Inverter AND converter charging?

[BasilFawlty]

I have a question I can't seem to find a direct answer for in the forum. I am wondering on how my unit is charging the house batteries.

Back story: 2015 38RL w/ residential fridge. Factory lead acid batteries changed to AGM maintenance free long time ago. Even if they are maintenance free, I wanted to crack open the battery boxes after a year just to make sure there wasn't any mechanical issues (bugs, wire chaffing, cats, etc.)

On shore power, I turned off my INVERTER to facilitate removing the batteries. I saw the voltage was still 13.2 volts even with the inverter off. I clicked off the CONVERTER and voltage dropped to about 12.6 - about what I would expect for a battery under no load.

So... I have this super fancy INVERTER with computer controlled, battery temperature sensing, battery type programable, super duper maintainer and yet, the basic CONVERTER is charging as well.

Can I just turn off the CONVERTER at the 120v circuit breaker and let the INVERTER take care of the batteries?

[Shane Wood]

The convertor supply all 12v power and charges the battery's. The invertor is fed off the batteries and supplies 120v to the residential fridge only

[BasilFawlty]

Originally Posted by Shane Wood

The convertor supply all 12v power and charges the battery's. The invertor is fed off the batteries and supplies 120v to the residential fridge only

I am sure the INVERTER charges as well when on 120v shore power. It can even be programed for battery type, amp hours and charge rate. It also shows charging status (bulk, absorb, equalize & float) as well as charging current.

[brenkco]

If your equipment is like mine, it is a Magnum 1000 pure sine inverter/converter combination with a transfer switch. Yes, it works as a converter. You can turn off the second converter and let the Magnum carry the load.


I did notice when looking at the specs (sometime ago) that the Magnum will not charge as fast as the on board converter.


On second thought, it will charge the batteries but I'm not certain that it will provide power for the 12v system. Give it a try by turning off the breaker to your on board converter. I'm fairly sure mine worked with it off....not positive though!

Ken

[BasilFawlty]

UPDATE: I have been reading the manuals for the Magnum MMS1012 INVERTER and the Progressive PD45920 CONVERTER. From what I can tell, they are both battery chargers BUT the Magnum INVERTER is not designed to provide constant load current once the batteries are charged.

With that in mind, I think I will let the Magnum INVERTER charge the batteries when they are low because of it's advanced charging method but once it has topped off, I'll click on the Progress CONVERTER to cover the normal 12v load of the coach.

Thanks for your help!

[Shane Wood]

Originally Posted by BasilFawlty

I am sure the INVERTER charges as well when on 120v shore power. It can even be programed for battery type, amp hours and charge rate. It also shows charging status (bulk, absorb, equalize & float) as well as charging current.

You are thinking of the main convertor which has the digital readout. The residential fridge invertor has no readout and supplies 120v off the batteries when not connected to a pedestal and has a transfer switch that will run it on 120v when connected to power it runs straight to the 120v plug that the fridge is plugged into and feeds nothing else 1000w

[brenkco]

Originally Posted by Shane Wood

You are thinking of the main convertor which has the digital readout. The residential fridge invertor has no readout and supplies 120v off the batteries when not connected to a pedestal and has a transfer switch that will run it on 120v when connected to power it runs straight to the 120v plug that the fridge is plugged into and feeds nothing else 1000w

Shane,
No, the Magnum, at least in my rig, has a digital display that shows the voltage, charge rate, set the type of batteries etc. It is in the closet with the gen prep, slide and awning switches. It also allows the on/off function of the inverter. When trouble shooting a problem with it last year, Magnum had me run through a series of tests using the display.

The main converter may have a display but it is on board and mounted in the basement and not visible.

Ken

[mhs4771]

Ours is the same as Ken's except our remote for the Inverter is mounted on the outside wall from the slides and other switches. The main converter/charger doesn't have a meter, but it does have a Red LED that indicates different status I believe.

[BasilFawlty]

Our Magnum INVERTER in mounted in the basement on the front wall. Its remote is in the command center with tank level monitor, water heater switches, etc.

The Progressive CONVERTER is built into the power distribution panel along with the 120v circuit breakers and 12v fuses. There is a blinking LED light to show its status.

[Shane Wood]

Apparently we are talking about the same thing only different

[Mike&Pam]

Hello All,

I saw this thread and found it very interesting. I have done a lot of investigation of the Magnum Inverter MMS1012 and the Progressive Dynamic PD4590 Converter.

I have the Residential Fridge which can be powered by Shore Power or by the 1000W Magnum Inverter. That is the only AC load that my Magnum Inverter serves.

Lets talk about the two different components. First lets talk about the Magnum Inverter.

1) The Magnum Inverter has a built in battery charger (50A). This battery charger is extremely smart. It has 4 different stages of charging. It has Bulk Charge mode, Absorption Charge mode, Float Charge Mode and Full Charge Mode. Bulk Charge is the initial phase and it begins charging at a relatively high voltage like 14.6v (actually 14.3v for LifeLine battery, you must select AGM1 for battery type from the remote). Bulk charging occurs when the batteries have been fairly discharged. This mode tries to get the batteries back up to voltage quickly so to get them back where they should be. Once the Bulk Charge voltage has been met, the 2nd phase Absorption Charge mode begins. In this mode the Absorption voltage is maintained by reducing current thus helping the batteries to "absorb" the voltage over time. This charge mode will last typically 120 min but is really a function of the input AH for the battery bank (mine is 440 AH... I have 4 6v lifeline batteries). The next phase is Float Charge. In this mode, the voltage is reduced to 13.4v (or 13.1v for LifeLine if AGM1 is selected) and this mode will go on for 4 hours. The final stage is "Full Charge" mode. In this mode, no charging is done and the battery is monitored. Once the voltage drops below 12.7v, the charger will kick back into Float Charge mode for 4 hours and then back to "Full Charge" mode.

