inverter power pass thru

johns4104 · April 20, 2009, 07:05:42 PM

Are Inverters power pass thru limited to the transfer switch amperage?

Thanks,
John

Lin · April 20, 2009, 08:52:47 PM

I would guess that is one limit, but the specs should define what the max pass through is. My Trace 2412 has a 30 amp limit, as I remember. I do not use the pass through feature though.

gumpy · April 20, 2009, 08:53:31 PM

Limited to it's internal transfer switch rating.

Cary and Don · April 20, 2009, 10:36:14 PM

Got another questions on the pass through.

If the electric is hooked up, the battery charger is always floating. Since this cooks the batteries in the summer we have been pulling the plug on the power. It would be nice to leave it on though. Can the battery charger be disabled by using the disconnect between the inverter and the batteries without damaging the inverter?

Don and Cary
GMC4107
Neoplan AN340

Lin · April 20, 2009, 11:03:32 PM

Can't your inverter just be turned off when you are plugged in? Aside from that, ours is set up so that we can bypass the inverter if we wish too.

Sean · April 21, 2009, 12:54:32 AM

John, Don, and Cary,

We need to know the makes and models of your inverters to answer your questions. Every inverter is different.

Pass-through capability of most inverters is the same as the inverter's maximum or surge rating, but not always.

Most inverters will not work at all without the batteries connected, but, again, there are exceptions.

-Sean
http://ourodyssey.blogspot.com

bs4104 · April 21, 2009, 09:24:59 AM

Cary: You can turn off your house & starting batteries with a disconnect switch removing them from the charging circuit and adding an extra old or used battery as a stand by or sacrifice one in place of them, and leaving it on full time when not dry camping. Bruce

belfert · April 21, 2009, 02:11:29 PM

A good inverter/charger should have a three stage charger so as to not cook the batteries. My Prosine 3000 has a control panel and I can turn off the battery charger if I wish.

Some of the high end inverters have 50 amp dual pole transfer switches so all power can run through the inverter if one wished to. This does leave the entire coach without power if the inverter transfer switch were to fail.

JohnEd · April 21, 2009, 02:51:28 PM

Cary,

You did use the word "float". Float means that the chARGER IS IN THE TRICKLE/MAINTAIn mode. That voltage should be somthing like 13.5 but you really need to chck your manual on that. Also, even if the charger is working flawlessly, you can torch the bats if you have set the charger to THE WRONG TYPE bats. I think there are three types and they all have different charge profiles and I think the float V is also pecular totth e type. Any name brand converter has that three stage charger. Yours may be malfunctioning. This ain't difficult. Plug in a good inverter andit will maintain your bats at optimum.

HTH

John

David Anderson · April 21, 2009, 05:30:48 PM

Quote from: Lin on April 20, 2009, 08:52:47 PM
I would guess that is one limit, but the specs should define what the max pass through is. My Trace 2412 has a 30 amp limit, as I remember. I do not use the pass through feature though.

Lin,

My Trace SW2412 is rated for 60 amps pass through according to the Trace tech manual. You sure yours is only 30?

David

johns4104 · April 21, 2009, 09:44:16 PM

Sean,
I have not bought an inverter yet that is why I was asking.
This leads me to another question, whether or not to run all the coach thru the inverter or not.
I have a honda gen with a 30 and 20 amp output 110 of course.
if I keep it seperate and use the inverter on one leg it would be easier to wire for a 50 amp two 110 leg service.

thanks John

gumpy · April 22, 2009, 05:33:17 AM

One of the advantages of the Trace SW series (and some other units) is the ability to set a limit on the input current from shore line or generator going through the transfer switch. This prevents tripping the shore breaker because you try to draw too much current for the rated connection. This is primarily useful when you are connected to a 120 v shore line, or your generator is small.

