15 dollar ebay 5A MPPT Solar Charge Controller

David in nh

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Oct 18, 2019
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has anybody tried this one
https://www.ebay.com/itm/5A-MPPT-So...-LiFePO4-Battery-Charging-Board/283982202592?

1600106007320.png1600106050305.png
Features:
1.100% Brand New and High Quality
2.MPPT Technology --- 5A solar maximum power point tracking
3.High efficiency synchronous rectification step-down charge management, the highest efficiency up to 96%
4.Solar cell maximum power point tracking (MPPT)
5.Solar cell maximum power point tracking (MPPT) is to ensure that in the light intensity changes, photovoltaic cells have been the maximum output power to make full 1600106007320.png1600106050305.pngse of solar energy. Under normal circumstances, need to use the switch mode DC-DC converter MPPT function, to maintain the output voltage and charge current product (output power) to maximize.
6.The switching step-down synchronous rectification DC-DC conversion of photovoltaic cells to achieve the maximum power point tracking function, the input voltage up to 28V, very suitable for the input voltage and battery voltage difference between the larger applications.

now i expect very little out this and i am still waiting for it , i have a 50 watt panel left over from a old project , do not really care if i only get 3 amps of power as long as it will not hurt my lfepo4 battery just doing it for fun lets see i have a 200ah battery 3 amps 66 hours to fully charge figure 5 hours a day average so about 14 days to recharge ,

adding this to my my furnace back up

next year i hope to add real solar panel and controller to it
 
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rin67630

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810
Yes, I have tested that one.
MPPT is a lie!
They have a fixed power point at ~17V, which matches most of the "12 V panels" having a MPP at 18V in bright sun.
They also completely lack the low voltage battery protection circuitry. Beware with LiPo cells!

They are not basically bad, since they have a very low quiescent consumption, so they match well low-power solutions, where the quiescent consumption matters, but you must keep an eye on your battery voltage on overcast days...
 

rin67630

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The price alone as well as the board layout tell you they are NOT MPPT.
Fleabay is a cesspit of fraud, lies and misrepresentation with all this stuff.
...
PWM controllers aren't bad but they should not be marketed as MPPT when they are not.
Hmm... you have got a lot of confusion with the terms MPPT and PWM.

Above-mentioned module features a "BQ24650 Battery Charge Controller" chip, that already mentions MPPT in the specifications.

In fact, there is a whole world in-between a full-fledged MPPT and a dumb PWM regulator.
PWM is just a kind of fast on-off switch with no power conversion at all.
MPPT are buck-converters (that work a bit like DC-transformers that convert a high voltage/low current to a lower voltage/higher current)
AND have a logic to find the optimal primary operational voltage.

Then you have at low-power end of SCCs, chips/printed boards that will provide a buck conversion, but just operate at a fixed/manually adjustable operational voltage on the panel side.
These systems should in fact be called MPPA (for maximum power point adjustable), but unfortunately nobody does.

They can be noticeably better than PWM if you use panels with a much higher Vmp then the battery. (> 1,5 * Vbat)
They can even outperform true MPPT at low-power end (10W-150W), since they have a lower quiescent current, which is a frequently forgotten aspect of the overall design in off grid solutions.

Last, but least ;-) you have plain buck converters, that provide a power conversion, but should be avoided since they tend to stall the panel at a maximum current far below the best operating power point.
 

rin67630

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Messages
810
now i expect very little out this and i am still waiting for it , i have a 50 watt panel left over from a old project , do not really care if i only get 3 amps of power as long as it will not hurt my lfepo4 battery just doing it for fun lets see i have a 200ah battery 3 amps 66 hours to fully charge figure 5 hours a day average so about 14 days to recharge ,

adding this to my my furnace back up

next year i hope to add real solar panel and controller to it
If you just use it to trickle float the battery that is else only used as a backup to keep your home warm in the eventuality of a power outage, this will be a perfect solution.
But do not expect a 50W panel to be able to recharge the battery during the winter days with overcast weather.
You will also not be able to run the fuel burner for longer than a couple of hours until you get a drained battery.
So as it could be the solution for a 24-hour power outage, not more.
 

rin67630

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The coil on that board just looking at the pic does not look like an inductor capeable of handling much power if thats what its being used for at all.

