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kennethknashaug asked

Victron SmartSolar(150/35) + SmartShunt(500) for FullRiver DC400-6(AGM)

Hi,

I am reaching out because I really need help configuring the Victron SmartSolar 150/35 and the SmartShunt 500A for my 48V AGM-battery (8 x Fullriver DC400-6).

Since I live in Norway and charging is very limited in the period from November - February this is tricky!

I have a potential for (theoretical) 33,6A solar charge with my six 325W panels (3s2p), but in the mentioned period I rarely see much current (aprox. 4-6A). So if I follow recommendations with 3-4% of C20 (415Ah) for my batteries I will have a problem with SOC calculations in the shunt. As I have understood the shunt will estimate a 100% SOC when 3 conditions are met: Charged voltage, tail current and charged detection time.

In my case the voltage for charging will be high enough to achieve "charged voltage" every day (because of my 6 panels), but the current will in periods be as low or even lower than the tail current setting if 3-4% (C20) is used. I'm afraid this will result in a very inaccurate SOC calculation..


For the Smartshunt I need help configuring the following settings:
- Charged voltage? Here I have seen that 0,8V below float is recommended, while others recommend 0,8V below absorption for Solar - what is correct?

- Discharge floor? For AGM I believe this value should be no lower than 50% based on what I have read - correct?

- Tail current? In my head I would have to set tail to 0,8% - 1% or even lower and adjust this to about 2% or slightly higher as charging gets better from mid February - sounds resonable?


- Charged detection time? For the charged detection time I have read that 8-10 min would give a better calculation than the default 3 min for solar charging with low current - correct?

- Peukert exponent? Here I have no idea what to configure, all my reading suggests different options so please help me.

- Charge efficiency factor? The only thing that is certain is that the standard 95% must be way too high for my system, and maybe 70-80% would be more correct?

- Current threshold? I have no clue what this means and need help

- Time-to-go averaging period? I have no clue what this means and need help



For the Smartsolar I need help with these settings:
- Temperature compensation? my batteries says -4mV per cell, and eight
6V batteries in series would then be -96mV according to my calculations - correct?

- Re-bulk voltage offset? Here I have no idea what to set and need help

- Maximum absorption time? My batteries should not be in absorption for
more than 8 hours, so maybe the default 6 hours is ok?

- Tail current? Here again I have no idea what to set because of the
varying charging conditions. My Fullriver batteries only have info of
the state when absorption changes to float: I = 0.012 - 0.02 x C20.

If I understand this correct the tail current will taper down from 8,3A
(0,02x415) to 4,98A (0,012x415). My main concern for this is that I
rarely see 8A charging in the darkest period of the year.. The default
value set on the SmartSolar is 1,0A, will it be OK to leave it at
default and max the absorption out to the battery max rating at 8 hours?
I will let the SmartSolar use "Adaptive mode" for Absorption.


I am really sorry to bother you guys with all my questions, but I know the knowledge is in this community and I haven't been able to get any reasonable answers from the "experts".


I would highly appreciate it if anyone could help me.

Thanks in advance!

MPPT ControllersSmartShuntVEConfigure 3AGM Battery
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1 Answer
JohnC avatar image
JohnC answered ·

Hi @kennethknashaug

A lot of questions, so I've abbreviated some of the terms..

Smartshunt:

CV: Set that just below the lowest Float V you'll see (with Temp Comp in effect). 0.3V should do. You might use Abs V with Li batts, but not with AGM.

DF: 50% is ok.

TailC: Your batts won't hold the CV unless there's charge available, and it's perhaps the length of the day you have that will determine where you set the Tail. Perfection is elusive here, and you'll need to decide how close you want to be. I use 0.5% (flooded batts), but in winter I need to lift it to 0.7%, as that extra few hours to tail further just isn't there..

CDT: 3 min works for me, and I'd only raise it if the need arose.

PE: I took the liberty of calculating yours from the batt specs using the Victron calculator: It's 1.17 between C5/C20, 1.07 (C20/C100) and 1.11 (C5/C100). The 1.11 would be ok for general use.

CEF: Try starting at 90%. If the SOC doesn't rise to 100.0% by the time it syncs, then you can raise it. And vice versa.

CT: The shunt won't count Amps below a certain value. Set to zero unless you have specific needs.

TTGAP: How far back it uses the data to calc TTG, Leave at default maybe.

Mppt:

TC: Yes.

RBVO: This will restart Abs if V drops too low. Leave at default for now.

MAT: 6 hrs is ok if set with adaptive algorithm. Reduce it if you get to >99.0% SOC and it remains in Abs. No point flogging the batts.

TC: If you have continuous loads then it will count them too. A great feature if you have a GX box with DVCC, then the mppt will react on batt current only. Put the figure in you have recommended, as it's better to have something there than not. For me that is actually too low, as I use just under 3% (A/Ah), and the SOC is 99% by then. Just watch it for now.

Whew, lotta questions. Come back if you need further help, but read the manual over'n'over to delve to the detail. Then study your own system in use to get to know it. That experience is invaluable..

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kennethknashaug avatar image kennethknashaug commented ·

Thank you very much for taking the time and give me all this information!! You made my day!!

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