New PowerMax Lithium Series Converter/Chargers

sunshine_eggo

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FWIW, constant voltage at 13.8V will get you to 98%+ charge over several hours. If you have to leave it on constant voltage, that's the best option.
 

Browneye

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So a higher charge voltage just charges faster during the initial interval?
But overcharges them if left on?

How does SCC and dc-dc play along all together with that as well? Not that I would or could. I’m thinking driving with the generator running for air conditioning and the SCC not turned off. Engine driving the dc2dc. Should I have switch for that too?

I think I would only use the converter/charger when actually needed.

I’m also installing a bluesea master cutoff switch for the LFP if I want to use the converter on shorepower - without the pack.

I’m going to need to remember to turn off the SCC too.

It’s been said these are not set it and forget it systems.
 
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sunshine_eggo

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So a higher charge voltage just charges faster during the initial interval?
But overcharges them if left on?

Yes.

How does SCC and dc-dc play along all together with that as well? Not that I would or could. I’m thinking driving with the generator running for air conditioning and the SCC not turned off. Engine driving the dc2dc. Should I have switch for that too?


I think I would only use the converter/charger when actually needed.

Anytime shore or generator is available, why not?

I’m also installing a bluesea master cutoff switch for the LFP if I want to use the converter on shorepower - without the pack.

Cool.

I’m going to need to remember to turn off the SCC too.

No need.

It’s been said these are not set it and forget it systems.

Not by me. They can be.

If each charger is programmed to absorb at 14.4V or less and float at 13.6V or less, it's pretty much set it and forget it.

The only time it's a concern is if the sum of all charging sources current exceeds max charge current of cells or BMS.
 

Browneye

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Thank you - I think I'm finally getting all this.
For this coach's life it's always a fully charged or it has to be charged cuz lead acid batteries sag and go flat. The concept of simply maintaining an energy level with the whole system just never occurred to me.

The 2-stage charging on the powermax may well work. Can't wait to get this pack built and try it all out. The thread with the guy burning his battery up is alarming to say the least. Makes one sit up and take notice. And I'm putting fuses on everything. 😇
 

Browneye

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Since we're talking about charging sources, I want to throw another source into the question - Victron Orion, dc to dc.
I went ahead and got one for those times I might be driving at night using house battery that is not getting charged otherwise.

I can see a scenario where if I make the orion turn on with the key switch, and then if my battery is turned off - disconnected from the system - and I'm plugged into shorepower with the converter providing constant voltage to the house circuits, and then I start the engine - what happens to any power the Orion would generate? Or would it just float along with the load since there's no draw?

I looked at the BT app and it's easy to just turn it off. But I'm old and I forget things. :rolleyes:

What happens if there's no battery here but the converter/charger is supplying power in it's place?

9823-1589244838478.png
 

sunshine_eggo

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I can see a scenario where if I make the orion turn on with the key switch, and then if my battery is turned off - disconnected from the system - and I'm plugged into shorepower with the converter providing constant voltage to the house circuits, and then I start the engine - what happens to any power the Orion would generate? Or would it just float along with the load since there's no draw?

Mostly.

It would do nothing or it would attempt to "float" the 12V bus; however, there are other features that determine on/off:

1640907719558.png

If the chassis voltage is above 14.00, it, it would attempt to charge. If there's no battery to charge it would just power the loads/float the 12V bus.

The delayed start settings mean it will delay charging until chassis voltage is 13.8V or two minutes have elapsed.

The shutdown voltage is the chassis voltage that terminates charging.

Simply turning the key on will not meet the voltage criteria, so nothing would happen.
 

Browneye

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An update for our avid readers and on-the-fence types for a new converter/charger for lifepo.

Just got off the phone again with Graham at PowerMax. They are busy getting product out before Chinese new year - evidently everything pretty much shuts down for a month over there - coming up here in about three weeks I guess.

He confirmed that the engineering design did not allow for a voltage adjustment in the 2 and 3 stage charging modes. This tends to mirror their other units going back to the beginning. So whatever it puts out - appears to be 14.6 and 13.6 for the 2-stage 'lithium setting' which may or may not suit everybody. I got my lifepo pack done and installed and tested out the 2-stage charging and it went to the lower setting nearly right away, but I'm not sure if that is by design, or if the battery reached what it thought was full charge and so switched off the bulk-mode voltage. My BMS showed zero charging, showed 'discharging' with the load I had on.

