diy solar

diy solar

New PowerMax Lithium Series Converter/Chargers

Browneye

Dr. WattSon
Joined
Nov 2, 2021
Messages
1,700
Location
Yakima WA
Newly released 2-stage converter/charger specifically for LiFePo4 batteries. Optional 3-stage for others if you need/want that option.

On doing a ton of research on updating my RV charging systems for a new lifepo pack I found these. Just got off the phone with them there today, they just got an initial delivery of these units so I ordered one in the 55A size. There's also a 100A version, and they said would likely have a 75A version later in the year.

The problem with all the 3-stage chargers is the boost stage is too short, and in some cases the voltage is too high for your lithium pack. Then the absorption stage kicks in and it's rather too low to get a full charge. What was a really good profile for FLA isn't so hot for lithium. This solves these issues, and gives the full charge voltage for 8 hours or until the battery reaches full charge. If it drops below the low set point (not sure what that is yet) then it goes back into full charge mode. And the voltages are adjustable, default setting is for 14.6 and 13.6. I intend to drop a couple of tenths and run it at 14.2 and 13.2.

It was mentioned that Battleborn is currently testing these and will likely offer them soon. Not sure who else has them, but they are currently non-existent on the WWW. Well, except for PowerMax.

I have one coming next week, will update my review here.

Linky to PowerMax if you want to order one now: https://powermaxconverters.com/product/pm3-lithium-series/

Product image:

PM3-LKL.jpg


Product manual: https://view.officeapps.live.com/op...21/11/PM3-LKL-Manual.docx&wdOrigin=BROWSELINK
 
Confused by the text saying 14.6V and the chart saying 14.3V.

If the absorption time is longer than the 3phase method AND it's 14.6V, it's a better option.

If it's really 14.3V, and the absorption phase isn't longer, then it's actually worse than the 3phase defaults.

IMHO, even with the better 2 phase option as I stated it, if this costs significantly more, it's likely not worth it.

1638558219169.png
 
Voltage is adjustable. Set it where you want it.
I can't explain the chart, sorry. But we could ask - they seem quite responsive.

For the three-stage setting, which it also has as an option, the boost stage is shorter - about half IIRC.

I gave $179 for the 55A. The bottom line is my IOTA DLS-45 IQ4 was simply not going to work - it starts out at 14.8V and floats at 13.8V, and equalizes at 15.8 every seven days. Supposedly there are adjustable pots inside, but I have not tried disassembling it to try.

I have 430W of PV on the roof, and with this able to charge with the genset, even on the road, I will likely forego a DC to DC charger for the engine alternator. Will have to do some testing and see how it works out. My hunch is the solar panels will keep my pack charged unless it's cloudy. My system is designed for about twice the capacity we've gotten by with for the past fifteen years.
 
Voltage is adjustable. Set it where you want it.

Voltage is not adjustable separately. If you raise boost, it raises float. You don't want float higher than 13.6.

I can't explain the chart, sorry. But we could ask - they seem quite responsive.

For the three-stage setting, which it also has as an option, the boost stage is shorter - about half IIRC.

Yep about 30 minutes. Not saying it's bad. As I mentioned, I have three of them. :)

I gave $179 for the 55A. The bottom line is my IOTA DLS-45 IQ4 was simply not going to work - it starts out at 14.8V and floats at 13.8V, and equalizes at 15.8 every seven days. Supposedly there are adjustable pots inside, but I have not tried disassembling it to try.

Doesn't sound too bad, but I don't remember what I paid for mine.

Bummer on the IOTA. Did you consider replacing the IQ4?

I have 430W of PV on the roof, and with this able to charge with the genset, even on the road, I will likely forego a DC to DC charger for the engine alternator. Will have to do some testing and see how it works out. My hunch is the solar panels will keep my pack charged unless it's cloudy. My system is designed for about twice the capacity we've gotten by with for the past fifteen years.

