New PowerMax Lithium Series Converter/Chargers

[Browneye]

They sold them both ways - as a fixed ‘power supply’, like for lab use, and as a multi-stage charger.
Your labeling and/or documentation should spell that out.

At 14.4V, charging should technically be terminated at about 5% of battery capacity for LFP.

For my 230Ah, that’s about 11.5A. Adjust accordingly.

 

[Texas-Mark]

They sold them both ways - as a fixed ‘power supply’, like for lab use, and as a multi-stage charger.
Your labeling and/or documentation should spell that out.

But as I said, the label does not indicate it is a fixed supply, nor does it specifically say it is a 3 stage charging system. It just lists 3 output voltages (low to high). And the documentation is generic like what they would include with all versions, only mentioning the 3 stage charging as an option. So I am just assuming is is actually a fixed supply either with the wrong label, or this is how they documented the very early versions.

 

[Browneye]

A charging model will have a switch on the power-cord side of the unit, for fixed output or staged charging. If it doesn't have an external slide switch then it's not adjustable, it's a fixed power supply, up to 100A of charging.

I ended up setting mine for fixed voltage output with the adjustable POT, at 14.0. It has a hole in the cover to reach the POT with a small screwdriver. It is plugged into a switched outlet. I simply turn it on when needed, switch it off when current drops to 11A on the shunt meter. I've only used it once or twice. It worked well in that capacity, but as mentioned, the last time I tried to use it, last week, it was switching charge current on and off driving the BMS bonkers. The next day it was working fine. But I had already ordered a Meanwell charger to replace it. Mine is the 55A 'new lithium model'. Pfft.

It is also noisy at full output, the fan whines, it's not a quiet fan.

A 100A charger is going to pull 15amps on the outlet, so consider a dedicated circuit for it - anything else plugged in will overload a 15A circuit. Mine pulls 11A at the full 50A+ charging. When charge current drops then so does the 120V draw, but it's still a lot. Another reason I don't like it. There's no way I'd want a 100A unit, but on a dedicated outlet for a 500-plus amp hour battery bank it might make more sense.

Powermax plays fast and loose with their circuitry and documentation. When I first called them about their manual saying you could adjust staged output voltage, they said they 'thought' it did. Somehow the design intent and actual production didn't quite translate. They acted surprised. That's just not very impressive, or confidence inspiring. And they claim they had fully tested them out. Then complained that they were really busy getting ready for some show. I just shake my head. I really cannot recommend the brand at all. I would take a Progressive Dynamics converter long before, but have reached the conclusion that none of them are a good solution for an RV with a lifepo4 battery. I thought the IOTA was a good unit, but they have never fully accommodated the profile needs for LFP either.

 

[John Frum]

It is also noisy at full output, the fan whines, it's not a quiet fan.

That is an understatement.

 

[Browneye]

LOL. Oh, you got to experience one first hand?! It's surely not something I would want running all the time. For a quick boost to the battery I figured I could live with it, but after having it in operation it gives the impression of being better as a boat anchor.

I'm glad to be rid of it. Maybe some ebay'r will want it. It wasn't cheap either, I think I gave about $180 for it. Can't wait to try out the Meanwell unit.

I hope I'm not sorry for not stepping up for the Victron charger - no fan, and has the BT app. I love my DCtoDC charger, they make a nice product.

 

[John Frum]

LOL. Oh, you got to experience one first hand?! It's surely not something I would want running all the time. For a quick boost to the battery I figured I could live with it, but after having it in operation it gives the impression of being better as a boat anchor.

I'm glad to be rid of it. Maybe some ebay'r will want it. It wasn't cheap either, I think I gave about $180 for it. Can't wait to try out the Meanwell unit.

I hope I'm not sorry for not stepping up for the Victron charger - no fan, and has the BT app. I love my DCtoDC charger, they make a nice product.

I've had three of these https://powermaxconverters.com/product/pm3-24v-series/
Still have the 50 amp version which is just collecting dust.

The fan nags like a soon to be ex-wife.

 

[John Frum]

.

 

[Texas-Mark]

If it doesn't have an external slide switch then it's not adjustable, it's a fixed power supply, up to 100A of charging.

Well, actually it is adjustable, you just have to pop the rivets off the case to get to the adjustment pot.

