PIP-4048MS and PIP-5048MS inverters

[ChrisHobson]

9:45am -Time for a cup of coffee. So I put the kettle on and it is a good time to see what the panels are doing.

P = V x I (91.8V x 36A) = 3304.8 W. But I only have 3kW of panels and it is the middle of winter (OK today's temperature could be making the panels more efficient).

The power being consumed is only 2415W so where is the unaccounted for 800 odd Watts (plus we are drawing 600 odd Watts from the battery - even worse - now we are looking for 1400W).

Does anyone have a reasonable explanation?

I do not think the figures on the PIP are accurate and will do the same experiment once I have my battery monitor set up.

[offgridQLD]

While most of the pv power would be going to the Ac loads.The missing power is most likely going to your battery charging it.

Kurt

[PlanB]

PV input current is measured post the MPPT Chris, so at the battery voltage, panel current at the MPPT 91.8v input is actually much less since the MPPT part of the pips steps the solar voltage down & the current up. So your actual solar power is 52.1v x 36A = 1876w.

[ChrisHobson]

Ah PlanB

That makes sense.

Yesterday I received a tip from a Saffa user. The SOC reading becomes accurate if you set the battery cut-off to the default (21V or 42V). The battery cut-off values are so low that they are in fact meaningless (even at the maximum (24V or 48V). So by setting program 29 to the default the software SOC is accurate and this may influence other parameters. This may account for some of the trouble that users are experiencing. One then has to use the dry contact or a battery monitor to activate a contact to control load instead of using the battery low cut-off.

[dockarl]

{duplicate removed}

[dockarl]

{duplicate removed - anyone else noticed the forum is taking 5 mins to load a page today? These duplicates came after the forum threw errors when I hit submit..)

[weber]

Thanks to gmacd33 I just learned what Giant Power have done to the IPS-4000WM to get it listed as meeting IEC 62109 on the Australian Clean Energy Council website.

Nothing.

They have written an Application Note that contains the following advice:

------------------------
The Giant Power IPS4000WM is a standalone offgrid inverter and is certified as IEC62109-1 & IEC62109-2 complaint as required by section 4.3.11. The IPS4000WM has a MPPT voltage range of 60-115v and as such is classified as ELV under AS5033:2014 so sections 3.4 Protection against Earth Faults do not apply providing the voltage is kept within this range.
------------------------

The truth is, a PV array is not classified as ELV based on its MPP voltage, but its open circuit voltage (at the lowest expected operating temperature). That maximum open circuit voltage has to be less than 120 V for it to be ELV. The IPS-4000WM (PIP-4048MS) can take open circuit voltages up to 145 V.

That means our our choice now for the PIP, in Australia, is probably only strings of two 72-cell modules (144 cells). You might just be able to use strings of three 54-cell modules (162 cells) depending on your minimum dawn temperature and their exact voltage rating and temperature coefficient. But there is no number of 60-cell modules that will work. Two would have their max power point below 60 V when hot, and three would have their open circuit voltage above 120 V when cold.

We can no longer use strings of three 60-cell modules, or three 72-cell modules as I did on Black Monolith #1.

[offgridQLD]

So what happens if you have freak cold day is your system illegal that day?

I agree and understand the issue. Just not 100% on what responsibility - accountability for the weather the designer - installer of the system has.

Do you just have to show you have taken reasonable steps based on historical weather data for the area.

Kurt

[weber]

So what happens if you have freak cold day is your system illegal that day?

No.

I agree and understand the issue. Just not 100% on what responsibility - accountability for the weather the designer - installer of the system has.

I'd say if it's a generic system, it's up to the designer to specify the lowest dawn temperature for which the array will remain ELV, and up to the installer to check that agrees with BOM data for the area it's being installed in. If it's being designed for a specific location then it's up to the designer to check the BOM data for the general area. It would not be reasonable to expect anyone to precisely account for any local microclimate, just as it would not be reasonable to expect them to exactly predict the future.

Do you just have to show you have taken reasonable steps based on historical weather data for the area.

Yes. In SE Qld, if you're in Brisbane or on the coast, 0°C is a safe figure to use. But it drops as you go inland.
http://www.bom.gov.au/climate/averages/ ... _All.shtml

[offgridQLD]

I'm just charging my 40ah/48v lithium pack with the PIP at the moment from mains power. I have the PIP set at 20A max charge. The PIP is pulling 1250w AC from the wall and its feeding 1088w into the battery. I work that out at a 5% loss or 95% efficiency. Not to bad.


