Tracer goes to float without charging to full - setting review?

Hi,
I'm having trouble with my installation:
- Tracer6415AN 60A
- 3x 375W solar panels
- 2x 250 AH 12V LiFePO4

I have a request for help with settings, my trouble is that having the battery about 70% charged, after 180 minutes of boost cycle, the solar charger goes to float and does not go back to boost. I have to turn it off at the fuses and then it runs for another 180 minutes. It goes about 50A with 14.4 volts from sun.

My settings currently are as follows:
Over Voltage Disconnect: 14,5 V
Charge Limit: 14.4 V
Over Voltage Reconnect: 14,0 V
Equalization Charge: 14.4 V
Boost Charge: 14.3 V
Float Charge: 13.6 V
Boost Reconnect: 13,0 V

It seems to me that I should increase the Float charge to 13.8/13.9 V. I'm afraid that at 100% charge, at this voltage the BMS will disconnect periodically due to overcharging. I would prefer the Tracer to disconnect the charge and not the BMS.

What should happen.
When the charger wakes up it finds the maximum power point, converts the energy to volts and amps delivered to the battery.
This process continues at maximum panel power until the target, boost volts, is reached, the next stage, boost duration is constant voltage for the boost duration, default 2 hours. After boost duration, float stage.

With a 50 amp charge and 14.3 boost volts, the 500 Ah of battery should be almost fully charged once the target volts is reached, even without boost duration.

How are you determining the 70% SOC?.

General point, there have been reported issues with Tracer units operating near maximum input volts, 138 volts for your unit.
I am guessing your 3 panels are in series, could this be an issue?

Mike

RaVaeL said:

I'm afraid that at 100% charge, at this voltage the BMS will disconnect periodically due to overcharging.

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Your boost setting is too high if you are getting BMS high voltage disconnects.
At 14.4V, it is unlikely that your cells will be equal and within BMS disconnect limits (cell over volt).

I charge to 13.8V. They quickly settle to about 3.35Vpc. I consider this my 10% charged state. I have my float just below where they settle to prevent micro cycling (charge, settle, charge…). I float at 3.32Vpc.

Set your boost lower, like 14V to see if this helps. Then see where they settle in an hour and base your float on this.

70% means nothing. That is subject to interpretation from one device to another.

When you adjust the over voltage or low voltage disconnect/reconnect on a Tracer it will give you a different interpretation of it's state of charge. Pay no attention to this and use your multimeter or shunted coulomb meter. NOTE that will only disconnect at the LOAD terminals, not the battery.

I believe with Lifepo4 you should keep the float voltage 0.1v below the resting voltage after charging without a load.

I have recently bitten the bullet and switched to Victron from Epever as I really like their adaptive absorption feature which will automatically adjust the absorption duration depending on the battery state of charge at sunrise as not to risk over or under charging the batteries. With Epever you have to take note of the voltage before sunrise and set this manually.

mikefitz said:

What should happen.
When the charger wakes up it finds the maximum power point, converts the energy to volts and amps delivered to the battery.
This process continues at maximum panel power until the target, boost volts, is reached, the next stage, boost duration is constant voltage for the boost duration, default 2 hours. After boost duration, float stage.

With a 50 amp charge and 14.3 boost volts, the 500 Ah of battery should be almost fully charged once the target volts is reached, even without boost duration.

How are you determining the 70% SOC?.

Click to expand...

I have this device (Juntek Voltmeter): https://www.aliexpress.com/item/330...o2fra&spm=a2g0o.order_list.0.0.21ef1802fcgC3L and it works quite well. It measures with an accuracy of about 5%. That is, if I have a 100% indication on it, the BMS is going to turn off charging any minute.

mikefitz said:

General point, there have been reported issues with Tracer units operating near maximum input volts, 138 volts for your unit.
I am guessing your 3 panels are in series, could this be an issue?

Mike

Click to expand...

Yes, they are connected in series, but from what I observe, the voltage is usually 100-110V, but I will check it in a few hours to be sure.

MisterSandals said:

Your boost setting is too high if you are getting BMS high voltage disconnects.
At 14.4V, it is unlikely that your cells will be equal and within BMS disconnect limits (cell over volt).

I charge to 13.8V. They quickly settle to about 3.35Vpc. I consider this my 10% charged state. I have my float just below where they settle to prevent micro cycling (charge, settle, charge…). I float at 3.32Vpc.

Set your boost lower, like 14V to see if this helps. Then see where they settle in an hour and base your float on this.

Click to expand...

I noticed that if I reduce the boost, the amperage drops by up to 10A, which is why I set it so high. I'm keen to charge the batteries as quickly as possible, as at this time of year the sun is not yet visible very often (the sky is often clouded over). Did I understand correctly that after charging I should disconnect the solar charger so that it doesn't charge via float and after an hour from then check what voltage the batteries have? I use them all the time, for example for the fridge.

pollenface said:

70% means nothing. That is subject to interpretation from one device to another.

