Epever Tracer 4210AN never charges past 13.8V

mrp

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I have a home-built campervan with a 200Ah LiFePO4-battery, a 400W-panel and Epever Tracer 4210AN. I've never installed a solar system before, so I have absolutely no experience, and the little knowledge I have comes from Youtube. The label on the battery clearly states that the max voltage is 14.4V, but the charge controller never charges the battery past 13.8V.

I understand that keeping the battery at 13.8V is good for the health of the battery, but there are times when I wish I could charge the battery to 100%. I'm using the default settings in the charge controller, as they appear to be correct, but maybe I'm missing something.

Does anybody know how I can make the charge controller charge the battery to 100%, at least occasionally when I need it? The Float Charging Voltage is 13.8V, so my assumption is that the charge controller is more or less constantly in float charging. Can I safely change the float charging voltage to 14.4V, or will that damage the battery?
 

brum

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The charging will go automatically in boost charging mode (14.4V) once the battery has been discharged to a certain voltage. Both the threshold voltage, the boost charging voltage, and the float charging voltage are configurable.

By the way, 13.8V is not a low voltage for a LiFePo4 battery. You will still get close to 100% charge, but it will be slower. I have a similar setup with the AN1206. The battery capacity is 100Ah, the charge voltage is 13.8V for 1 hour, the float voltage is 13.4V, and the re-boost voltage will be 13.2V. These are kind of recommended voltages for keeping the battery charged to 90-95 percent.

Google LiFePo4 SOC voltage and see what you'll find. A quick summary is that the LiFePo cells stay at ~3.2V from almost discharged to an almost fully charged state.
 

mikefitz

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You need to confirm that the problem is with charging setup of the controller or with the battery BMS preventing charge over 13.8 volts.
I suspect one or more cells are reaching high volts protect and shutting down the charge path. Monitoring charge current may confirm this.
I assume your 200 Ah battery is a complete purchaced battery, do you have a link to the battery?

It's possible the battery cells are not balanced, this is not unusual with some brands of battery.

13.8 volts will charge the battery fully, perhaps taking longer for the final few% than a higher voltage.

What settings are used on the Tracer controller?

My recommended settings for a modest campervan solar system like yours,

Boost volts 14.0
Float volts 13.4
Boost reconnect 13.2
Boost duration 10 minutes

Equilisation volts same as boost volts
Equiisation duration 0

Temperature compensation disabled

With a 400 watt solar panel, typical charge current will be in the order of 20 amps, so by the time the Boost volts of 14.0 volts is reached, the battery will be charged. I fact any volts over 13.8 will do the same.

Mike
 

12VoltInstalls

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Can you screenshot your parameters on your laptop/computer or list them from your phone app?
(You have to open the controller parameters screen and select ‘read’ to pull up the actual settings)

400W is probably going to deliver 25A charging, tops. In good sun full charge should be achievable daily.

Depending on your latitude a flat-mounted panel may reduce the potential output a bit.
 

mrp

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Thank you for all the replies. Here is a link to the manual for the controller. I have not changed anything, so I'm using the default settings shown on page 17. I get the impression that I can consider 13.8V to be fully charged and that I don't need to do anything?

I bought the battery used, so I can't be sure about the condition or the exact specifications, but the label says nominal voltage 12.8V and max voltage 14.4V.

Is there a specific reason the float charging voltage is set to 13.8V as default? Can I safely change it to 14.4V and rely on the BMS to shut off charging if necessary?
 

12VoltInstalls

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Can I safely change it to 14.4V
Yes, but no - with parameters set as mentioned at 14V make sense
and rely on the BMS to shut off charging if necessary?
No- think of the bms as a protective device. A life jacket if the boat is sinking. It’s not a charge controller- it does charge conditioning work.

The settings above posters listed seem reasonable- I’m not a lithium user, but those are frequently posted ranges.
 

MisterSandals

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I have not changed anything, so I'm using the default settings shown on page 17. I get the impression that I can consider 13.8V to be fully charged and that I don't need to do anything?
You at the very least need to set the battery type to the correct chemistry (LiFePO4 or something as close as possible word-wise).

mikefitz is spot on for settings. Give it a go and see how it works. You can tinker with settings if as you learn, and can learn as you tinker.
 

mrp

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mikefitz suggested lowering the float from 13.8 to 13.4 and lowering the boost from 14.4 to 14.0. Could you help me understand the reasoning behind this?
 

MisterSandals

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mikefitz suggested lowering the float from 13.8 to 13.4 and lowering the boost from 14.4 to 14.0. Could you help me understand the reasoning behind this?
Most of us subscribe to this chart with variations based on how one uses their batteries (full-time continual use vs weekend warrior).

I am more of a weekend warrior in that i do not have significant continuous draws like a fridge so i can be even more conservative. I charge to 13.8V (3.45Vpc) and consider that a gentle 100% charge. My cells quickly settle to around 3.35Vpc so i float just below that (3.33Vpc) to prevent micro cycling (charge, settle, charge, settle...).

If you have continuous use and want to maximize battery storage, mikefitz's recommendations address that. You can experiment and find what works with YOUR cells and with YOUR use case.
LiFePO4 SoC chart.png
 

Browneye

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Unless you have a MT50 remote display, or the EPEver RS485 usb cable to a laptop, you cannot change the controller to lifepo settings.
I recommend the latter - it make setting up and tweaking it an absolute breeze.

How are you observing or setting charge control parameters?

Mike's settings are fine - if your bms regularly shuts down charging then you may need to reduce the boost voltage. 13.8V is quite high for float, but if you're using loads and the panels are charging daily, it's likely okay. 13.6V is generally accepted for a float voltage when supporting loads/usage.

