Battery Power

Help!

I have carefully measured my current draw in my glider at .8 amp. l would
like to know if there is any reasonable explanation for why a 9 amp hour
battery goes from 13 volts open circuit fully charged to 11.6 volts in 4
hours.

MC

On Sunday, September 23, 2012 3:15:04 PM UTC-7, Mike McCarron wrote:
Help!



I have carefully measured my current draw in my glider at .8 amp. l would

like to know if there is any reasonable explanation for why a 9 amp hour

battery goes from 13 volts open circuit fully charged to 11.6 volts in 4

hours.



MC

Would need to know a lot mo Fully charge the battery and then let it rest off the charger for 12 hours. If it measures 13 V, then either your battery, charger, or DVM is bad. It should read about 12.6 - 12.8 depending on the technology assuming some sort of lead acid. Then run the battery for 4 hours with your 0.8A load. Then remove the load and let rest for several hours, then measure. Should measure about 12.1V or so. Measuring just after removing the charger, or under load, or just after removing the load will give you erroneous results, if your goal is to use voltage as a state of charge indication.

I have carefully measured my current draw in my glider at .8 amp. *l would
like to know if there is any reasonable explanation for why a 9 amp hour
battery goes from 13 volts open circuit fully charged to 11.6 volts in 4
hours.

What's the battery type?

Bart

At 15:53 24 September 2012, Bart wrote:
I have carefully measured my current draw in my glider at .8 amp. =A0l
wo=
uld
like to know if there is any reasonable explanation for why a 9 amp
hour
battery goes from 13 volts open circuit fully charged to 11.6 volts in
4
hours.

What's the battery type?

Bart

Power Sonic Model PS-1290 F2 Sealed Rechargeable

I am guessing lead acid

Mike

At 15:53 24 September 2012, Bart wrote:
I have carefully measured my current draw in my glider at .8 amp. =A0l
wo=
uld
like to know if there is any reasonable explanation for why a 9 amp
hour
battery goes from 13 volts open circuit fully charged to 11.6 volts in
4
hours.

What's the battery type?

Bart

Power Sonic Model PS-1290 F2 Sealed Rechargeable

I am guessing lead acid

Mike

At 15:53 24 September 2012, Bart wrote:
I have carefully measured my current draw in my glider at .8 amp. =A0l
wo=
uld
like to know if there is any reasonable explanation for why a 9 amp
hour
battery goes from 13 volts open circuit fully charged to 11.6 volts in
4
hours.

What's the battery type?

Bart

Power Sonic Model PS-1290 F2 Sealed Rechargeable

I am guessing lead acid

Mike

At 15:53 24 September 2012, Bart wrote:
I have carefully measured my current draw in my glider at .8 amp. =A0l
wo=
uld
like to know if there is any reasonable explanation for why a 9 amp
hour
battery goes from 13 volts open circuit fully charged to 11.6 volts in
4
hours.

What's the battery type?

Bart

Power Sonic Model PS-1290 F2 Sealed Rechargeable

I am guessing lead acid

Mike

At 15:53 24 September 2012, Bart wrote:
I have carefully measured my current draw in my glider at .8 amp. =A0l
wo=
uld
like to know if there is any reasonable explanation for why a 9 amp
hour
battery goes from 13 volts open circuit fully charged to 11.6 volts in
4
hours.

What's the battery type?

Bart

Power Sonic Model PS-1290 F2 Sealed Rechargeable

I am guessing lead acid

Mike

At 15:53 24 September 2012, Bart wrote:
I have carefully measured my current draw in my glider at .8 amp. =A0l
wo=
uld
like to know if there is any reasonable explanation for why a 9 amp
hour
battery goes from 13 volts open circuit fully charged to 11.6 volts in
4
hours.

What's the battery type?

Bart

Power Sonic Model PS-1290 F2 Sealed Rechargeable

I am guessing lead acid

Mike

On Sep 24, 10:30*am, Mike McCarron wrote:
Power Sonic Model PS-1290 F2 Sealed Rechargeable

http://tinyurl.com/c4n9hem

This battery is rated for 8.1 AH @ 810mA, when discharging to 10.5V.

The manufacturer's discharge curves suggest that if 11.6V is your
minimum, then you should get approximately 8 hours out of your battery
at 0.8A. Obviously, something is wrong.

There may be a voltage drop somewhere in your installation. This would
not affect open circuit measurements, but could be significant under
load. Where do you measure battery voltage? At the battery terminals,
at the panel?

The manufacturer says "Charge until battery voltage (under charge)
reaches 14.4 to 14.7 volts at 68°F (20°C). Hold at 14.4 to 14.7 volts
until current drops to under 90mA." Can you verify that this is what
your charger is doing?

Bart