LiFePO4 Converter Change?

[Ranger_Tim]

I just want to switch from lead acid to lithium, not upgrade wires and everything else. Finding a new replacement board for my WF-8955PEC seems to be complicated. Straight 14.6V continuous boost single phase vs. 14.6 boost and 13.4 idle dual phase approach, some have a switch for LA/Li, others are auto sensing, still others are Lithium only. Huge range of prices indicates there may be some poor quality fake/unauthorized parts out there. I don’t want to replace the entire thing, just the converter section.

Reading forum posts from many sites usually ends in discussions that go into the weeds quickly. Can anyone cut through it and keep it simple?

[3_tons]

time2roll said:

“This generally gives the standard PD or the PowerMax with adjustable voltage an advantage. Both drop to 13.2 volts for long term.”

Agreed, a PD 9245 is what I have (with tethered CW for ‘boost’ mode) though I mostly charge via solar, and only occasionally to 100% SOC…However, when seeking a full charge (say for periodic cell balancing and SOC meter resync’s) I prefer 14.4 for boost voltage…I discontinue charging (assuming shore power…) once cell balancing has completed, and since we primarily camp off-grid, don’t bother with a ‘float’ mode…Thereafter, 660w *solar and 400a/hr LFP typically fills-in any daily consumption gaps…

*(summer desert camping, additional 360w ground deployable)

3 tons

[time2roll]

3 tons wrote:
snip.... the charger reverts back to and holds at 13.6v…Charger stays at 13.6v to again repeat the 14.6v charging cycle in 8 days, or presumably triggered upon reaching a voltage somewhat lower than 13.6v…

I would not want to float an LFP above 13.4 volts. 13.2 - 13.3 is better. I don't know anyone that recommends holding LFP long term at 100% charged.

14.6 is also higher than necessary and is more likely to cause a fault in some lower cost brands from CN that many look at.

This generally gives the standard PD or the PowerMax with adjustable voltage an advantage. Both drop to 13.2 volts for long term.

That is my opinion. Good luck to the OP.

[3_tons]

pianotuna wrote:
Power factor on PD units is 0.7.

Power factor on powermax is 0.85. (they call it efficiency)

https://www.boatandrvaccessories.com/en-ca/products/powermax-pm3-75-12-volt-75-amp-converter-charger

Power factor in this application is nearly an inconsequential stat, and one that might even be skewed depending on voltage-current adjustment…

However, from what I can tell there appears to be other more substantial differences between the Power Max and the Progressive Dynamics charging strategies as follows;

Power max basics:

The charger’s ‘trigger point’ to return to 14.6v stage is not well defined, nor is the duration at this voltage, so it’s hard to know whether cell-balancing (or meter resync) has occured.

One advantage here seems to be that there’s no real need to periodically monitor SOC, yet when held at a possible near constant full charge, one might suspect this may adversely impact battery longevity…

https://powermaxconverters.com/wp-content/uploads/2021/11/PM3-LKL-Manual.docx


PD basics:

Once the battery voltage has risen to 14.6v, then followed by 1 hr holding period (presumably to allow for cell balancing) the charger reverts back to and holds at 13.6v…Charger stays at 13.6v to again repeat the 14.6v charging cycle in 8 days, or presumably triggered upon reaching a voltage somewhat lower than 13.6v…

(Note: ‘CW’ means built-in smart Charge Wizard’)

https://www.progressivedyn.com/wp-content/uploads/Support/manuals/Technical-library/Two-stage-lithium.pdf

Considering either device, my preference would be the latter, JMO,

3 tons

[3_tons]

Ranger Tim wrote:
I do know what I want. Two LiFePO batteries and a converter that I can leave unattended while on shore power that will maintain them. I have no solar, a small generator and very low demand. We camp in varied locations from boondocking to KOA. I have gleaned enough info from the thread to be very useful and thank the contributors for their input.

You’re in luck!…Depending on one’s existing equipment and habits (older generation chargers, solar harvesting, attended charging, etc…) several methods have evolved for charging a LiFePO4 battery…New adopters will benefit from a new generation of ‘set and forget’ 2 stage chargers…

3 tons

[pianotuna]

Power factor on PD units is 0.7.

Power factor on powermax is 0.85. (they call it efficiency)

https://www.boatandrvaccessories.com/en-ca/products/powermax-pm3-75-12-volt-75-amp-converter-charger

[StirCrazy]

otrfun wrote:

time2roll wrote:

StirCrazy wrote:

pianotuna wrote:
power max is top of the line.

