Best mppt charge controller for LiFePO4?

[Pappion]

Is that because the late-waking-up MPPTs see the voltage of the already-wakened MPPTs already actively charging the battery rather than voltage of the battery itself?

I think you got it. It's a good question for them. My Epever spec: Boost Reconnect Charging Voltage, 13.2v

FYI: My old camper had just a 100W panel and 2 size 31 AGM. 2 hrs of absorption at 5.5A was not enough for lap top use and furnace blower. I would retrigger Boost by throwing a towel over the panel and use the laptop to bleed off the AGM surface charge. At 12.9v I could pull off the towel and Boost would start again.

 

[fafrd]

I think you got it. It's a good question for them. My Epever spec: Boost Reconnect Charging Voltage, 13.2v

FYI: My old camper had just a 100W panel and 2 size 31 AGM. 2 hrs of absorption at 5.5A was not enough for lap top use and furnace blower. I would retrigger Boost by throwing a towel over the panel and use the laptop to bleed off the AGM surface charge. At 12.9v I could pull off the towel and Boost would start again.

I just heard directly from Epever that syncing multiple Tracer AN MPPT chargers to the same charge mode requires an extra module called PAL-ADP-50AN.

 

[Pappion]

I am not sure you need this. It can be added later.
MT50 uses the same port, so you can't use both.
A good battery shunt monitor would be better than multiple MT50s.
They say real time monitoring, but are you going to leave your laptop connected?

Pal pdf
PAL data sheet

4. Power Switch Control turns them off and on based on 3-5 amps. But these are system amps, not battery amps.
My 90W laptop (7.5A max) would mess with that. Maybe that's OK too.

Please let us know how it works out.

 

[fafrd]

I am not sure you need this. It can be added later.

I’m not sure it’s absolutely needed either. The issue seems to be when one Epever MPPT ‘wakes up’ with first solar power when other MPPTs have already charged battery above Float Charging Voltage but below Boost Charging Voltage. The Neely-awakened MPPT will apparently wake up into Float mode in this situation and the only way to get it to synchronize with the other MPPTs is through use of the PAL-ADP-50AN.

I’m not sure how big of a problem this will be for me (though my third MPPT will become unshaded and ‘wake-up’ much later in morning than the other two - late morning close to peak radiance).

MT50 uses the same port, so you can't use both.

Haven’t figured out if I’ll need an MT50 yet (or if I’ll need to leave it connected once settings have been configured).

A good battery shunt monitor would be better than multiple MT50s.

I’ve not yet understood whether there is any way to add Victron-like battery intelligence using a smart shunt tool an Epever MPPT system.

They say real time monitoring, but are you going to leave your laptop connected?

I was interested in the PAL-ADP-50AN purely to synchronize battery charging mode between multiple Epever MPPYs charging in parallel. Monitoring is not really a big concern for me. If there is an easy way to check that the system is ‘operating properly’ from inside the house without having to go down to the basement, that’s all I really need as far as ‘monitoring’.

[quote{
Pal pdf
PAL data sheet

4. Power Switch Control turns them off and on based on 3-5 amps. But these are system amps, not battery amps.
My 90W laptop (7.5A max) would mess with that. Maybe that's OK too.

Please let us know how it works out.
[/QUOTE]

Will do.

I haven’t settled on Epever yet but it’s becoming a solid contender.

Now that I’ve found a solution at 2S / 150V that will give me close to optimal performance during my partially-shaded mornings, I’m evaluating a few alternative suppliers including:

Tier-1
-Victron
-Magnum
-Schneider
-Outback
-Midnight

Tier-2
-Epever
-Sigineer
-WZRELB

I’ll report back on relative capability and cost when I’m done with my research (and still open to other brands I should be considering for charging LiFePO4).

 

[DerpsyDoodler]

I was getting set to jump on an Epever MPPT charge controller but between reading some of the struggles members have had getting their Epever MPPTs to not overcharge their LiFePO4 batteries and this warning I found in this Epever document: https://www.epsolarpv.com/upload/file/1812/EPEVER Tracer AN_Main_Pres.pdf

“High current series doesn’t have self-activation function for lithium-ion battery, thus it cannot be used with lithium-ion battery.”

I’m having second thoughts about Epever and broadening my search for the easiest/best MPPT charge controllers for LiFePO4 batteries.

