Inverter Question

[SgtB]

OK, here's the old retired Marine Grunt again with an inverter question. Pictured is the control panel in my rig. What exactly does "Pass Thru" mean for my inverter settings? Read my manual repeatedly and cannot find where it speaks of that setting for the inverter. I have a Magnum MS2000 inverter. And I have a house fridge, I know the inverter has to be enabled for the fridge to run when travelling, but beyond that I am baffled.
Need some help guys, but please don't peel the grape, don't need to know all the techy stuff; remember who you are talking to. LOL. Just explain to what that setting means and how it should be used e.g., when plugged in to my house, which is only 30 amp.
Thanks guys.

[powercat_ras]

"Pass Thru" means that the inverter is bypassed and shore power is being fed thru the inverter to the outlets. What you want when your generator is running or you are on shore power.

[SgtB]

Originally Posted by powercat_ras

"Pass Thru" means that the inverter is bypassed and shore power is being fed thru the inverter to the outlets. What you want when your generator is running or you are on shore power.

So if I am driving with the Gen running (in high temp areas) should the inverter be on pass Thru or enabled?

[creativepart]

I fixed your photo.

Where it says "Pass-Thru" below that it says "Inverter On/Off."

Originally Posted by SgtB

So if I am driving with the Gen running (in high temp areas) should the inverter be on pass Thru or enabled?

You would turn the inverter ON.

But, that's optional. If you are running the generator you technically can leave the inverter off. But if you turn off the generator for any reason there will be no power to your fridge.

If you turn the Inverter ON then while the generator is running your fridge will be powered by the generator And when you turn the Generator off it will automatically be powered by the Batteries via your inverter.

That "pass-thur" wording is just a status heading. It's the wording below it that matters - Inverter On or Inverter Off. In fact, The only reason it says "Pass-Thru" at all is because the generator is running. Pass-thru is automatic. That heading "Pass-Thru" is telling you that it is in Pass-Thru mode. Just like the Charger section above it says "Float" it's telling you that the battery charger is in Float mode.

One more thing. If you are driving, and the generator is OFF you turn the Inverter ON. Then as you drive your fridge is powered by the batteries via the inverter - AND because you're driving, your RV's alternator is charging those batteries at the same time.

If it's getting hot inside and you want to run the A/C so you reach down while you drive and start the generator it will automatically take over powering the fridge - that's what "pass-thru" means.

[SgtB]

Originally Posted by creativepart

I fixed your photo.

Where it says "Pass-Thru" below that it says "Inverter On/Off."

You would turn the inverter ON.

But, that's optional. If you are running the generator you technically can leave the inverter off. But if you turn off the generator for any reason there will be no power to your fridge.

If you turn the Inverter ON then while the generator is running your fridge will be powered by the generator And when you turn the Generator off it will automatically be powered by the Batteries via your inverter.

That "pass-thur" wording is just a status heading. It's the wording below it that matters - Inverter On or Inverter Off. In fact, The only reason it says "Pass-Thru" at all is because the generator is running. Pass-thru is automatic. That heading "Pass-Thru" is telling you that it is in Pass-Thru mode. Just like the Charger section above it says "Float" it's telling you that the battery charger is in Float mode.

One more thing. If you are driving, and the generator is OFF you turn the Inverter ON. Then as you drive your fridge is powered by the batteries via the inverter - AND because you're driving, your RV's alternator is charging those batteries at the same time.

If it's getting hot inside and you want to run the A/C so you reach down while you drive and start the generator it will automatically take over powering the fridge - that's what "pass-thru" means.

Thank you thank you thank you, NOW I understand!!!

Since you seem to be in the know and can explain it without peeling the grape, I have another for you. First my status, I am plugged to my house outlet (30 amp), am running the front AC since we are loading for a trip. I see that my house/coach batteries are at 13.7, my chassis batteries are at 12.8, and they NEVER show any higher/ Is there a reason for that and is it OK? Of course my coach bttys are flooded and my chassis battys are sealed.

[creativepart]

This is too easy Jim.

First, your 30-amp house "shore power" and front A/C have nothing to do with your charging. So, that's like throwing in a trick part to your question.

Now about batteries. A fully charged 12v battery is no more than 12.7-12.8v. So, your chassis battery is fully charged. I'll get into that part later.

Your Inverter is also your Charger and it charges just your House batteries. It has 3-stages of charging: Bulk, Absorption and Float. It puts out between 14+ volts in Bulk and then drops to 13+v when bringing your house batteries up to fully charged. So, when you look at that screen and you see 13.7v you are not seeing the battery's voltage - you are seeing the CHARGER's voltage. Anytime your battery is being charged you'll see the charger's voltage not the battery's voltage. Remember a fully charged 12v battery is 12.7 volts.

So, why is your Chassis battery "never above 12.8v?" That's because your RV's engine is not running.

Here's the whole story. You have a device on your RV called a BIM (Battery Isolation Monitor) it sits between your house battery bank and your chassis battery bank. It's job is to keep the two banks separate sometimes and to combine them other times. It is programed to charge your Chassis battery whenever your House battery bank is near fully charged.

