Can you use a 15amp circuit to Pre-Configure and Test a MultiPlus II 3000/2x120?

[InMyImage]

Does anyone know of a reason why you couldn’t or shouldn’t hook a MultiPlus to a standard 15amp household circuit using an extension cable with the end chopped off for the AC input?

We are having a problem with our on-board 12v converter which I think I want to keep as I quickly discovered that when the battery was disconnected all our 12v systems lost power, including the thermostats for our air conditioners. The MultiPlus doesn’t have a way to convert 120v’ to 12vs so if we completely dump the converter then we will have the same issue anytime we have to disconnect the batteries.

I’m working with a tech from Progressive Dynamics and don’t want to tear apart the trailer’s wiring before giving him a chance to figure out the problem if I can avoid it. Regardless of what happens, I’d like to preconfigure the MultiPlus for my batteries and test the configuration before installing it to cut down on the amount of time we might need to have the 12v offline given that it’s been about 90 degrees here so we need to run it or get cooked in our trailer.

 

[sunshine_eggo]

Does anyone know of a reason why you couldn’t or shouldn’t hook a MultiPlus to a standard 15amp household circuit using an extension cable with the end chopped off for the AC input?

That's how I have my Quattro "wired" to connect to one leg of my generator.

We are having a problem with our on-board 12v converter which I think I want to keep as I quickly discovered that when the battery was disconnected all our 12v systems lost power, including the thermostats for our air conditioners. The MultiPlus doesn’t have a way to convert 120v’ to 12vs so if we completely dump the converter then we will have the same issue anytime we have to disconnect the batteries.

The MP doesn't need to convert 120VAC to 12VDC because it's powered by a 12VDC battery.

I’m working with a tech from Progressive Dynamics and don’t want to tear apart the trailer’s wiring before giving him a chance to figure out the problem if I can avoid it. Regardless of what happens, I’d like to preconfigure the MultiPlus for my batteries and test the configuration before installing it to cut down on the amount of time we might need to have the 12v offline given that it’s been about 90 degrees here so we need to run it or get cooked in our trailer.

Based on my interpretation of your situation, you need a separate connection from shore directly to the converter to accomplish what you want. most just have a 3 prong plug, so an extension cable will work, or rewire that outlet to connect directly to shore input.

Another option is to have all of your 12V powered by the converter and a separate small coach battery with converter powered by the inverter. Downside to this is about 75% efficiency, but you're likely not using a large amount of 12VDC daily.

You need to make sure your setup isn't powering the converter with the inverter while the inverter is drawing from the batteries while the converter charges the batteries... a recipe for failure...

 

[rmaddy]

A MultiPlus needs DC battery power, not AC power, to get it all setup. There are a few related questions on the Victron Community forums. See:

Search - About 10000 Results Found - Victron Community

community.victronenergy.com

 

[TomC4306]

Deleted. Wrong thread

 

[InMyImage]

True, but in an RV there are a LOT OF 12v systems, everything from the lights to our air conditioner thermostats. Normally when plugged into power at a campground (shore power) there is a converter that converts the 120v input to 12v output for all the 12v systems and also charges the batteries. When connected to shore power, nothing uses the batteries for 12v power unless there is a blackout. Because the converter is supplying all 12v power, you can run without the batteries installed if necessary for any length of time. Mine isn’t working for some reason.

If we can’t get the converter to work when connected to shore power, then anytime you need to disconnect your batteries, you lose power to all the 12v systems. My current plan is to disconnect the converter from the batteries completely and just have it supply the 12v systems anytime you are connected to shore power although I haven’t confirmed that will work, don’t want to distract the Tech while he is trying to figure out the problem. Just not sure if I can disable the converter’s charger so it’s only function is providing power to the 12v systems when plugged into shore power.

 

[InMyImage]

A MultiPlus needs DC battery power, not AC power, to get it all setup. There are a few related questions on the Victron Community forums. See:

Search - About 10000 Results Found - Victron Community

community.victronenergy.com

Thanks but the operative word was “test” which would include setting the AC input limit, verify it works with input power and fails over to battery and back again, battery charging etc. All require AC input to be installed.

Appreciate you trying to post results from the Victron community that you thought might be helpful unfortunately Victron’s seach functionality uses any keyword algorithm not an all words or word proximity algorithm, I couldn’t find anything related because all of the words except test or testing appear in almost ever single thread on the site.

