nuckolls.bob(at)cox.net
Guest
|
 Posted: Fri Jul 25, 2008 5:42 pm Post subject: recommendations for building a 24V battery? |
 |
|
At 05:25 PM 7/25/2008 -0500, you wrote:
| Quote: |
I'm looking into building a 24V battery for an airborne payload with
the following spec's:
- 12AH minimum, no CCA requirement (not used for starting)
- bolted terminals
- no FAA/PMA approval required
- no need for metal jackets, etc., to protect from the environment
- hanging off of a bus fed by a 28V alternator
Several offerings from Odyssey (PC535/545/625/680), Panasonic
(LC-RD1217P), and Powersonic (PS-12180) fit the bill. Thus far, the
Powersonic battery beats the rest on price and weight per AH. Has
anyone had good/bad experience with Powersonic batteries?
The paperwork from Powersonic posts a charge voltage range of 14.4 to
14.7V and a float range of 13.5V to 13.8V. First, is it valid to
simply double these for the 24V battery?
|
yes
| Quote: | Second, the 28V bus will be
sitting between 28.5 and 28.9V nominally which is just under the
"charge" range (assuming doubling the 12V range is valid) but a volt
or so above the "float" range.
|
the TC fleet setpoint for 28v lead-acid batteries is
28.5 volts . . . 28.9 won't reduce service life in
ways that you can observe.
What are your battery-only energy storage requirements?
Does the system DEPEND on a battery for functionality?
In other words, would a failed battery contactor put
the outcome of the flight at risk? What preventative
maintenance program do you plan for replacing batteries
before they're incapable of supporting battery only
systems for the designed endurance mode?
| Quote: | Probably not worth a worry but I want
to make sure.
Any other tricks/techniques/gotchas related to the care and feeding of
ganged batteries will be appreciated.
|
There's nothing magic about a 24v battery vs two 12v batteries.
The electrical and chemical characteristics of one 24 is
identical to a pair of 12s.
There's no objective data to suggest that any particular
brand of battery is the better value in terms of
$replacement$/service-hours. Periodic cap testing of the
batteries in service is the 100% foolproof way to guarantee
system performance irrespective of the batteries you choose
to try.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
