Battery Temperature compensation and Battery charge settings
photovoltaic
Solar Expert Posts: 37 ✭✭
Setting up the temperature compensation on the Morningstar Tristar 60 MPPT controller. In the setup menu it has temperature compensation V/ degree C
The specs for my East Penn Deka batteries say -3mV/ Cell/ degree C
So should I multiply the 0.003 x 6 ( cells) and put the result 0.018 in the for the V/degree ? I have 24 volt system but I believe the Morningstar multiplies the temperature compensation value by two like it does for other battery parameters.
The battery specs give a range between
14.4 to 14.7 Absorb end change in current < 0.10 per hour 12 hour maxtime
13.8 to 14.1 Float no time limit
15.0 to 15.3 Equalize end change in current < 0.10 per hour 12 hour maxtime
Setup asks for Absorbtion and Equalize Times in hours
Any suggestions on the hour times I should put in ? Or do I have to use the batteries awhile and observe how long it takes to get to the .010 per hour current ?
What voltage for the range is best to choose ? High, low , middle ?
On the other controller Midnite Classic I know it has end amps settings but I haven't determined that yet either. New batteries and I have not put a load on them yet.
Thank you for any suggestions - I know from reading there are lots of angles on best battery charging care.
The specs for my East Penn Deka batteries say -3mV/ Cell/ degree C
So should I multiply the 0.003 x 6 ( cells) and put the result 0.018 in the for the V/degree ? I have 24 volt system but I believe the Morningstar multiplies the temperature compensation value by two like it does for other battery parameters.
The battery specs give a range between
14.4 to 14.7 Absorb end change in current < 0.10 per hour 12 hour maxtime
13.8 to 14.1 Float no time limit
15.0 to 15.3 Equalize end change in current < 0.10 per hour 12 hour maxtime
Setup asks for Absorbtion and Equalize Times in hours
Any suggestions on the hour times I should put in ? Or do I have to use the batteries awhile and observe how long it takes to get to the .010 per hour current ?
What voltage for the range is best to choose ? High, low , middle ?
On the other controller Midnite Classic I know it has end amps settings but I haven't determined that yet either. New batteries and I have not put a load on them yet.
Thank you for any suggestions - I know from reading there are lots of angles on best battery charging care.
Comments
the .018v would be the correct figure for a 12v battery. not sure if you need to apply the multiplications on the mstar mppt or if it does it automatically as i do not own one. of course that voltage is for every degree c higher or lower than 25 degrees c with the trend being the voltage to rise as the temp lowers.
i would not eq agm batteries unless you know there is a problem with inequality and i would try another extended absorb charge before trying an eq.
as far as the absorb time this can vary somewhat and it does not hurt the battery to go a bit over the actual point it has finished its absorb charge, but if you want to know for sure then you can time it from the onset of absorb to the time it reaches the .01c (1% of charge capacity) point. i'm not sure just what the time intervals would be on the ms, but round the time up to the next higher time interval from what you've actually timed. for example if you see 1.88hrs then round this up to 2hrs.
as far as the best voltage to use you can opt for the middle of the settings range in most cases. this also allows for some possible errors such as voltage reading accuracy.
hope i covered this well enough for you.
Thanks Niel - you are wealth of new years knowledge. I have flooded lead acid batteries.
8L16 20 hr rate 370 amps 6 hr rate 295 amps Minutes discharge at 75 amps 190
One percent of 370 amps being 3.7 amps as the point to watch for ?
Here are the settings I put in it for now.
Morningstar Corp. TriStar MPPT Setup Summary
Printed on 1/1/2013 8:37:40 AM
Mode: Solar Charge
Setpoints (set the System Voltage with DIP switches 2 3):
Regulation Voltage: 14.70 V (12V), 29.40 V (24V), 58.80 V (48V)
Temperature Compensation: -0.019 V/degC (12V), -0.038 V/degC (24V), -0.077 V/degC (48V)
Min. Compensation Temp.: -30 deg C
Max. Compensation Temp.: 80 deg C
Absorption Time: 2:00:00 h:m:s
Absorption Ext. Voltage: disabled V
Battery Service Reminder: disabled days
Float Voltage: 14.00 V (12V), 28.00 V (24V), 56.01 V (48V)
Float Timeout: 0:00 h:m:s
Float Cancel Voltage: disabled V
Equalize Voltage: 15.20 V (12V), 30.40 V (24V), 60.80 V (48V)
Equalize Time: 2:00:00 h:m:s
Auto-Equalize Interval: 28 days
Equalize Timeout: 12:00:00 h:m:s
HVD: 15.40 V (12V), 30.79 V (24V), 61.59 V (48V)
HVDR: 14.00 V (12V), 28.00 V (24V), 56.01 V (48V)
Maximum Regulation Limit: 15.30 V (12V), 30.60 V (24V), 61.19 V (48V)
Maximum Battery Current: 0.00 A
Array Voltage Fixed Target: disabled V
Hi pv,
Just to be clear, you have a 24 V battery system. There are 12 ea 2 V cells in this system. So you need to multiply the neuber of cells by the per-cell Temp Comp voltage -- so, .003 V X 12 cells is 36 millivolts total for the bank if it is 24 V. Just how the MS CC arrives at this number, I do not know.
Have fun with the new system. Vic
Yeah I know , you put all the settings in Morningstar as 12v and it will adjust them according to the system voltage you select. I did put in the correct .018 for 12 volts but for some reason it changes it to .019 . Maybe a slight glitch - I might ask Morningstar but don't think it will make that much difference.
No problem using a smaller fuse than the wire rating--As long as the fuse is, at least, 1.25x the maximum continuous load (charging or discharging current) you plan on supporting.
I would also suggest tying off cables so that the fuses/connections do not carry any mechanical loads (heavy cables can tear out many printed circuit board terminations)--And if a fuse/connection/crimp mechanically fails, a flopping cable does not short something out.
-Bill
Yes good idea about supporting the cable - but might need warmer weather - it was -16 F last night and that cable is way too stiff to move around too much right now ! I will see what I can do.
photovoltaic,
please be sure of the end amps % you need as i was taking your word for that and in my search i had not found that spec. this is all i found,
http://www.dekabatteries.com/assets/base/0919b.pdf
Here are the East Penn Deka solar charging specs. Their solar L16 and their floor scrubber batteries L16 are the same just different labels.
Attachment not found.
ok, they aren't giving a percentage here.
Charge until change in current < 0.10A per Hr / Max Time: 12Hr
this is going to be a tedious babysitting job in observing this, but once you see that it is not changing much as per their spec you should note the current at that time and you can use that as your end amps setting. this may be impossible for solar to achieve if it takes the 12hrs max as they have sited.
Yeah - too bad a feature that would time stamp current charging isn't built into something like the Trimetric . That way you wouldn't have to be around watching it. Actually I think they do have some kind of data output on the new Trimetric - I will have to look into that.