Here's a bit more detail. When you are driving your RV's alternator charges your House Batteries and your Chassis Batteries. However, when you are on shore power or generator your Inverter/Charger charges your House Batteries ONLY. So, when you go to some campground for 2-weeks, plugged into shore power, your engine isn't running. And, the Chassis batteries can lose power from various parasitic loads. That BIM comes to the rescue when it sees the House batteries are fully charged and the Chassis battery is getting low. It combines the two battery banks and charges your Chassis battery up to full charge - 12.7v. Once the Chassis battery is fully charged the BIM disconnects the two battery banks and everything goes back to charging your House batteries.

Here's something you didn't know. Whenever the charger is in float mode for 4 hours with no DC loads running, the charger will turn OFF. It's called "Battery Saver Mode." This lets your house batteries loose a little power and then when the charger come back on it will work a bit harder to get the batteries back up to full charge. This full-charge > no charge > full charge cycle keeps your house batteries fresher.

One more thing. You said you never see your House battery above 12.8v - ah, but they do go above that voltage when you are running your engine. Turn on your RV's engine, wait about a minute then look at that voltage meter. You should see that 13v to 14v we talked about when a charger is charging your battery.

Hope this answers your questions.

[SgtB]

Originally Posted by creativepart

This is too easy Jim.

First, your 30-amp house "shore power" and front A/C have nothing to do with your charging. So, that's like throwing in a trick part to your question.

Now about batteries. A fully charged 12v battery is no more than 12.7-12.8v. So, your chassis battery is fully charged. I'll get into that part later.

Your Inverter is also your Charger and it charges just your House batteries. It has 3-stages of charging: Bulk, Absorption and Float. It puts out between 14+ volts in Bulk and then drops to 13+v when bringing your house batteries up to fully charged. So, when you look at that screen and you see 13.7v you are not seeing the battery's voltage - you are seeing the CHARGER's voltage. Anytime your battery is being charged you'll see the charger's voltage not the battery's voltage. Remember a fully charged 12v battery is 12.7 volts.

So, why is your Chassis battery "never above 12.8v?" That's because your RV's engine is not running.

Here's the whole story. You have a device on your RV called a BIM (Battery Isolation Monitor) it sits between your house battery bank and your chassis battery bank. It's job is to keep the two banks separate sometimes and to combine them other times. It is programed to charge your Chassis battery whenever your House battery bank is near fully charged.

Here's a bit more detail. When you are driving your RV's alternator charges your House Batteries and your Chassis Batteries. However, when you are on shore power or generator your Inverter/Charger charges your House Batteries ONLY. So, when you go to some campground for 2-weeks, plugged into shore power, your engine isn't running. And, the Chassis batteries can lose power from various parasitic loads. That BIM comes to the rescue when it sees the House batteries are fully charged and the Chassis battery is getting low. It combines the two battery banks and charges your Chassis battery up to full charge - 12.7v. Once the Chassis battery is fully charged the BIM disconnects the two battery banks and everything goes back to charging your House batteries.

Here's something you didn't know. Whenever the charger is in float mode for 4 hours with no DC loads running, the charger will turn OFF. It's called "Battery Saver Mode." This lets your house batteries loose a little power and then when the charger come back on it will work a bit harder to get the batteries back up to full charge. This full-charge > no charge > full charge cycle keeps your house batteries fresher.

One more thing. You said you never see your House battery above 12.8v - ah, but they do go above that voltage when you are running your engine. Turn on your RV's engine, wait about a minute then look at that voltage meter. You should see that 13v to 14v we talked about when a charger is charging your battery.

Hope this answers your questions.

SIR, you are a PINCE!!!!!! LOL. Now that is Marine Grunt language that this dumb Grunt can understand. I am going to remember you!!! LOL

[deckape]

Thanks for the great information to how this all works . Thank you Jim

[SgtB]

Originally Posted by creativepart

This is too easy Jim.

First, your 30-amp house "shore power" and front A/C have nothing to do with your charging. So, that's like throwing in a trick part to your question.

Now about batteries. A fully charged 12v battery is no more than 12.7-12.8v. So, your chassis battery is fully charged. I'll get into that part later.

Your Inverter is also your Charger and it charges just your House batteries. It has 3-stages of charging: Bulk, Absorption and Float. It puts out between 14+ volts in Bulk and then drops to 13+v when bringing your house batteries up to fully charged. So, when you look at that screen and you see 13.7v you are not seeing the battery's voltage - you are seeing the CHARGER's voltage. Anytime your battery is being charged you'll see the charger's voltage not the battery's voltage. Remember a fully charged 12v battery is 12.7 volts.

So, why is your Chassis battery "never above 12.8v?" That's because your RV's engine is not running.

Here's the whole story. You have a device on your RV called a BIM (Battery Isolation Monitor) it sits between your house battery bank and your chassis battery bank. It's job is to keep the two banks separate sometimes and to combine them other times. It is programed to charge your Chassis battery whenever your House battery bank is near fully charged.

