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  #51  
Old 11-24-2012
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Re: Battery Sizing - am I crazy?

Quote:
Originally Posted by blt2ski View Post
Along with the OP has not been heard from since day one!

maybe over his/her head!?!?!?!?!???

Marty
Not all over my head!

Enjoying the great replies and reading them closely. Sounds like the consensus is that I can get away with a much smaller set up. I am intrigued by the GC battery idea, but think I'm going to go with the simpler project of swapping 12v batteries with smaller/cheaper new ones. Then at least I'll keep a charge overnight!

-Charts
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Old 11-24-2012
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Re: Battery Sizing - am I crazy?

Safest would be to use the same style. If current are flooded, get flooded. If AGM, get AGM, etc.

Your charging system should already be designed for which you have. The wrong combo can kill the new batts.
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Re: Battery Sizing - am I crazy?

Well, I ended up buying two Everstart Marine 29DC (selection #95), 845 marine cranking, 122AH@1amp batteries. This afternoon I loaded them up on the boat, and took out the old ones.

Taking out the old ones involved a lot bumps, scraps, lots of ropes, block and tackle, a metal bar across the top of the companion way, etc etc...

I can't believe I got them out! They're in the cockpit now. Need to figure out how to get them off the boat. I can't see slinging them in/out of my dinghy like I did the new ones.

Probably need to enlist some strongbacks.

I'll post again with how the batteries work out.

-Charts
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Re: Battery Sizing - am I crazy?

Now you need to repaint your waterline.
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Re: Battery Sizing - am I crazy?

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I can't believe I got them out! They're in the cockpit now. Need to figure out how to get them off the boat. I can't see slinging them in/out of my dinghy like I did the new ones.

Pull up to dock. Block and tackle off the end of the boom and lift and swing boom over the dock and drop



Dave
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Re: Battery Sizing - am I crazy?

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Originally Posted by chartscharts View Post
Well, I ended up buying two Everstart Marine 29DC (selection #95), 845 marine cranking, 122AH@1amp batteries.
Something is fishy. Industry standard is to rate batteries at a 20hr discharge rate. 1amp discharge suggests these batteries would last 122hrs, but if you increase the draw to 2amps, the hours drop by more than half due to resistance.

Increase the draw to a fairly light 5 or 6 amps and, while the linear math would suggest 20+ hours, I'm sure it would be substantially less. Maybe only a few hours.

Further compound this by best practice not to draw your batteries down by more than 50% of their capacity for longest life and these sound like they may be a little light.

Going to one or two smaller batteries sounded like a good idea, its just that something doesn't sound right about these, if they are advertised at 1amp. There are some battery gurus around here that may know better than I.
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Re: Battery Sizing - am I crazy?

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Something is fishy. Industry standard is to rate batteries at a 20hr discharge rate. 1amp discharge suggests these batteries would last 122hrs, but if you increase the draw to 2amps, the hours drop by more than half due to resistance.

Increase the draw to a fairly light 5 or 6 amps and, while the linear math would suggest 20+ hours, I'm sure it would be substantially less. Maybe only a few hours.

Further compound this by best practice not to draw your batteries down by more than 50% of their capacity for longest life and these sound like they may be a little light.

Going to one or two smaller batteries sounded like a good idea, its just that something doesn't sound right about these, if they are advertised at 1amp. There are some battery gurus around here that may know better than I.

As I mentioned in an earlier post the Ah rating on those batts is meaningless. Likely a BAD mistake by the marketing department... Problem is no one at Wal*Mart knows the correct specs....
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Re: Battery Sizing - am I crazy?

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As I mentioned in an earlier post the Ah rating on those batts is meaningless. Likely a BAD mistake by the marketing department... Problem is no one at Wal*Mart knows the correct specs....
Ohhhhh, Wallyworld batteries. It will be interesting to hear how they make out in year 2.
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Re: Battery Sizing - am I crazy?

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Ohhhhh, Wallyworld batteries. It will be interesting to hear how they make out in year 2.
Mine are going on year six......

However my Wal*Mart batteries were made by US Battery for Johnson Controls who then sold them to Wal*Mart. US Battery makes excellent quality batteries, some of the best "12V marine" batteries, & 6V, other than Trojan..

Wal*Mart has since sourced a less expensive replacement for the batteries I have and they are NOT the same. I can't however comment on the longevity because I stopped using them due to the "lack of a clue" about batteries that Wal*Mart exhibits. Sam's Club, the sister company, took on Deka/East Penn so that is a HUGE + !!

6 Year Wal*Mart Battery Observations
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Last edited by Maine Sail; 11-25-2012 at 08:53 AM.
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Re: Battery Sizing - am I crazy?

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Mine are going on year six......
And, no doubt, the version you purchased weren't rated at 1amp or you would have run.
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