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Best mppt charge controller for LiFePO4?

fafrd

Solar Wizard
Joined
Aug 11, 2020
Messages
4,188
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).
 
There are very few complaints about Victron reliability. Most of the complaints are the upfront expense. Pay once, cry once. Victron's integration across their landscape is excellent.

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.
 
I use a Midnite SCC, it can handle the LFP but it does NOT have a native profile for LFP but being highly programable it works fine and this is a $1000 USD +/- SCC. Victron is also a Top End product which are highly programable but also not cheap being Tier-1 product. EPEver is a Respectable Value Tier-2 product, again many people use them with great success.

Quite often (non PC moment) it is a User - Device interface malfunction where a person thinks they know what they are doing muff up the settings. "Some" people always seem to think they know more than the designers & engineers of these systems but aren't.

IF I was building my system TODAY with what is available on the market, I would probably go with Victron Family, then SolArk or Growatt. For a Modular mode, with separate SCC(s) Inverter/Charger I would consider EPEver for a "Value" system or Victron but modular.

I do really like the Midnite BUT the company is STALE & Static for the most part. Sure they are developing things but it is the slowest dev process seen in ages. The Company is NOT what it was 6 years ago when they were a Top Leader in their segment.

Thing to consider when looking at equipment. Look at how progressive (Active) the company is with Product development & support.
Do they release products on a regular basis ?
Do they issue regular firmware updates for their products ?
Do they have an Active Support System / Bulletin Board / Forum with people exchanging information, tips. I mean Active with several postings & responses per day, not just a blurp a week or two)
Do they have Good Readable Documentation with plenty of background information? (Look at Victron, Samlex DOCS for example)
Are they popular - As in, are there many users of the equipment that can be secondary support ?

!!! You NEVER want to get stuck with a product that can be orphaned, so you want a company that has been around and is established with a good reputation that has a history of supporting their hardware over the years. One way to see if they do that, is by looking to see if they update firmware/patches & manuals for products over the years which shows commitment to support longevity. Tier-3 Value gear is where this usually fails the acid test.

Do not be fooled by Promotion/Advertisements either.
Take Renogy for example, they spend HUGE on ads, promos all nice glossy & shiny to draw in folks, it works too.
There are many people who are OK with their Renogy purchases BUT the complaints & issues on support, product quality and even DOA out of the box issues are Very High ! They are Tier-3 Value product but with a Glossy face painted on it. I can not ever recommend anything Renogy to anyone because I have read more than enough complaints & issues to know better than to foist that stuff on anyone. SOME WILL ARGUE That it is great "for them" and fine, glad it worked out for them, they got lucky or the gear is just good enough for them to be happy with it.
 
While I haven't owned any Renogy products, I agree that they are tier 3. Their DC-DC/MPPT device sounds so great, but under the hood, not so great.

Go Power! is somewhere in the tier 2/3 range. I do have Go Power! devices in my trailer and they have been solid, so that's why I would even consider them in tier 2. They don't have the depth/breadth of Victron, so that nudges them towards tier 3.
 
I totally agree with Steve_S and HRTKD's observations.

I was not able to see the makeup of your system, (panels, batteries and daily usage) but my main feeling summed up, is to protect my $X,XXX worth of batteries and maybe $X,XXX for items connected to those batteries, an extra hundred or two is a small investment for that insurance.

My off-grid systems go back over 20 years... Morningstar's pre MPTT and port MPTT, early imported units and ALL of those units are sitting on my mantle. I call it my wall of shame.

I've finally settled on Midnight Classics. I bought second Classic for my backup system. Never a surprise, always worked.

But I also agree 100% with Steve_S's statement about Stale and Static. Only thing new, is the price has popped up $400....

Lately I've been building remote site's (on my property and for neighbors) using the Victron Smart controllers and Inverters.

I am totally impressed with the integration and expansion features in their systems.

A neighbor had 10 panels running with a 30amp victron. He came across a great deal on another 6 panels, but they were totally mismatched with his current set of panels.

2 days later Amazon delivered a 20amp Victron controller and a $39 Victron Smart Sense Controller. In 15 mins both controllers were networked and charging his battery bank.

And, he got both low temperature charge protection and monitoring battery voltage AT the battery terminals, in the deal.

Great stuff..... good luck with your system.
 
Appreciate everyone’s comments.

And yeah, Renology is an example of a company/product that will never interest me - all marketing, no technology. I’m only interested to purchase charge controllers from companies that designed them themselves (and can support them).

