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WakeWorld Discussion Board » Boats, Accessories & Tow Vehicles » Archive through June 28, 2009 » AGM Battery Swap out « Previous Next »
By "G" (grant_west) on Wednesday, May 20, 2009 - 10:27 pm:    Edit Post Delete Post
I have been running West Marine Sea Volt Battery's for 3 years now. Just recently I have noticed that the battery's are not holding a charge like they used to. I had asked around to try and decide if I should go with a different battery. Kenitic, Odyssey, Stinger ect. It's hard to make a choice about a battery from other peoples stories because everyone's system demands are different. Mike used to run 6v golf carts. He switched over to Kinetics. He said that he didn't think the Kinetics were any better than the golf carts so they were out. I started thinking. Maybe it's better to go with what you know than to try a new battery thatís more $ and is no better than what you had. So after doing some checking around I decided to stick with the West Marine Sea Volts. They have a 5 year pro rated warranty. So I still had some equity in the 5 old batteries. I took them back to West Marine and It turns out the old battery's were worth like $75 each. With my port supply discount the batteries ended up costing like $158 each. The original batteries were 92 Amp hrs each. The new battery's are 105 Amp hrs each and are just slightly longer by like 1 1/2 inches longer. When you add up all 5 battery's at 105 Amp hrs im getting an extra 65 amp hrs (that's more than 1 blue top optima) just by going from group 27 to group 31.
Here are some picks of the bats. The last 2 cell phone picks are of the original 92 amp hr battery next to the new larger 105 Amp hr battery. You can see the size difference between the 2.

By Darren Yearsley (ralph) on Wednesday, May 20, 2009 - 10:38 pm:    Edit Post Delete Post
Going to do a sexy rack system G?
By Brett Yates (polarbill) on Wednesday, May 20, 2009 - 11:33 pm:    Edit Post Delete Post
G, West Marine batteries are Deka rebranded. Although group 31's are only slightly bigger than the group 27's the specs are quite different. I think you will be happy with them.
By Ryan Bush (ryanbush11) on Thursday, May 21, 2009 - 5:36 am:    Edit Post Delete Post
Those things look heavy
By "G" (grant_west) on Thursday, May 21, 2009 - 6:59 am:    Edit Post Delete Post
Bill: Yes the size of the 31's are only slightly bigger but they weigh 13 lbs more. So that tell's me there is somthing diffrent going on inside. Thicker plates more acid I don't know but IMO the size dosen't add up to the extra weight.
Darren: No my Batt's are tucked away you don't see them so they stack on top of each other behind the rear seat.

By Richard Coop (mendo247) on Thursday, May 21, 2009 - 8:00 am:    Edit Post Delete Post
Nice. Ive been looking at some West Marine 6 volt batteries. Did you notice if they had many of them in stock?
By Bill K (bill_airjunky) on Thursday, May 21, 2009 - 9:41 am:    Edit Post Delete Post
So I checked the Deka website & found one of their retail outlets here in town. I was quoted:
$176 for the group 27 AGM (580 CCA, 63 lbs)
$149 for the group 24, AGM (525 CCA, 53 lbs)

By "G" (grant_west) on Thursday, May 21, 2009 - 10:08 am:    Edit Post Delete Post
Bill: West Marine has the Grp 24's for the same price $149
The grp 27's are a bit more $199.
Your local retail'r does he offer the 5 year pro rated warranty? Is there a West amrine near you?

By "G" (grant_west) on Thursday, May 21, 2009 - 10:35 am:    Edit Post Delete Post
2 or 3 more tid bits of info I got yesterday. My AGM's have discharge cycle # of 300. That means the battery can be fully discharged up to 300 times. That's from full to empty 300 times. More times if you don't discharge all the way so for example if you only discharge 1/2 way all of the time you could jump the discharge cycles up to 600 times.
The gel batteries in the same size had a discharge cycle of 500 times.
A AGM grp 31 has 105 Amp hrs and is $259
A Gel grp 31 has 97 Amp hrs is $ 339

2nd Tid Bit. Iím using the West Marine Digital smart charge. It has a MAX amp output of 30 Amp's

#1 thatís not enough for all 5 of my batteries. That might explain way I have killed 2 of these digital smart chargers.
#2 Iím going to start looking for a charger that has individual charging banks. Right now my charger looks at the entire 5 batteries hooked all together as 1 large battery. A charger with the ability to charge individual banks or battery's can take care of the needs of each different battery not just throw a charge to all of them. One of the down sides of having a large battery bank with multiple batteries in different location of the boat is. If one of the 5 in my battery bank go's bad it will pull or draw down the other 4. Trying to figure out what battery is bad is a pain in the butt. They would all need to be disconnected from each other and tested to find the bad one. From my understanding a charger with individual banks would show you the state of each individual battery. A bad battery would should up as a battery that never reaches full charge or takes way longer than the other 5 to reach full charge.

I was told AGM's need a bulk charge right off the bat. Like 40 amp's to each one. Then the charger ramp's down and up and all over the place till the batteries are at full. A single 30 Amp charger divided among 5 AGM batteries I guess is just not cutting it.

Anyone have any ideas or suggestions. Is my information correct? The only thing im confused about is how the hell does the charger with individual battery banks monitor batteries that are all hooked together as one? I thought the only way a charge could do this was if they were all disconnected from each other?