One question I have regarding The serial interface board on my PIP. When I use the pip to recharge my Imiev from the little 40ah - 48v battery. I set the LVD at 48v this is 48v under load with a 2200w load on the batterys.

What I find is that at some voltage above 48v but bellow 50v (sorry I will get a exact voltage number) the relay on the Serial interface board starts clicking away. I would guess about two times pr second and continues to do so until just befor LVD where I get a break in the clicks and then they slow down.

What setting can I change to stop this or why is it doing this. Admittedly I haven't investigated it yet and will do so on the weekend when I have my coms cable handy.

Kurt

[weber]

What I find is that at some voltage above 48v but bellow 50v (sorry I will get a exact voltage number) the relay on the Serial interface board starts clicking away. I would guess about two times pr second and continues to do so until just befor LVD where I get a break in the clicks and then they slow down.

What setting can I change to stop this or why is it doing this. Admittedly I haven't investigated it yet and will do so on the weekend when I have my coms cable handy.

Hi Kurt. That's nothing to do with the serial comms. That's the so-called "dry contact" described in the manual. It can be wired to an alarm to warn you of impending shutdown on undervoltage. I think you can turn it off using setting number 18 "Alarm on/off".

[offgridQLD]

Thanks Weber, I will dig through the setting and turn it off as listening to it for 10 min straight in the confines of the car had us all a little loopy in the end.

Yes some times you just can't win if the screw doesn't have room to back all the way out. It's a bit like building large objects in a workshop and then realizing it wont fit out the doors ( don't ask me how I know that one )

I guess my point on the tools is just a reminder that some times a simple specialized tool or just the correct tool for the job can turn a world of pain into a quick and enjoyable process. I understand some time's it's difficult to justify the expense or time spent creating them. But often there are modesty priced options out there now days or the time spent making them pays it's self off in the long run.

Kurt

[ChrisHobson]

Depending on what program 1 is set to program 12 and 13 and the low battery cut off influence the dry contact. Program 18 switches off the buzzer/alarm on the unit (gets rid of the annoying beep when you are pressing buttons on the unit and silences alarms).

[weber]

Does anyone know what the conditions are that cause a PIP-4048MS to drop out of float mode, so that next time it charges it will go to the absorb voltage? What voltage does it have to drop below, and for how long? And is it a fixed voltage or is it a certain number of volts below the float voltage setting, or is it setting number 12 (back-to-utility voltage) even when the PIP is in UtI mode?

There was some discussion in this thread beginning at
viewtopic.php?title=pip4048ms-inverter& ... 332#p57546
but we did not come to any conclusion.

I need to know about this for the Black Monolith, because I was relying on going to the absorb voltage to balance the cells, and I was relying on the completion of cell balancing (all cells in bypass) to decide when to reset the SoC meter to 100%. And this was just never happening and the SoC meter was slowly drifting downwards so that eventually it was only reading 60% when it was really 100%.

The Black Monolith has 16 x LiFePO4 cells and I had the float voltage set to 53.8 V (3.36 V per cell) and the absorb voltage 55.2 V (3.45 Vpc).

I have worked around it temporarily by raising the float voltage to 54.2 V (3.39 Vpc), but this is not a good long term solution.

[Edit: Replaced "absorb voltage 54.5 V (3.41 Vpc)" with "absorb voltage 55.2 V (3.45 Vpc)"]

[Tjadenw]

Did you guys see the new model Voltonicpower launched

http://www.voltronicpower.com/oCart2/in ... uct_id=151

Only 1.5 and 3 KVA but the new model has got selectable output voltage, charger stage selection and CV charging time selection.

The solar charger is only 40 amp unfortunately, i wonder if a 4 Kw model will follow.

[ Edited Coulomb: made link clickable ]

[coulomb]

new model Voltonicpower launched

I'm not totally convinced that it's a new model, though it does have some interesting features, like a selectable 2/3-stage charger.

Thanks for pointing it out.

