Rolls S460 AGM 415AH

pyintheye · January 2017

Hi to All
I have just finished installing a BMK and batteries on a neighbors 12 volt system. Are there any members familiar with these batteries with regard to the LBCO setting. Also need guidance for the proper absorb voltage/time and if End Amps should be used for AGM's. I have been all over the Rolls site and cannot find a Voltage to SOC chart, is there such an animal out there from Rolls? I believe they are under paneled @ 260 watts and will be using a 3000W Genset quite a bit.
Thanks

westbranch · January 2017

The battery will die an early death if they expect one panel to charge it up unless they only SIP the power from the battery, ..at 14.4+V charge they will get ~ 18A max,
3 6 of those 260 130W panels are need to get > 10% charge. SEE Post #4
Yes the genny will run a lot.
Yes End Amps can be used , as the SG can not be checked it is the best way to ensure a full charge.
sorry not familiar with those batteries.
Don't forget the commission charge before heavy use...
What is the application?, it has a bearing on system design...

Vic · January 2017

If the battery is the S6-460, then it is an AGM.

Look in this Rolls Surrette Battery Manual. The AGM section of the manual begins on page 25:
http://rollsbattery.com/wp-content/plugins/rollsbatteries/pdfs/Rolls_Battery_Manual.pdf

Remember, that voltage readings need to be taken after a battery has Rested for many hours, as in about 6 hours or more with NO charging, and NO discharges for this period. Also, voltage readings need to be temperature compensated.

LBCO voltages can be a bit difficult to set correctly, as battery voltage does depend upon battery temperature, and loads on the battery in a previous time interval, as well as charging in a previous time period, and so on.

Even f there is a single string of these batteries, a single 260 W PV will generally be too small for this size battery, and the frequent generator use helps as an indicator for the need of more PV power.

FWIW, Vic

pyintheye · January 2017

Westbranch and Vic,Thanks
There are 3 Solar tech SMP 130P -18.1V, 7.38A panels.
I did do a commissioning charge, batteries are a Sept/2016 Lot. Voltage was 6.36 on both.
I have read the Rolls PDF and set the AB at 14.8v and Float at 13.8v, Temp inside house is 71F.
System is basic, small 12v water pump, TV and modem, a few LED lights and phone charger.

TT
Edited to show 3 panels.

Vic · January 2017

Thanks pyintheye for the added info.

What Charge Controller (CC) is being used on this system?

AGMs need correct Temperature Compensation, and quite possibly Limits to the range of charge voltages. Does the CC on your neighbor's system have a Battery Temperature Sensor (BTS) mounted onto one of the batteries, and a correct temperature compensation value, etc entered into the CC?

Thanks, Vic

pyintheye · January 2017

Vic
They have a Solar Boost 3024i. Inverter/charger is the Magnum MS 2812 with a BTS.
Thanks for pointing out I will have to set the AB volts back to 14.7v and let the MS do its thing.

Thanks TT

Marc Kurth · January 2017

Expect to see something like this from that particular battery.

Image: http://centexbatteries.com/vload.jpg

You get to choose the low voltage limit based on what you want for a lifespan.

Marc

westbranch · January 2017

Have amended the numbers in my first post.... same principle applies, he needs MORE PV for a full charge...
Good that the commissioning charge was done and they are from the same lot...

pyintheye · January 2017

Hi Marc
Nice chart, where did you find that. What would you think of 12.25v for a happy medium between Bat life and run time?
Westbranch Thanks for the Panel update suggestion. It will give them a good idea what to be shooting for.

Thanks TT

Marc Kurth · January 2017

@pyintheye - It is from Concorde's tech manual: http://centexbatteries.com/xtendertech.pdf

Your batteries were manufactured by Fullriver and many of Fullriver AGM characteristics are similar to Concorde's. That data is known to be accurate for Concorde, but can be used as loose reference for Fullriver. See the data sheet for your battery here. http://www.centexbatteries.com/fullriver/dc400-6.pdf their DOD vs number of cycles has proven itself.

