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Posted: 8/19/2001 2:16:15 PM EDT
Any one know the cutoff? I want to use it for a fan. M4-AK
Link Posted: 8/19/2001 2:20:22 PM EDT
Link Posted: 8/19/2001 2:32:49 PM EDT
Yes... Thanks. What is the lowest safe voltage I can drain it to before I should recharge. M4-AK
Link Posted: 8/21/2001 3:34:33 PM EDT
Geez, I figured someone knew. M4-AK
Link Posted: 8/21/2001 6:32:23 PM EDT
From a chart in a Trace inverter owners manual, a 50% discharged battery will be 12.1 volts, at 77F, that has been at rest for 3 hours. You shouldn't drain it more than 50% or so on a regular basis if you want it to last. Since this voltage will vary with temperature and recent charge/discharge this may not be a good way to judge the condition. Better to use time, and discharge it less than 50% of its A-Hr capacity between chargings. The time you can run it is half the A-Hr capacity divided by the current draw of the fan. Be sure to use a special gel cell charger, since a regular charger will over charge a gel cell, and ruin it over time.
Link Posted: 8/22/2001 5:17:02 AM EDT
Thanks for the help. I am surprised at the half way cutoff. That seriously compromises usage of the battery capacity. Oh well. Again thanks for the help. M4-AK
Link Posted: 8/22/2001 5:39:08 AM EDT
[Last Edit: 8/22/2001 5:35:25 AM EDT by RBAD]
The cut off was a surprise to me too.. This is one disadvantage of using lead-acid batteries. When we designed our (don't laugh at me !) Y2K backup power plan, we had to double the capacity of our lead-acid battery bank at the last second to allow for this. I ended up with over 16 of the large L16 batteries in my basement ! (we had planned on charging w/ diesel generator during the day and using battery power via inverter at night) It is not wise to deep discharge these batteries and it is pretty important to use a good charger (with conditioning capabilities) when charging.
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