Here's a bit more detail. When you are driving your RV's alternator charges your House Batteries and your Chassis Batteries. However, when you are on shore power or generator your Inverter/Charger charges your House Batteries ONLY. So, when you go to some campground for 2-weeks, plugged into shore power, your engine isn't running. And, the Chassis batteries can lose power from various parasitic loads. That BIM comes to the rescue when it sees the House batteries are fully charged and the Chassis battery is getting low. It combines the two battery banks and charges your Chassis battery up to full charge - 12.7v. Once the Chassis battery is fully charged the BIM disconnects the two battery banks and everything goes back to charging your House batteries.

Here's something you didn't know. Whenever the charger is in float mode for 4 hours with no DC loads running, the charger will turn OFF. It's called "Battery Saver Mode." This lets your house batteries loose a little power and then when the charger come back on it will work a bit harder to get the batteries back up to full charge. This full-charge > no charge > full charge cycle keeps your house batteries fresher.

One more thing. You said you never see your House battery above 12.8v - ah, but they do go above that voltage when you are running your engine. Turn on your RV's engine, wait about a minute then look at that voltage meter. You should see that 13v to 14v we talked about when a charger is charging your battery.

Hope this answers your questions.

Hi Creative part, Old Jim here again. I just went out and tried to find out exactly what battys are in the rig for coach battys. They are Interstate Marine/RV so-called" deep cycle. Called Interstate and I can't believe what they told me. The battys are "SRM-27 and the CCA is 600. She told me the amp/hr rating is 88. That seems awfully low to me. My settings for the coach battys only allow me to choose between 200 or 400. And 88 X 4 only comes to 352. Am I calculating that correctly? Or being stupid again?

[SgtB]

Update: Spoke to an Interstate guy who what he was talking about and answered all my question. I am GTG now!

[creativepart]

Originally Posted by SgtB

Update: Spoke to an Interstate guy who what he was talking about and answered all my question. I am GTG now!

I was just writing up a post to ask you if the Interstate batteries that you were asking about were your Chassis (starting) batteries or your House batteries.

You have two chassis batteries and I'd expect those to the the Group 27 88 amp hour batteries.

And then there are 4-house batteries in another compartment on the other side of your coach at the rear. I would expect those to be 100-amp hour AGM batteries.

So, could you clear that up for me? What do you have in each bank of batteries - two starting batteries on one side of your coach at the rear and four house batteries on the other side of the coach???

Here's the wiring diagram for your batteries in relation to the rear of your motorhome - Chassis batteries on the left and House batteries on the right:

[SgtB]

Originally Posted by creativepart

I was just writing up a post to ask you if the Interstate batteries that you were asking about were your Chassis (starting) batteries or your House batteries.

You have two chassis batteries and I'd expect those to the the Group 27 88 amp hour batteries.

And then there are 4-house batteries in another compartment on the other side of your coach at the rear. I would expect those to be 100-amp hour AGM batteries.

So, could you clear that up for me? What do you have in each bank of batteries - two starting batteries on one side of your coach at the rear and four house batteries on the other side of the coach???

Here's the wiring diagram for your batteries in relation to the rear of your motorhome - Chassis batteries on the left and House batteries on the right:

House battys are four SRM-27 88 Amp/hr Flooded on the right rear. Chassis battys are sealed on the left rear

[creativepart]

Originally Posted by SgtB

House battys are four SRM-27 88 Amp/hr Flooded on the right rear. Chassis battys are sealed on the left rear

That is an odd pairing for a Class A Diesel motorhome. But OK. That's good info for you to know.

Don't forget to check the water level in those Flooded batteries frequently - like every month or so.

[Morich]

Since you are involved in the "learning curve" and Creative has mentioned how the power works, there is one area that has a lot to do with how that power works right next to the batteries for starting at left rear of RV.

A few pictures from the part catalog make it easier to follow what you have.

Looks like four screws to remove this panel if you ever need to get to all these things that may need help.



Inside is the battery isolation manager and the solenoid which does the connection between the two groups of batteries. You start the RV engine and it does the connection OR if you have a weak starting battery, there will be a switch somewhere near the driver called boost, aux or something like that (they keep changing the name!) and while you are pushing that momentary switch, this solenoid connect them together kind of like an automatic "jump start"!




And then there are the two relays that do the actual work of connecting/disconnecting the power when you hit the coach or chassis disconnect switches. The two switches move one of these two relays.




The big thing to know about these relays is that both of them DO NOT disconnect ALL the power but leave several things that will run down the batteries if you don't guard against it!
On the coach side, there are safety items like the propane and CO detectors and on the chassis side there are things like radio presets ignition and other small things that can sneak up on us while itis stored.
Just a headsup on watching close to avoid running the batteries totally flat as that tends to ruin them!

[MovingMann]

The AMAZING thing about this forum is the fact that there is an AMAXING amount of knowledge that is so easily shared ...

Thank you Creative Part & Morich for sharing your knowledge & expertise...and I didn't even ask the question !

And I don't even have a Class A - gas or diesel but a gas Class C.