 

[rmaddy]

Thanks but the operative word was “test” which would include setting the AC input limit, verify it works with input power and fails over to battery and back again, battery charging etc. All require AC input to be installed.

I believe I misunderstood your question. The very first sentence of your original post led me to think you were asking if the MultiPlus could be powered via just AC for initial setup. Sorry for the confusion.

 

[sunshine_eggo]

True, but in an RV there are a LOT OF 12v systems, everything from the lights to our air conditioner thermostats. Normally when plugged into power at a campground (shore power) there is a converter that converts the 120v input to 12v output for all the 12v systems and also charges the batteries. When connected to shore power, nothing uses the batteries for 12v power unless there is a blackout. Because the converter is supplying all 12v power, you can run without the batteries installed if necessary for any length of time. Mine isn’t working for some reason.

If we can’t get the converter to work when connected to shore power, then anytime you need to disconnect your batteries, you lose power to all the 12v systems. My current plan is to disconnect the converter from the batteries completely and just have it supply the 12v systems anytime you are connected to shore power although I haven’t confirmed that will work, don’t want to distract the Tech while he is trying to figure out the problem. Just not sure if I can disable the converter’s charger so it’s only function is providing power to the 12v systems when plugged into shore power.

This is likely an installation issue.

Important: What battery did you disconnect and then lost power? The MP battery or a different one?

 

[InMyImage]

This is likely an installation issue.

Important: What battery did you disconnect and then lost power? The MP battery or a different one?

I haven’t started the actual install yet. I was disconnecting the old batteries so that I could start working on the 12v side of the wiring and when the 12v systems disconnected.

 

[sunshine_eggo]

I haven’t started the actual install yet. I was disconnecting the old batteries so that I could start working on the 12v side of the wiring and when the 12v systems disconnected.

Ah.

How many 12V?

Do you have single wires on the battery(ies), or do you have multiple cables attached to one or more batteries?

On one of my trailers, it was a hodgepodge of multiple wires connecting two batteries together. I had to "simulate" a battery terminal by bolting all the loose cable ends together to ensure 12V power continued to be fed by the converter.

 

[InMyImage]

The batteries themselves are connected together fine, the issue actually shows itself if I disconnect them at the battery disconnect or the battery breaker.

On that line of troubleshooting I have asked the tech if the charging function of the converter can be disabled. I planned to follow the same process as everyone else I have seen do this upgrade and just disconnect the converter, but not considering the fact that the thermostats are 12v, I’d like to keep it and keep troubleshooting the problem IF the charging feature can be disabled.

The next thing he wants me to do is to test the converter negative to frame ground which are about 20 feet apart and extremely difficult to navigate so I don’t want to waste any more effort on it if it isn’t going to matter anyway.

 

[sunshine_eggo]

The batteries themselves are connected together fine, the issue actually shows itself if I disconnect them at the battery disconnect or the battery breaker.

This isn't a surprise. Both disconnects and breakers are intended to completely isolate the source, whether battery or converter.

On that line of troubleshooting I have asked the tech if the charging function of the converter can be disabled. I planned to follow the same process as everyone else I have seen do this upgrade and just disconnect the converter, but not considering the fact that the thermostats are 12v, I’d like to keep it and keep troubleshooting the problem IF the charging feature can be disabled.

Why disable?

The next thing he wants me to do is to test the converter negative to frame ground which are about 20 feet apart and extremely difficult to navigate so I don’t want to waste any more effort on it if it isn’t going to matter anyway.

I like retaining the stock converter/12V when space allows. It's like a backup system. In this case, you're inserting the inverter power system between shore and converter. The downside is the aforementioned reduced 12V efficiency. The upside is a secondary backup and buffer for the 12V loads.

 

[InMyImage]

This isn't a surprise. Both disconnects and breakers are intended to completely isolate the source, whether battery or converter.

Sorry, just to be clear, there is a breaker directly connected to the battery positive then out of the breaker the positive leads to the battery disconnect, then out of the disconnect to a set of 2 positive busbars.

Are you saying that by having one, both or either of these disabled your expectation is that the converter would normally stop supplying power to the 12v side of the panel and I’m chasing a symptom without a problem?

Why disable?

Because the MultiPlus will be responsible for charging and my converter doesn’t support lithium batteries so it would attempt to complete it’s desulfation phase so it shouldn’t be used for charging.

I like retaining the stock converter/12V when space allows. It's like a backup system. In this case, you're inserting the inverter power system between shore and converter. The downside is the aforementioned reduced 12V efficiency. The upside is a secondary backup and buffer for the 12V loads.