People often insist that 50% is some kind of hard rule. In reality, it is difficult to offer a hard number for happy medium because of all of the variables.
- An off grid system that is only used on weekends can be cycled far more deeply than a full time facility.
- A grid tied battery backup system can go very, very deep because the batteries will die of old age before reaching excess cycles.
- A full time occupied system should be cycled at closer to 20%-30% to get many years of life.
- Average annual operating temperature is often a bigger factor than average cycle depth.

At some point the battery bank size required to achieve a low average DOD has an invested cost that exceeds the lifespan gain! In other words, it can be cheaper to cycle deeper and replace more often - depending upon the value of your invested capital.

Only you can determine your expectations and goals, but I would go "gently" for now and possibly get more aggressive as you get comfortable with your specific operating parameters. Hope this all makes sense!

Do pay attention to the previous folks warning about undercharging, they have experience and know what they are talking about! Undercharging kills more batteries than overcharging and excess cycling combined - by a factor of 10!

Marc

BB. · January 2017

The only thing or two I would add to Marc's post is try to avoid taking your battery below ~20% state of charge (especially flooded cell).

If the cells are not "balanced" (need equalization)--It is possible for one cell to be weak (near zero % state of charge) and go into reverse charging (reverse polarity of cell(s)). Doing that will kill a lead acid cell/battery.

Also--Higher voltage battery banks are easier to take a cell dead... A 12 volt battery bank has 6 cells, one goes dead the battery bank is 10.0 volts (or less).

With a 48 volt battery bank, one cell goes dead, you are at 46 volts--More than enough voltage to run the AC inverter and such (~42 vdc low battery cutoff).

Going around your battery bank with a volt meter and checking each cell (or battery) under load / under charge (once every 1-4 weeks) and looking for "differences" (high or low voltage cells/batteries) will catch a lot of problems before they occur.

-Bill

Marc Kurth · January 2017

pyintheye said:

Hi to All
I have just finished installing a BMK and batteries on a neighbors 12 volt system. Are there any members familiar with these batteries with regard to the LBCO setting. Also need guidance for the proper absorb voltage/time and if End Amps should be used for AGM's. I have been all over the Rolls site and cannot find a Voltage to SOC chart, is there such an animal out there from Rolls? I believe they are under paneled @ 260 watts and will be using a 3000W Genset quite a bit.
Thanks

Yes, use end amps with a time limit. Go for something in the range of 1% of the C/20 rating. A good starting point is 2-4 hours, but that is also dependent on the system. Watch the system after commissioning and get feel for how quickly the batteries reach full charge, then adjust as required. Remember that the absorption phase is where the charging current starts tapering down because the battery has reached 80% to 85% charge. (In your specific case)

If you err a little on the long side, don't panic because the sun goes down every single day with extreme reliability, reducing long periods of overcharge.

Marc

pyintheye · January 2017

Marc. Great links and good info for everyone running batteries.
Thanks to all members that have shared your experience and insight. That is what makes this forum one of the best.
Your knowledge means MORE power for the rest of us.
Kind Regards TT

pyintheye · January 2017

Hi to All
A couple of new questions I have for the neighbors system.
Apparently the installer said the system was Maxed out. Solar Boost 3024i, 3 Solar tech SPM 130P- 18.1V, 7.38A panels.
Q1- Can panels be added to this CC?
Q2- What is the safest panel configuration for the system? If they can be added.
Q3- Is this cc limited in respect to INPUT Amps or is the 54V Input max the deciding factor for MPPT controllers?

I can't figure out how to paste the Spec sheets and I don't know why the text changed.
TT

BB. · January 2017

Roughly, the maximum cost effective array would be:

30 amps * 14.5 volts charging * 1/0.77 panel+controller deratings = 565 Watt array cost effective maximum
565 Watt array / 130 Watt panels = 4.3 ~ 4 panels cost effective maximum (130 Watt panels)

You should be able to run 4 parallel (Vmp-array~18 volts) or 2 series x 2 parallel (Vmp-array~36 volts). The 2x2 is better if you have a longer distance from array to charge controller (less voltage/power losses in wiring).