13.8V will work as a boost voltage but the battery will likely not reach full charge before the controller switches to a lower float voltage. For a low boost voltage a longer duration is needed - the controller will reduce current as the battery reaches full charge.

Setting boost to 14.1 or 14.2 will charge the battery faster - full current - and no duration is needed, can switch to float when the controller finds the battery at that voltage. I believe 10 minutes is the minimum boost duration allowed by the program.

Equalization should be set to zero, and no temperature control unless you're going to utilize the optional temp sensor and attach it to your battery.
 

mikefitz

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To help with the discussion.

The actual condition of the battery is not known and a 'nominal voltage label ' of 12.8 volts is strange. It would be useful to determine,
a) why is the battery not charging above 13.8 with a charger default boost of 14.4..
b) the health of the battery, does it have a useful capacity.

Referring to the chart, over most of the working range the output is 13.2 volts, slightly less towards empty, and slightly more towards full.

If you measure the voltage of the battery with an accurate meter after a full charge and a rest of a few hours with no load or charge, it will read 13.35 to 13.55 volts. (A variation exists between different cell manufacturers) .

The controller default settings are for lead batteries and although will work with lithium batteries are not ideal. The long term effect will be shortened service life and charging issues where the cells are not in balance. As Chris suggests you need to set up user values.

Other factors that may be causing issues.

We don't know the typical daily solar yield and the daily loading on the battery. There may not enough solar to charge the battery.

If the controller is installed some distance from the battery with undersized cables, voltage errors can confuse the charge process.

Mike
 

mrp

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I haven't actually tried to change the settings yet, so I didn't know that the MT50 or the USB-cable was required for that. I'm going to order the USB-cable and experiment a bit with the settings. Thanks again!
 

brum

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On the 1206AN you can do that from the controller itself. It is a lot of clicking and is not user-friendly, but you can change quite a few parameters. Last I recall was that I switched something there to get it working properly with my gel battery.

I suppose the need for MP50 is to be able to do that in a user-friendly way.

Check the manual to avoid getting something that you may not need.

OK, ignore that. Just checked the manual and you do need a PC connection/MT50 for setting the voltages.
 

Substrate

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I have a home-built campervan with a 200Ah LiFePO4-battery, a 400W-panel and Epever Tracer 4210AN. I've never installed a solar system before, so I have absolutely no experience, and the little knowledge I have comes from Youtube. The label on the battery clearly states that the max voltage is 14.4V, but the charge controller never charges the battery past 13.8V.

That can happen, since you can fully charge a battery to capacity if the CV is anywhere from 3.45v / cell to the commonly accepted 3.6v / cell.

The only difference to reach full capacity charge is time. At 3.45v / cell (13.8v total) it will take longer to reach 100% capacity.

Since we are not dealing with a steady-state AC charger, but irregular sun, there is the distinct possibility of walking your full capacity in slowly without ever exceeding 3.45v/cell, especially if very minimal discharge is placed upon it.

So the question is, are you "daily cyclic", or do you have plenty of time between uses with minimal discharge and weak/cloudy sun? So it all depends.

I understand that keeping the battery at 13.8V is good for the health of the battery, but there are times when I wish I could charge the battery to 100%.
That is the wrong understanding generally, now that we know that any CV between 3.45v to 3.6V / cell will accomplish a full capacity charge - the only difference being the time to do so.

In fact, 13.8v (3.45v / cell) if held for long periods of time, will try to push the cells LiFePO4 past a full charge and premature aging / damage results. The only reason people don't notice this a lot, is that they are discharging the battery at regular intervals. But there are those that have tried to use 13.8v hanging off regular power supplies thinking all is ok - until weeks later when it all goes awry. Strictly speaking, the so-called tail-current is allowed to go to zero amps (takes a long time though), and LFP does not like to be held at a voltage of 3.45v or more with no current flowing. The cathode becomes unstable.

Does anybody know how I can make the charge controller charge the battery to 100%, at least occasionally when I need it? The Float Charging Voltage is 13.8V, so my assumption is that the charge controller is more or less constantly in float charging. Can I safely change the float charging voltage to 14.4V, or will that damage the battery?
Do not do that. If anything, change the float voltage to 13.5v. (13.55 ok) This gets you away from the "knife-edge" setting where if given a chance, LFP at 3.45v (3.4/cell is a bit hairy too) will try to fully charge - albeit very slowly. Below that voltage, LFP won't try to fully charge.

So "daily-cyclic" people tend not to see the problem, but if you are a weekend warrior with plenty of time in the sun, even at low total voltage of 13.8v, and irregular sun exposure, you could be fully charged already.

A discharge capacity test will confirm this or not for you.
 

mrp

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Apr 19, 2022
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So I bought the USB-cable, and I tried to follow the advise from all of you. These are the settings I'm currently using. From what I understand, 13.4V is close to 100% charged, so having a float voltage at 13.4V is fine. Any input?
 

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Browneye

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So I bought the USB-cable, and I tried to follow the advise from all of you. These are the settings I'm currently using. From what I understand, 13.4V is close to 100% charged, so having a float voltage at 13.4V is fine. Any input?
Which battery type?
For lifepo4 use the PARAMETERS\CONTROL PARAMETERS\LITHIUM BATTERY TYPE - then READ your settings to edit them.

The default settings can be tweaked a little but work fairly well depending on personal use.
13.4V float is good, or can be 13.6V for service loads - the control will ramp up current when loads are demanded.

Watch your actual battery voltage level - the SCC reads it with any charge current on top. Mine always reads higher when charging.
 
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