New PowerMax Lithium Series Converter/Chargers

[Browneye]

>snip

When I did install the converter, I have a separate cable going strictly to the batteries. It does not go through the electrical panel. I did leave the stock power supply wire from the converter to the distribution panel. I did not increase any demand their.

4awg wire is appropriate here, with proper crimped lugs, and fused - a mega or anl of 125A at the battery would also be appropriate.

I had 4awg leads for my 55A - obviously those wouldn't fit on the new 25A meanwell charger.

 

[Goboatingnow]

I also got a reply today from TRC Electronics on the Meanwell chargers, regarding charge termination and loads, and reboost.

As suspected, with 2-stage charging, current is terminated when the battery is full, when current drops to 5%. Actually, in testing it out, it drops a little lower before shutting off - at about 10-12 watts. The 'gel' setting is perfect for my pack, 14.0V bulk, to near zero current, and terminate. Conceivably you could park at a RV park with a low battery, plug in, turn the charger on, and walk away - it would charge it back to full and stop.

The question was if there are loads is there a potential to never stop charging. The answer is YES, it would carry the loads after charging the battery(s). They suggested their SBP-001 programmer and setup a timer that terminates charging after a time, regardless of current. They suggested like 100 hours to prevent indefinite charging.

The other question was if there was a re-boost - will the charger start the charge cycle over at a certain battery voltage. The answer was 'no'. It terminates charging and stops, so it would have to be power-cycled to start charging again.

I'm okay with both because we really only use this charger on an as-need basis, not in any automated sort of way. The solar panels keep up with usage, and if we drive at all then the Orion DCtoDC also charges. Having the Meanwell charger on a switched outlet makes it more convenient to manage.

Just FYI...for anyone interested in the alternatives to the Powermax converter/chargers, or any of the others as well, i.e.; IOTA, Progressive Dynamics, Wafco, etc.

This is a perennial problem with lithium chargers.

To work properly lithium chargers must really sense tail current.

Then once they know absorption mode is complete they should DISCONNECT “ no float or “ power supply mode “ should be utilised.

The rebulk settings should trigger recharge

Chargers of Li banks should not support system loads post charge termination.

 

[Butcher]

I'm running 2ga cable to the battery buss bars. No more than 2ft long.

 

[Browneye]

This is a perennial problem with lithium chargers.

To work properly lithium chargers must really sense tail current.

Then once they know absorption mode is complete they should DISCONNECT “ no float or “ power supply mode “ should be utilised.

The rebulk settings should trigger recharge

Chargers of Li banks should not support system loads post charge termination.

Agreed.
Which ones do this? Does the Victron IP series work this way?

 

[triplethreat]

I have my MeanWell NPB-750-12 set up in a three stage charging mode for FLA .....on my LFP battery. Bulk/Boost will output 14.2V, and then the float voltage is at 13.4V. Those numbers will obviously charge my 302AH battery that is made from EVE 302 cells. The 14.2V will obviously take a bit longer to fully charge the battery, but it also doesn't stress it as much as using the normal 14.6V LFP setting. Once it settles on 13.4V for float, I now have a converter that is always on, and the voltage is not enough to damage the battery in any way. I do have a 300A master battery cutoff switch and usually when the battery is fully charged, but I still need power in the trailer, I open the 300A Master and just let the converter provide power for lights etc. I do have a "reminder" note on the control panel for operating the landing gear/auto leveling/hydraulic slides to make sure the battery Master is turned on and to not depend on the converter for power. My hydraulic pump will draw right at 70A when operating and the converter is only rated to 43A......so the Master switch really needs to be on for operating the hydraulic pump to keep the risk of damage low or non existent of the converter.

 

[JPMusic]

I've modified my converter with an external switch to select 2 different voltages. I also ran 12V from the converter to the switch panel to power an LED to show which mode is selected. The DPDT slide switch I used doesn't stick out beyond the little panel. So it can't be switched mistakenly.
Those voltages result in 3.3 V/cell and 3.55 V/cell

Jimmy, I have the Powermax Lithium version converter that has the 3-position selector switch for: 3-stage, Li-Ion 2-stage & Fixed. I'm looking at relocating that switch (and associated led indicators) from the converter to an external location similar to your resistor/switch setup. That way I can easily switch between 2-stage and fixed when I need the fast charge current (Bulk) when Boondocking on generator. Interested in your thoughts on this configuration. Thanks.

 

[Browneye]

This 'go-boating guy' will should you to death.

As an aside, the meanwell chargers set for two-stage charging SHUT DOWN when the charge current reaches 5%. They do not 're-boost', they have to be reset or power-cycled to start over.

