Maker Pro
Maker Pro

Lead Acid battery Monitor

J

Jim Crow

Jan 1, 1970
0
Hi, I am trying to monitor a 12 volt 3.2 Ah Yuasa lead acid battery to
prevent deep cycle discharge in a standby battery, does anyone know
what the minimum voltage is that I can discharge to, without damaging
the battery. Many Thanx
 
M

martin griffith

Jan 1, 1970
0
Hi, I am trying to monitor a 12 volt 3.2 Ah Yuasa lead acid battery to
prevent deep cycle discharge in a standby battery, does anyone know
what the minimum voltage is that I can discharge to, without damaging
the battery. Many Thanx


http://www.batteryuniversity.com/


martin
 
J

Jim Crow

Jan 1, 1970
0
Thanx for the link martin but I can only find open circuit minimum
voltage levels, I am not sure if they are what I want. The voltage is
to be monitored whilst on load to prevent the deep discharge. In the
yuasa manual the 20 hour discharge rate goes down to 1.75 volt per
cell. Is this the level the batteries can discharge to before being
damaged.
 
A

AJ

Jan 1, 1970
0
Jim Crow said:
Hi, I am trying to monitor a 12 volt 3.2 Ah Yuasa lead acid battery to
prevent deep cycle discharge in a standby battery, does anyone know
what the minimum voltage is that I can discharge to, without damaging
the battery. Many Thanx

Depends a bit on the current but 10.5V is generally safe

Regards


AJ
 
M

martin griffith

Jan 1, 1970
0
Thanx for the link martin but I can only find open circuit minimum
voltage levels, I am not sure if they are what I want. The voltage is
to be monitored whilst on load to prevent the deep discharge. In the
yuasa manual the 20 hour discharge rate goes down to 1.75 volt per
cell. Is this the level the batteries can discharge to before being
damaged.

I am no expert, but it may be possible that the damage is accumlative,
so the more times you discharge heavily, the less capable is the
battery of holding its next charge.

I would take the yuasa figures as the " never ever exceed, preferably
dont even get close". Maybe wkipedia will help, now that google is
past its sell by date


martin
 
L

Luhan

Jan 1, 1970
0
Jim said:
Hi, I am trying to monitor a 12 volt 3.2 Ah Yuasa lead acid battery to
prevent deep cycle discharge in a standby battery, does anyone know
what the minimum voltage is that I can discharge to, without damaging
the battery. Many Thanx

I think I used about 10.5 volts under whatever load...

http://members.cox.net/berniekm/bchg.html

Luhan
 
H

Homer J Simpson

Jan 1, 1970
0
Thanx for the link martin but I can only find open circuit minimum
voltage levels, I am not sure if they are what I want. The voltage is
to be monitored whilst on load to prevent the deep discharge. In the
yuasa manual the 20 hour discharge rate goes down to 1.75 volt per
cell. Is this the level the batteries can discharge to before being
damaged.

You can measure the intercell voltages by using lead probes in the battery
acid.
 
J

Jake

Jan 1, 1970
0
I think I used about 10.5 volts under whatever load...

http://members.cox.net/berniekm/bchg.html

Is 10.5 volts at 25degC not the 100% discharged figure?

I thought the intention was not to deep cycle the battery?

The battery manufacturer will be the best place to get the info as all
"lead acid" batteries are not the same.

Note that these batteries have a temperature dependence that should not be
ignored when monitoring voltages. There ia also a shift in voltage with
age and condition....

Texas, Unitrode, Vishay and others have application notes that will be
useful. See UC3906 app notes.

http://www.technick.net/public/code/cp_dpage.php?aiocp_dp=guide_bpw2_00_toc

More than you wanted to know

Jake
 

neon

Oct 21, 2006
1,325
Joined
Oct 21, 2006
Messages
1,325
The question is not how deeply you can discharge the question is the rate of discharge Vs the damage. A rule of thumb is 1/3 of the voltage there is no damage provided that there is no heat involved heat will do the damage.
 
Top