I’m not sure I’m following your logic, when connected to shore power the converter is supposed to do two things, 1) Provide power to the 12v systems and 2) Charge the batteries.

If my MultiPlus is now going to be responsible for charging the batteries then the only responsibility the converter would have is providing power to the 12v systems while connected to shore power, if it doesn’t do that I don’t see any situation that makes it worthwhile to leave the converter installed at all.

As an aside, if there are 12v draws on the batteries while the MultiPlus is charging, how does that affect the absorption phase?

 

[sunshine_eggo]

Sorry, just to be clear, there is a breaker directly connected to the battery positive then out of the breaker the positive leads to the battery disconnect, then out of the disconnect to a set of 2 positive busbars.

Are you saying that by having one, both or either of these disabled your expectation is that the converter would normally stop supplying power to the 12v side of the panel and I’m chasing a symptom without a problem?

If the converter is directly connected to the battery, yes.

Because the MultiPlus will be responsible for charging and my converter doesn’t support lithium batteries so it would attempt to complete it’s desulfation phase so it shouldn’t be used for charging.

There is rarely a need for a converter to "support lithium." IMHO, most "lithium" converters are poor or marginal implementations. Second, "desulfation" phase on RV converters is almost always nothing more than a confusing label. If an RV converter has a TRUE desulafation pase on it, you can't put anything but flooded batteries in it. It would ruin AGM and GEL batteries.

what model converter?

I’m not sure I’m following your logic, when connected to shore power the converter is supposed to do two things, 1) Provide power to the 12v systems and 2) Charge the batteries.

Nope. It only does ONE thing. it provides voltage and current according to demand following charge voltage rules. A typical converter will provide 14.6, 13.8 or 13.2V depending on where it is in the charging phase. At no time does it ever provide a simple or regulated 12V. The "12V power" is "piggybacked" onto the converter's charging function.

If my MultiPlus is now going to be responsible for charging the batteries then the only responsibility the converter would have is providing power to the 12v systems while connected to shore power, if it doesn’t do that I don’t see any situation that makes it worthwhile to leave the converter installed at all.

Again, the value is in a backup capacity. IIRC from past conversations, keeping a consistent environment is important for your son. I would see this as another layer in that approach - retaining 12V power in case the MP system goes down. Here's a conceptual sketch:

As an aside, if there are 12v draws on the batteries while the MultiPlus is charging, how does that affect the absorption phase?

Depends.

Bulk mode: MP continues putting out maximum output. Loads reduce net current charging the batteries, e.g., 50A MP charging in bulk (below absorption voltage) and a 10A load on the 12V means a net 40A is charging the battery.
Absorption/float mode: MP observes the voltage drop due to the increased load, so it outputs additional current to maintain the absorption/float voltage, e.g., MP is maintaining absorption voltage with 20A. 10A load applied to 12V. The load causes the voltage to drop, so the MP increases output to 30A to maintain voltage. 20A going to battery, 10A going to load.

 

[InMyImage]

If the converter is directly connected to the battery, yes.

Interesting, the tech didn’t pick upon that at all even though I was clear that the battery had been disconnected.

what model converter?

Progressive Dynamics PD4590 with Charge Wizard, but not the Charge Wizard lithium charging option.

Absorption/float mode:

So if the converter is pumping out amps in excess of draw during charging, and the MP is in absorption when this happens, wouldn’t that screw up the absorption?

I like the redundancy aspect that you describe, and definitely see a benefit but wonder if unplugging the converter is a better route for the batteries long term amd then just plug in the converter if the charger portion of the MP fails. If the whole thing fails, then I’ve got other problems because the 120v is much more important for him than the 12v.

 

[sunshine_eggo]

Interesting, the tech didn’t pick upon that at all even though I was clear that the battery had been disconnected.


Progressive Dynamics PD4590 with Charge Wizard, but not the Charge Wizard lithium charging option.

https://www.progressivedyn.com/wp-content/uploads/Support/manuals/PD4500-110030J-owners-manual-english.pdf

PD4500 - The full rated load is available for load, battery charging or both. When functioning as a regulated battery charger the converter has a nominal voltage output of 13.6 VDC. The system is designed to sense voltage on the battery and automatically selects one of three operating modes (normal, boost and storage) to provide the correct charge level to the batteries.