And among the value/Chinese Tier-2 brands, Epever seems to be a real company as does Reliable (very happy with my Reliable PSW inverter). Are there any others? Sigineer seems to be a real company and many marketing facades like PowerMr are reselling those Sigineer MPPTs in this country: https://www.amazon.com/PowMr-MPPT-S...ocphy=9032080&hvtargid=pla-915535039822&psc=1
I have no idea whether Sigineer has any kind of track record or reputation here on the forum.

I’ll need 4 MPPTs for my system, so cost is a concern. But OffGridGuy raises another concern - I need to be sure these MPPTs will play nice together.

I’d read that using multiple MPPTs to charge the same battery is not an issue, as long as they share the same settings (and even if they come from different manufacturers), but I better look into that more closely.

The fact that Victron MPPTs can be networked together so the work in concert is attractive if it is needed, but would 4 (non-networked) MPPTs work together just as seamlessly?

I can afford to take some risk with these 4 MPPTs because this 4.5kW array will only be used to offset some self-consumption and will not be in the critical path. My main concern is that I don’t want a charge controller that I need to monitor constantly for fear that it will overcharge my LiFePO4 battery.

The BMS provides protection against that as well, but some of these stories of new Epever owners having to watch their new charge controllers and intervene before they overcharged have me spooked. And then there is the statement by Epever that their new ‘high current’ MPPTs will not support Lithium Batteries (need to get to the bottom of what that means, exactly).
 
I just looked over the Victron MPPT product lineup. D*mn nice but d*mn pricey.

I could hook up a 4S1P string to their SmartSolar 250/70 MPPT, but for $736, the SCC would be costing me 123% of the cost of the panels.

I have a problem paying more to capture the solar energy than to generate it in the first place.

If I go to the extreme of forming 5 2-panel strings from my 10 450W panels (2P), I can get by with 5 100V 30A Epever MPPTs, which run $90 each, or $450 all-in.

So that’s the kind of budget I’m comfortable with (MPPT costing ~30% of panel cost).

I don’t see any other budget MPPTs that will support a 4S string with 200V<Voc_max<250V (yet), but an Epever Tracer 6415AN can handle a 2P2S string and should perform about as well as the Victron SmartSolar 250/70 for $240 (1/3rd the price),

Of course, I’ve got to confirm with Epever that the 6415AN will charge LiFePO4 first.

But between that and the new Reliable 60A / 170V MPPT which is currently $240 but can be found for as little as $150 if you are patient, it seems like I should be able to find a relatively reliable solution for under $450 for the full 4500W of panels.

Any other vendors on this budget range I should be keeping my eye on (I’m in no rush)?
 
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I've only built up Victron systems using 2 Victron MPPT controllers.

The Victron site states 'two or more controllers', so I'd assume....

An important thing to remember - Is that with the Victron Smart Sense, the charge controlling voltage, for both controllers, is sensed at the battery terminal.

If you have two separate random charge controllers connected to the same battery, each is independently trying to regulate the battery, sensed at each controller's input. (And that voltage drop will change, as a function of how much current that controller is actually producing at that moment).

This ignores voltage drops in connecting cables including any corrosion that may have crept in since last winter.....

I'm surprised that almost all Charge controllers lack this ability (except the Midnite's WizBang).

With old AGM and flooded systems, a few hundreds of a volt didn't mean much, but Lithium is a whole different game.

I've actually added the Smart Sense module to all of my Victron controllers.... the low temp charge inhibit is worth the $39 alone.

Again, I understand your price requirements.... and good luck with your system !!!!
 
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On a strict interpretation of the subject line, I would argue that any SCC that does not natively support cold-temp charge protection is out of the running. Victron does. Others might, but I'm not familiar with them.

The best way to save on SCC cost is to increase bank voltage. If you need 4X SCC, you really need to ask yourself if 24V is right for you. I have 6kW of panels, and I have one SCC. The cost was about 35% of the cost of the panels. 48V system.

Those were NEW prices of course. I'm not comparing a new SCC to cheap used panels.

Of course, I’ve got to confirm with Epever that the 6415AN will charge LiFePO4 first.

But between that and the new Reliable 60A / 170V MPPT which is currently $240 but can be found for as little as $150 if you are patient, it seems like I should be able to find a relatively reliable solution for under $150 for the full 4500W of panels.

What do you base that on? $150 for the full 4500W of panels? You need to ask yourself if you're being rational and not letting your desire to pay less influence your thinking. You state that you can get 60A for $150, which will only get you about 1600W. But you somehow conclude that you would be able to get 3X that for the same price?

You need upwards of 165A to ensure you can utilize the 4500W for charging a 24V battery. I'm using 3.4V/cell as the bulk of the charge will occur in that range.