The 54 volt maximum input is the "never to exceed" input voltage (higher voltage can/will damage the charge controller). You need to look at the Voc (voltage open circuit cold) of the array (at the lowest temperatures for your area--Voc and Vmp rise as temperatures fall).

Some charge controllers also have a maximum input current limit--You have to mix and match the panels+s/p configuration to meet all of the controller limits (min/max current/voltage).

I guess this is your charge controller:

http://www.blueskyenergyinc.com/uploads/pdf/Manual_BSE_SB3024i.pdf

-Bill

pyintheye · January 2017

Thanks BB
Sad to see the contractor installed them into a corner, so to speak. Not much room for expansion without a major system refit.
Originally he installed 2 -Rolls S550 batteries and by the looks of it, a bare minimum of PV charging capacity.
These are now trash after 2 yrs and a bit, due to sulfation.

To your question, yes, that is the CC. And I do get your point that "cost effective" is due to the 30A output for the CC.
Thank you very much TT

Vic · January 2017

pyintheye,

Just my opinion, but wonder just how quickly that your neighbor could get rid of that Solar Boost CC. It appears to be fairly difficult to change settings on it, but guess that it could do the job, if properly set.

According to the Surrette Battery Manual, the Temperature Compensation value should be set to -- 4mV/Cell/C, it defaults to -- 5 mV.

It I s good that you are helping your neighbor, and it appears that you DO know how to change settings on that CC. Perhaps the version of the CC is the one with the meter, believe that this was an option.

FWIW, Good Luck, Vic

pyintheye · January 2017

Hi Vic
What was one of the most curious aspects of the install, was that the Digital readout model of the CC was installed first. A few weeks went by and the contractor then showed up and changed the CC to the lesser flashing LED model, the exact reason was lost in translation for the solar newbies. But hey he was the professional.
As for the CC and the ignorantly small Dip-switches, you are correct, very frustrating to work with and access.
There was no temp sensor installed to the Solar Boost CC so that in itself is a huge drawback in functionality and being user friendly.

My advise to them is to run the genset in the morning until the Absorb End amps reaches the Solar amp output value, then let the PV take over the finish charging, SUN PERMITTING.
Also that without fail, regardless of weather, they attain a verified FULL charge at least once a week. Such as laundry day or house cleaning day, when the genset is running anyway for those large, long loads.
They will be using the chart that Marc has given, based on the 8hr discharge, to compare the battery voltage to the BMK SOC% to ensure they are not discharging to a harmful level.
As you can surmise, the maintenance free aspect of the AGM's is now out the window.

One thing I should note that has disturbed me with this installation. When I put in the new BMK, I opened the panel box to find wires crisscrossing every where, and there was a ground from the PV that crossed over the AC buss. So when the door was closed it had touched and was melted half through. Also found a wire lug that required 1 1/2 turns to tighten. Scarry!

Thoughts on fine tuning my advise would be appreciated.

TT

Vic · January 2017

Hi TT,

For most AGM installations, the Battery Temp Sensor is really mandatory, as Sealed batteries are very sensitive to accurate charge voltages. Hope that your neighbor can get and install it soon.

Batteries in root cellars, are in conditioned spaces, or otherwise will have very stable, known temperatures probably will not absolutely need the BTS, but they are inexpensive, so why not always use one.

Too bat about that installation "Pro", and all of the issues.

I am NO expert on AGMs, so will let others who are, address fine tuning the settings, etc.

Good Luck, Vic

pyintheye · January 2017

Hi Vic
The Magnum 2812 charger has a Temp sensor and will be doing most of the charging. The batteries are inside the living space on the floor so the Battery Temp has stayed pretty constant at around 66-69F.
Since the PV fluctuates by nature and is a fraction of the charging this time of year, I figure leaving the CC at the default setting should not be a big factor. As it gets into summer and longer PV charges I expect the Battery Temp will be at the normal operating range of 77F and good to go.
I have them recording the temp rise vs AB time to be able to catch anything out of sync.
I could be way out to lunch on my assumptions as I too have no experience with AGM.

TT

Rolls S460 AGM 415AH

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