I don't know about that.. I have been looking at it and I see a lot of mixed reviews and their power factor is commonly referred to as being bad. I do like the fact that you can fine tune the top voltage but I wish you could tune the 2nd stage independently.

With some solar controllers you can program everything. Why hasn't anyone done this for converters yet?

Steve

Do you have one? I don't think the adjustment holds for the multistage. I read PM is either fixed voltage adjustable or preset multistage.

We just purchased a new 75a Powermax. The unit can be switched to operate as a single-stage charger (i.e., power supply) or 3-stage charger.

There's a very small pot that adjusts voltage for *both* the single-stage mode and the *bulk* stage when in 3-stage mode. It can be adjusted from 13.0 to 16.5v. Comes from Powermax preset for 14.6v. Haven't confirmed it yet, but I believe the float (13.2v) and absorption (13.6v) voltages remain fixed and are not changed by this pot.

I was reading about that I believe the manual I was reading on line said it lowers the secondary voltage also and will work in single dual or three stage, just has to be adjusted in single and the amount the other stages change are directly related to the adjustment of the 1st stage. I want three dials and to be able to adjust them independently. the only bad thing I have seen about power max has to do with their Power factor, apparently it isn't very good, so they use more power to output the same as say PD

[StirCrazy]

time2roll wrote:

StirCrazy wrote:

pianotuna wrote:
power max is top of the line.

I don't know about that.. I have been looking at it and I see a lot of mixed reviews and their power factor is commonly referred to as being bad. I do like the fact that you can fine tune the top voltage but I wish you could tune the 2nd stage independently.

With some solar controllers you can program everything. Why hasn't anyone done this for converters yet?

Steve

Do you have one? I don't think the adjustment holds for the multistage. I read PM is either fixed voltage adjustable or preset multistage.

no with my renogy I can customize a three stage set up (well 4 stage if you count equalization but I just set that to my storage voltage as it doesn't have an off feature) so I didn't pick a LI and modified it when you do custom you have to set up full 3 stages so I have it set up to charge to 100% at 14.4 then I drop to 13.6, but I have a second profile for when I get home and I am storing it between trips where it will charge to 14.6 on bulk then drop off to 13.0V which will let it discharge down to 50% before it charges again as nothing is really on at home and normally it doesn't charge between trips till the day before when I bring the battery up to 100% for the trip. the 3d stage I just set the same as the 2nd stage as it isn't needed and I do that with equalization also as you cant shut it off.

[StirCrazy]

otrfun wrote:

StirCrazy wrote:
I think part of that is they were waiting for a consensus of what would be good for a second voltage on a two stage and to see which format (chemical composition) was going to become the leader for rv use. There are some companies that came out with 2 stages right off the bat.

I'm a bit surprised any reputable converter/charger manufacturer would produce a single-stage 14.6v lifepo4 converter/charger.

The converter/charger industry transitioned from single-stage to multi-stage converters/chargers for lead-cell batteries many, many years ago.

Lead-cell and lifepo4 chemistries share the same, exact charging dilemma. There is no one, ideal charge voltage for lead-cell. There is no one, ideal charge voltage for lifepo4.

Why some converter/charger manufacturers completely ignored this simple concept by introducing single-stage (single voltage) lifepo4 converters/chargers for lifepo4's is beyond me.

wasn't just some, they all did single stage Li output for a bit, some went to dual stage quicker than others.. don't forget LiFePO4 isn't the original LI that the converters were intended for so the second stay wasnt considered necessary as the one voltage would cover the two or three types of Li out there. now that LFP has emerged as the most usual format you are seeing all the two stages coming out at around 14.6 and 13.6. Now would I buy a 2 stage... for me I don't know if it makes any sense. I use my BMS to control my charge so it would charge to the voltage I have set and then shut off the charge so the 2nd stage would never really come into play anyways. all the modern electronics, led or florescent lights will handle a 14.6V no issues. so for me I am not quite sure it makes sense, unless you can think of something I am missing. but for someone who is buying off the shelf batteries and cannot control the charging cut in and outs then ya a 2 stage is great as it will hit 14.6, do its balance thing, then drop off to 13.6 or whatever the second stage is.

[Ranger_Tim]

I do know what I want. Two LiFePO batteries and a converter that I can leave unattended while on shore power that will maintain them. I have no solar, a small generator and very low demand. We camp in varied locations from boondocking to KOA. I have gleaned enough info from the thread to be very useful and thank the contributors for their input.