By Brandon Holmes (bmh2208) on Thursday, May 21, 2009 - 11:33 am:    Edit Post Delete Post
Have you checked into what the guys are doing with electric cars?

They all employ some sort of BCM (battery control module), I think, that monitors and charges similar to what you want to do. I think they just have an extra wire or two that goes to each cell. Might be worth a look at adapting that to your situation.

Here's a link to a blog where a guy converted a S2000 to full electric. He has a lot of info about the charging stuff and monitoring stuff.

By bthom (billthom) on Friday, May 22, 2009 - 1:21 pm:    Edit Post Delete Post
Grant - I think it depends on how you hook it up. If you have multiple batteries wired in parallel, and only one output from the charger attached to the bank it just sees one battery. But if you have multiple outputs from the charger hooked to each battery then it can see them independently.

I have a ProMariner 20 Plus 3 bank charger and I think thatís how it works.

By Brett Yates (polarbill) on Friday, May 22, 2009 - 2:00 pm:    Edit Post Delete Post
Bill, if you come over to Seattle anytime soon I can do the 8A27M for 157/ea or the 8a24M for $133/ea.
By Mikeski (mikeski) on Saturday, May 23, 2009 - 2:15 pm:    Edit Post Delete Post
Here is a link to IOTA chargers built in Arizona.

These are designed for charging solar power backup batteries. You can get chargers ranging from 15-90 amps at 12 volts. Anything over 55 amps is going to required a dedicated 20 amp 110 volt outlet in your house (standard garage plugs are on a GFCI and rated at 15 amps). At your house we can just pigtail a dedicated charger cable right out of the main panel, but that won't help you when you are at a friends house.

You may want to get one of these as your primary charger and keep the 40A charger as your "mobile unit".

You may also consider adding some disconnect plugs so you can charge individual banks at different times:

By Brant Williams (kitewake) on Friday, May 29, 2009 - 1:38 am:    Edit Post Delete Post
My system:
-WMarine AGM 105 as my start battery
-WMarine AGM 4D as my house battery
-Balmar 140A Alt
-Balmar Alt Regulator
-Balmar Duo Charge
-Pro-Tech 1240i Plus Shore Charger
-All chargers and Alt Reg are set up for AGM charging voltages and cycles.

System has been 100% bulletproof so far. I don't even think about electrical issues.

By "G" (grant_west) on Friday, May 29, 2009 - 6:40 am:    Edit Post Delete Post
How long have you had this system?
I would say my system has been bullet proof for 3 years. But in the last month I noticed It would not hold a charge as long

By Tanner Russell (tanner) on Friday, May 29, 2009 - 4:44 pm:    Edit Post Delete Post
I've been thinking of switching to AGM's as well. I've been running w/ Trojan T-145's and getting tired of messing w/ the acid spills I occasionally have. Problem is the AGM's just don't match the capacity. :-(

On two T-145's I can play for almost 6 hours exactly at 3/4 volume. I switched to running 4, b/c 6 hours just isn't enough :-) I got just enough room to keep them totally concealed and not lose any storage. I don't really wanna go to more batteries. The amps pulling on the batteries are as follows...

2 - Arc KS 300.2's (700W each)
1 - Arc KS 1000.1 (1000 W)
1 - Arc KS 300.4 (90W x 4...more like 125x4)


I've been using a refurbed Xantrex 40+ true charge for 3 years now... and I love it! This weekend was the first I ran the 4 6V's batteries instead of 2. I charged them as a bank w/ series and parallel connections like you. But I've been thinking about making a bus bar and seperating the two 12V strings and charging them seperately.... as the charger has 4 banks available. But are you really gaining anything? Your still having connect 2 batteries in my situation to get the 12V charge. I've got a call into Quinton at Trojan to discuss this with him next week. Might look into that charger though... it's def. nice. Especially w/ the optional temp guage.

(Message edited by Tanner on May 29, 2009)

By tom fischer (tomfish) on Friday, May 29, 2009 - 5:24 pm:    Edit Post Delete Post
I installed the quick fill on my 6 volts then you dont have to take off the caps and just a couple of pumps and they are all topped off w/no mess. worth the money for sure.
By talltigeguy (talltigeguy) on Saturday, May 30, 2009 - 9:40 am:    Edit Post Delete Post
What do you guys think about putting an inline circuit breaker with a manual reset between the batteries? Then you could hit a button and isolate each battery from one another easily with just flipping a switch? Attaching a separate charger or lead to each battery would then be a piece of cake and identifying when one battery dies might be easier as well.
By Mikeski (mikeski) on Saturday, May 30, 2009 - 3:37 pm:    Edit Post Delete Post

I think it would be easier to have a row of Perko type switches, you could do it with 3 A/B switches pretty easily.

By Tanner Russell (tanner) on Saturday, May 30, 2009 - 5:15 pm:    Edit Post Delete Post
Either way, it's essentially serving the same purpose. Unless your running 6 volts like me and then your still stuck trying to figure out which battery of the 12V string is bad. At least u can isolate it to the string. OR CAN YOU???

It's not like my charger has an arrow that points and says this connection has the bad battery on it. So when your charging on a multi bank charger.... like G asked.... how do you know which battery is bad?

By craig f (craig_f) on Saturday, May 30, 2009 - 6:40 pm:    Edit Post Delete Post
I guess you need 5 batteries to run 27 underwater led.....

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