of transfer switch, which is really handy to have. Of course, you can always install a separate transfer switch before the inverter, and that works, also.

2. None of this bears on the original point, however, which is that I was thinking sideways in response to your original question, which was: if you have no large loads, could you simply wire to a main panel and do away with the sub-panel?

The proper answer is: If you have 30 amps of shore power, and your inverter has a 30 amp pass-through, then you can wire the shore power to the inverter, and wire the inverter to the main panel. No need for a sub-panel. If your inverter has less than the full 30 amps of pass-through, then it would be inadvisable to wire the 30 amps of shore power directly to the inverter.

Thanks for getting me to think straight!

[Glider]

Originally Posted by arctictraveller

I have a 3000W Xantrex inverter / charger that requires 12vdc in order to energize the pass through relay. When my batterys went dead, I was unable to get shore power to any outlets or to get the charger started until I connected a different battery charger to the batterys. Having the ability to energize the pass through without having the inverter on is a good feature.

That is a really useful bit of knowledge. I do not know if the AIMS units require a 12v input in order to energize the pass through relay, but if they do, that would definitely be a drawback. Thanks for raising this point.