BOOST MODE: If the converter senses that the battery voltage has dropped below a preset level the output voltage is increased to approximately 14.4 VDC to rapidly recharge the battery.
NORMAL MODE: Output voltage set at approximately 13.6 VDC.
STORAGE MODE: When there has been no significant battery usage for 30 hours the output voltage is reduced to 13.2 VDC for minimal water usage. When in storage mode, the output voltage will periodically increase to 14.4 VDC to help prevent sulfation of the battery plates.

Those voltages look pretty familiar, eh? I was 0.2V off, but this is very typical. note that the "desulfation" voltage is simply the absorption voltage, so it's basically just repeating a full charge once every 30 days.

This unit is a good choice for LFP.

Your #1 issue with ALL converters is the connection to the battery. Most use minimally sufficient gauge over a long distance, thus there is notable voltage drop. This causes the 14.4V to be hit prematurely and the unit to drop to normal mode. The good news is that if you're on grid, 13.6V is enough to get LFP charged to 95%+ SoC.

I regard the Li version in the manual as a poor implementation without additional information. The way this is worded is that it holds 14.6V and tapers current to ?. Then what? holding LFP at 14.6V is NOT a good idea.

PD4500LI - The full rated load is available for load, battery charging or both. When functioning as a regulated battery charger the converter has a nominal voltage output of 14.6 VDC. The system is designed to sense voltage on the battery and will taper the charging current as the battery becomes charged.

If you need to charge via generator, and you will manually terminate upon completion, the lithium is the better choice as the standard converter will hit 14.4V too soon due to voltage drop to the battery and charging at 13.6V will take much longer.

So if the converter is pumping out amps in excess of draw during charging, and the MP is in absorption when this happens, wouldn’t that screw up the absorption?

I'm not following you on this one.

I like the redundancy aspect that you describe, and definitely see a benefit but wonder if unplugging the converter is a better route for the batteries long term amd then just plug in the converter if the charger portion of the MP fails. If the whole thing fails, then I’ve got other problems because the 120v is much more important for him than the 12v.

I also like it because it's less modification to the original system, and it offers a little more flexibility. let's say the MP is down hard, and your only option is a generator. With the converter and original 12V in place, you don't have to make any provisions to get the 12V system back up.

 

[InMyImage]

I regard the Li version in the manual as a poor implementation without additional information. The way this is worded is that it holds 14.6V and tapers current to ?. Then what? holding LFP at 14.6V is NOT a good idea

I find pretty much all their docs to be lacking and their diagrams look like the were drawn using something like Microsoft Draw back from back in Windows 95. But the do have US support which is nice.

The tech got back to me and there is actually a “copper jumper” that comes with the converter as an option to be installed that enables the converter to contine supplying power to the 12v panel without a battery being connected. Guess Jayco doesn’t bother to use it and doesn’t include it with all the manuals, warranty cards and a couple of parts for things that were installed, at least it wasn’t in the packet we got with trailer but we are the second owners.

He also said that the charge “feature” couldn’t be disabled and his explanation pretty much matched yours in that it isn’t charging the battery specifically, it is increasing the voltage it produces, both charging the batteries and powering the 12v panel simultaneously.

I asked for the jumper wire specs so that I can make one since it seems to just be a short wire, maybe 2 inches long tops. All I want to know is the proper gauge and he responded with a part number, said it could only be purchased through them and that he couldn’t get me a price or availability until Monday. Don’t want to buy one just need to know what gauge it is the only thing I can assume at the moment is that “copper jumper” implies solid wire, not stranded. ?

I’m going to post over on the Jayco Owners forum to see if anyone over there knows because google isn’t helping.

I'm not following you on this one.

I struggled with how to word this so not surprised, might have been clearer if I used volts but I’m realizing that as long as absorption is set to at least be greater than the Charge Wizard’s “normal” charge output mode of 13.6v then it shouldn’t ever matter.

Based on my research so far, I think I’m going to set the MultiPlus to hang out around an effective 3.0v to 3.5v per cell and the BMS with a high disconnect of 3.55v and low of 2.9v. Assuming that the MultiPlus and converter are generally playing well with each other, that should hopefully keep the converter from kicking into boost mode so it won’t be kicking out a charge level of voltage during the MultiPlus absorption phase although the question remains, will the MultiPlus ever go into absorption if there are other active draws on the 12v system? Really wish Progressive Dynamics would specify what level of charge triggers boost mode.