Specifically, what I am looking for:

8S/24V
60A (or possibly 50A)
100V minimum (but ideally 120V or 170V)

As easy/failsafe to use when charging LiFePO4 as my 10A AC charger (specifically not having to worry about either overcharging or wasting solar power when the battery is discharged enough to take charge).

Looks like that’s for the AN series. IIRC the BN series is the one Will recommends. I have a couple I plan to test for my system in a few days. I bought a remote panel, too. Makes it easy to program them. I’ll let you know how it goes.

 

[fafrd]

Looks like that’s for the AN series. IIRC the BN series is the one Will recommends. I have a couple I plan to test for my system in a few days. I bought a remote panel, too. Makes it easy to program them. I’ll let you know how it goes.

Thanks. I was leaning towards a BN as well until Epever Support wrote me this:

‘BN series do not support lithium battery, AN series support lithium battery.’

And this (about the Epever AN presentation I found claiming ‘high-current’ chargers could not support lithium batteries):

‘That presentation was made in 2018, it supports lithium battery now.

To be sure you get the new version, you can check with the vendor and ask them whether the label on the package box has
i. 12/24/36/48
or
ii 12/24/36/48/Li

The 'Li' means it supports lithium battery.’

So I’m now focused on the Epever 6415AN 12/24/36/48/Li’

But I’m interested to hear your experience with a BN - what size do you have?

 

[DerpsyDoodler]

The 40a. It supports lifepo4.

 

[fafrd]

The 40a. It supports lifepo4.

Odd that Epever would tell me the BN series does not support LiFePO4 - maybe they have a corporate strategy to upsell?

I’m also struggling to u detest and what characteristic of the ‘High-Current’ AN series bid not support Lithium batteries which has since been corrected.

Based on your input, I’ll keep the BN on my shortlist.

What battery are you charging?

 

[DerpsyDoodler]

12v DIY aluminum prismatic cell battery.

 

[fafrd]

12v DIY aluminum prismatic cell battery.

I’ll be interested to hear how your testing goes. When I thought I needed 3S, I could not use a BN, but now that I’ve settled on 2S (150V) the Epever BN series is a viable option for me again...

I may write back to Epever and ask why they state the BN series will not support LiFePO4 - is there any reference to Lithium or LiFePO4 in the manual?

 

[snoobler]

Given that LFP is essentially a drop-in replacement for FLA/AGM/GEL, it typically works even without native LFP support. The only danger is if the default voltages are too high.

The BN doesn't have a Li charge profile, but it has a user defined battery type.

BN will work with LFP. It just doesn't have a canned program for it. For every single LFP-specific program I've seen, I have found something I didn't like, and would opt to go with user-defined in all cases.



With the user configuration, you could program the controller for almost any kind of chemistry.

 

[fafrd]

Given that LFP is essentially a drop-in replacement for FLA/AGM/GEL, it typically works even without native LFP support. The only danger is if the default voltages are too high.

The BN doesn't have a Li charge profile, but it has a user defined battery type.

BN will work with LFP. It just doesn't have a canned program for it. For every single LFP-specific program I've seen, I have found something I didn't like, and would opt to go with user-defined in all cases.

View attachment 41402

With the user configuration, you could program the controller for almost any kind of chemistry.

If that’s all they mean by ‘Support Lithium’ then that’s pretty silly.

From what they sent me, it seems the AN does have a Lirhium battery page with it’s own specific settings, but if the exact same thing can be achieved using USR settings, that’s just as good.

I suppose the only thing to be sure of is what conditions cause the SCC to ‘forget’ the battery type, if/how it ‘auto detects’ battery type, and what it defaults when it cannot recognize battery type.

But assuming it can be configured to be safe for LiFePO4 in all circumstances, I agree Lithium support may really be no more than ‘our-of-the-box’ lithium support...

For what it is worth, attached is the settings Epever sent me as their recommended LuFePO4 settings for AN Series.

 

[snoobler]

If settings were ever lost, it would likely revert to the default. The default is Sealed, and the only thing of concern on that one is the 13.8V float. Should be 13.6V max.

I can't read the attachment you included.

 

[DerpsyDoodler]

If that’s all they mean by ‘Support Lithium’ then that’s pretty silly.

From what they sent me, it seems the AN does have a Lirhium battery page with it’s own specific settings, but if the exact same thing can be achieved using USR settings, that’s just as good.

I suppose the only thing to be sure of is what conditions cause the SCC to ‘forget’ the battery type, if/how it ‘auto detects’ battery type, and what it defaults when it cannot recognize battery type.