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This corresponds to reality. I use the Juntek voltmeter.

pollenface said:

When you adjust the over voltage or low voltage disconnect/reconnect on a Tracer it will give you a different interpretation of it's state of charge. Pay no attention to this and use your multimeter or shunted coulomb meter. NOTE that will only disconnect at the LOAD terminals, not the battery.

Click to expand...

I do not use this because this version of Tracer does not have a load module.

pollenface said:

I believe with Lifepo4 you should keep the float voltage 0.1v below the resting voltage after charging without a load.

Click to expand...

Ok, I'll unplug all devices for a few dozen minutes and check once the batteries are charged. I'll report back.

pollenface said:

I have recently bitten the bullet and switched to Victron from Epever as I really like their adaptive absorption feature which will automatically adjust the absorption duration depending on the battery state of charge at sunrise as not to risk over or under charging the batteries. With Epever you have to take note of the voltage before sunrise and set this manually.

Click to expand...

Could you elaborate? I have to pay attention to the voltage before sunrise every day? I've been using this Tracer for 4 months now, and I haven't seen the need (except for the float mode problem).

RaVaeL said:

I use them all the time, for example for the fridge.

Click to expand...

Yea, this is a good reason to float above what I recommended. I think folks dehorning have constant use float around 13.6V.

RaVaeL said:

noticed that if I reduce the boost, the amperage drops by up to 10A

Click to expand...

That is troubling.
I would start a thread asking about that, not the float.

MisterSandals said:

Yea, this is a good reason to float above what I recommended. I think folks dehorning have constant use float around 13.6V.

Click to expand...

Ok, thanks. On Tracer manual it even says to set it up at 13,8:

MisterSandals said:

That is troubling.
I would start a thread asking about that, not the float.

Click to expand...

I didn't know that could be a problem. I've read that lowering the charging voltage, say to 13.8V, will cause the battery to charge slower. So I figured this was normal behavior. I will test it again in a few hours and come back with more accurate results. Today is supposed to be cloudless so I should get accurate information.

13.8 to 14.2 is plenty for boost(bulk). 13.4 is plenty for float.

If the charging is going to hold boost voltage three hours after reaching the voltage set point I would stay at the low end 13.8 maybe slightly less.

Unfortunately with the Float setting at 13.5 volts, when the Boost timer runs out it goes to Float and does not go back to Boost. Boost reconnect is set to 13.4. It looks like the problem may be the voltage measurement in the regulator, which is overestimated compared to the actual on the BMS or Juntek device. A possible cause would be the length of the cables between the batteries and the regulator (about 4 meters). Am I right? If so, do I change the settings in the regulator by 0.2 V at each setting?

mikefitz said:

General point, there have been reported issues with Tracer units operating near maximum input volts, 138 volts for your unit.
I am guessing your 3 panels are in series, could this be an issue?

Mike

Click to expand...

Yes, I was correct it it's about 110V:

RaVaeL said:

This corresponds to reality. I use the Juntek voltmeter.

Click to expand...

The juntek looks good, I thought you might have been using the controllers LCD display. I noticed that when I played around with the over and under voltage disconnect/reconnect parameters the displayed battery meter gave a different reading afterwards.

RaVaeL said:

Could you elaborate? I have to pay attention to the voltage before sunrise every day? I've been using this Tracer for 4 months now, and I haven't seen the need (except for the float mode problem).

Click to expand...

Not every day, maybe once every few months depending on the season and your energy usage overnight. I have a lead acid (AGM) bank so my requirements are different, here is an example from a Victron manual for lead acid (I'm unsure about Lifepo4)

I regret that none of my banter here will fix your float/boost reconnect problem :|

The long cable run between controller and battery may be part of the problem, the controller will be seeing a higher voltage than battery voltage. Install instructions indicate cable size and install distance, usually within two meters.

Your methods of determining battery state of charge may be incorrect. The BMS turning off will be due to pack or cell volts being higher than protection values, not necessarily SOC.

I suggest comparing your charged battery with the graph of SOC against voltage, measuring voltage with an accurate meter.
A fully charged battery, with no charge or load should have a voltage 13.35 to 13.55 volts. The actual voltage seems to vary with cell manufacturer.

Also I will repeat my earlier statement, with a charge current of 50 amps into 500Ah of battery at a target volts over 14 volts, the battery will be almost , (well over 90% SOC), fully charged, when the battery voltage reaches target volts.

Mike

mikefitz said:

The long cable run between controller and battery may be part of the problem, the controller will be seeing a higher voltage than battery voltage. Install instructions indicate cable size and install distance, usually within two meters.

Click to expand...

There is no information about it in manual: https://www.epever.com/wp-content/uploads/2021/05/Tracer-AN50-100A-Manual-EN-V3.1.pdf
Only about size.

mikefitz said:

Your methods of determining battery state of charge may be incorrect. The BMS turning off will be due to pack or cell volts being higher than protection values, not necessarily SOC.

I suggest comparing your charged battery with the graph of SOC against voltage, measuring voltage with an accurate meter.

Click to expand...