Sounds good to me.
 
Better than Progressive Dynamics and WFCO going right to 14.60 that will virtually always cause a DIY battery BMS to disconnect.

Not convinced the adjustable voltage affects more than just the boost voltage. Have read posts the 13.2 and 13.6 remain fixed.

I wish it was power factor corrected.
 
Better than Progressive Dynamics and WFCO going right to 14.60 that will virtually always cause a DIY battery BMS to disconnect.

In my experience, all RV installations have such crappy voltage drop between the converter and the battery, this isn't a common problem. Same phenomenon makes a fast full charge a challenge.

Not convinced the adjustable voltage affects more than just the boost voltage. Have read posts the 13.2 and 13.6 remain fixed.

On the three PM units I own, the float changes with the POT adjustment. Maybe mine are defective.
 
They told me the manual voltage adjust does both charge and float voltage level. I have no idea how it affects the 3-stage setting(s).

My IQ4 is a built in one. My plan was to open it up and see if I could identify it, remove it, clip it, whatever. It was a good idea at the time, and does a marvelous job for the FLA's. I should be able to move it here or on ebay, it works perfectly. Not sure if I could use it elsewhere. These campers came with those Paralax converters that cook batteries. DAMHIK

I would have much rather paid $125 for it, but alas... :p
I did call them to see if they had a promotional coupon or something, or if there was an online reseller (whom normally discounts, was the thought). No such luck - they're just too brand new.

@time2roll and I were talking on the subject and he suggested I wait and see what I might be able to do with the IOTA before replacing it, which made sense, but the fellas from PowerMax called back (good response) so I felt obligated to jump on one. It seemed ideal for this application, and it also seems these days if you delay on anything you just miss out. I got FOMO bad. :ROFLMAO: So I went ahead and gave them my CC. Yeah, they helped me out a bit. (y)

As I mentioned, my intention is to roll the 2-stage settings back to 14.4 and 13.4. I think that would be ideal. With a 230A lithium pack it's not going to take long to fully charge it. This is especially nice for running the genset to charge. We end up running it some for the AC if it's warm anyway.

They also said if I'm running my genset with the SCC on, the converter would shut off if it sensed high voltage from the SCC. As soon as the battery settled back down it would resume. He also said if you set the voltage it maintains it when cycling power on it. I like set it and forget it. ?

The overall feeling on RV converter/chargers has been that they are old technology that was developed for FLA and no one had done much to adapt them well for lifepo. They have half a fix, but I'm not sure how great it is, especially if they stay 3-stage. 4-stage just doesn't work at all - you can't/shouldn't equalize a lifepo pack ever.

I don't have voltage drop in my setup - the converter connects to a remote post that is 2' away from the batteries with a 1/0 or 2/0 cable. The converter is on a 6 or 8awg that's not even a foot long. If I'm getting any, it might be a tenth of a volt. My new pack might be more of an issue as it will be moved inside the house next to the battery compartment, so I will probably need leads a foot longer. I never deal with more than 50A draw anyway, so I still don't think it's going to be a problem. A volt-meter will come in handy. :giggle:
 
Really interested in how this PM3 Lithium Series works for you @Browneye. My neighbor has a Thor 24sa motorhome he is wanting to change out the Progressive Dynamics PD9260C and the 2 80ah FLA batts. There is just not enough juice when simply overnighting and running the propane heater with 12 volt fan and a few items intermittently, when not on shore power.

Considering updating to PM3 Lithium Series 55A and 2 Ampere Time 200+ batts. The 100A may be a consideration but have to look at the wiring and guess the current 60A wiring for the current PD9260C won't be enough. As the Ampere Time batts won't fit in the current location it may make sense to just upgrade the wiring when moving and upgrade to wiring that will support 100A.

I do have concerns about pulling 100 amps when only plugged into a 15amp receptacle instead of campground 30amp. Not that 15amp AC can't support 100amp DC, but if a few other items are running, will the 100amp drop to not cause issue with the 15amp AC breaker? New to modding RV systems.

