Batteries?

[S L Dave]

It is time to start thinking about replacing the two batteries in my boat. I know bupkiss about the different brands.
does anyone use the real expensive AGM's. If someone is replacing the batteries every year...I wouldn't think the money would be well spent. BUT maybe it is, if you can keep the batteries for a few years with confidence. What do you guys think?

[welder]

AGM's and don't look back . I'm going to them next go round .
The fun part is shopping for a good price . The last time I looked Cabela's was the cheapest believe it or not.

[Bob5292]

If you go with Cabelas, make sure you track down one or two of the $25 off coupons first.

Bob

[JETTYWOLF]

I bought my boat and traded out (upgraded) to the AGM's because it was such a deal.

I'll replace with the exact same batteries, and NEVER use another battery.

Makes just too much sense to use the AGM's in my opinion,

[Capt. G]

AGMS are the way to go.

I bought Sears Marine Platinum Die Hards....good price and the best warranty (3 years free replacement)of any others I looked at.

http://www.sears.com/shc/s/p_10153_1260 ... +Batteries

[tlmjr]

I know this is a common theme with any group of boaters and I'll try to be as concise as possible. Having a bit of experience as a marine electrician I've replaced a lot of batteries. And for the most part they would not have been replaced had they been properly used and maintained.
The biggest problem I see is batteries getting put away without a full charge. The second problem is lack of maintenance.
I use flooded lead acid batteries. Period. I check cell levels regularly. And never store a battery without a full charge.
Storing batteries without a full charge causes the batteries to sulfate and they will no longer hold a full charge.
For years boats have come with a single battery and that's supposed to do everything, start the engine, power the house, electronics, down-riggers, lights etc.
At some point the battery won't start the engine. You test the battery and it comes up marginal or no good
So the guy at the shop says you need dual batteries so you always have one in reserve.
When he does the install he puts in a dual battery switch 1, 2, all, seems simple right. And he recommends deep cycle batteries for the extra power. All sounds good so far. Now comes the application error and improper use story.
Deep cycle batteries are designed for a low amperage sustained draw, not a rapid high amperage discharge ( say starting your engine) so right off the bat we've got a bad fit. Deep cycle batteries are designed for a slow recovery. Engine starting batteries are designed for a short high amperage burst, not long slow discharge, and rapid recovery. Most deep cycle batteries used for starting engines will endure a fair amount of abuse before they won't recover. The ideal arrangement is a cranking battery for starting and a deep cycle for the house load. Now comes the switch. Ideally you never run the boat in the all position. With two batteries with different charging characteristics you will never get both charged in the all position. When the switch is in "all" the charging system will sense a need for charging, when the smaller reserve is full it will cease charging. The pronblem is the charging system doesn't know one battery is a dep cycle and isn't recovered yet. I use the analogy of an ice cube tray having to overflow from one end to fill all the spots in the tray. So the easiest thing to do is to control where the power is coming from and where it needs to go.
Simple routine: Start your engine in the #1 position with the cranking battery. Run for a half hour or so. Switch to #2 (deep cycle) fish, play whatever all day. When coming home run in the #2 position to charge up. If you've only got a short run in the put a good "smart" charger on when you get home to finish up the charging. You recovered the #1 engine batt on the way out. Used the accy #2 batt all day and charged on the way home. Easy. Now keep the cells full of water.

Bottom line if somebody is replacing batteries every year or two he's not managing his system well. And even the most expensive batts wont last like they are intended to. The only time I'd put the switch in "all " is when I want 2 dead batteries.
Blue Sea Systems has a great kit to install an on/off switch with an automatic charge relay to keep your house battery fully charged without over charging you engine battery. The ACR hooks to the engine battery and allows current to pass to the house battery when needed.

The next thing to factor in i the engine. Older outboards running a mag/stator charging system have a relatively low output for charging and the max output is only acheived at WOT, not trolling. So when you are fishing you can figure your not charging squat. The modern engines with a belt driven alternator are much better. The AGM batts give outboard charging systems fits. I've seen it many times, slow to crank, hard starting, minimal charging system output. New AGM batts. All the diagnostics point to a fualty charging system and expensive repairs. Grab a regular lead acid flooded battery and put it in and all the problems go away. The battery guys argue this tooth and nail and can not answer the "why" question.

So like I said, maintain the fluid levels and store them fully charged and you'll get years of service. A $300 charger will keep your batteries going for years and will pay for itself in batteries alone, let alone labor or being DIW.

Sorry to soap box but this is an area too many people don't understand.

Tom Moore
Sales Manager/Systems Engineering
Nichols Diversified Industries
www.ndiboats.com
Because you don't really want the cheapest boat you can find.

[welder]

Tom , GREAT post ........
But would you recommend shutting down the motor to switch batts. so we don't take a chance on hammering the alternator with a no load situation ?

[Chaps]

Les, marine battery switches are a "make before break" design so the only time you might smoke something is if you turn them to "off" while he engine is running.

[JETTYWOLF]

Quote: "So like I said, maintain the fluid levels......"

Yeah, that's the part I don't like, and why I like the AGM's.

[Justindfish]

I'll be running AGM's in my new boat cause I'm like Jetty and hate maintaining batteries. Other benefits of the AGM design that I have found are one because the glass mat in the batteries is packed tight between the plates it acts as a support for the plate which means that they are more shock and vibration resistant. The support that the mat gives also allows the battery designer to use a purer lead plate which is better for capacity and cranking amps and such, which can't be used in a flooded cell because the plates would not be able to support their self in a marine use application with all of the bouncing and stuff. The other benefit is that they are sealed and under normal conditions should never leak even if mounted upside down however I do know that some of the group 31 deep cycles do have a vent but they don't vent out under normal use only if it was overcharged or something like that not quite sure of the details.

Just the fact of no maintenance and being sealed I was sold.

One other thing that I can say about batteries in general, this don't count for boats kept in the water as much as it does for trailered boats and vehicles.

I try to buy batteries from a store and brand that if I'm in Flordia or in South Texas 400 miles from home and my battery dies I can get it warrantied other wise it done me no good to get a battery with a warranty because you know your going to buy a new one to replace warranty or not if your on a fishing trip.

[mojomizer]

Great post Super. Even better answer Tom (tlmjr). What do you think of Solar panel chargers on helping keeping your batteries healthy? Any extra care using them on the aluminum alloy.

Thanks
Mark
2325 WA5 Pacificskiff