Testing inverter/converter

[The Rookie]

2017 Windsport 29M

What is the best way to test the converter and inverter to ensure proper operation?

[RV Driver]

What is happening that makes you think you need to test it?

[Beau388]

Originally Posted by The Rookie

2017 Windsport 29M

What is the best way to test the converter and inverter to ensure proper operation?

With the generator and shore power off - Turn the inverter on and look at the battery voltage. If there is no voltage or the inverter doesn't show at least 12.3 volts or greater; then try to start the generator. If it doesn't crank the batteries are dead.



To test the converter plug into shore power. Turn the store/use switch to store or the master power switch to off. Turn the 12 volt ceiling lights on under cabinet lights on -- if the light are on the converter is good. That is assuming the house batteries are good and you did isolate the batteries.

[16ACE27]

Originally Posted by The Rookie

2017 Windsport 29M

What is the best way to test the converter and inverter to ensure proper operation?

"best" is subjective; what's best for me may not be best for you.

Next - terminology: a converter and an inverter are not the same thing and in fact do opposite thing.

A converter takes 120 VAC from SP or the generator and converts it to 12+ VDC to power house DC loads and charge the house batteries.

An inverter takes the power from the house batteries and creates 120 VAC to power selected AC loads - generally residential and outdoor kitchen fridges and TV/Entertainment power receptacles in an OEM installation.

To test the converter you have to be connected to SP. With the battery disconnect latching relay OPEN (USE/STORE switch in STORE or MAIN POWER switch OFF) the converter is working if the interior lights and water pump work. Or leave the battery disconnect shut and measure the house battery voltage - it should be between 13.1 and 14.5 VDC.

To test the inverter you have to be disconnected from SP and not running the generator - battery disconnect position does not matter. Your TVs should power on and your outdoor fridge (and the main fridge if residential) should also work if the inverter is turned ON.

[The Rookie]

Originally Posted by RV Driver

What is happening that makes you think you need to test it?

From an inspection report:
“ Power Converter - Did DC Voltage Drop at Least 1/2 Volt
No
Batteries tested at 3.03 volts DC on meter with the Convertor on and 12.98 volts with the converter off. Typically see at least a half volt drop if the convertor is charging as designed”

I haven’t noticed anything to be concerned about, however I figured I should try to test various systems both for education and piece of mind.

[Lt Keefer]

Key word in that report is 'typically'. Does the inspector think the converter is over charging?

[The Rookie]

Originally Posted by Lt Keefer

Key word in that report is 'typically'. Does the inspector think the converter is over charging?

He did not say that it was overcharging, just that he did not see the expected voltage drop and an RV tech should determine more.

[16ACE27]

Originally Posted by The Rookie

From an inspection report:
“ Power Converter - Did DC Voltage Drop at Least 1/2 Volt
No
Batteries tested at 3.03 volts DC on meter with the Convertor on and 12.98 volts with the converter off. Typically see at least a half volt drop if the convertor is charging as designed”

I haven’t noticed anything to be concerned about, however I figured I should try to test various systems both for education and piece of mind.

Is that supposed to be 13.03 VDC? Because 3.03 VDC makes no sense.

[The Rookie]

Originally Posted by 16ACE27

Is that supposed to be 13.03 VDC? Because 3.03 VDC makes no sense.

3.03 is what the report says. I’m thinking that must a typo.

[dkoldman]

Why would report say to expect 1/2 vdc drop with converter on?

I certainly follow why you ask the question.

If you want to really understand, get the make model of your converter. Verify what profile it is running. It matters what type of house batteries you have. It will tell you bulk, absorption and float voltages and time.

Most will go into bulk mode when 1st turned on for some set time before dropping the voltage automatically.

How much did you pay this inspector

[The Rookie]

Originally Posted by dkoldman

Why would report say to expect 1/2 vdc drop with converter on?

I certainly follow why you ask the question.

If you want to really understand, get the make model of your converter. Verify what profile it is running. It matters what type of house batteries you have. It will tell you bulk, absorption and float voltages and time.

Most will go into bulk mode when 1st turned on for some set time before dropping the voltage automatically.

How much did you pay this inspector

I can’t find how much I paid him, but I’m ok with his services. He told me there could be an issue. It’s my responsibility to get it figured out. That’s my philosophy.

As always, thank you for the info!

[dkoldman]

Originally Posted by The Rookie

I can’t find how much I paid him, but I’m ok with his services. He told me there could be an issue. It’s my responsibility to get it figured out. That’s my philosophy.

As always, thank you for the info!

Yup, the inspector is all water under the bridge at this point and you are happy.

So you are where you said he stated he said "it is your responsibility to get it figure out"

Most everything could be an issue, if not now later. Over time you will want to learn everything possible about your coach and how it works. It will eventually come together. Keep reading the forum and of others problem so you can learn what to check to be proactive.

If you have questions about your converter and inverter it really is best to start with what models you have and if you are able to take voltage reading with voltmeter? Or you may have some battery monitor but all of these things you will need to share and some one can tell you or help you with whether your converter or inverter is doing something funny.

[The Rookie]

Originally Posted by dkoldman

Yup, the inspector is all water under the bridge at this point and you are happy.

So you are where you said he stated he said "it is your responsibility to get it figure out"

Most everything could be an issue, if not now later. Over time you will want to learn everything possible about your coach and how it works. It will eventually come together. Keep reading the forum and of others problem so you can learn what to check to be proactive.