But assuming it can be configured to be safe for LiFePO4 in all circumstances, I agree Lithium support may really be no more than ‘our-of-the-box’ lithium support...

For what it is worth, attached is the settings Epever sent me as their recommended LuFePO4 settings for AN Series.

Make sure the AN isn’t positive-grounded. Ive seen listing that mention some are.

 

[DerpsyDoodler]

Yeah, Victron is great if you’ve got the coin, but I should have specified ‘within the budget category’.

Epever seems to have a pretty solid following here on the Forum - are there any other of the budget MPPT vendors that deliver close-to-Victron/Outback/Midnight performance at prices that are much friendlier to the pocketbook?

Quality and reliability are one thing (and a risk I’m willing to take for appropriate savings), but lack of support for LiFePO4 or too much complexity in getting a LiFePO4 battery to charge correctly, are the main things I’m concerned about.

Again, the model I have is his well and easily my cheapo 10A 8S LiFePO4 AC charger works - plug it in and it does it’s thing.

If you go with the bn, make sure you get at least one of the remote terminals. It simplifies the configuration process.

 

[fafrd]

If settings were ever lost, it would likely revert to the default. The default is Sealed, and the only thing of concern on that one is the 13.8V float. Should be 13.6V max.

Good to know - thanks.

Can Sealed Float be set to 13.6V to avoid a possible issue, even in that case?

And if not, how bad is having Float at 13.8V (3.45V / cell) instead of 13.6V (3.4V / cell)?

I can't read the attachment you included.

Funny, it’s an image I attached and I can see it fine. Are there any tricks to use when attaching a file or an image?

 

[fafrd]

If you go with the bn, make sure you get at least one of the remote terminals. It simplifies the configuration process.

Yes, that much I had understood.

Still unclear whether the AN Series also needs a remote terminal or it can be serviceably configured through the screen and entry buttons.

Some of these devices have ‘hidden parameters’ that can only be accessed through a remote terminal, so that’s something I’ll want to understand.

 

[snoobler]

Good to know - thanks.

Can Sealed Float be set to 13.6V to avoid a possible issue, even in that case?

And if not, how bad is having Float at 13.8V (3.45V / cell) instead of 13.6V (3.4V / cell)?



Funny, it’s an image I attached and I can see it fine. Are there any tricks to use when attaching a file or an image?

I don't think you can change any of the settings unless you use user-defined.

If the battery spent many hours over many days in that condition, it would risk a slight over-charge every day, but charging only to 14.4V gives a little leeway.

 

[fafrd]

I don't think you can change any of the settings unless you use user-defined.

Perhaps I’m wrong, but I was under the impression that all settings could be modified within specific battery-type settings pages.

If the battery spent many hours over many days in that condition, it would risk a slight over-charge every day, but charging only to 14.4V gives a little leeway.

Maybe I’m not correctly understanding how these chargers work, but I thought ‘Float’ was the threshold that caused the charger to renter Bulk (CC) mode.

If that’s correct, you’d start charging in CC mode below 13.8V (3.45V/cell) instead of below 13.6V (3.4V/cell).

Charging in CC more from that fully-charged starting point would quickly hit the Sealed Boost Voltage of 14.4V (3.60V / cell) which would then switch to CV mode at that same voltage for whatever minimum time has been set (120 minutes if the default Sealed setting cannot be changed).

Is that really so much more damaging to a LFePO4 battery than that exact same cycle but under 13.6V (3.4V/cel)?

 

[snoobler]

Float is the voltage at which the charger will maintain the battery. If loads pull the battery voltage low, the charger will provide current until the battery voltage raises back to float. When the load is removed, voltage rises, and current drops until the float voltage is maintained.

It's called this because of lead-acid conventions. In order to maintain full charge, they must be "floated" to the float voltage, or their voltage drops, and they slowly start bleeding off their own charge.

You're thinking about the "boost reconnect charging" - the level at which the charger will transition from float mode (trying to maintain 13.8V) to boost mode and repeat the CC/CV charge cycle. In the sealed program, if the charger can't maintain 13.8V and loads pull the voltage to 13.2V, the charger leaves float and bulk/absorp/float again.

With LFP, a battery at less than 100% SoC can still charge at 3.4V. A LFP held at 3.4V will continue to absorb charge until about 95% SoC. Hence most battery manufacturers recommend they not be floated above 3.4V. At 3.45V, likely to hit 100% and beyond.