Your thinking is skewed by the $600 you paid for 4500W of used panels. You're not buying used MPPT at less than 50% of new price.
 
I've only built up Victron systems using 2 Victron MPPT controllers.

The Victron site states 'two or more controllers', so I'd assume....

An important thing to remember - Is that with the Victron Smart Sense, the charge controlling voltage, for both controllers, is sensed at the battery terminal.

If you have two separate random charge controllers connected to the same battery, each is independently trying to regulate the battery, sensed at each controller's input. (And that voltage drop will change, as a function of how much current that controller is actually producing at that moment).

This ignores voltage drops in connecting cables including any corrosion that may have crept in since last winter.....

I'm surprised that almost all Charge controllers lack this ability (except the Midnite's WizBang).

With old AGM and flooded systems, a few hundreds of a volt didn't mean much, but Lithium is a whole different game.

I've actually added the Smart Sense module to all of my Victron controllers.... the low temp charge inhibit is worth the $39 alone.

Again, I understand your price requirements.... and good luck with your system !!!!

The battery protection by sending directly at the battery itself is a nice feature. If I decide to pay-up for a Victron-based solution, that will be the reason why.

Thanks for raising that capability - I’l do some research into it.
 
On a strict interpretation of the subject line, I would argue that any SCC that does not natively support cold-temp charge protection is out of the running. Victron does. Others might, but I'm not familiar with them.

I’ve been assuming that any SCC that comes with a battery temperature sensor includes cold-temp charge protection, but if that is not necessarily the case, I’ll look into that spec more closely, thanks.

[quote{
The best way to save on SCC cost is to increase bank voltage. If you need 4X SCC, you really need to ask yourself if 24V is right for you. [/quote]

First, I’m dealing with severe shading issues on this new array, so the more MPPTs the better (I’d be going with Microinverters if I could).

And second, I’ve got 16 cells and can go either 24V or 48V and ideally want SCCs that support either option. 24V is better for 1S strings of half-cut-cell panels when dealing with shade, but I’m still evaluating both options.

And going 2S / 48V is not going to change the picture dramatically. I’ll still need at least 3 MPPTs in any case. But I’ll keep your input in mind and price it out - if going 48V / 2S cuts my MPPT cost in half (or allows me to afford Victron over cheaper Chinese 2nd-tier options), that might cause me to forgo some potential energy lost to shading in favor of a more capable solution...

I have 6kW of panels, and I have one SCC. The cost was about 35% of the cost of the panels. 48V system.

Those were NEW prices of course. I'm not comparing a new SCC to cheap used panels.

What do you base that on? $150 for the full 4500W of panels?

Apologies for the he typo (since corrected). I meant $450. 5 $90 30A Epever MPPTs serving a 2P string is that baseline.

And the panels I’m talking about are new, not used. I just purchased 3 new PhonoSolar 380W panels for $0.39/W and by the time I purchase 10 450W panels, I expect them to be ~$150 each (already under $200 each today).

So yeah, $1500 for 4.5kW of new panels and hope to get charge into the battery for no more than 30% of that ($450).

Because of the shading, I’ll struggle to use a single large MPPT chargecontroller like yours, but I’ll look into it. What brand/model do you have?

You need to ask yourself if you're being rational and not letting your desire to pay less influence your thinking. You state that you can get 60A for $150, which will only get you about 1600W. But you somehow conclude that you would be able to get 3X that for the same price?
[/quote{

Again, apologies for the typo, but I believe I’m being realistic (correcting for that).

60A for $150 (Reliable 60A) would cover 4 panels or 40% of the full 4500W array (with a bit of overpanelling).

Complement that with 3 30A Epevers costing $90 and handling 2 panels (20%) each, and the full 4.5kW is handled for $420 (not $150 as I typed by mistake).

You need upwards of 165A to ensure you can utilize the 4500W for charging a 24V battery. I'm using 3.4V/cell as the bulk of the charge will occur in that range.

My existing 4kW array peaks at under 3.3kW or 83% of rating, so I’m planning for some overpanelling. Applying that same -17% of rating peak translates to a maximum of 3.375KW from this new 4.5kW array, meaning under 140A @ 8S 3.4V / cell.

One 60A 2S2P MPPT and 3 1S2P 30A MPPTs provides a total of 150A, so a bit beyond this.

[quoye{
Your thinking is skewed by the $600 you paid for 4500W of used panels. You're not buying used MPPT at less than 50% of new price.

I think I understand how you got to $600. You took my typo of $150 got total MPPT coat and my 30% of-panel-cost target to get to $600 (or $500??!).

Anyway, I’m not buying used panels. I could purchase 10 new 450W panels for under $2000 today and am pretty certain I’ll be able t get them for under $1500 by the time I install the full array in 2023.