If you have questions about your converter and inverter it really is best to start with what models you have and if you are able to take voltage reading with voltmeter? Or you may have some battery monitor but all of these things you will need to share and some one can tell you or help you with whether your converter or inverter is doing something funny.

Thank you for everything. I may be weird, but I love trying to figure it all out and educate myself. I do something everyday related to my RV. This forum has been/will be indispensable. You all are a tremendous help!

[PS89]

From an inspection report:
“ Power Converter - Did DC Voltage Drop at Least 1/2 Volt
No
Batteries tested at 3.03 volts DC on meter with the Convertor on and 12.98 volts with the converter off. Typically see at least a half volt drop if the convertor is charging as designed”

Sounds to me like the inspector either didn't allow the battery bank to fully charged or he failed to run off the excess surface charge of fully charged batteries before making his observation.

With the shore power and generator off and the USE/STORE switch ON, turn on every possible 12 volt load (lights, inverter, furnace fan, vent fans, TVs etc) and watch the battery voltage. Assuming SLA batteries and the standard 2x100 AH configuration for the 29M, you should notice a slow but steady drop in the battery bank voltage as power is consumed. Start the generator or re-connect shore power and the voltage should rise back above 13 volts as the converter starts recharging the batteries and supplying any DC loads.

More likely than not, your '17 29M is equipped from the factory the same as my '18 29M - a 1000 watt Xantrex PRO 1000 inverter and a piece of junk WFCO laughingly rated at 55 amps.

[Lt Keefer]

I have an '18 Hurricane 29M so I'm gonna guess we have the same stock setup. It's parked in the lot outside, plugged in all the time. Out of curiosity, I went out and turned on the inverter. The display said 13.6. I unplugged the coach and the display dropped to 13.4. The only thing on is the inverter, and the vent fan exhaust in the galley. After a moment or two it dropped to 13.3. I would think, for what it is, your system is doing fine.

[The Rookie]

Originally Posted by PS89

Sounds to me like the inspector either didn't allow the battery bank to fully charged or he failed to run off the excess surface charge of fully charged batteries before making his observation.

With the shore power and generator off and the USE/STORE switch ON, turn on every possible 12 volt load (lights, inverter, furnace fan, vent fans, TVs etc) and watch the battery voltage. Assuming SLA batteries and the standard 2x100 AH configuration for the 29M, you should notice a slow but steady drop in the battery bank voltage as power is consumed. Start the generator or re-connect shore power and the voltage should rise back above 13 volts as the converter starts recharging the batteries and supplying any DC loads.

More likely than not, your '17 29M is equipped from the factory the same as my '18 29M - a 1000 watt Xantrex PRO 1000 inverter and a piece of junk WFCO laughingly rated at 55 amps.

Correct on the Xantrex and a fair assumption on the converter.
Thank you for the steps.

[The Rookie]

Originally Posted by Lt Keefer

I have an '18 Hurricane 29M so I'm gonna guess we have the same stock setup. It's parked in the lot outside, plugged in all the time. Out of curiosity, I went out and turned on the inverter. The display said 13.6. I unplugged the coach and the display dropped to 13.4. The only thing on is the inverter, and the vent fan exhaust in the galley. After a moment or two it dropped to 13.3. I would think, for what it is, your system is doing fine.

Thank you for taking the time to do that!

[The Rookie]

So, I decided to do a simple test on the converter.
With battery switch in the Store position, no gen, no engine running, not plugged into SP. Both batteries at the posts read 12.54 volts with my voltmeter.

I plugged into 15 Amp (checked major appliances for off position). Switched to battery switch to Use. I did the same voltmeter test at the batteries with 13.22 volts reading.
The batteries are FLA. The converter is a WFCO 9855.
From my limited knowledge, it seems that the converter is sending a charge high enough to charge the batteries during storage.
Am I incorrect in assuming that the output should be 13.6 volts?

[Beau388]

Originally Posted by The Rookie

So, I decided to do a simple test on the converter.
With battery switch in the Store position, no gen, no engine running, not plugged into SP. Both batteries at the posts read 12.54 volts with my voltmeter.

I plugged into 15 Amp (checked major appliances for off position). Switched to battery switch to Use. I did the same voltmeter test at the batteries with 13.22 volts reading.
The batteries are FLA. The converter is a WFCO 9855.
From my limited knowledge, it seems that the converter is sending a charge high enough to charge the batteries during storage.
Am I incorrect in assuming that the output should be 13.6 volts?

All LA batteries turn electrical energy to chemical energy and can reverse the chemical processes to produce electricity. The temperature of the batteries greatly effects the maximum output in voltage and amperage. The charger uses its internal temperature to to regulate charger's float voltages.



Everything is figured around 20 C or about 77 F. to keep the voltage as high as possible without effecting a chemical change in a fully charged battery battery. A fully charged FLA battery voltage is considered to be 12.7 volts at 20C. For AGM's the voltage is 12.9 volts. The battery has a hysteresis value 0.8-1.1 volts. So if the voltage of the charger exceeds 12.7 plus 0.9 volts (13.6 volts), the fully charged battery will boil out water vapor. Charger float voltage can vary from 13.1 volts on really high temperatures to 13.7 on really cold temperatures. Better converters have a battery temperature monitor connected to the battery and disregard the converter's internal temperature. (your results may vary)

[The Rookie]

Great thank you