I am on the beach, can't do it now, but will do it when I go back from travels, in a few months I guess.

mikefitz said:

A fully charged battery, with no charge or load should have a voltage 13.35 to 13.55 volts. The actual voltage seems to vary with cell manufacturer.

Click to expand...

I will check it, but still - floating problem persists.

mikefitz said:

Also I will repeat my earlier statement, with a charge current of 50 amps into 500Ah of battery at a target volts over 14 volts, the battery will be almost , (well over 90% SOC), fully charged, when the battery voltage reaches target volts.

Click to expand...

Yes, it comes 50A from SUN, but I am also using energy through a day, so it's about 30A. It takes about 7 hours to charge 250A (50%) I have started with 55-60% ant now I have 92% (Had to restart controller to hit boost again after 180 minutes)

RaVaeL said:

Unfortunately with the Float setting at 13.5 volts, when the Boost timer runs out it goes to Float and does not go back to Boost. Boost reconnect is set to 13.4.

Click to expand...

If the controller is in float at 13.5 the battery should stay fully charged all day. However every sun up the charge cycle should restart. Otherwise the controller seems defective.

RaVaeL said:

Unfortunately with the Float setting at 13.5 volts, when the Boost timer runs out it goes to Float and does not go back to Boost. Boost reconnect is set to 13.4. It looks like the problem may be the voltage measurement in the regulator, which is overestimated compared to the actual on the BMS or Juntek device. A possible cause would be the length of the cables between the batteries and the regulator (about 4 meters). Am I right? If so, do I change the settings in the regulator by 0.2 V at each setting?

View attachment 87994

View attachment 87995

Click to expand...

a SoC of 54% and a remaining Ah of 134Ah doesn't add up to a 500Ah battery bank.

Kemills1 said:

a SoC of 54% and a remaining Ah of 134Ah doesn't add up to a 500Ah battery bank.

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Yes I set voltometer for lower- 450 AH, to make sure that I did not drain it I have two batteries like this: https://pl.aliexpress.com/item/1005002392267354.html

RaVaeL said:

Yes I set voltometer for lower- 450 AH, to make sure that I did not drain it I have two batteries like this: https://pl.aliexpress.com/item/1005002392267354.html

Click to expand...

i see, but setting the capacity to 450ah is not going to help with the % accuracy. With the boost voltage at 14.3V, what does the charge current drop to before the Tracer goes to float? LiFePo4 cells shouldn't need 3 hours of absorb.

Kemills1 said:

i see, but setting the capacity to 450ah is not going to help with the % accuracy.

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Of course, but that's totally not the point here. The point is for me to visually see that it is 0% when there is still energy in the battery. This allows me to not drain the battery completely. But that's a completely different issue and not what this topic is about.

Kemills1 said:

With the boost voltage at 14.3V, what does the charge current drop to before the Tracer goes to float?

Click to expand...

BMS (cell overvoltage) cuts off the charge, but depending on the intensity of the sun, max ~40A

Kemills1 said:

LiFePo4 cells shouldn't need 3 hours of absorb.

Click to expand...

Then what should I do to charge the 500A battery as soon as possible to 95%-100%, given that there are usually 3-4 hours of sunshine per day, (then charging at 14.3 is 52A) there are rarely any clouds at all?

RaVaeL said:

BMS (cell overvoltage) cuts off the charge, but depending on the intensity of the sun, max ~40A

Click to expand...

Have you a cell imbalance? What is the cell cut off voltage set to?

You mentioned earlier a voltage discrepancy between the Tracer and the battery monitor. At a charge current of 14A, you’re getting a 0.2V difference. Have you confirmed the voltage differences with a DVM? Perhaps your cables are too thin and the Tracer is going to Absorb voltage too soon. Increasing the the absorb voltage is not going help as you will get BMS disconnects when the charge current drops. If you can’t reduce the cable losses (thicker/shorter cables) you will need a SCC with remote voltage sensing.

Kemills1 said:

Have you a cell imbalance?

Click to expand...

I think all cell are balanced:
First battery:

Second battery:

Kemills1 said:

What is the cell cut off voltage set to?

Click to expand...

Kemills1 said:

You mentioned earlier a voltage discrepancy between the Tracer and the battery monitor. At a charge current of 14A, you’re getting a 0.2V difference. Have you confirmed the voltage differences with a DVM?

Click to expand...

At 14.1V and 40A charge, I have 13.8V on the cable going to the battery on the Tracer side, and 13.4V at the battery and 13,38 on 12V installation side.

Kemills1 said:

Perhaps your cables are too thin and the Tracer is going to Absorb voltage too soon. Increasing the the absorb voltage is not going help as you will get BMS disconnects when the charge current drops.

Click to expand...

It helps in the sense that I'm now at 14.1V and maxing out at 40A, and at 14.4 charging I'm at 52A. So I charge the battery faster.

Kemills1 said:

If you can’t reduce the cable losses (thicker/shorter cables) you will need a SCC with remote voltage sensing.

Click to expand...

It looks like I will have to move the batteries closer to the Tracer. For now, if I have low charge batteries, I will increase the charge current.