Now I also tested the 'fixed voltage' setting and it works just killer. I disconnected the lead, switched on the unit and with DMM set the fixed output to 14.25 volts. Reconnected and turned it on, BMS showed 55A charging, then as the voltage came up on the cells/pack it tapered the current off to nothing at full charge. Very slick. I wouldn't want to float it there, it's too high, but as I may have mentioned I installed a switched outlet for the unit so I could simply shut it off. I intend to use the unit in this manner - charging when I need to charge, and turning it off.

My battery pack has a selector master disconnect switch so I can isolate the lithium pack - so then the converter unit in fixed mode will supply the house loads when plugged in.

So I have the best of wall scenarios. If I'm running the genset for air conditioning during the day, my SCC can supply the house pack - just turn off the charger. I also got one of those Victron Orion dc-to-dc chargers so if the pack needs charging while driving at night or on a cloudy day I'll have that option as well. This unit is easy to connect to the old ignition switch lead that ran the old isolator solenoid. Nice new utilization of what's there.

I'm not sure which all of the PowerMax converter/charger units had the option for adjustable fixed output, but if you have one of those they work well for lifepo charging.

As far as the adjust pot under the cover labeled VR2, Graham still doesn't know what that does. They had some kind of big show to go to but he said when they got back he would break out a unit and play with that, see if he could figure out what it does. I guess getting a reply out of the factory or the design team is difficult. Seems everything is a 'black-box' coming out of China. I suggested it could be the power supply adjust for the fan, it could also be for the threshold where it auto-selects for 120 or 240V input. So that's still a mystery at this time.

My new 230A pack is in and running - the Overkill BMS bluetooth app is really slick - it monitors pack voltage, input and output, and each cell level, and temp - both ambient and cell - it has two sensors.

It's new home under the settee in the salon...you can see the powermax charger back in there too:

 

JimmyM

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I just called the powermax people and left a message. I'm looking for a response on the design as built and what was intended on the voltage adjust parameters and settings. In doing some research online there are some old RV threads that hashed this out years ago - and the converter units really don't seem much different from what they were a decade ago.

Evidently the founders were originally with WFCO and started another company in competition. And one of their primary retailers was BestConverter guy Randy in Alabama. Boy does he have some negative feedback. Anyway, I just ordered a class-T fuse and block from them, and they sell powermax converters under their own brand: Boondocker.

The other thing I want to know is how the fixed-voltage setting works. If there's a voltage drop to the load then I assume it will push max current up to it's rated capacity - the 55 amps or 100, whichever unit you have. But it seems like any other power supply in that once the load voltage rises up closer to the charger voltage the current would taper off as it reaches a matching voltage. Perhaps someone more knowledgable here could shed some light on this.

If this is the case, then setting the fixed voltage at 14.0 to 14.4 and letting it charge a lifepo pack until the current tapers off, then just shut it off.

Their older models only had a 15 minute boost charge at 14.6 and then the unit would drop to 13.6 for an absorption phase, and once the battery reached full charge it would drop to 13.2 as a float phase. This new charger doesn't seem much different, just that they've eliminated the FLA float setting. They also had their PM4 which had the fourth phase for equalization/de-sulfating. Graham claimed this new charger had a 4 hour boost duration if the pack had low voltage/low SOC.

For anyone with more interest on charging lifepo packs here's a pretty good blog from Marine How To - @Dzl has a link in his sig for these guys:
Just heard back from Graham.
I asked about your non-adjustable findings.
-------------
This currently seems to be the case, I'm waiting to hear from engineer if this can be changed in anyway so this was the way it was intended to operate for the different voltage per manufacturer requirements.
-------------

It's not like these things are software adjustable. So I think I'll just buy one with a constant voltage mode and skip the 2-stage Lithium.
 

Browneye

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I think their earlier model that does fixed-voltage charging is cheaper too. This one was $180. It is 55w though, and tested that for sure - 53-54 A showing incoming on the BMS.

I'm happy with it cuz the old IOTA wasn't going to work anyway, so at least there's another option here for a high-voltage/amps charger. Being able to set the voltage to 14 and change is pretty slick - you can keep them under the 100% max charge and float level - that's just better for them than maxing them out all the time.

This is the main reason I went with it - for fast charging when needed. The 100A version would need its own circuit. Graham did say he thought the 55A unit only drew about 8amps on the 120V side. I have a watt-meter coming and will be able to verify that.

