# eSmart-3 solar controller.



## PhillT (May 17, 2011)

Can anyone here assist me in setting the User Defined option up for charging Lifepo4 batteries please?
Some of the terminology is confusing to a newbie ;-)


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## MichaelK! (Oct 22, 2010)

Which one do you have? What is your system voltage? It's MPPT, correct? How many panels do you have, what is their voltage, and how many will you be wiring in series? If it's MPPT, and you are wiring multiple panels in series, you need to pay attention to the max Voc of the controller, adjusted it your winter low temperatures.

There are four broad charging parameters, bulk, absorption, floating, and equalization.

Bulk is the first phase of charging of a depleted battery. The most amps are pumped in at this point. That should be set at 14.2 to 14.6V for a 12V Li battery.

Absorption is the second phase, which starts at about >80% full. That should also be 14.2 to 14.6V for a 12V battery. If there is a time limit setting, select 20-30 minutes for each 100Ah of battery capacity.

Float is the final stage, after the battery is totally full, and a somewhat lower charge is continously passing through to keep it fully charged. Set that at 13.4 to 13.8V.

Equalization is really appropriate for lead-acid batteries, but if it needs to be set, set it to the same as absorption, or 14.2 to 14.6V

For 24V or 48V batteries, just multiply the above numbers by 2 or 4 respectively.


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## PhillT (May 17, 2011)

Thanks for the reply Michael. It is a LiFePo4 12 volt system, 135AH. (Caravan)
The controller is eSmart-3 40 amp.
2 x 36V 170W panels in series.

I have the voltages worked out I think, but the problem is where to put them, and which parameters on the unit are un-necessary and what to set them at because it is not possible to disable them.
The following are the available parameters, and the figures are where my best guess tells me to put them.


Constant Voltage: (14.5?)
Float Voltage: (13.5?)
Boost Voltage: (13.5?)
Boost Charge Time: (no idea)
Bat. O/voltage: (14.6?)
Bat. O/voltage recovery: (no idea)
Bat. U/voltage: (10.8?)
Bat. U/voltage recovery: (no idea)
Max. discharge current: (100A?) 
Maximum charge current: (40A?)

The figures I have filled in are based on the following:
The Solar Controller is 40A
Battery supplier info: (not a lot, waiting for more)
Charge voltage: 14.6
Discharge cut-off voltage: 10.8V.
Max. Discharge current continuous: 100A
Max. Charge current: 100A


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## PhillT (May 17, 2011)

PhillT said:


> Thanks for the reply Michael. It is a LiFePo4 12 volt system
> The controller is eSmart-3 40 amp................


I have since found some more information on this charger, as follows:

a) Constant Current Charging_CC(Bulk Charging) In this stage, the battery voltage has not yet reached constant voltage (Constant or Boost Voltage), the controller operates in constant current mode, delivering its maximum current to the batteries (MPPTCharging). 

b) Constant Voltage Charging_CV( Constant and Boost Charging) When the battery voltage reaches the constant voltage set point, the controller will start to operate in constant voltage charging mode, this process the charging current will drop gradually. The constant charge voltage will increase 0.2V on the basis of constant voltage at 1st of each month, charge time is 60mins. ( The data of boost charge voltage can be set via PC software and APP) 

c) Floating Charging_CF After the constant voltage stage, the controller will reduce charging current to maintaining the battery voltage on the Floating Voltage set point. Charging the battery with a smaller current and voltage on Floating Voltage stage, while maintaining full battery storage capacity.

I think I might be finally getting my head around this charging subject.
I have been trying to figure out how to set the chargers two stages (for LiFePo4), but I am now thinking that the first stage, Constant Current, is not something I have to "set", it is determined by the available power from the panels, up to the 40A max.
If I set the 2nd stage (Constant & Boost) to 14.6V (or a little less, 14.5) and the Float to a lower setting so it doesn't do anything (13.5V) that should be all I need to do.
IF that is the case, my settings would look like this:

Constant Voltage: 14.5 
Float Voltage: 13.5
Boost Voltage: 14.5
Boost Charge Time: 0
Bat. O/voltage: 15V
Bat. O/voltage recovery: Not needed?
Bat. U/voltage: 10.8
Bat. U/voltage recovery: Not needed?
Max. discharge current: (100A?)
Maximum charge current: 40A

Please confirm or correct as necessary.
Cheers.


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## JRHill02 (Jun 20, 2020)

PhillT said:


> Battery supplier info: (not a lot, waiting for more)


The battery manufacturer's charge settings are critical with Lifepo4. Get their info and recommended settings and stay within them. Hi and low voltage shut down, probably no absorption time or a few minutes, never equalize them, etc. Several of the voltages you speak of like constant current and boost may be fine for lead batteries but not necessarily for lithium, esp at the voltages you are considering.


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## PhillT (May 17, 2011)

JRHill02 said:


> The battery manufacturer's charge settings are critical with Lifepo4. Get their info and recommended settings and stay within them. Hi and low voltage shut down, probably no absorption time or a few minutes, never equalize them, etc. Several of the voltages you speak of like constant current and boost may be fine for lead batteries but not necessarily for lithium, esp at the voltages you are considering.


Which one of the above parameters is Constant Current?
Which of the above settings is Absorption?
Which of the above settings is Equalization?

This is where my main confusion is,....none of these settings you talk about is listed in the parameters menu I showed above.