[T1 Terry]

Does anyone know what the conditions are that cause a PIP-4048MS to drop out of float mode, so that next time it charges it will go to the absorb voltage? What voltage does it have to drop below, and for how long? And is it a fixed voltage or is it a certain number of volts below the float voltage setting, or is it setting number 12 (back-to-utility voltage) even when the PIP is in UtI mode?

There was some discussion in this thread beginning at
viewtopic.php?title=pip4048ms-inverter& ... 332#p57546
but we did not come to any conclusion.

I need to know about this for the Black Monolith, because I was relying on going to the absorb voltage to balance the cells, and I was relying on the completion of cell balancing (all cells in bypass) to decide when to reset the SoC meter to 100%. And this was just never happening and the SoC meter was slowly drifting downwards so that eventually it was only reading 60% when it was really 100%.

The Black Monolith has 16 x LiFePO4 cells and I had the float voltage set to 53.8 V (3.36 V per cell) and the absorb voltage 55.2 V (3.45 Vpc).

I have worked around it temporarily by raising the float voltage to 54.2 V (3.39 Vpc), but this is not a good long term solution.

[Edit: Replaced "absorb voltage 54.5 V (3.41 Vpc)" with "absorb voltage 55.2 V (3.45 Vpc)"]

Why a 3.36v float, what was the reasoning behind that? Can your program include an equalising charge frequency and parameters? As I don't use the MPPT controller at all I have no idea of what parameters can be set, but I use this function for the Victron BMV 100% SOC reset on the charge control system we have.

T1 Terry

[weber]

Hi T1 Terry. When you quoted my question, I got all excited, thinking maybe you were going to answer it. Never mind.

Why a 3.36v float, what was the reasoning behind that?

The lower the float voltage the longer the life. Although in a place like Queensland we shouldn't forget that keeping them cool is way more important. Ideally we wouldn't float them at all but simply stop charging until the estimated open circuit voltage fell below some threshold, say 3.29 Vpc. A number of experiments have shown that the rested voltage of a fully charged LiFePO4 cell will eventually settle around 3.36 V. Also it is just sufficiently above the 3.33 V plateau between 80% and 95% SoC to be sure it is fully charged.

Can your program include an equalising charge frequency and parameters? As I don't use the MPPT controller at all I have no idea of what parameters can be set, but I use this function for the Victron BMV 100% SOC reset on the charge control system we have.

The PIP's MPPT charging parameters are the same as its 230 Vac charging parameters, and they do not include a periodic equalisation charge. Nice try though.

[solamahn]

I just tried a 4048 on 240 charging and the start voltage was 50.9 and it went up to the bulk charge setting of 57v. I know with 2424 the start voltage has to be below 25 for it to go into bulk charging but I did not think it mattered with a 4048. If the charging starts at a high voltage then it will not stay in bulk for long. That was using firmware 52 30. Has anyone tried changing the scc firmware. I can do it on a 2424msx but with a 4048ms I just get a debug assertion error

[offgridQLD]

Are you thinking of what some charge controllers call a (rebulk) mode When it will go back through the bulk/absorb stage if the voltage drops below a set value while in float?

If so then no I don't think it has that particular feature. It doesn't have any programmable adjustment of the time spent in CV - absorb stage. It's more or less. Set a float - absorb voltage and max charge limit and that's it for charging adjustment.

How long it spends at CV is predetermined by the time it took to get to the absorb voltage (with a limit on the min & max time from memory (10min / 8hrs)


I took my PIP out the other day in my Imiev (Ejerycan backup) As I had a long trip to do and wasn't sure of the capacity needed to complete it. It turned out I had plenty of capacity when I got home in the stock Imiev pack. So I now had a full 2kwh 48v Calb battery that I didn't want to let sit for long periods at 100% SOC.

So I drained the pack back down to 50% SOC using the PIP powering a small 2.5kw (non inverter) style RC split system Aircon unit. It was cool at the time so I was using it in RC heat mode. It was a funny feeling sitting in a room with the thermostat set at 28C! bathed in warm...hot air. While a tiny battery and inverter where doing all the magic. I had to run it for several hrs to get the battery back down to roughly 50% SOC (Silly split system AC's and there high efficiency .

It was interesting to see the live consumption reading on the PIP4048's display. 630w when the compressor was running and the Meter I was running it through showed 630.1w. I then increased the fan speed on the aircon unit and the PIP4048's display read 641w and the inline meter read 640w. It was nice to see them agree somewhat. I was also suprised at how low the consumption was on that particular inexpensive no name non inverter style AC unit . (I had always just assumed it's consumption was around 1kw) so that was a nice outcome.