I can't comment on the technicals of the victron ip chargers.

 

[krby]

Sorry for the necropost, I'm trying to figure out the max wire size that will fit in DC terminals of a Powermax PM3 or PM4. From a previous project, I've got 2/0 AWG. It's oversized for a 55A model, but I have it and ring terminals for it so I could to use it for the whole project. Looking at pictures, it looks like the terminals are too small, if I'm going to buy wire, would like to buy the right size.

 

[HRTKD]

Sorry for the necropost, I'm trying to figure out the max wire size that will fit in DC terminals of a Powermax PM3 or PM4. From a previous project, I've got 2/0 AWG. It's oversized for a 55A model, but I have it and ring terminals for it so I could to use it for the whole project. Looking at pictures, it looks like the terminals are too small, if I'm going to buy wire, would like to buy the right size.

According to the diagram on their website for the PM4 the DC terminals are spec'd for 2 or 4 gauge cable. 2/0 is going to be too big.

PM4 Series - PowerMax Converters in 12, 24 & 48 Volts

AC to DC Power Converters can be used for RV Converters, Car Audio Power Supplies and any Battery Charging for 12, 24 & 48V systems

powermaxconverters.com

 

[Browneye]

I moved my 55A to the battery compartment so 4awg leads were about 18” long, 80A fuse.
Could not get it to sense voltage correctly, so it was replaced with a Meanwell NPB 25A charger with 10awg leads and 30A fuse.

 

[krby]

According to the diagram on their website for the PM4 the DC terminals are spec'd for 2 or 4 gauge cable. 2/0 is going to be too big.

PM4 Series - PowerMax Converters in 12, 24 & 48 Volts

AC to DC Power Converters can be used for RV Converters, Car Audio Power Supplies and any Battery Charging for 12, 24 & 48V systems

powermaxconverters.com

Ahh, thank you. 4AWG cable with appropriate ring terminals (batteries and inverter both have M8 studs). Looking at that diagram, I really want to put a ferrule or something similar on the end of the cables. Any suggestions?

 

[S Davis]

Get some pin lugs of the appropriate size, you could then go larger on your wire size for some cushion. That’s what I did on my Powermax charger, but I don’t use it anymore as it would never charge at its rated amperage.

 

[HRTKD]

Ahh, thank you. 4AWG cable with appropriate ring terminals (batteries and inverter both have M8 studs). Looking at that diagram, I really want to put a ferrule or something similar on the end of the cables. Any suggestions?

Since you want to use 4 gauge, a ferrule should fit just fine in that terminal. The challenge that I had with ferrules larger than 6 gauge is that crimpers are less common. They exist, but they're harder to come by and can be somewhat expensive for a good one. I wanted to use a ferrule on some 1 gauge cable. I bought the ferrules and then bailed on the idea because of the selection of crimpers. At the time, I had a tough time finding a 1 gauge die to fit my ratcheting crimper.

Because I have ferrules and a ferrule crimper for 6 gauge, I probably would use 6 gauge wire. But 6 gauge is good for only about 14' (7' one way, each wire) at 55 amps for 12 volts.

Since the terminal will fit up to 2 gauge, when you use a 4 gauge ferrule you may be making less surface contact than if you used no ferrule at all. It's hard to tell from the pictures on the PowerMax website if the bottom of the terminal is flat or not. Most crimpers for the size you're looking at will produce square crimps (as opposed to round/hexagon crimps that you can get with smaller size ferrules). A 4 gauge square crimp probably will fit in that terminal. When you get the converter on-site you may decide that a ferrule isn't a good fit.

 

[krby]

Thanks for the replies! The PM4-55A showed up yesterday, the cables and ferrules show up tomorrow. I have a cheap (random supplier from Amazon) hydraulic crimper that I used for 2/0 gauge ring terminals for a previous project I've posted about on this forum. It has dies down to 6AWG. well, it has the mm^2 sort of close equivalents. It's not a high quality tool, but it has worked for me for at least 10-15 crimp so far.

Looking at the Powermax unit now, the terminal is a round metal "tube" with a set screw in the top. This looks like it is attached to a post on a PCB inside the unit. I'll take a look once the ferrules show up and see how it goes together, my hydraulic crimper makes a sort of 6 sided shape. I don't love bare wire in terminals, but it may be the best option for maximizing contact area. I may even open up the case and have a look at the thing the external terminal block attaches to, Maybe I can get ring terminals to work!