[otrfun]

time2roll wrote:

StirCrazy wrote:

pianotuna wrote:
power max is top of the line.

I don't know about that.. I have been looking at it and I see a lot of mixed reviews and their power factor is commonly referred to as being bad. I do like the fact that you can fine tune the top voltage but I wish you could tune the 2nd stage independently.

With some solar controllers you can program everything. Why hasn't anyone done this for converters yet?

Steve

Do you have one? I don't think the adjustment holds for the multistage. I read PM is either fixed voltage adjustable or preset multistage.

We just purchased a new 75a Powermax. The unit can be switched to operate as a single-stage charger (i.e., power supply) or 3-stage charger.

There's a very small pot that adjusts voltage for *both* the single-stage mode and the *bulk* stage when in 3-stage mode. It can be adjusted from 13.0 to 16.5v. Comes from Powermax preset for 14.6v. Haven't confirmed it yet, but I believe the float (13.2v) and absorption (13.6v) voltages remain fixed and are not changed by this pot.

[time2roll]

StirCrazy wrote:

pianotuna wrote:
power max is top of the line.

I don't know about that.. I have been looking at it and I see a lot of mixed reviews and their power factor is commonly referred to as being bad. I do like the fact that you can fine tune the top voltage but I wish you could tune the 2nd stage independently.

With some solar controllers you can program everything. Why hasn't anyone done this for converters yet?

Steve

Do you have one? I don't think the adjustment holds for the multistage. I read PM is either fixed voltage adjustable or preset multistage.

[Grit_dog]

^Yeah. I wouldn’t have thought that for a minute. But we are talking about RV component mfgs here. Not exactly near the top of the list for innovation or technology and often quality as well.
Also thought it went without saying….as idk why anyone would purchase a single stage battery charger of any sort except for maybe a known dedicated purpose.

I got an old kick butt single stage charger. Only use it if I’m trying to recover a battery. But with smart chargers, haven’t killed one dead in a long time. Except occasionally the key or hand warmers get left on, on the mower or 4 wheeler.
And I bought my first LiFePO4 charger (smart charger) years ago. Not like the charging technology just got sorted out a couple years ago.
Weird stuff, these AreVees….

[otrfun]

StirCrazy wrote:
I think part of that is they were waiting for a consensus of what would be good for a second voltage on a two stage and to see which format (chemical composition) was going to become the leader for rv use. There are some companies that came out with 2 stages right off the bat.

I'm a bit surprised any reputable converter/charger manufacturer would produce a single-stage 14.6v lifepo4 converter/charger.

The converter/charger industry transitioned from single-stage to multi-stage converters/chargers for lead-cell batteries many, many years ago.

Lead-cell and lifepo4 chemistries share the same, exact charging dilemma. There is no one, ideal charge voltage for lead-cell. There is no one, ideal charge voltage for lifepo4.

Why some converter/charger manufacturers completely ignored this simple concept by introducing single-stage (single voltage) lifepo4 converters/chargers for lifepo4's is beyond me.

[StirCrazy]

pianotuna wrote:
power max is top of the line.

I don't know about that.. I have been looking at it and I see a lot of mixed reviews and their power factor is commonly referred to as being bad. I do like the fact that you can fine tune the top voltage but I wish you could tune the 2nd stage independently.

With some solar controllers you can program everything. Why hasn't anyone done this for converters yet?

Steve

[StirCrazy]

otrfun wrote:

Grit dog wrote:
^ Are single stage battery chargers of any flavor a thing anymore? Whether talking converters, typical automotive chargers, marine chargers or small power equipment chargers/maintainers…
Every charger I’ve bought for the last 20lbs years has been a smart charger (well except the WFCO, it’s the Dollar Store of battery chargers and it came with the last RV I bought and it purports to be a smart charger as well. It’s just learning disabled…hence the recommendations here to get something else).

In the lead-cell world, I agree.

In the lifepo4 world, not so much. Look closely at the "lithium/lifepo4 approved" converters and chargers now on the market. Many are single-stage (single voltage) 14.6v chargers. For instance, Progressive Dynamic, one of the largest OEM converter/charger manufacturers for the RV market, didn't start offering multi-stage (multi-voltage) lifepo4 converters/chargers until a year or so ago. There's still a large inventory of single-stage Progressive Dynamic lifepo4 converters still being sold.

I think part of that is they were waiting for a consensus of what would be good for a second voltage on a two stage and to see which format (chemical composition) was going to become the leader for rv use. There are some companies that came out with 2 stages right off the bat.