Battery Manufacturers Specs
*SPECIFICATIONS*

Nominal Capacity:135Ah Usable Capacity:135Ah Nominal Voltage:12.8VEnergy:1728WhMax.Load/Inverter Power1280WCharge Voltage:14.6VMax. Continues Charge Current:100AMax. Continues Discharge current:100APeak discharge current:300A (Duration: less than 3 seconds)Case MaterialABSTerminal TypeM8Cycle Life:4000+ timesDimension:L406xW174xH232mmWeight:Approx.12.7kg/28lbsWorking Temperature:Range Charge:0°C--50°CDischarge:--20°C--60°CStorage Temperature:-10°C--50°C


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## JRHill02 (Jun 20, 2020)

The Constant Current thing is really better translated as Continuous Charge and Continuous Discharge. And it can be really important with 12v systems. In other words, the most you can draw on the battery or charge it. The circuit breaker from your charge controller should be 40 amps DC and 100 Amps to the inverter. Do not use AC breakers - you must use DC breakers. Order them on line if necessary. Use 4ga COPPER, not aluminum.

Here is some info from SimlpiPhi for their 12v battery, somewhat similar to yours:









Notice the difference in warranty depending on how deep you draw the battery. Yup, you can draw Lifepo4 100% dead but you *may* lose 2/3 of its full service life. Notice the Absorb is for only 6 minutes. Many charge controllers require at least some absorb to confirm it has completed. With Lifepo4 batteries this should be in Minutes, certainly not Hours like on a lead battery. This is why there is no Equalize voltage or time provided for the Lifepo4 because you do NOT Equalize them, ever. If your controller requires an Equalize setting then set it at the same as your Absorb and for ZERO time. Never initiate an EQ with Lifepo4.

Notice the Lower limit voltages for a Lifepo4 battery drawn down from a full charge to 12.6, 12.4 and 12.0 for the low battery cut-off. 0.6vdc difference!?! Yup, that's for real. This is resting voltage or mostly resting. With lithium batteries its really hard to tell how much battery you have left by looking at the voltage. With lithium its really not a voltage curve but really a straight line until you hit 12v and then it'll drop like a rock (and you don't want to do this).

I'm attaching a link to a well written installation manual for a 12v Lifepo4. If I were you I'd use all the settings from that manual for your battery. The maximum battery voltage (Absorb) is slightly lower but that's OK. If anything being a bit conservative with the Absorb on lithiums is to your advantage in terms of service life.



https://simpliphipower.com/wp-content/uploads/documentation/phi-series/simpliphi-power-phi-3-8-2-9-1-4-730-installation-manual.pdf



Best,
JRH


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## JRHill02 (Jun 20, 2020)

BTW, I like HT but there are better places to ask questions specific to solar and get really good direction. I would recommend Northern Arizona Wind & Sun Solar Forum for you. The forum is not equipment specific and it is sponsored by Northern Arizona Wind & Sun Northern Arizona Wind & Sun | Off Grid & Grid-Tied Solar Power Systems which is the vendor for virtually everything I've bought over 15 years. It's really cool to get experienced feedback from everyone from installers to end users who's hobby it is to fine tune their system.

Lithium batteries have really stirred the technology pot for solar. Not to much has changed for lead batteries for 100+ years. The physics and limitations are still there with lead. So a lot of folks have really dove into the science, the programming and best practices for lithium. And lithium blocks are available all over the place for better or worse. Hopefully your battery gives you good service for a LONG time.

I Absorb my batteries to 55.3v full.(13.8 on a 12v system). They rarely get below 51.8 (12.95). They are as happy as piggies in $***. Here is yesterday's graph and loads are higher than normal because I did a bunch of pressure washing along with the air compressor:


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## PhillT (May 17, 2011)

Thank you JRHill for that detailed answer and added info.

Just to put things in perspective, this system is installed in an RV, used for a total of about 4-6 weeks out of a year, most of this time off-grid, some on-grid, but always using the solar panels as the preferred charging device.

The info in that link is very useful indeed, and raises the question as to why the manufacturer on my battery recommends 14.6 volt charging, while offering a 5 year warranty 4000+ cycles at 100% DOD (5000 at 80% DOD)
They also say that this battery is manufactured to have a lifespan of 10 years, so I am hoping to get close to that.
So, in pursuit of that end, I will be going lower on charge voltage and higher on cutoff voltage, however, the DC-DC charger and the ac-dc charger that I have are both set fixed to 14.6 volts charging. Fortunately, neither of these chargers will be used regularly, so shouldn't impact battery life too much.
The DC-DC 40A charger will only be used when off grid, and there just isn't enough power coming from the 340W of solar.
Similarly, when on-grid but too cloudy, the AC-DC (20A) charger may have to be used.

Your system obviously has sufficient solar available to cater for the majority, if not all your power requirements, which makes for an easy life for your batteries.
Our house has a 3Kw system installed, but we have opted for grid-tie at this point in time because power is still available from the grid at a price not possible with batteries at this point in time. That may well change in the future, but I have been saying that for 15 years, yet it still seems that off-grid systems run just above the break-even point. It is almost as though they set the price of grid power to be just right at that point where it is a fractionally better option to remain connected.
The Sunny Boy 3Kw inverter is 10 years old now, so the time to re-evaluate might be soon. I'm not sure how long these things last, or if they are worth repairing,...things to worry about another day ;-)


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## JRHill02 (Jun 20, 2020)

PhillT said:


> Just to put things in perspective, this system is installed in an RV,


Ah, that's quite a different thing then. So you know, don't put them into a period of non-use with a full charge. Somewhere around 60% would be best.


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## PhillT (May 17, 2011)

JRHill02 said:


> Ah, that's quite a different thing then. So you know, don't put them into a period of non-use with a full charge. Somewhere around 60% would be best.


I certainly did not know that, so thanks for the heads up. I knew they shipped only partly charged, but never asked why. Fifty years of dealing with lead acid, and virtually none of that knowledge applies. :-(


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