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Author Topic: State of Charge Confusion (SOCC)!  (Read 3163 times)
Shay
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« on: October 04, 2008, 01:02:17 PM »

Iím slightly confused as regards my Battery bank SOC.

To recap, my setup is as follows:

Navitron 300w Wind Turbine, 660Wp Navitron PV array, Outback MX60 solar charge controller, Tristar 45 used in diversion mode dumping to heating element, 3000w Kipoint Pure Sine Wave Inverter, 10 no. 110ah Elecsol Batteries

From the Tristar manual:

Battery State of Charge LED Indications (when battery is charging)

Green On                         80% to 95% SOC
Green/Yellow On               60% to 80% SOC
Yellow On                        35% to 60% SOC
Yellow/Red On                   0% to 35% SOC
Red On                            Battery is discharging


When the Tristar indicates Yellow the Outback controller shows a battery voltage of 25.5v. According to the Outback manual over 25.2v is charged which dose not tally with the Tristar SOC.

I disconnected all loads and inputs and left the batteries idle for 3 hours.
The Outback gave a voltage of 25.8v. Taking a reading directly form the batteries I got 25.6v.

Again this does not tally with the Tristar LED indicator. I have fitted separate wires for the battery sense.

Am I missing something?
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billi
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« Reply #1 on: October 04, 2008, 01:40:04 PM »

Hello Shay

Have you charged your batteries fully recently  ? 
Or did the Outback ever reached absorbtion charge state ?

Quote
When the Tristar indicates Yellow the Outback controller shows a battery voltage of 25.5v

That sounds like there is still a lot of charging to do until  30 Volt ( at temps we have now for lead acid batteries (depends on model) and then still more in absorbtion mode with reduced input in Ampere

As well i would set the tristar to start dumping after the MX60 goes into absorbtion ( sure you have to be carefull on windy nights that the battery is not overcharged )

But saying this i donot know a lot about the tristar

Billi
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Shay
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« Reply #2 on: October 05, 2008, 09:27:28 AM »

Hi Billi,

Yes I'm pretty sure the battery bank has been fully charged. The last few days the wind has been great and heat dump has been kicking in regularly.

I left the batteries unload again last night and got a reading of 25.4v this morning. The Trisatar is showing 35% to 60% SOC.  Huh
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martin
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« Reply #3 on: October 05, 2008, 09:44:23 AM »

I'm with Billi on this - sounds as if you're not fully charging for some reason (unless Elecsols have peculiar characteristics). Whenever I see a sodding great inverter, my heart always falls, as they tend to be over-enthusiastically used, and it's very easy to drain your batteries. Going with the sort of lead-acids I'm used to, 25.4v can be the sign of some pretty flat ones - if they are under charge of any sort, I'd want to see voltages well above 28v - preferably 29 or even 30 - at rest, when fully charged you should be seeing over 26 Undecided
The Outback stuff has a good reputation, but I'd tend to take their manual with a very large pinch of salt~
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Shay
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« Reply #4 on: October 05, 2008, 09:56:50 AM »

That makes sense. I was taking (as per the Outback manual) that 25.4v was fully charged.

You are right about the inverter. I envisaged a larger battery bank initially and expanding the PV array hence the 3000w inverter.

In hindsight I should have possibly gone for a Victron 1500w inverter (as Billi has) and paralled an additional 1500w inverter if and when I expanded the system.
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billi
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« Reply #5 on: October 05, 2008, 03:26:00 PM »

Say

I have seen my dumpelement (came with the turbine) dumping the PV power  from the outback  Embarrassed  , before the MX 60 went into absorbtion charge  ( and that shouldnot be the way or the MX 60 is not used as good as designed)

Quote
In hindsight I should have possibly gone for a Victron 1500w inverter (as Billi has) and paralled an additional 1500w inverter if and when I expanded the system.


Hey  have 2times   3000 watt inverters in parallel  get one more and have three phase electricity  Grin ( who needs that   Huh , perhaps for a heatpump one day )

Any how  i recon about 40 watt the 2 inverter consume an hour and about 25 watt if nothing is on in the house
My battery monitor shows about 2 A draw , when we go to bed and still we have some LEDs on all night  and the satilite modem ..... still that ads up during the day ....

Billi

Here is some information out of the manual of my battery monitor .....on battery charging , but still i donot trust him 100% and like my multimeter a lot  and the MX60  Grin

http://www.victronenergy.com/upload/documents/Manual%20-%20BMV600%20-%20rev%2004%20-%20GB.pdf

Some times the monitor says battery fully charged 100%  and i still squize sometimes 60 -80 AH in my (1600 ah battery)  thats still 1.6 kw or 10 % of the capacity , but saying this the monitor then adjusts himself  and takes the 10% more charge into account and sets this then as 100 %  so 110 % = then 100 %








« Last Edit: October 05, 2008, 04:28:47 PM by billi » Logged

1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Shay
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« Reply #6 on: October 08, 2008, 04:22:37 PM »

Billi,
You were right about adjusting for the current temperatures.
Checking the Outback manual it suggested adding 0.60v to the absorb and float regulation set points which has made big difference. The battery bank was not fully charging alright.
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billi
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« Reply #7 on: October 08, 2008, 06:00:54 PM »

Nice one .... not that i know a lot.... but just learned that myself 6 month ago  Grin

I guess battery charging is as complicated as keeping the wife happy   Tongue

Billi

Shay did you get the temp sensor for your MX60 ? worth it i think ( ok my batteries are outside)
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
Shay
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« Reply #8 on: October 08, 2008, 08:41:49 PM »

No I didnt get the temp sensor for the MX60. One of many things on my long to do list.

Although I'm looking for a suitable one for my wife!  Grin
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billi
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« Reply #9 on: October 08, 2008, 08:54:44 PM »

Hey Shay ....in between us  Grin... the tempsensor works for both

But she is pretty cool now  Cool took a while ... but system is now acting  fine ... so  lovefirefox


Best charging about 30.5 volts and i still like ACDC


Macho iam

Billi
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1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
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« Reply #10 on: October 09, 2008, 02:13:07 PM »

Hi Shay,

I've heard from a reliable source when I was faced with a similar problem that the Tri Star LEDs are more of a rough guide and not to worry about it Wink I am however completely inept in all matters electronic Grin

Cheers, Paul
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http://lifeattheendoftheroad.wordpress.com/

'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SI6.OH, 800ah Rolls, 4.75kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
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