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Which MPPT/PWM controller between sun panel and LiFePO4 battery?

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labora

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I am looking for a charge controller for one or two sun panels (each ~ 400 Wp) to charge a proper 12 V BMS+LiFePO4 battery in a cost effective but reliable way.

This seems to be a very simple question. However, I am a bit lost here, having found so many answers with caveats like "very expensive" and "unreliable".

For example, this article scares me to choose MakeSkyBlue MPPT or its clone PowMR. Epever MPPT seems a bit less scaring. Or is using PWM a good choice for small scale projects?

I would really appreciate getting some practical user experiences, some thoughts. Thanks!
 
Hi.
Having wired up my camper trailer with 12v I went through a few different MPPT controllers before settling on Victron, they may be a little bit more expensive but they are a really good controller, I eventually swapped out the 2 PV's on the camper for Victron too.
With the Victron controller you can see what is going on via the app for your phone.

I also have a Victron 12v shunt in the camper, I run Lithium and LA on the same circuit, everyone says not to run different types of batteries on the same circuit but after 12 months or more I cant see a problem..?

My power wall/charging station runs Victron too.
 
Tooth Fairy said:
I run Lithium and LA on the same circuit, everyone says not to run different types of batteries on the same circuit but after 12 months or more I cant see a problem..?
Click to expand...

It can work but as soon as the sun goes down the lithium starts "charging" the lead acid (being of a higher nominal voltage).
 
The only time Ive sort of noticed that is in mid winter if we get a few cloudy days in a row which we get a few of in Melbourne AU.
Other that that the batteries are all at 57V until they start to discharge to run the house in the evening.

Ive got 150ah of each LI and LA, Im about to embark on another round of LI battery pack building and see if I can get to 300ah of LI.

Just for interest we only use about 5Kw of power per day from the grid in the evening and night time, average sell back to the grid is about 20Kw per day.
 
labora said:
I am looking for a charge controller for one or two sun panels (each ~ 400 Wp) to charge a proper 12 V BMS+LiFePO4 battery in a cost effective but reliable way.

This seems to be a very simple question. However, I am a bit lost here, having found so many answers with caveats like "very expensive" and "unreliable".

For example, this article scares me to choose MakeSkyBlue MPPT or its clone PowMR. Epever MPPT seems a bit less scaring. Or is using PWM a good choice for small scale projects?

I would really appreciate getting some practical user experiences, some thoughts. Thanks!
Click to expand...

I use an EPEver Triron and I have no issues with it. Buy the Bluetooth module to go with it and set the App up on your phone and you can see all the data you require.
 
Thank you all very much, it helps to make a good choice.

Based on two solar panels, specs of one panel: Pmax=390W, Voc<42V, Isc<12A.

I like redundant, almost everything is redundant so far. There is a preference for two separate units. I'll add prices to compare.

@MisterSandals : Unfortunately my mother doesn't need it anymore (but I had to laugh at your approach). But it's like you suggest: It has to work well enough, but it doesn't have to have any golden handles.

@Tim Tim : EPever Triron looks like other EPever models with minor differences like USB, correct me if I'm wrong.

That said, a salesman suggested the following:

EDIT: not a proper comparison, see next posts...
  • Redundant: 2*EPever Tracer 3210AN = 2*€110 (need a laptop cable too) ~ €230
  • Non-redundant: 1*EPever Tracer 6415AN = 1*€280 (need a laptop cable too) ~ €290

Based on Victron SmartSolar MPPT x|y with x=Voc and y=Imax:
  • Redundant: 2*Victron SmartSolar MPPT 75|15 = 2*€115 ~ €230
  • Non-redundant parallel: 1*Victron SmartSolar MPPT 100|30 = 1*€210
EDIT: end of comparison.

If this overview is not questionable for anyone, I am actually surprised that Victron comes out well.
 
