More Rolls Surrette Battery Questions

sub3marathonman · January 2010

Hopefully this will be the best forum to post this battery question, I wasn't sure.

I too have really had questions about my Rolls Batteries from the time I got them in 4/2009. To me, they just never seemed to have the power I expected when I did a cycle on them.

There are four 12CS11PS batteries, 357ah each at 20hr rate, hooked up in series. My theoretical calculations are that this should have about 14kw of energy. The resting voltage is about 50.8, and I will discharge it to 49.2 for a cycle. I based the 49.2 on the NAWS battery FAQ section, which would be about a 30% cycle. But I'm not even really sure about that, since so many different places, even the Rolls Surrette people, have different values. But by my estimate, there would be about 2.25 to 3 kw used, discharging at the C20 rate. By my calculations, this is coming up somewhat short of the 4.2 kw I had estimated. I don't know though if it is a reason to be concerned.

Also, I have now gotten a high quality hydrometer (from NAWS), and took the following readings, after letting the batteries rest for about 10 hours:

Battery 1: 1.255, 1.250, 1.245, 1.255, 1.235, 1.215
Battery 2: 1.255, 1.245, 1.245, 1.270, 1.245, 1.245
Battery 3: 1.265, 1.265, 1.265, 1.265, 1.265, 1.230
Battery 4: 1.255, 1.250, 1.255, 1.215, 1.215, 1.220

So I'm now that I've got the data, I just need to know what it means. I'm hoping someone here will be able to further explain this.

Also, I just found from the Rolls website: http://www.rollsbattery.com/content/renewable-energy-bulletins-solar-wind?q=node/45&phpMyAdmin=2eda4dec0bd69647b9e3cf0f71e01d23&phpMyAdmin=9dec4a269d70t7a63be7c where it says, "A good rule of thumb is if there is 0.025 points or less between the high and low cell the battery is not defective. " With a 0.040 range on two of the batteries, and 0.035 range on one of the batteries, and really at the border of 0.025 for the other battery, I am becoming concerned.

hillbilly · January 2010

Re: More Rolls Surrette Battery Questions

Are those voltage readings under load, or open cell readings? I'd say if the 49.2V reading is under load, then you've not discharged 30% of your capacity (probably closer to 15-20% DOD). The other thing is that when you're judging capacity by extrapolating that far out, even a slight error in readings can make a big difference in your overall assessment. With lots of factors affecting voltage readings, it's best taken as a rough approximation, not a precise measure.
I think I'd be more concerned with the wide spread of your SG levels, that seems pretty far out of line to me (although I am far from an expert in this area).

blackswan555 · January 2010

Re: More Rolls Surrette Battery Questions

Did you commission them as per the rolls instructions and record the SG`s and levels ? When did you last EQ them , How ?

I would say they are in need of EQ,

Have a good one
Tim

edited to add ,http://www.rollsbattery.com/content/tech-faqs what is equalization.

maok · January 2010

Re: More Rolls Surrette Battery Questions

Hi,

I am a new user of rolls batteries, and I am a little bit concerned..
my SG also had yesterday diference around 0,040.
and when I am charging, the SG rising up very very slowly. after 5 hours of charging with 24 amp , the SG didnt rise at all. what does it mean?
maybe I am makeing a mistake somewhere.. I don know.
what do you think about this ?

thanks

blackswan555 · January 2010

Re: More Rolls Surrette Battery Questions

Which batteries ? What voltage you charging at ?