The really cool thing about the Magnum 50A charger is that it has a BTS (Battery Temperature Sensor) built in. Therefore, all of those voltages that I quoted above will "slide" as a function of temperature. This is crucial to ensure the most life out of your batteries. There is no set voltage to use because realistically, the voltage requirement changes as a function of temperature and the charge mode that is required. The colder it gets, the higher the voltages will be and the hotter it gets, the lower the voltages will be. The magnum charger is smart enough to do all this. Furthermore, if you own LifeLine batteries as I do, Magnum actually consulted them and when you select AGM1, you will get the proper settings for your LifeLine batteries. If I am not mistaken, AGM2 is for Trojan, East Penn, Deka and Discover batteries. This information can be found in the manual for the remote (ME-MR manual) for the Magnum inverter. I had to hunt online to find this manual.

There is also one more "manual" mode that the Magnum charger has and that is equalization mode (or conditioning mode). This mode is to be used to prevent sulfation of the batteries or maybe they have not been charged with the appropriate voltage and can only go to 90%. In this mode, a much higher voltage like around 15.5v is used. The LifeLine battery company says that this mode should only be used when the batteries are showing symptoms of this. This isn't something that should just be done to be done. Therefore, it is good that this is a "manual" mode operation instead of automatic.

Now lets talk about the Progressive 90A battery charger. This charger has 3 stages of operation and does not have the ability to adjust for temperature. Therefore, ALL OF THE VOLTAGES ARE FIXED... THEY DON'T CHANGE WITH TEMPERATURE.

The 1st phase is BOOST MODE. In this mode, the voltage is 14.4v.
The 2nd phase is NORMAL MODE. In this mode, the voltage is 13.6v. This mode is used once the battery is 50% to 90% charged.
The 3rd phase is STORAGE MODE. In this mode once 30h have gone by such that there has been no significant battery usage, the voltage is dropped to 13.2v. This voltage is constant, it never stops. However every 21h, the voltage is increased to 14.4v for 15 min so to "Condition" or "Equalize" the battery and help cut back on sulfation.

----- Comparing the 2 chargers -------

Looking at the two different chargers, it is very clear that the Magnum charger is much smarter than the Progressive charger. Furthermore, I don't like that the Progressive charger automatically does the "conditioning" mode. After talking with the battery experts (LifeLine), they recommend that this only be done if necessary.

Furthermore, the Progressive charger doesn't know anything about temperature. That is also (in my opinion), another good reason to just use the Magnum charger.

------------

Now lets talk about how these things work in the RV.

As for the Magnum Inverter...

1) When hooked to Shore Power, this device will allow the Inverter AC load (in my case it is the Fridge) to be served via the incoming AC from shore power. In addition, (as long as the charger is setup do to this via the remote), the charger is allowed to kick in and charge the batteries. As for 12v DC loads, I have not read anywhere in the manual that these loads are served by shore power. The manual only says that the Inverter AC loads (i.e. the fridge in my case) are served. Therefore, all 12v DC loads are not served by shore power... they would only be served via the batteries when it comes to the Magnum Inverter device.

2) When NOT hooked to shore power, this device will convert DC power (coming from the house batteries) to AC (assuming that the inverter is "ON"). This AC power will then serve the AC load which is the fridge in my case. As for the charger, the charger is on "standby" in this mode because the batteries are doing the work instead of shore power. Thus the charger is not doing anything in this mode.

When it comes to the Progressive Converter/Charger...

1) When hooked to Shore Power, the 90A charger will charge the batteries as outlined above. Furthermore all 12v loads will be served by the converter thus taking load off of the house batteries.

2) When NOT hooked to Shore Power, this device really doesn't do anything except act as a 12v fuse box.

----- Conclusion --------

In summary, I am seriously thinking about figuring out how to disable the Progressive PD4590 charger (only the charger... not the entire converter section). Now that I have spent all of this money on these 6v batteries from LifeLine, I want to be sure that the "smart" charger is doing the work. I realize that the charge time will be longer because instead of both a 50A and a 90A charger doing the job, there will only be a 50A charger working, but at least the charger is doing the job correctly. Furthermore, my wife and I don't do a lot of dry camping. We do have a generator but we use it to do small time boon docking like doing the overnight walmart thing or maybe staying overnight at a Pilot. In those circumstances, we normally do this when the weather is cool so we don't run the generator at night. Instead we depend on the batteries to operate the furnace and keep the fridge/inverter going and other small loads like lights and the onboard water pump.

Having said that though, I am thinking that I cannot disable the Progressive Converter entirely because like I said, when hooked to Shore Power, the Converter takes care of the 12v loads instead of making the battery do this. I don't want to lose this capability.

I am thinking that only the Progressive charger should be disabled. I have looked at the manual a bit for the progressive charger. It looks like I could just disconnect the battery wires from the posts (sportive and negative) in the progressive fuse box but keep the converter posts connected. I am not an electrician. Does anyone know if this is the correct way to do this?

Furthermore, I am going to contact LifeLine and let them know that this secondary charger (the Progressive 90A charger) is in the system as well and tell them about how it operates. If they end up telling me that this shouldn't be a problem, I will probably leave it alone. If they tell me that I should definitely bypass this secondary charger, I think I am going to try and figure out how to do that w/o losing the "converter" functionality that services my 12v loads while hooked to shore power.

I will keep you all in the loop regarding what LifeLine tells me.

Thanks,
Mike