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StirCrazy
Kamloops, BC, Canada
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Joined: 07/16/2003
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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.
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StirCrazy
Kamloops, BC, Canada
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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
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pianotuna
Regina, SK, Canada
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Joined: 12/18/2004
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Power factor on PD units is 0.7.
Power factor on powermax is 0.85. (they call it efficiency)
https://www.boatandrvaccessories.com/en-........-pm3-75-12-volt-75-amp-converter-charger
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.
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3 tons
NV.
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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
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3 tons
NV.
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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
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time2roll
Southern California
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Joined: 03/21/2005
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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.
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3 tons
NV.
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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
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StirCrazy
Kamloops, BC, Canada
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Joined: 07/16/2003
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you couldn't even link to one that is a LI converter eh haha
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StirCrazy
Kamloops, BC, Canada
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Joined: 07/16/2003
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time2roll wrote: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.
I am not sure I agree with 8 days being considered "Long Term" , and every cell I have looked at uses the 14.6 as the recommended voltage for charging to 100%. I think the 13.6 has come about, as after a rest period off the charge that is considered a 100% resting voltage for the purpose of capacity checking, and like you said should be a max.
when I am camping I set the voltages for 13.3 which during the day will charge back up to 90% and hold so I don't use the two stage at that point but once a week I do use the profile that will charge to 13.9, hold for 1 hour as My BMS will start equalizing at 13.6V. I then have it drop to 13.3. I do have to change back to the normal one in the app but its easy.
as far as a two stage converter..
I don't know if I even need a dual stage converter I think because of my ability to bluetooth into my battery and set charge limits, discharge limits and charge start limits I could just plug it into a normal single stage charger, but I would have to test that, or maybe someone here has and can let us know. right now, since I installed my LFP batteries I don't plug it in at home.. just the solar is hooked up as I don't have a LFP compatible converter... well, it was supposed to be, but it is old stock they set me which doesn't have that function. I'll have to try messing around with that and do some testing... once I get a converter.
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3 tons
NV.
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Application matters…Power factor becomes relevant on things like electric motors or inverters, but becomes more of a ‘shiny object’ distraction (wholesale claims) ‘when talking’ about chargers - As with certain SiO2 battery claims, skepticism pays…
3 tons
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