However, if you wire for 50 amp service (240v, two legs), and you use a dogbone adapter common to RVs when on a 120v connection, you have just defeated the ability to use the input current limit feature of the inverter, because you can only pass one leg through the inverter. The dogbone adapter splits the 120v to both legs of the 50 A input connection. In this situation,
if you want to use the feature of the inverter, you should make your own adapter which routes the 120 v through one leg of the 50 amp input. Then, split the 120v to both legs after it passes through the inverter.

Just something to think about...

Sean · April 22, 2009, 09:27:40 AM

Quote from: gumpy on April 22, 2009, 05:33:17 AM
One of the advantages of the Trace SW series (and some other units) is the ability to set a limit on the input current from shore line or generator going through the transfer switch. ...
However, if you wire for 50 amp service (240v, two legs), and you use a dogbone adapter common to RVs when on a 120v connection, you have just defeated the ability to use the input current limit feature of the inverter, because you can only pass one leg through the inverter. ...

I'm not sure I follow this, Craig.

Remember that the Trace SW series has a single-pole transfer switch, so it can only ever deal with one side of a 240-volt service. (The single-pole nature of the internal transfer switch causes other headaches as well, including complicating the ground-neutral bonding issue.)

-Sean
http://ourodyssey.blogspot.com

Sean · April 22, 2009, 09:42:44 AM

Quote from: johns4104 on April 21, 2009, 09:44:16 PM
I have not bought an inverter yet that is why I was asking.

Ah. Well, basically, you need to check the specifications for any unit(s) you are contemplating. It is best to assume that the most any internal bypass switch will pass is the surge rating of the inverter; after all, an interruption in input power will cause the inverter to start inverting, and if you are already passing more than the surge rating, you will either damage the inverter or trip the overcurrent protection.

Quote
This leads me to another question, whether or not to run all the coach thru the inverter or not.
I have a honda gen with a 30 and 20 amp output 110 of course.
if I keep it seperate and use the inverter on one leg it would be easier to wire for a 50 amp two 110 leg service.

This is one of those questions where you can get a dozen different opinions, and it comes down to "do it your way." That said, I will offer my opinion:

I prefer a split system, with an "inverter" sub-panel, and a "dry" sub-panel. If you wire the coach for 50-amp, 240/120 service (highly recommended, and mandatory if you have multiple air conditioners, electric heaters, or more than five total circuits), one simple way to do this is to run one leg through the inverter, and the other leg to the "dry" sub-panel (unless you need to run 240-volt loads, which requires a different and more complicated configuration).

What most folks do is configure loads that they don't ever want to run on batteries to the dry side. This might be air conditioners, the electric element (if any) of the water heater, washer/dryer, electric heaters, etc.. Loads that you want to be able to run all the time go to the inverter panel, such as convenience and kitchen receptacles, entertainment center, etc.

A lot depends on how big your inverter is, and how much battery you have.

If you end up with an inverter that does "load support," you might want more of your loads on the inverter. What we did was to put several key loads (one air conditioner, the electric water heater element, the electric heaters, and the electric cooktop outlet) on a transfer switch. When we are on 240, those loads are connected to the "dry" leg, but when we are on 120, they are connected to the inverter. When we are on batteries alone, they are disconnected entirely.

-Sean
http://ourodyssey.blogspot.com

gumpy · April 22, 2009, 05:18:56 PM

Quote from: Sean on April 22, 2009, 09:27:40 AM

I'm not sure I follow this, Craig.

Remember that the Trace SW series has a single-pole transfer switch, so it can only ever deal with one side of a 240-volt service. (The single-pole nature of the internal transfer switch causes other headaches as well, including complicating the ground-neutral bonding issue.)

-Sean
http://ourodyssey.blogspot.com

The problem comes in when you are on a 30 amp or less 120V power pole, and you've wired the bus for 240v with one leg going through the inverter. If you use the commercial dogbone that converts from 30 amp to 50 amp, it is wired internally to power both sides of the 240 v shore cord from the 120v power pole. If one leg of the power cord bypasses the inverter, you cannot reliably set the max input power on the inverter to prevent tripping of the power pole breaker.

Hard to describe in a few words, but a real pain in the read if you want to use the full features of the SW series inverters.