At least initially, I will just turn off the converter’s breaker in the panel unless it’s actually needed that way when power fails or we are traveling or boondocking the converter isn’t drawing battery power to charge the battery since as far as it knows, it would always seem to be on shore power.

I also like it because it's less modification to the original system, and it offers a little more flexibility. let's say the MP is down hard, and your only option is a generator. With the converter and original 12V in place, you don't have to make any provisions to get the 12V system back up

Current path is to leave the existing system pretty much in place as-is, including the converter. Now that I’ve started pulling wire I’ve discovered that the converter is hard wired in, not plugged in. I’m going to leave the original battery circuit breaker and battery disconnect in place for the 12v systems. I’m addng a 400 volt slow blow fuse for the battery connection to the MutiPlus as well as a dedicated battery disconnect.

Otherwise it’s just romex between shore power, MultiPlus and Panel.

Unfortunately even though Victron made a great solution for 50amp RV’s they didn’t really size the MultiPlus II 3000/2x120 large enough for a 50 amp RV. I’m going to have to add a sub-panel to pull our washer and dryer off the main panel and power them using AC Out 2. I’ll probably also move the refrigerator and possibly the bathroom to a sub panel also and take advantage of the existing Xantrex inverter to power them that will give me an effective 4200w vs the 2400w that the MultiPlus has on it’s own. They really should have sized this thing in the 4,000 to 5,000 watt range.

 

[HRTKD]

Based on my research so far, I think I’m going to set the MultiPlus to hang out around an effective 3.0v to 3.5v per cell and the BMS with a high disconnect of 3.55v and low of 2.9v. Assuming that the MultiPlus and converter are generally playing well with each other, that should hopefully keep the converter from kicking into boost mode so it won’t be kicking out a charge level of voltage during the MultiPlus absorption phase although the question remains, will the MultiPlus ever go into absorption if there are other active draws on the 12v system? Really wish Progressive Dynamics would specify what level of charge triggers boost mode.

Why are you using a converter when you have the Multiplus? I consider the Multiplus to be a better, more flexible, charger.

I would keep the BMS high voltage cell limit at 3.65 volts. That gives the BMS time to balance a cell instead of cutting off the charge altogether.

Unfortunately even though Victron made a great solution for 50amp RV’s they didn’t really size the MultiPlus II 3000/2x120 large enough for a 50 amp RV. I’m going to have to add a sub-panel to pull our washer and dryer off the main panel and power them using AC Out 2. I’ll probably also move the refrigerator and possibly the bathroom to a sub panel also and take advantage of the existing Xantrex inverter to power them that will give me an effective 4200w vs the 2400w that the MultiPlus has on it’s own. They really should have sized this thing in the 4,000 to 5,000 watt range.

Hey, don't blame Victron for this. If you needed more watts you should have ordered an inverter rated for that.

 

[InMyImage]

Why are you using a converter when you have the Multiplus? I consider the Multiplus to be a better, more flexible, charger.

I wasn’t planning to keep the converter until I disconnected the batteries and realized our air conditioner/heater thermostats are 12v so if we lost battery power without a converter configured to run without a battery connection we wouldn’t be able to have AC or heat which could be a problem if we were in 90 degree heat or 20-40 degrees cold (see Texas Blizzard).

After realizing this the desire to keep the converter rose. Will most likely keep it turned off at the circuit breaker unless we need it.

Additional benefit of keeping it is as @sunshine_eggo pointed out, if the MP ever fails, having a backup way to charge the batteries is a good redundancy plan.

Hey, don't blame Victron for this. If you needed more watts you should have ordered an inverter rated for that.

Didn’t “blame” Victron. I was in of the first people in the country to buy one of these pretty shortly after starting to dig into all the hardware necessary for one of these installs. I was under the impression that it was a 3000 watt inverter not a 3000va / 2400 watt inverter. 3000w watts continuous is definitely manageable in a 50 amp RV, 2400 watts is going to either take a second inverter or separating some of the trailer’s circuits to a sub-panel and running them off AC-Out-2.

My fault for jumping in before I understood the difference between 3000va and 3000w but still will save a lot of money and hassle regardless of which way I solve the problem. Bet you make decisions without fully understanding the circumstances, kind of like asking a question that had been pretty clearly discussed in detail in an extremely short thread before you asked your question, not my fault or @sunshine_eggo

 

[sunshine_eggo]

Worth a lookee:

How to read inverter specifications: The difference between VA and Watts

30% overload for 30 minutes.