Panel prices are dropping more quickly than charge controller prices, but aiming for 30% or $450 seems realistic.

I might pay more for better battery-centric capability and protection (Victron).

I appreciate everyone’s contributions on the thread (and apologize yet again for the confusion I caused with my bone-headed typo).
 
In my opinion magnum pt100 is the best I've never had an issue.
but it's also close to a $1000 .
My favorite part is you can 12 24 or 48 volts if you started small need to go bigger. But the midnight does that also .
 
Victron 250/100.

$600 came from $736 being 123% the price of the panels. I didn't consider additional controllers.

Something to consider is paralleling more panels on the same controller. A 2S4P array would only suffer in the individual string being shaded even on the same controller. Keeping your array to a controller capable of 150V would help with the budget. 200 and 250V units carry a premium. I believe a 48V system coupled with paralleling within the array can accomplish the same results as multiple SCC.

While only half is installed (3S3P), my array will be 3S6P. I could shade 1 entire string, and the other 5 would be unaffected on the single controller. It would be no different if I had 6X 3S arrays on 6X SCC, 3X 3S2P arrays on 3X SCC, etc. I have also oriented them horizontally such that only one "string" within the panel will be impacted rather than all strings within the panel.
 
In my opinion magnum pt100 is the best I've never had an issue.
but it's also close to a $1000 .
My favorite part is you can 12 24 or 48 volts if you started small need to go bigger. But the midnight does that also .

Yeah, I really like the Magnum products (including their inverters) but their MPPT is too expensive for 100A.

The 100A Epever can also handle 12, 24, or 48V for less to Han half the price (but only at 200V (3S), not 250V (4S).

And 2 of those Sigineer 60A 150V MPPTs give you 20% more current/power for ~40% of the cost.

Paying more to more confidently protect the battery is something I’d consider, so I’ll look into Victron and Magnum to better-understand their integrated ‘smart’ capability...
 
I am tossing this out in a general response.
Many people SCREW UP their charging profile simply because they do NOT understand the gritty details. This often leads to overcharging cells and having BMS's cutoff and worse. We ALL know that LFP only requires CC which get's it to 85-90% and CV to top the battery pack to 100%. 100% IS NOT 3.65V per cell ! Anything above 3.55 is a WASTE 3.500-3.650 only really represents <5% and the cells will ALWAYS settle within 1 hour of charging to 3.65 to 3.55 or a tad lower.

Chargers / SCC's use BULK (CC) which pushes as much current as available to the packs.
FLOAT is CV for varying amperage as demanded by either the battery packs OR inverter draw. An SCC will provide a Fixed Voltage and floating amps as far as the incoming solar power can provide.

IE: My system ATM is generating 7.5A just to service the demand of the Inverter and the battery bank is getting 0.4A because it is at 99% - 27.9V - 3.487V per cell AVG. If I turn on my coffee maker which pulls 51A, the SCC will try to provide as much as it can to the Inverter and draw the rest off the batteries for any shortfall. If my battery pack drops to 27.4 or lower, that initiates a RE-Bulk Mode which the pushes teh Amps & Volts to bring the battery bank back up before it flips into Float Mode.

FLOAT allows for the cells to Top Off and Balance because it is a Trickle Charge related to capacity demand. As balancing is happening some cells will drop while others go up and often that creates a bit of differential so the Pack will take an Amp or Two for a few minutes or more to top the pack before it drops into Storage Mode (not available on all BMS'). It is NOT overcharging or pushing the cells too high, it is capped by the voltage setting for it.

Stacking SCC's works fine and you are correct, the settings MUST be the same or unpleasantries happen. Smart Linking in Parallel adds more management capability usually with one interface as opposed to two or more. Also pending on SCC, there may be Ground Fault Protections and more functions and features which only ONE SCC needs to address. Having two trying to manage Ground Faults can cause havoc, a friend spent 2 weeks chasing that wild monkey, finally ended up listening to what he was told, at his wife's insistence.

Sigineer, YiYen are two Huge OEM's who produce equipment for VARS (Value Added Resellers) such as AIMS and many others. Their equipment is generally Tier-3 & Tier-2 level gear, they don't do "Value Tier-4" stuff. Yiyen will not sell direct but Sigineer will if you do it right. Sigineer now also have full on EV Charging "Kits" and manufactured linkable smart battery packs as well which link to their higher end gear. We do have users here using Both Brands and assorted models of their products. I started out with a Yiyen APC-3024 and the thing is a TANK and only cost me about $550 USD back in 2015. Since been replaced by my Samlex EVO which is a world of difference. NOTE, Yiyen/Sigineer average between 82-90% efficient and they have a higher Idle Draw as well. There are tradeoffs to consider.