Last edited:
pollenface said:
If you can afford it, go with the Victron Smart Solar series.
Click to expand...
Seconded. I've been off-grid for ten years, and used to use Renogy controllers, but I melted a 40amp controller with less than 40 amps, with oversized wiring. I tried ampinvt next, but it was hard to set up, and the setup was not flexible enough for LiFePo4. And the fan was annoying as f***. I finally bit the bullet and got the Victron SmartSolar 150/100. I'm thrilled. Adaptive charging, myriad settings of every sort through a good, functional app, and I've exceeded 100% of nameplate capacity using it. There is a reason these are preferred by the marine industry. Dependable.
 
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Two 400 watt panels under ideal conditions will produce around 60 amps for a 12 volt system. Since its very unlikely to get full output, a 50 amp controller would be OK. With one panel a 100/30 would be used
Use a single Victron smart 100/50 for two panels and a 100/30 for a single panel, rather than two separate units. The app used with the unit , for setup and display of the units performance, records data for the last 30 days solar performance. You have access to the solar yield and battery state.

Although two units would work, analysing the stored data would require mental activity.

A further benefit of a single unit 100/50 is that the panels could be wired in series, producing a slightly more efficient system.

Mike
 
labora said:
Thank you all very much, it helps to make a good choice.


@Tim Tim : EPever Triron looks like other EPever models with minor differences like USB, correct me if I'm wrong.
Click to expand...
There is also a difference in imput voltage, 100v v 150v.

Don’t forget there is a difference between the Victron smart solar and Blue solar in that with the former the Bluetooth is built in. Seems like a good price compared to Australia.

Not sure why you would buy a laptop cable to connect up with an EPEver when a Bluetooth module is so much easier.

Good luck with which ever you choose.
 
Last edited:
mikefitz said:
Two 400 watt panels under ideal conditions will produce around 60 amps for a 12 volt system. Since its very unlikely to get full output, a 50 amp controller would be OK. With one panel a 100/30 would be used
Use a single Victron smart 100/50 for two panels and a 100/30 for a single panel, rather than two separate units.
Click to expand...
The input of these controllers are 100V|30A and 100V|50A. The output is in a 12V situation not mentioned by Victron it seemed to me. However, they mention nominal PV power, resp. 440W and 700W. I was under the impression tot numbers 30 and 50 were maximum currents of the panel. That is probably wrong, based on the numbers (roughly 440/14 and 700/14) it is the charge current to the batteries. Thanks for bringing that up.
mikefitz said:
A further benefit of a single unit 100/50 is that the panels could be wired in series, producing a slightly more efficient system.
Click to expand...
Situation: Two horizontal panels on a workhorse van - just park and charge. I am afraid the advantage of serial connection is overshadowed by regular shadows.

Possibilities, added bluetooth:
  • Redundant:
    • 2*EPever Tracer 3210AN + bluetooth = 2*~€125 = ~ €250
    • 2*Victron SmartSolar MPPT 100|30 = 2*~€210 = ~€420
  • Non-redundant:
    • 1*EPever Tracer 6415AN + bluetooth = 1*~€305
    • 1*Victron SmartSolar MPPT 100|50 = 1*~€300
I nice nut to crack, the panels contain 3 bypass diodes and going for the €300 solution is tempting.
 
Last edited:
Due to panel bypass diodes series connection is not a serious issue if you have partial shading.

The Victron device rating, for example 100/30 relates to the maximum input voltage,100 volts, and the maximum output current the unit can produce, 30 amps.
The units can be over panneled to a degree but it would be prudent to limit the input current below the 30 amp. Victron state that the short circuit current of the panels should be less than 35 amps, for the 100/30, exceeding this may cause damage.

There is a non replaceable Internal fuse.


Mike
 
mikefitz said:
Due to panel bypass diodes series connection is not a serious issue if you have partial shading.
Click to expand...
Okay, I'll go for Victron SmartSolar MPPT 100/50, serial panels, not redundant. There is also 60A charging from the alternator and regular driving, so it is easy to defend going "not redundant".
 
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