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nuckollsr(at)cox.net
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 Posted: Fri Jun 22, 2007 8:08 pm Post subject: Cutting off battery posts |
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At 10:21 PM 6/22/2007 -0400, you wrote:
| Quote: |
<terrence_miles(at)hotmail.com>
Hi all,
I bought a pair of Yellow Top Optima batteries. They are the absorbed gas
matt type. They are located in the nose area and stacked one on top of the
other in my Velocity XL. I cut the top posts off the bottom battery due to
height limitations and planned to use the side posts.
That turned out to be a mistake. Even though I have good continuity between
the top post nub and the side posts, the battery will not accept an external
charge. It shows 12.1 v or so, but collapses under any kind of load.
Without being all that clear despite my best efforts to learn more of the
mechanical connections involved...the tech service arm of Optima said
cutting off the posts somehow compromises the top-post-to-side-post physical
connection. He also said removing the posts opens the battery's controlled
venting system to outside air.
I was surprised at both of these discoveries...and out $200 to boot.
Anybody out there running side post batteries w/ the top posts removed?
|
Without knowing the details of how the post is molded and retained
in the battery housing, the experiment is not without risk . . . when
you cut the posts off, were they not solid? I.e., a smooth lead alloy
surface with no holes? I'm mystified as to how this would have compromised
the seal if they were smooth, contiguous surfaces after cutting.
| Quote: | Likely I am back to the drawing boards for a complete redesign now of
battery size and hold downs, but I am considering one alternative and that
is mounting a new Optima upside down with the top posts still in place by
drilling holes in my mounting floor for the posts to protrude into. Risks
there would be if I ever overcharged it, electrolyte would leak on the base
surface. Any thoughts? Suggestions?
|
Those are real "pig" batteries. Do you NEED the capacity? Or the weight?
As I recall, the smallest of the yellow-top batteries are something on
the order of 50 a.h. batteries at a 2-hour rate and weighs about 44 pounds.
Is this the battery we're talking about?
http://tinyurl.com/2z8xgu
Unless you need the weight, surely there are smaller batteries that meet
your electrical needs that don't cost so much and will fit into the space
allotted?
Bob . . .
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Eric M. Jones
Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts
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| Posted: Sat Jun 23, 2007 5:33 am Post subject: Re: Cutting off battery posts |
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The Optimal Battery one might use is the D51:
See http://tinyurl.com/2e3drf
The Optima website is abysmal and never improved or added to.
D51 is 26 pounds and 46 AH. The reason I like this battery is the claimed superior resistance to vibration. My plan is to eschew the twin-battery and switchover technique in favor of single-battery simplicity. If you wanted two batteries these are probably too heavy.
But in my plan, there is an XBM Xantrex Battery Monitor that tells me everything I need to know beforehand about the battery condition AND how many minutes of battery life remains if the alternator quits. A second battery is another way to do this job, but I think the reserve battery is not as good as total info about the only battery.
I use a racecar battery connect-disconnect switch instead of a contactor. to satisfy the FAA "one-hand disconnect" rule. The kill switch also cuts off the fuel and perfoms other "pre-crash" functions.
Yes cutting off the terminals was a mistake. Perhaps Opitma can repair it for you. Or perhaps "That's the price of an education".
---------
Every act of conscious learning requires the willingness to suffer an injury to one's self-esteem. That is why young children, before they are aware of their own self-importance, learn so easily.
--Thomas Szasz
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_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net |
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pwmac(at)sisna.com
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| Posted: Sat Jun 23, 2007 5:42 am Post subject: Cutting off battery posts |
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Hi Terry,
I have 4 un,molested yellow tops (2 trucks with dual setups) and
one with very little use acts just like yours. I think the guy you
talked to is blowing smoke. The vent is independent with the battery
posts, unless you cut into the plastic case. By looking at the
battery it is obvious that there is a conductor path from top to side
posts. If you cut above the plastic surface the conduction path or
vent would not be affected. I think the design uses the top terminal
as the primary connection to the plates and the side post are just an
extension. Thus cutting the top post just above the plastic would
maintain the integrity of the battery. If you have voltage at the
side terminal after the cutting then you still have contact to the
plates and the battery should take a charge.
Bottom line, I think you just got a bad battery. You are not the only
one out there. The last time I bought yellow tops I had to wait for 3
weeks as their production was backed up. Just a sign of problems at
the factory. The quality had been going down hill since Johnson
bought the company.
I am having second thought about Optima.
Regards, Paul
=============================
At 08:21 PM 6/22/2007, you wrote:
| Quote: |
<terrence_miles(at)hotmail.com>
Hi all,
I bought a pair of Yellow Top Optima batteries. They are the absorbed gas
matt type. They are located in the nose area and stacked one on top of the
other in my Velocity XL. I cut the top posts off the bottom battery due to
height limitations and planned to use the side posts.
That turned out to be a mistake. Even though I have good continuity between
the top post nub and the side posts, the battery will not accept an external
charge. It shows 12.1 v or so, but collapses under any kind of load.
Without being all that clear despite my best efforts to learn more of the
mechanical connections involved...the tech service arm of Optima said
cutting off the posts somehow compromises the top-post-to-side-post physical
connection. He also said removing the posts opens the battery's controlled
venting system to outside air.
I was surprised at both of these discoveries...and out $200 to boot.
Anybody out there running side post batteries w/ the top posts removed?
Likely I am back to the drawing boards for a complete redesign now of
battery size and hold downs, but I am considering one alternative and that
is mounting a new Optima upside down with the top posts still in place by
drilling holes in my mounting floor for the posts to protrude into. Risks
there would be if I ever overcharged it, electrolyte would leak on the base
surface. Any thoughts? Suggestions?
Thanks
Terry
|
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cjensen(at)dts9000.com
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| Posted: Sat Jun 23, 2007 8:25 am Post subject: Cutting off battery posts |
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Hi, Terry,
I understand the dual battery setup and the reasons for it, but am still
not convinced the added complexity and weight is offset by the benefits.
I converted to the Odyssey PC925 with 980amp cranking. It's small,
lightweight, $130 and can be positioned any way except upside down. I
removed my original dual battery setup and went for simplicity. Even
with 14-15amp draw with everything turned on, I have more than enough
reserve to get to VFR is the alternator goes down. As far as cranking
power, the single PC925 has enough cranking power that the starter is
likely to melt before the juice is gone, so a second battery doesn't buy
me much except more weight, maintenance, electrical control complexity.
I've done both but would not go back to the two battery arrangement.
The single PC925 fits with lots of room to spare. Just a thought.
Chuck Jensen
--
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