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SRNE MPPT programming for LiFePO4

ruiz.manuel94

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Nov 16, 2021
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Hi everyone.

"Questions in the end, feel free to answer only some. Disclaimer: Me be noob"


I bought this MPPT (40 A version) (Branded as WEIZE but apparently made by SRNE, the Rich Solar one also looks very similar), which appears to be very decent for the price, however I am having a little trouble programming it and there isn't much info online.

According to the manual, these are the charging modes:

1640972346130.png



So right now I have "LI" selected, however, that doesn't seem to be in accordance (i.e. no "float" voltage) with what another thread by Will Prowse says about charging parameters:

12V 4S LiFePO4 Battery w/ BMS:
  • Absorption: 14.5V
  • Float: 13.6V
  • Inverter Cut-off: 10.7V-12V (depending on size of load and voltage drop etc)

I am considering to use the "USER" charging profile if needed, however I don't know what parameters should be set.

When you get into the settings menu, these are the only parameters you can set for the USER profile (the first image misleadingly seems to suggest there are more):

1640972622256.jpeg



Questions:
1.- Is the LI default profile good to go?
2.- Is BOOST voltage the same as ABSORPTION? (terminology-wise)
3.- Can you provide a link where it explains what all of these things are?
4.- How would you set the five parameters?

Notes:
  • Battery bank is 12V DIY from four 230 Ah LiFePO4 cells with a Daly 150A smart BMS
  • PV is three 160W panels in series
 
I think Will Prowse perhaps intended to say is if float exists, just make sure it is set low enough for LFP?

LFP don't need floating once they're charged to desired max SoC.

Just so you know, when they refer to BULK charge, it means, Constant Current (CC) where voltage can move freely (up until it hits a trigger to move to absorption).
ABSORPTION charge refers to Constant Voltage (CV), where amperage can move freely, until it comes down to a certain trigger point, to go into float stage.
FLOAT is also CV but is lower voltage...

SLA, AGM, GEL batteries need float as they have self-discharge and the drain just sitting there. LFP doesn't need floating, but if you are using a charge profile that has float, just make sure float voltage is at or lower than your max SoC percentage where you want it to be at max.

Some do not want to charge LFP to max SoC like 100%, some wish to stop charging at 90% SoC for longer battery life (more cycles lifespan).

 
Midnite Solar has a diy series that is manu by SRNE. IIRC, just recently, somewhere on this forum, I ran across a user's manual from Midnite that was much more in depth for that controller. It is Midnite's older? version of the SCC that looks just like the Weize/SRNE, not the newer versions. Has Midnite changed the menu? Don't know, haven't dug deep enougn into the Weize menu as it was a fairly straight forward plug-n-play affair.

... here it is Midnite diy manual

FWIW, I opened the unit up and the trans were decently sized with good wire awg, and IIRC, the caps were 105c and 125v.
 
I had a SRNE and it had so many issues. The fans are VERY loud, and the inverter losses are HUGE! 70-90 watts on a 170 watt load. you do the math, I now retain an extra 1 to 1.5 kWh per day when I switched to the SPF growatt 3000 watt that I got from watts247.com

Huge differences. Search my other posts to see what issue s here are. The biggest issue was It did not stop charging at the right voltages. I had to get rid of it before it damaged the batteries.
 
I had a SRNE and it had so many issues. The fans are VERY loud, and the inverter losses are HUGE! 70-90 watts on a 170 watt load. you do the math, I now retain an extra 1 to 1.5 kWh per day when I switched to the SPF growatt 3000 watt that I got from watts247.com

Huge differences. Search my other posts to see what issue s here are. The biggest issue was It did not stop charging at the right voltages. I had to get rid of it before it damaged the batteries.
One of the caveats of my spf6000t Growatt, other than the totally bogus manual, is that it draws around ~150w idling. When running only two 5kwh batteries, it was a noticeable loss.

Knock on wood, not even a hiccup from the Weize (rebadged srne product) at dad's cabin.
 
One of the caveats of my spf6000t Growatt, other than the totally bogus manual, is that it draws around ~150w idling. When running only two 5kwh batteries, it was a noticeable loss.

Knock on wood, not even a hiccup from the Weize (rebadged srne product) at dad's cabin.
does the SRNE clone ramp up and down every 12 minutes? What about the fan speed? The one I had the fan was just based on PV load, and would ramp up to max even though temp was normal. Honestly aggravating, but I didnt know others didn't do that.
 
does the SRNE clone ramp up and down every 12 minutes? What about the fan speed? The one I had the fan was just based on PV load, and would ramp up to max even though temp was normal. Honestly aggravating, but I didnt know others didn't do that.
I don't think the SRNE has a fan. It's a small 12v unit. The fan on the Growatt is more annoying than a leaf blower.
 
Mine was a 24v version. and same with the growatt. both 3Kw the growatt is very quiet. so not sure what yours was doing, was it cloned version of the growatt?
 
Growatt spf6000t dvm purchased from Signature Solar. Very noisy. Glad it's out in the shop.
 
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