PIP4048's display (fan low)


Energy meter (fan low)


PIP4048's display fan high


Energy meter (fan high)


It was a good test to see how the PIP4048 handles Air Conditioner spike loads as I was considering dedicating it (when it's not in Ejerrycan mode) to run several split system Aircon units at the same time. I will have to try it on one of my inverter style units and see if it has any funny issues with it (like it did a few times with the variable load of the Imiev charger)

Kurt

[coulomb]

Does anyone know what the conditions are that cause a PIP-4048MS to drop out of float mode...

I suspect that it is a fixed voltage lower than the float voltage parameter. In fact, 4.0 V less. There would be a time required to be at this level, say 10 seconds or so, to avoid temporary load surges from "prematurely" taking it out of float mode.

[ Edit: I now suspect that 52.02 firmware has a fixed return to boost voltage, where it needs to see less than 48.0 V for about 5 seconds. ]

This is in line with the "lead acid thinking" that seems to have shaped the design of this inverter. Unfortunately, this is a bad fit for LiFePO4 batteries. (It may well be fine for other chemistries, such as the NMC (?) used in Nissan Leaf cells.)

For LiFePO4, that means that if the float voltage is set to say 53.8 V (3.36 VPC), then the battery would have to go down to 49.8 V or 3.11 VPC. This is around 5% SOC, and the battery should almost never go that low. So the answer might be to go back to sending commands to change the float voltage, but instead of doing this every few seconds (and this constantly resetting the solar charger's MPPT algorithm), it would only be sent about once a day, when the battery falls to say 52.8 V (3.30 VPC).

[T1 Terry]

Hi T1 Terry. When you quoted my question, I got all excited, thinking maybe you were going to answer it. Never mind.

Why a 3.36v float, what was the reasoning behind that?

The lower the float voltage the longer the life. Although in a place like Queensland we shouldn't forget that keeping them cool is way more important. Ideally we wouldn't float them at all but simply stop charging until the estimated open circuit voltage fell below some threshold, say 3.29 Vpc. A number of experiments have shown that the rested voltage of a fully charged LiFePO4 cell will eventually settle around 3.36 V. Also it is just sufficiently above the 3.33 V plateau between 80% and 95% SoC to be sure it is fully charged.

After 4 yrs and 1500 cycles capacity testing as house batteries I can tell you that a 3.45v per cell float voltage when charged from solar does not reduce capacity. However, consistent under charging will require a full cycling charging regime** to get the capacity back up. Basically the same routine as after putting the cells into stored mode or when you first commission them.
Taking the cells to 3.6v and holding them there, now that does shorten their life and increases their internal resistance. The resistance issue isn't much of a problem with house batteries unless you regularly apply a load greater than 1C, you see the sag then and it's all too late.
If the cell voltage drops below 3.4v rested, it was not fully charged, try recharging and measure how much goes in each time till the voltage holds 3.4v or better, that will give you an idea how far below 100% you really were.

T1 Terry

**100% down to 20%, back to 100% continued until the capacity does not improve further

[offgridQLD]

"However, consistent under charging will require a full cycling charging regime** to get the capacity back up. Basically the same routine as after putting the cells into stored mode or when you first commission them."

That all sounds like lead acid talk to me.

Kurt

[T1 Terry]

"However, consistent under charging will require a full cycling charging regime** to get the capacity back up. Basically the same routine as after putting the cells into stored mode or when you first commission them."

That all sounds like lead acid talk to me.

Kurt

Maybe coincidence, the cycling routine required to get full li cell capacity would kill a lead acid battery though. Have a read through the cell manufacturers hand book, the same information is in there for Winston, Thundersky and Sinolpoly, in Chinglish of course but the gist of the information is the same.
Knowledge comes with hands on experience added to book learning, the more hands on experience the more you learn.... well actually discover what you don't know or thought you knew but got it wrong.

T1 Terry

[offgridQLD]

Floating a cell at 3.45v isn't floating it. It's charging it.

Edit: I don't know of any lifepo4 cell that I have played with that will hold 3.4 v rested for long periods.



Kurt