A 100A charger is going to pull 15amps on the outlet, so consider a dedicated circuit for it - anything else plugged in will overload a 15A circuit.

It is in my shed and I have several dedicated 20A circuits. Also the fan won' bother me. All of my other cooling fans would probably drown it out anyway.,

On a side note, one disappointment. When I opened it up (I took it completely apart) and looked at the where the external cable lugs are, They are simply bolted the the PCB. The only thing you have connecting all of the fuse cables and ground cables to the lugs, is the copper foil on the PCB. That sure does not seem like it would hold up to 100A continuous. So I took the bolts out and then put a ring connector under the bolts and soldered that to the board where all of the cables are. That quadrupled the current carrying capability in that area. The rest of the unit seemed well built, just that weak link area.

 

[Browneye]

The new MeanWell NPB-450-12 charger arrived, yes it's a 25A version. I decided since the vast majority of all my charging is from solar panels, a little bump when plugged in, or when generator runs, was enough. Besides, it's about $75 less than the 750/45W version.

It's a very nice compact unit, easy to install, is very quiet - I can't even hear it running under the sofa, and charges perfectly. 2-stage charging starts out in bulk/boost, which is constant current, set for 'gel battery' with dipswitches at 14.0 volts. When the battery gets close to the boost voltage it tapers current - CV - and terminates charge when current gets to about 10 watts.

I have sent them a tech support question on whether the unit re-boosts at some system voltage point, and will follow up. My inclination is that it does not - it has to be power-cycled to restart the charge cycle.

The manual also says charge termination is when current reaches 10% of charge capacity, which is 450 watts or 25A, so I would expect that at about 40W or 2A. But it's about a quarter to a third of that. I've asked for clarification on that as well.

I had 4awg leads for the old Powermax, so I removed those and made up new 10awg leads (spec recommended), and replaced the 80A connection to bus fuse with a 40A I had on hand. I may try to find a 30, it's ANL, but it's probly fine. The terminal posts on this size charger are pretty small - they are like 5 or 6mm screw contacts, so a forked terminal was appropriate. At full charge everything is cool, and the fan runs on full but is very quiet.

I'm thrilled. For anyone that would need more juice, or has a bigger battery, the 750 model with 45A of charging would be recommended. Overall, and so far, this one is a slam-dunk winner.

 

[triplethreat]

The new MeanWell NPB-450-12 charger arrived, yes it's a 25A version. I decided since the vast majority of all my charging is from solar panels, a little bump when plugged in, or when generator runs, was enough. Besides, it's about $75 less than the 750/45W version.

It's a very nice compact unit, easy to install, is very quiet - I can't even hear it running under the sofa, and charges perfectly. 2-stage charging starts out in bulk/boost, which is constant current, set for 'gel battery' with dipswitches at 14.0 volts. When the battery gets close to the boost voltage it tapers current - CV - and terminates charge when current gets to about 10 watts.

I have sent them a tech support question on whether the unit re-boosts at some system voltage point, and will follow up. My inclination is that it does not - it has to be power-cycled to restart the charge cycle.

The manual also says charge termination is when current reaches 10% of charge capacity, which is 450 watts or 25A, so I would expect that at about 40W or 2A. But it's about a quarter to a third of that. I've asked for clarification on that as well.

I had 4awg leads for the old Powermax, so I removed those and made up new 10awg leads (spec recommended), and replaced the 80A connection to bus fuse with a 40A I had on hand. I may try to find a 30, it's ANL, but it's probly fine. The terminal posts on this size charger are pretty small - they are like 5 or 6mm screw contacts, so a forked terminal was appropriate. At full charge everything is cool, and the fan runs on full but is very quiet.

I'm thrilled. For anyone that would need more juice, or has a bigger battery, the 750 model with 45A of charging would be recommended. Overall, and so far, this one is a slam-dunk winner.

I feel the same way about my NPB-750-12......43A output....it's been flawless so far.

 

[Butcher]

I installed a 100A converter and it would trip the 15A breaker at times, not instantly, just when it was charging the batteries. I installed a 20A breaker and fortunately, the electrical plug for the converter was already rated to 20A.

The converter is behind some cabinets and you can hear the fan. Nothing is left stock with me so I will look into this later.

 

[triplethreat]

I installed a 100A converter and it would trip the 15A breaker at times, not instantly, just when it was charging the batteries. I installed a 20A breaker and fortunately, the electrical plug for the converter was already rated to 20A.