I found out my fridge draws half an amp on LPG, and lighting about 4 amps - mostly all LED now. I have a second inverter just for the flat-screen, it draws 65W@120 on a 300w inverter - I guess that's about 6amps at 12volts.

I like that the converter will power the house loads even without the battery connected. Or shut it off and let the battery run the house off grid with solar charging.

I had to order the com cable for the Tracer SCC to adjust it to lithium charge parameters. And I have the Orion to install.

My old golf cart batteries are coming out next, and I have another 750CCA starting battery to match the one already there. That will give me some extra capacity for starting and running the slideouts, awning, and electric step. I installed a 100W panel just for them - a separate charge controller to keep them maintained.

My starting circuit and house circuit are now completely isolated from each other. A single 1awg 6"jumper cable can join them which lets the chassis batteries supply the house should something happen to the lifeopo unit.

I like having options - you never know when things are going to go sideways. :p
 
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Browneye

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Yeah, the standard PM3-55lk is $145 on amazon. It does the fixed-volts output too:


I think the PM4 is even cheaper and it can do fixed-voltage output as well. 55A is like $135. You just wouldn't use it in the automatic mode, nor leave it connected indefinitely - these need to be shut off when the battery gets full.

 
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JimmyM

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Yeah, the standard PM3-55lk is $145 on amazon. It does the fixed-volts output too:


I think the PM4 is even cheaper and it can do fixed-voltage output as well. 55A is like $135. You just wouldn't use it in the automatic mode, nor leave it connected indefinitely - these need to be shut off when the battery gets full.

If it's set to 13.8V (3.45 V/cell), it can be floated at that voltage indefinitely. Maybe go with 3.40 V/cell. But balancing should be done higher in the voltage range where dV vs SOC is steep. So each cell's SOC is more closely matched after balancing.

That voltage is only set by a simple pot. I'm going to get the PM4-55 and open it up. I want to take the pot and replace it with a "module" and a switch to switch from 3.4V/cell to 3.55V/cell. I'd only use that higher voltage when I want to get a good top balance. What's the worst that could happen? I blow $135 learning a lesson?
 

Browneye

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I spent the entire day re-doing my battery compartment. Now that the lifepo4 has moved into the house under the settee, the old golf-cart batteries came out. This gave me room to add a second starting battery for capacity and redundancy.

Update items
1. New cables to connect to the loads and ground, and connect the two starting batteries in parallel.
2. Added a 2-post high-amp bus - they had four leads on one 12v post for the alternator leads, battery, and a feed to the chassis loads. The chassis/starting battery runs the power step, power awning, slideouts, and hydraulic leveling jacks.
3. Added a 100W solar panel and Renogy 10A PWM charge controller.
4. Installed the Victron DC to DC charger. It's just a basic 12/12-18A - they have an adjust pot to set charge voltage, same as the PowerMax converter/charger. So this one I set at 13.5 volts so it can charge or float while driving. I used the old ignition lead from isolator solenoid that got removed - it turns on the Orion when the engine is started. A very slick feature.
5. Victron calls for a 60A fuse on both source and load on the Orion, so those are mounted under the solar charge controller.
6. The frame-rail grounding bus was pretty dirty, and Winnebago doesn't shrink wrap the cable ends - so everything got cleaned up and wrapped, re-routed, and tidied up.

Everything is working great. The Overkill bms is really a nice tool for seeing what's going on with charging and discharging, state of charge, etc.
I'm waiting on a RS485 cable to program my two Tracer charge controllers to a lithium profile.

 
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JimmyM

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I just ordered a PM4 60A charger. Only cost $139. When I get it, I'll be messing with the voltage setting pot to see what I can do to have 2 switchable voltages. 13.6 & 14.4 maybe.
 

Browneye

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I think you'll find you can only adjust the fixed voltage setting. The 3-stage charging is pre-programed.

I did some testing today with the PowerMax unit, got a watt-meter for the 120 outlet so I could see what it was doing.

In the fixed-volt mode, set at 14.4, it puts out 53-54A and draws nearly 11A on the 120 side. It tapers off once the battery voltage comes up to near the charging voltage - indicating full charge. At full output the cooling fan sings pretty good.

I put it on the 2-stage mode and it charges at 53-54A amps for a pretty short time, maybe three or four minutes, then drops to the float level of 13.6 volts and the amps taper off to about 12. At this point it's drawing 3A at the 120 outlet. The cooling fan runs but is very quiet.

