Absorption Voltage question.

Put it down in the 14.4 to 14.8 volt range. Set the equalize at 15.2 once a month 15 minutes if you find you are not getting fully charged. Adjust as needed.

BFL13 wrote:
This comes up from time to time. Interstate wrongly gave that high voltage for the Vabs when they really meant it for the "finish" stage in a particular charging profile (third one down at bottom of this)

http://pdf.wholesalesolar.com/battery-folder/charging_instruction_2011_2.pdf

So for "normal" charging like the two- step one in the middle graph, use 14.8v for your Vabs and you will be fine. Only use the 15+ voltage step occasionally to do the recommended "overcharge." Keep an eye on your SG with an hydrometer to tell when you need one of those overcharge sessions. (also makes you look at your "water" level, which is a good thing)

Dang BFL13 you put it sooooo much nicer then i did. :B

VintageRacer wrote:
First question is why look up the specs if you are going to second guess them? I use right around that voltage. Absorbtion is a higher voltage but with a continually dropping current that goes right down to almost nothing at the end, then you get the maintenance or float charge. Your numbers look perfect to me.

Because Interstate are idiots at getting correct information to there customers. The batteries are made in Mexico in a factory that US battery built. US battery charging specs

This comes up from time to time. Interstate wrongly gave that high voltage for the Vabs when they really meant it for the "finish" stage in a particular charging profile (third one down at bottom of this)

http://pdf.wholesalesolar.com/battery-folder/charging_instruction_2011_2.pdf

So for "normal" charging like the two- step one in the middle graph, use 14.8v for your Vabs and you will be fine. Only use the 15+ voltage step occasionally to do the recommended "overcharge." Keep an eye on your SG with an hydrometer to tell when you need one of those overcharge sessions. (also makes you look at your "water" level, which is a good thing)

mchero wrote:
I have 4 Interstate 6v GC2-XHD-UTL house batteries, two series strings in parallel. Setting up the Midnight Solar 200 Classic Light and I think the Absorption rate appears to be on the high side.


Specs at http://www.interstatedealers.com/pdf/201535.pdf
show Absorption at 7.65 for 6v so I double to get 15.3
I did find other documentation below that also states 7.65 Absorption Last towards bottom;
http://www.batteries-faq.com/activekb/questions.php?questionid=1

Look at this it will show volts per cell. Just use the vpc and times by 6

Batteries
Interstate GC2-XHD-UTL
232ah/battery 464 total
Bulk 14.4
Abs. 15.3
Fl. 13.4
Eq. 15.6
InputV Battery Offset adj. -0.1
InputV Array Offset adj. 1.8

Should I stick with the 15.3 or drop it down?

Use this Use the VOLTS PER CELL VPC numbers times six

First question is why look up the specs if you are going to second guess them? I use right around that voltage. Absorbtion is a higher voltage but with a continually dropping current that goes right down to almost nothing at the end, then you get the maintenance or float charge. Your numbers look perfect to me.