 
I do have concerns about pulling 100 amps when only plugged into a 15amp receptacle instead of campground 30amp. Not that 15amp AC can't support 100amp DC, but if a few other items are running, will the 100amp drop to not cause issue with the 15amp AC breaker? New to modding RV systems.
If your main draw off the 15a supply is a 55a converter and maybe the fridge you are fine pulling 100 amps off the battery. The PM3 will provide 55 amps and the battery will supply the remaining 45 amps for a few hours. I would assume the 100 amp draw would actually be a much shorter duration.
 
If your main draw off the 15a supply is a 55a converter and maybe the fridge you are fine pulling 100 amps off the battery. The PM3 will provide 55 amps and the battery will supply the remaining 45 amps for a few hours. I would assume the 100 amp draw would actually be a much shorter duration.
Guess I was thinking of it this way @time2roll. Was concerned about the draw on 15a AC circuit to charge the batteries. The diff between using a 55a vs 100a charger.

On a 15a AC outlet, if a 100a/12v DC charger is pulling 12a AC, that only leaves 3a for other items, like a fridge as you mentioned, to run. Think the fridge in the camper is AC and Propane. I don't think it's a 3 way with 12v DC.

Add a few items that are running on AC and begin thinking that may be a bit too much on 15a AC?

Again maybe I am not thinking all through correctly. The 55a seems to provide enough headroom to safely allow other AC outlets in the RV to be run, whereas the 100a may limit? Not familiar with the charge controllers if they are fixed so that if it is a 100a charger, it will pull that regardless of whatever else is drawing current and trip a breaker.
 
Guess I was thinking of it this way @time2roll. Was concerned about the draw on 15a AC circuit to charge the batteries. The diff between using a 55a vs 100a charger.

On a 15a AC outlet, if a 100a/12v DC charger is pulling 12a AC, that only leaves 3a for other items, like a fridge as you mentioned, to run. Think the fridge in the camper is AC and Propane. I don't think it's a 3 way with 12v DC.

Add a few items that are running on AC and begin thinking that may be a bit too much on 15a AC?

Again maybe I am not thinking all through correctly. The 55a seems to provide enough headroom to safely allow other AC outlets in the RV to be run, whereas the 100a may limit? Not familiar with the charge controllers if they are fixed so that if it is a 100a charger, it will pull that regardless of whatever else is drawing current and trip a breaker.
Pulling >12 amps on a 15 amp non-dedicated circuit is not a good idea.
Continuous use devices(duty cycle >= 3 hours) are de-rated by .8.
15 amps * .8 = 12 amps.
A converter is a continuous use device.
Also since converters in general don't have a very good power factor.
Power-max converters in particular have very poor power factor so its important to also consider the power factor when sizing the supply.
 
Last edited:
Pulling 12 amps on a 15 amp non-dedicated circuit is not a good idea.
Continuous use devices(duty cycle >= 3 hours) are de-rated by .8.
15 amps * .8 = 12 amps.
A converter is a continuous use device.
Also since converters in general don't have a very good power factor.
Power-max converters in particular have very low power factor so its important to also consider the power factor when sizing the supply.
Thanks for the sanity check. Figured the 55a would be a safer bet. If I knew it was always going to be hooked to a 30a AC shore power at campgrounds it may be different. Best to play it safe, especially when not my RV.
 
Really interested in how this PM3 Lithium Series works for you @Browneye. My neighbor has a Thor 24sa motorhome he is wanting to change out the Progressive Dynamics PD9260C and the 2 80ah FLA batts. There is just not enough juice when simply overnighting and running the propane heater with 12 volt fan and a few items intermittently, when not on shore power.