The beauty here is you can have fast or slow charging depending on what you want. I'm glad I can shut it off - I don't want to float it for any length of time at 13.6. It's fine for a day but not for weeks or long term, or when it reaches full charge. The lifepo seems really happy at about 13.3-13.4 volts - the meat of the SOC range.

The cool thing is the Lifepo Overkill bms app shows everything going in and out on the pack, so it's easy to see what's going on with it.

When I switched to the 2-stage charging mode the amps dropped to around 6, then the battery voltage settled and it ramped back up to 12A charging. The voltage sensing works very well, current is adjusted accordingly, whether you're in 2-stage or the fixed setting.

With the fixed output at the higher voltage it kicks the current up to the 55A until the battery voltage comes up, then it tapers off. This will be ideal for generator running when you need some juice fast. Plugged in at a RV park in the 2-stage it will just keep them peaked to 99% or so, just like the Orion does.

Having all three charge modes means I don't have to worry about my battery running out. The Orion when driving, the solar when parked (or driving), and the converter/charger when plugged in or running the generator for 120 volts. The 55A fast charging option is just outstanding. I'm not sure what the SCC will do with the charger feeding the battery 55A. I guess as long as the volts are down on the pack, it will put out it's 20-25A too. One could gather a lot of amps in a pretty short time.

Today my Tracer Xtra MPPT was showing its classic optimization of solar energy - 1.6A coming in at 43V and 3.5A out optimized charging. The overkill bms confirmed the pack was getting the 3.5 amps in.

 
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sshibly

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Guys, please AVOID any powermax products.

I bought one and it is useless, the boost state is a TIMED event, pretty much a boat anchor for me.
Powermax intentionally misrepresented how it charges. The new product looks like the old pig with new stickers and some lipstick.

Get a MEANWELL PB or NPB series.
Meanwell does powerfactor and is very efficient.
 

Browneye

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Smoke and mirrors. :LOL:
It's not even heavy enough to be a boat anchor.

I am a little curious how long it would charge in the high state with a low battery charge level. I started out today at about 75% - all my cells were a little over 3.35. I am pleased with how close their voltage stays over discharge then charge.

From what I saw, the unit tapers current based on battery voltage in both settings, but in 2-stage it did switch to float mode when my pack was at 13.35. I was going to wait for it to reach the 13.6 float voltage to see if it quit charging, but the current had already tapered off so I didn't want to sit and wait for it.

Charging it at 55A brings it up pretty quick.
 

sshibly

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I just ordered a PM4 60A charger. Only cost $139. When I get it, I'll be messing with the voltage setting pot to see what I can do to have 2 switchable voltages. 13.6 & 14.4 maybe.
Jimmy, bro, cancel your order and/or refuse delivery, whatever you can SEND IT BACK and get your money back pls.

There is NO 2 switchable voltages, ALL LIES,
All there is ONE pot which raises initial voltage and float voltage by the SAME amount.

One word "Deception",

See Op's own desc, this NOT how a true 2 stage charge behaves, you can put lipstick on a Powermax but it is still a dumb Powermax

I put it on the 2-stage mode and it charges at 53-54A amps for a pretty short time, maybe three or four minutes, then drops to the float level of 13.6 volts and the amps taper off to about 12. At this point it's drawing 3A at the 120 outlet. The cooling fan runs but is very quiet.

The beauty here is you can have fast or slow charging depending on what you want. I'm glad I can shut it off - I don't want to float it for any length of time at 13.6. It's fine for a day but not for weeks or long term, or when it reaches full charge. The lifepo seems really happy at about 13.3-13.4 volts - the meat of the SOC range.

Please take sometime and read what a true 2 stage charge does and how it should behave, also see you can set the charge CURRENT and VOLTAGE

 

sshibly

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Smoke and mirrors. :LOL:
It's not even heavy enough to be a boat anchor.

I am a little curious how long it would charge in the high state with a low battery charge level. I started out today at about 75% - all my cells were a little over 3.35. I am pleased with how close their voltage stays over discharge then charge.

From what I saw, the unit tapers current based on battery voltage in both settings, but in 2-stage it did switch to float mode when my pack was at 13.35. I was going to wait for it to reach the 13.6 float voltage to see if it quit charging, but the current had already tapered off so I didn't want to sit and wait for it.

Charging it at 55A brings it up pretty quick.
Op,

Can you please enlighten us on the logic which this fine charger uses to STOP charging?
When does it stop charging and what indication does it give to the end user that it has stopped charging?
 
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