The converter is behind some cabinets and you can hear the fan. Nothing is left stock with me so I will look into this later.

Hopefully, you checked the wiring going from the breaker to the convertor......it needs to be 12ga if it's being fed by a 20A breaker.

 

[Butcher]

As I mentioned, the electrical receptacle is rated to 20A. The wiring is part of the receptacle. It's only about 4-6 inches long and tags right into the breaker. So, the way I see it, I am good to go.

I suspect all WFCO 50A electrical panels are similar and the RV manufacturers just install the breakers as needed. Not all larger RV's get large converters. My stock one was rated at 55A. It's not hard to look and see what you have. I am sharing my experience since I did not find anyone offering that information on any site.

 

[triplethreat]

As I mentioned, the electrical receptacle is rated to 20A. The wiring is part of the receptacle. It's only about 4-6 inches long and tags right into the breaker. So, the way I see it, I am good to go.

I suspect all WFCO 50A electrical panels are similar and the RV manufacturers just install the breakers as needed. Not all larger RV's get large converters. My stock one was rated at 55A. It's not hard to look and see what you have. I am sharing my experience since I did not find anyone offering that information on any site.

No, you stated the the "electrical PLUG" for the converter was 20A. That would be the plug on the end of the cord. Maybe you MEANT the electrical receptacle......but that's not what you said.

 

[Texas-Mark]

I knew what he meant given the rest of his comment.

 

[Butcher]

And now it is all cleared up.

 

[Browneye]

I would check for heating on full charge current. I'm assuming your load center has a dedicated receptacle and breaker for the converter, all in one place.

Originally mine was right next to the 120V breaker box, had the refer outlet on it too. I moved the charger to the next compartment to be next to the lifepo battery pack, for distance and convenience, and not having to run heavier 12V wire. But it put the charger on one of the two 120V outlet circuits for the coach, which I wasn't exactly thrilled with, but we hardly use the charger, and I added a switch and outlet to the circuit so it could be simply turned on and off. Now with the 25A charger it only draws 4A, so it's good to go. Still nice to have the switched outlet.

100 amps of charging is quite a lot. We generally use about 100Ah over the course of a day/night. All of the major appliances are LPG - furnace, fridge, water heater, stove/oven. If we need the microwave/convection, or AC, then we plug in or run the generator.

 

[Butcher]

This load center is capable of 2 50A lugs. That is at 120v. I do not think replacing the 15A breaker with a 20A is going to break the system. Knowing that everything attached to the breaker is rated to 20A, I think I'm feeling warm and fuzzy about that. Having a 100A converter to charge 2 304ah LifePo4 batteries is only about 46A each [seen it]. If I recall, these batteries can take a larger current to charge them so less than 50A each is just a yawn fest.

I did not measure the current of the converter but simple math shows that at full current, it's going to be close to 15A. I have no problems what so ever to replace it to a 20A. If I originally started with a 20A breaker and it blew regularly under that load, I would take a different thought process to resolve this problem. I get that installing a larger fuse is not the answer for a fuse that blows.

100A may be a lot for some, but ok for my set up. My original converter was not lithium rated so I was in the market to buy one anyway. So, since I was going to buy one, why not go big. Faster charging was one of my goals. I am currently building/installing another 304ah battery and I am thinking of one more.

Solar is coming next year.

 

[Browneye]

All I'm saying is to put a laser-thermometer on it and make sure you're not overheating the circuit. Something that should be done with larger 12V current loads as well.

I plugged the 30A power cable from the RV into a 20A outlet to run the 15.5btu Coleman AC. It runs fine, but even the cord gets warm - not too hot to touch, but up to about 120*. It draws 1750W on full cool, right about 14.5A with a watt-meter.

My middle daughter is a commercial electrician - she said the 20A is fine, the appropriate continuous rating is 80%, so 16A on a 20A circuit, and yes to 12awg wire.

High-resistance contacts and connections can generate a LOT of heat before any breaker trips. We just don't want your place burning down.

 

[triplethreat]

I knew what he meant given the rest of his comment.

The terms...Plug...and Receptacle are not interchangeable terms. It's no different that say a NEMA 14-50R and a NEMA 14-50P......one is a receptacle and one is a Plug for that receptacle.