Considering updating to PM3 Lithium Series 55A and 2 Ampere Time 200+ batts. The 100A may be a consideration but have to look at the wiring and guess the current 60A wiring for the current PD9260C won't be enough. As the Ampere Time batts won't fit in the current location it may make sense to just upgrade the wiring when moving and upgrade to wiring that will support 100A.

I do have concerns about pulling 100 amps when only plugged into a 15amp receptacle instead of campground 30amp. Not that 15amp AC can't support 100amp DC, but if a few other items are running, will the 100amp drop to not cause issue with the 15amp AC breaker? New to modding RV systems.

I had to read this a couple of times to understand what you were saying about the 100A - so 12V charging at 100 amps, got it. Per the specs I'll link below that unit in the PM3-LK series is 15 amps 120V AC input. I get it, you plug into a 15A receptacle with an adapter - we do that a lot as well, like visiting someone's home, or even at home - I don't know why I never bothered to install a 30A outlet for the RV - it's been sitting there next to the house for 17 years!!

Anyway, a standard 120V outlet is on a 20A circuit, so the 15A your converter would pull would be fine. And no, it won't run your AC, nor probably a microwave either at the same time. You would likely pop the breaker at the source. I caught my mom turning on the AC plugged in to the standard outlet and boy oh boy does that extension cord get hot where it plugs into the RV shorepower cable. It will do it for a short while but it's a really bad idea.

Here's the spec sheets on the standard PM3 units showing AC draw: https://powermaxconverters.com/wp-content/uploads/2019/02/PM3-Spec-Sheet.pdf

The units are 'current limiting', so I don't know if that means it pulls it's full load and then puts out what the battery needs, or if it ramps up draw based on the load, like an inverter does. Some of these guys may know for sure on that.

I can see if you're going to want to go with 400Ah of lithium that you might want a 100A charger. Especially if you don't have another charge source like solar. Also keep in mind that a drop in replacement with your alternator and isolator runs the risk of burning out your alternator. The lithium packs have so little internal resistance, unlike lead acid batteries, that they'll pull everything your alternator can put out - at idle or close it can easily overheat it. So a DC to DC charger is in order, and the Victron Orion seems to be the go-to for these, their bigger one is only 30A.

Anyway, so those are some things to consider. Your wiring should be fine for a battery upgrade, and likely for a converter upgrade for a 55A. For the 100 you would want to take a look at the connect wires - sometimes they use 6 or 8awg, and 6awg should be enough but you would want to take a look-see. If they're 8awg wires you could easily replace them with heavier gauge wire. If you're going to install a large inverter then all bets are off - you'll want to reassess the whole setup. Do you have 30A or 50A service in your unit?? I would opt for the 55A unit if it were me - makes it easier to configure, and that's still a lot of charging amps, even for a 400A battery bank.

And for sure if you're moving your bank location you're going to need new connect wires to your main power bus or switching area. I'm making up new 2awg cables for mine, which will easily carry the max 60-80A's I would ever draw from my bank, and the round trip is under 7'.

I had thought my remote positive post in my electrical bay had a heavy lead to it - the batteries are 1/0, but low and behold the feed for the main 55A 12V breaker is 6awg. Which was fine as built, with the 45A converter/charger and house loads, but then I put my new 600W inverter on the same circuit and noticed quite a bit of voltage sag. Well, that explains that. So I'm running a new 4awg feed from the main battery disconnect remote switch directly to the inverter. It only pulls 5A max at full power, but that's 50A and with 6awg wire the voltage sags quite a bit.

For your buddy with the two 80A deep-cycles, yeah, if those are 12V RV/marine type, they're not very heavy duty. And they never seem to get properly charged up and de-sulfated, so they tend to go south in a couple of years. The furnace blower is 6-8A, and if there's a fridge board and lights, could easily add another few amps, so if it's cold and the furnace runs a lot you could easily deplete the 80A usable from the two.