Another random note for anyone else buying these. I ordered a PM4-55A from Amazon, but the box is clearly a PM3 box with some PM4 stickers on it. I emailed someone at powermaxconverters.com and got this reply:

So the PM3 and PM4 are now the same unit as their functions they used to be different a few years ago. Amazon only sells the PM4s and we use that as a way to keep track of how much they get. We recently ran out of PM4 boxes and had to use the PM3 box and re-sticker it. You have a legit powermax unit.

 

[Browneye]

Just FYI, there isn't a lot of confidence in those people as a reliable source of products or information. They appear to be a sales promotor of imported China goods. The head guy doesn't even know what the spec was on his new units, claiming the POT would adjust boost and float voltage in the 2 and 3 stage modes - it does not. He blamed 'engineering'. Sure.

My unit simply quit sensing or measuring battery/bus voltage and would not charge - the green indicator light would just flash. I sold it on ebay - evidently it works for the buyer as I never heard from them again. I was prepared to buy it back if it didn't work for them.

The Meanwell charger I got works just SO much better, adjustable charge voltages, and it's very quiet. The PM55 was a noisy beast - you could hear the cooling fan whining away in its compartment, and it pretty much ran for all charging current. The Meanwell NPB750 unit is 45A, so pretty close. I got a 450 which is 25A, good enough. The downside of these chargers is they don't re-boost, they have to be power-cycled. Which is fine for a mobile application where you have intermittent connection to 120VAC anyway. For a fixed application that could be an issue. And their smaller units have an voltage adjust pot instead of dipswitches or a BT app.

Worse, the Powermax charge profile isn't a good match for lifepo4. In automatic charge mode it would over-volt cells. In fixed mode it would just never shut off. I put it on a switched outlet so I could turn it on or off as needed, but it became a PITA so it got junked.

 

[krby]

Thanks for the feedback. I'll be using this as a UPS, so it will be stationary and hooked up to AC nearly all of the time. Because weight isn't an issue and I'll barely cycle the batteries over the next 5+ years I'm using AGM batteries to save cost. I trust and like MeanWell PSUs, and would use them, but I really need something that will work unattended and will handle a 100% duty cycle (vs just being a charger that expects to get shut off.

I did get some ok information from their engineering contact (listed on the website), Connor.

In the 3 stage mode whatever the start voltage is then after it drops into the second mode is -1 volt then the float mode is -0.4 volts so for example if you start at 15 volts the second mode will drop to 14 volts then float mode will be 13.6 volts. It all depends on what the start voltage is set to for the rest of the cycle.

Hopefully this works as advertised, if not I'll end up buying an Progressive Dynamics, IOTA, or maybe an AIMS unit.

 

[Browneye]

That makes sense.
I don't think the 3-stage charge voltage is adjustable - you'll be able to check that out when you get it. Be sure to do that before you spend a lot of time fully installing it.

I had a IOTA with IQ4 for FLA prior to upgrading to LFP - it was nothing short of fantastic. Ran it for about 15 years or so. It would keep my GC2's fully topped up, equalize them, and they only needed water every couple of months. I replaced the set once in those 15 years. When the second set started to lose a cell I decided to migrate the whole system to lifepo4. IOTA is not a good option for lifepo4 either - charge voltage is too high, and equalization cannot be turned off. Perhaps it its basic form, but the one I had the IQ4 'smart dongle' was built in.

 

[HRTKD]

I had a IOTA with IQ4 for FLA prior to upgrading to LFP - it was nothing short of fantastic. Ran it for about 15 years or so. It would keep my GC2's fully topped up, equalize them, and they only needed water every couple of months. I replaced the set once in those 15 years. When the second set started to lose a cell I decided to migrate the whole system to lifepo4. IOTA is not a good option for lifepo4 either - charge voltage is too high, and equalization cannot be turned off. Perhaps it its basic form, but the one I had the IQ4 'smart dongle' was built in.

This is similar to my IOTA experience. However, in my case, the charge for LiFePO4 was safe, but not hot enough. If I was charging from generator, I wanted a full 55 amp charge. Instead, the charge was weaker against a battery bank that was at a state of charge that should have received a full 55 amps.

My Multiplus kicks ass. The IOTA with LiFePO4 IQ4 is sitting in the garage somewhere.

 

[krby]

My Multiplus kicks ass. The IOTA with LiFePO4 IQ4 is sitting in the garage somewhere.

Ya, I used a Multiplus 3000VA unit in a different project a few years ago and I love it. Decided to cheap out on this DIY UPS because I already had an inverter and hoped I could just add a converter charger. We'll see if I regret it. It's not critical if it fails the first time I need it and discover I should have just bought quality gear in the first place.