Tim

maok · January 2010

Re: More Rolls Surrette Battery Questions

It is S-530, two in series, so it is 12V system. and bulk voltage I have on 14,6V
charging current is 24 A. could it be the thing of little current?

blackswan555 · January 2010

Re: More Rolls Surrette Battery Questions

Rolls recommend 5 >13 % of C20 as a charge current, your bats are 400ah so you need 20 > 52 amps, You are at the very low end of charging and it will take a long time to (if you can) charge them at that, and I would think it impossible to EQ them.
Do you have temp compensation ?
Tim

BB. · January 2010

Re: More Rolls Surrette Battery Questions

Maok started another thread. A few of us have already replied and it will probably be less confusing (at least to me :roll: ) if his responses continue on his own thread:

SG rising up on ROLLS

-Bill

sub3marathonman · January 2010

Re: More Rolls Surrette Battery Questions

blackswan555 wrote: »

Rolls recommend 5 >13 % of C20 as a charge current, your bats are 400ah so you need 20 > 52 amps, You are at the very low end of charging and it will take a long time to (if you can) charge them at that, and I would think it impossible to EQ them.
Do you have temp compensation ?
Tim

Actually, for equalization, Rolls says "5 amps per 100 ah" which of course is 5% of capacity, or stated another way, C20. I too thought that was a very low current, but I followed their directions. So far though, it seems like the batteries aren't where they should be. The questions I sent to Rolls haven't been answered either.

BB. · January 2010

Re: More Rolls Surrette Battery Questions

The 5 amp per 100 AH is their "low current" recommended equalization current. Of course, you can only properly equalize a battery once it has reached the fully charged state.

-Bill

Dave Angelini · January 2010

Re: More Rolls Surrette Battery Questions

BB. wrote: »

The 5 amp per 100 AH is their "low current" recommended equalization current. Of course, you can only properly equalize a battery once it has reached the fully charged state.

-Bill

Xantrex has even locked out the possibility of EQ without going thru an Absorption on the XW's. They just have too many uninformed users. Liability problems also as an EQ on a low battery can be a reason for a fire. Hey let's all be green even if we are clueless!

BB. · January 2010

Re: More Rolls Surrette Battery Questions

Dave,

Interesting. How can "equalization" cause a fire on a low battery? Is not C/20 just a current mode charge that is timed and/or voltage limited?

I could see if somebody sets "equalize" voltage/current without any time limit/off conditions causing problems (overcharging to failure)... But that would be true of any current mode based charging (with voltages > 14.X volts).

-Bill

Dave Angelini · January 2010

Re: More Rolls Surrette Battery Questions

Bill, You read some of the S****** up systems that post here! If a system can't get to the set-point (bad battery connection) for instance and the guy/gal had someone program this to happen unattended. ....There are even more failure modes (3 that I know) and this is not directed at the OP so please do not take offense!

By making the charger complete absorption (in a normal way) the charger then goes thru the algorithm and says OK let's try EQ. It is frustrating because an advanced user must program EQ early in the day or accept the fact that once you program it the unit will start the process from scratch even if the cycle had completed earlier in that same day. Firmware fix time.

Explosions often start fires !

sub3marathonman · January 2010

Re: More Rolls Surrette Battery Questions

Dave Sparks wrote: »

Bill, You read some of the S****** up systems that post here! If a system can't get to the set-point (bad battery connection) for instance and the guy/gal had someone program this to happen unattended. ....There are even more failure modes (3 that I know) and this is not directed at the OP so please do not take offense!

By making the charger complete absorption (in a normal way) the charger then goes thru the algorithm and says OK let's try EQ. It is frustrating because an advanced user must program EQ early in the day or accept the fact that once you program it the unit will start the process from scratch even if the cycle had completed earlier in that same day. Firmware fix time.

Explosions often start fires !

OK, I'm not offended. But unfortunately still somewhat confused.

On the XW6048 you can just push the Equalization button, and it will start. I would do that after it had recharged the batteries, and the batteries had rested for many hours. It did seem like it started once again to recharge the batteries, but it didn't last very long, maybe even only a few minutes. Then it went to Equalization, which it would do for exactly one hour. What is confusing to me though is I thought Equalization was supposed to last several hours, but I didn't really see any parameters to set for Equalization besides the voltages and the charging rate.

Dave Angelini · January 2010

Re: More Rolls Surrette Battery Questions

The setting is 1 hour for the CC and the XW inv/chg in the current firmware for both. I seem to remember that the time was adjustable in the advance mode on a previous revision. One hour should be what you normally use unless there are problems with the battery! Good Luck!

More Rolls Surrette Battery Questions

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