Hope it helps, Good Luck
 
In my opinion magnum pt100 is the best I've never had an issue.
but it's also close to a $1000 .
My favorite part is you can 12 24 or 48 volts if you started small need to go bigger. But the midnight does that also .
I agree 100%, I've been using PT-100 for 5 years now, and never had problem. Last year I upgraded with another aray of 3200 watts panels with a fm60 from outback, and it's been really good. The only problem with this is to have both different controller to sync Togo in float mode at the same time. Doesn't happen if you have a big current demand, I have to manually force float on one or the other. I should be getting my second PT-100 in few days. Now I will be able to connect them (stack) together with one remote and set them for lifepo4 cc/cv.
 
I am tossing this out in a general response.
Many people SCREW UP their charging profile simply because they do NOT understand the gritty details. This often leads to overcharging cells and having BMS's cutoff and worse. We ALL know that LFP only requires CC which get's it to 85-90% and CV to top the battery pack to 100%. 100% IS NOT 3.65V per cell ! Anything above 3.55 is a WASTE 3.500-3.650 only really represents <5% and the cells will ALWAYS settle within 1 hour of charging to 3.65 to 3.55 or a tad lower.

Chargers / SCC's use BULK (CC) which pushes as much current as available to the packs.
FLOAT is CV for varying amperage as demanded by either the battery packs OR inverter draw. An SCC will provide a Fixed Voltage and floating amps as far as the incoming solar power can provide.

IE: My system ATM is generating 7.5A just to service the demand of the Inverter and the battery bank is getting 0.4A because it is at 99% - 27.9V - 3.487V per cell AVG. If I turn on my coffee maker which pulls 51A, the SCC will try to provide as much as it can to the Inverter and draw the rest off the batteries for any shortfall. If my battery pack drops to 27.4 or lower, that initiates a RE-Bulk Mode which the pushes teh Amps & Volts to bring the battery bank back up before it flips into Float Mode.

FLOAT allows for the cells to Top Off and Balance because it is a Trickle Charge related to capacity demand. As balancing is happening some cells will drop while others go up and often that creates a bit of differential so the Pack will take an Amp or Two for a few minutes or more to top the pack before it drops into Storage Mode (not available on all BMS'). It is NOT overcharging or pushing the cells too high, it is capped by the voltage setting for it.

Stacking SCC's works fine and you are correct, the settings MUST be the same or unpleasantries happen. Smart Linking in Parallel adds more management capability usually with one interface as opposed to two or more. Also pending on SCC, there may be Ground Fault Protections and more functions and features which only ONE SCC needs to address. Having two trying to manage Ground Faults can cause havoc, a friend spent 2 weeks chasing that wild monkey, finally ended up listening to what he was told, at his wife's insistence.

Sigineer, YiYen are two Huge OEM's who produce equipment for VARS (Value Added Resellers) such as AIMS and many others. Their equipment is generally Tier-3 & Tier-2 level gear, they don't do "Value Tier-4" stuff. Yiyen will not sell direct but Sigineer will if you do it right. Sigineer now also have full on EV Charging "Kits" and manufactured linkable smart battery packs as well which link to their higher end gear. We do have users here using Both Brands and assorted models of their products. I started out with a Yiyen APC-3024 and the thing is a TANK and only cost me about $550 USD back in 2015. Since been replaced by my Samlex EVO which is a world of difference. NOTE, Yiyen/Sigineer average between 82-90% efficient and they have a higher Idle Draw as well. There are tradeoffs to consider.

Hope it helps, Good Luck

Very helpful, Steve, and more or less confirms how I believed/hoped these SCCs worked (as far as Bulk vs. Float when powering an inverter with variable load while also charging a battery.

And I appreciate the reference on Sigineer (who I am in direct contact with) but have never heard of YiYen before. Do you know of any easy way to research the products they are manufacturing? Are there YS-based brands/partners who are reselling their products here?

I just bought two SunPower GTIL inverters branded ‘Y&H’: https://www.amazon.com/gp/aw/d/B07GC53QBD?psc=1&ref=ppx_pop_mob_b_asin_title

Those are not manufactured by YiYen, are they?
 
I had a 20A EPEVER. External Temp Sensor. USB cable adapter. A bit difficult to get it sync with laptop. Also dropped Custom for default setting.
I upgraded my camper to a 27' travel trailer. 100w suitcase style panel to two 250W used panels.
I also upgraded to Victron for the blue tooth networking with the Smart Shunt (with voltage sense) and Smart Phone display.
 
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