I'd want to see this board hooked to a panel and see if it kept the panel at vmp or just pulled it down to battery voltage. If it does not keep the panel in its working range then to me its pwm or just a cut off, no matter what chips it has or what the spec sheet says.
That coil is perfectly able to handle the 5A for which the board is designed, it is according to my experience with buck converters even slightly over dimensioned.
You're free to test it: it will keep the panel at ~17V and provide about 15% more current out, than what goes in.

Are you just denigrating without having got a personal experience?
 

gnubie

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Sep 20, 2019
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FWIW I have quite a few of these 5V sync buck regulators running stuff in my house. They will supply 5A without complaint. The windings in the inductors on these things, and the little 5A MPPT board are quite heavy. The copper strip that can be seen in the inductor on the MPPT board, going down to the PCB pin is the winding wire, quite wide, reasonably thick.

 

David in nh

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Oct 18, 2019
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64
the way i am looking at is i have a free 50 watt panel , that matches nothing else i have so for 15 bucks i get a few extra watts into the battery that has a bms
 

dehv

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Oct 26, 2020
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17
Yes, I have tested that one.
MPPT is a lie!
They have a fixed power point at ~17V, which matches most of the "12 V panels" having a MPP at 18V in bright sun.
They also completely lack the low voltage battery protection circuitry. Beware with LiPo cells!

They are not basically bad, since they have a very low quiescent consumption, so they match well low-power solutions, where the quiescent consumption matters, but you must keep an eye on your battery voltage on overcast days...

Most of the cheaper MPP boards seem to lack the tracking function, they're either fixed or you select the mpp by adjusting a pot.
 

rin67630

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Messages
810
Most of the cheaper MPP boards seem to lack the tracking function, they're either fixed or you select the mpp by adjusting a pot.
"MPPT" means there "Manual Power Point Trimmable", better than nothing...
But I plan to modify them by adding an ESP8266 or an Arduino Pro Mini and an INA226 from which I will modify the default MPP by injecting a calculated bias to the trim potentiometer, it is probably a matter of weeks until I can present a result...
 
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rin67630

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Joined
Apr 29, 2020
Messages
810
"MPPT" means there "Manual Power Point Trimmable", better than nothing...
But I plan to modify them by adding an ESP8266 or an Arduino Pro Mini and an INA226 from which I will modify the default MPP by injecting a calculated bias to the trim potentiometer, it is probably a matter of weeks until I can present a result...
I have purchased a module based on the LTC4012 (without the -1 or-2 extension, meaning they are adjustable).
The red modules mentioned above are based on LTC4012-1 or LTC4012-2 and are non-adjustable, suitable for LiPo or LiFePo4 only.

I have currently another similar module based on the CN3767 chip, that is also non-adjustable and intended for lead acid chemistry.
I can use it for my software development until the LTC4012 modules arrive.

The CN3767 chips did however disappoint me: they are not adjustable, do not provide a real absorption phase and do trickle charge at 13.56V only.
OK, the battery will live longer, but is not used at full capacity.
 

juan3211

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Dec 30, 2019
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I have purchased a module based on the LTC4012 (without the -1 or-2 extension, meaning they are adjustable).
The red modules mentioned above are based on LTC4012-1 or LTC4012-2 and are non-adjustable, suitable for LiPo or LiFePo4 only.

I have currently another similar module based on the CN3767 chip, that is also non-adjustable and intended for lead acid chemistry.
I can use it for my software development until the LTC4012 modules arrive.

The CN3767 chips did however disappoint me: they are not adjustable, do not provide a real absorption phase and do trickle charge at 13.56V only.
OK, the battery will live longer, but is not used at full capacity.
Hi, any improve with your "adjustable MPPT with INA226" project? Thanks.
 
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