The PD9260C is a very good converter/charger for FLA though, so he may just need a new battery bank. If he's going to keep FLA, I recommend a pair of 220A golf cart batteries - the plates are a lot heavier and you can equalize the crap out of them to keep them de-sulfated. lf he's going to lithium like you want to, then yeah, the old chargers that auto-equalize is a bad idea for them. OTOH, the newer PD92XX units have an optional 2-stage charge profile, so that's worth looking into. It might well be fine with either type of battery option.

I just got my new PowerMax unit this week, excited to try it out. But my lithium cells won't be here for a couple more weeks, so I'm not in a hurry to install it. Plus I'm moving it from my electrical cabinet where my inverter is, over to where the new ltihium pack will be, and a direct wire to the battery.

The installation manual is a bit different than what they published prior - that I linked to above. The new one says 2-stage charging volts are 14.6 bulk and 13.2 resting. If that's the case the default setting should be perfect for my new lifepo pack.

It also accepts 4awg wire and I have some extra, so it will have heavy charge leads direct to the battery. I have to install a new 20A receptacle for shorepower/genset where it will be placed.

IMG_4166.HEIC


IMG_4165.HEIC
 
100 amp is a bit much for a 15a circuit. Stay at 55. Best to stay at 12 amps max for a near continuous draw on 15 amp circuit.
 
Pulling 12 amps on a 15 amp non-dedicated circuit is not a good idea.
Continuous use devices(duty cycle >= 3 hours) are de-rated by .8.
15 amps * .8 = 12 amps.
A converter is a continuous use device.
Also since converters in general don't have a very good power factor.
Power-max converters in particular have very low power factor so its important to also consider the power factor when sizing the supply.

What's a 'power factor'?

Residential receptacle circuits are 20A - lighting are 15A. If you plug an RV into a standard receptacle with nothing else on that circuit, it will easily power a 15A appliance. You have to use a heavy cord - I know I have a 5hp air compressor and it's at the full limit of a standard 120V AC circuit.

My silly old house has a dual circuit receptacle in the laundry room - two 20A feeds. Why they didn't put two receptacles in is beyond me - maybe I should do that - they put both legs into the one outlet, clipping the connect tab. I found out when replacing the receptacle without clipping it and every time you turn on the breaker it would trip. That was a trick to figure out. LOL :rolleyes:

The RV plugs into one of them with a 12ga extension cord. ?
You just can't run the air conditioning.

EDIT: on 'power factor': https://www.equiptest.co.uk/what-is-power-factor-correction-and-why-is-it-important/
Never heard of this...and why does a converter have a low power factor? What is the laymen's terms explanation? ?
 
Last edited:
What's a 'power factor'?
"Where reactive loads are present, such as with capacitors or inductors, energy storage in the loads results in a phase difference between the current and voltage waveforms. During each cycle of the AC voltage, extra energy, in addition to any energy consumed in the load, is temporarily stored in the load in electric or magnetic fields then returned to the power grid a fraction of the period later."
"In an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment."
Residential receptacle circuits are 20A - lighting are 15A.
That is a recent thing.
EDIT: on 'power factor': https://www.equiptest.co.uk/what-is-power-factor-correction-and-why-is-it-important/
Never heard of this...and why does a converter have a low power factor? What is the laymen's terms explanation? ?
Because the mondo capacitors make them a reactive load.
 
What's a 'power factor'?

EDIT: on 'power factor': https://www.equiptest.co.uk/what-is-power-factor-correction-and-why-is-it-important/
Never heard of this...and why does a converter have a low power factor? What is the laymen's terms explanation? ?
Power factor is not a huge concern for utility power. PF really comes into play with a limited source such as generator or inverter. When the powered device only uses part of the sine wave there needs to be additional apparent power to prevent overload. Converter has low power factor because the electronics are not designed to synchronize with the sine wave to use the full curve.

http://www.xantrex.com/documents/Power-Inverters/PROsine/MS20070214_pfc-whitepaper02.pdf
 
Back
Top