Absorbed glass mat batteries (Optima, etc.)

[toyotafreak]

(this was cut from my alternator/dash cpu post) Hopefully this info will be useful to some of you, and maybe save you a little time.

After a few hours of research, I chose an Optima deep cycle absorbed glass mat battery which was maybe like an inch taller, and fit a bit more snug into the well of our 2000 S22.

To digress for a moment, let me spill my new knowledge (before I forget it ;-) Automotive and many marine batteries are 'starting' batteries. Their application is to generate lots of current to turn starters. They need low internal resistance, so their lead plates are very thin. Because the plates are thin, serious damage happens when they're run down. Leave the lights on in your car (to the point where the battery's really dead) two, three times and you'll severely damage it's future ability to accept and hold a charge. The capacity of starting batteries are measured in amp-hours (meaning how many amps can be delivered over x number of hours.) Their cranking ability is measured in CA and CCA (how many amps can they push out in certain temperature ranges.)

Deep cycle batteries are intended to be run down 'deep'. Think sailboat: charge it up at the dock, then use it all day to power radios, air conditioners, refrigerators, etc. When it's dead, it's dead and in need of a recharge. Get back to the dock and charge it up. Do that 50 times and the battery is still in good shape. A true deep cycle battery will never have cranking amps listed, because it's intended to be a house battery, not a starting battery. These batteries can be used for starting, it's not a harm issue, it's just that since they're optimized for storage capacity, they don't put out a lot of cranking amps (high internal resistance.) To get your required starting amps from a deep cycle, you need a larger, higher capacity battery to turn out the required amps.

So why do our marine deep cycle batteries have CA and CCA listed? Because their not really deep cycle, they're hybrids. My Optima ($150 at Costco) has CA and CCA listed, and because it's both bigger, higher capacity, better technology and hybrid, it's got a few more cranking amps than the little battery we were provided with new.

The absorbed glass mat (AGM) batteries such as the Optima are superior to conventional wet and newer gel batteries in every respect except price. They are safer (less prone to leaking and outgassing) than wet batteries and more robust (vibration and heat resistant) than both types. AGMs can accept charge rates far higher than either type (like 4C, or four times the battery capacity - a 100 amp/hour battery can be safely charged a 400 amps during the early part of the charge.) We have good alternators (80 or 100 amps), but if you had a real alternator (like a 200- or 400- amp marine unit), you could recharge a dead AGM deep cycle to 80% in an hour or two.

The final kicker for me was the low discharge rate of the AGM. In SoCal, we ski pretty much year round. Much reduced frequency in the winter, but still doable. Even so, we might go a month or two months without putting her in the water. I knew we were going to have to invest in a decent charger/maintainer to keep the battery from getting killed in the first couple years. Typical wet batteries self-discharge at 1% of capacity per day. Let it set for 30 days and you've taken the first 30% off the top. AGM batteries self-discharge at 1% per month. Cool, that just saved me $100 for a Chargetech.


Derek Boyer
(714) 758-4029

[cyclone]

Good info. I put an Optima deep cell marine battery in my boat using a Hellroaring isolator just to run the stereo. I have a Napa starting  battery, both charge by the alternator but there is no diode (.7vdc) loss as with typical isolator/combiners. See the how too page for pics.

[toyotafreak]

Ran across this the other night while trying to plan a sound system for the S22. Once again, I wish I hadn't, cuz now my mind is just trying to find additional ways to justify getting it.

It's just a pair of Optima deep cycle AGMs in a bitchen platic case. Super clean setup. In parallel (to yield 12VDC) it offers 110 Amp-hours of capacity.

I've got a single AGM, but know that adding three amplifiers will create quite a load underway or at anchor. I'm afraid that with a 'normal' two battery setup, we might only get an hour or so of music out of it while we're sitting on the beach. Two house batteries would double that.

Clearly Cyclone's isolator scheme will be in effect, and the Hellroaring site provides a ton of different schemes (think I'd treat it like a trolling battery.)

The package sells for $349 (including shipping, etc.)

Anyway, here's the first pic:

[toyotafreak]

Second pic:

[cyclone]

That's cool, I wonder if you would ever need it. I stashed my second battery in unused space, no lost storage. I think that if I were you, I would put in one extra battery and see if that's enough. You won't run the stereo nearly as hard at the beach as you will when towing. If you  do, nobody will go out with you.

[Windy2]

So I posted this once - but can't find it now - so here goes again - apologies if it's a double.

I picked up a second battery (Optima, blue) and want to figure out how to hook it up.  Can't do the high end set-up on the maintenance page so just want something simple & right which won't blow fuses or scramble computers.  Suggestions please - is there a right way to add a second battery to an 01SX?

[cyclone]

I would use either a 1/2/all Perko type battery switch, one batt hooked to 1, one hooked to 2, or a continuous duty solenoid that connects the alternator output to the second battery only when the ignition is on. Stinger makes a 200 amp one.

[toyotafreak]

Sympathize with the budget (trust me on that), but ask yourself how many $150 batteries do you want to risk with undercharging/overcharging?

This is a tricky subject, and I think there's still some dispute about the best way to take care of these batteries. Recently, there was a post by the King of Bling on Wakeworld about the 'proper' way to charge an Optima. It involved varying voltages during the charge cycle, and if I recall correctly, he stated that such a charger would cost over $1K. His alternative was to charge them at home with a wall charger before going to stuff that last bit of juice into the batteries. Grant's good, but I'm not sure that there aren't some cheaper alternatives out there that still provide the multi-voltage charge pattern.

So long as you aren't running the batteries below 10.5 volts or whatever that figure is, AND you don't over-charge them, your batteries are going to live a long, happy life. The way to protect yourself from the former is vigilance. The latter is prevented through a good isolator that charges each battery separately.

The final issue is simply trying to get them to hold a decent charge - that's why you have them in the first place, correct? Besides the issue that Grant brought up about really optimizing the charge, Pete's Hellroaring isolator improves over the simple (cheap) isolator because it charges the batteries to a voltage 0.7 vdc higher than what a normal isolator will do. If you consider 14 volts full charge and 10.5 full discharge, you can see that 0.7 vdc is a pretty big percentage increase.

If I were adding a second or second and third (Optima's Troll Fury is still cool IMHO) battery, I'd probably do some more research into what Grant's talking about before making any purchases. If I found no new info, I'd go the Hellroaring route. No doubt. There have been a couple times I've had the duckets for an amp or two and some speakers, but the expense of upgrading the power system has kept me down. I've decided that a second battery is mandatory and that a third battery would be highly desired. I also decided that with $450 in batteries, I wouldn't take a chance with a cheap isolator. It's kinda like infrastructure or logistics - generals want cargo planes and senators want fighters. So yeah, my desire for infrastructure has kept me from going to war with my stereo, but when I do it, I want to do it right.

I don't want to kill expensive batteries, and I don't want to have to jump start my boat. Ever.

[cyclone]

He was just hard headed about using a true battery charger (multistage) vs. a trickle charger, which he's been using for years, and his minions were convinced that anything he does must be right. He runs his batteries down and has never had a charger that would replenish all his batteries, so they sulfate and die a premature death.

Keep in mind, the guy doesn't wakeboard. He puts boards in the rack, fires up the 12v blender and the sound system and commences cocktail hour while tied up.

The rest of us, who run our boats, get our batteries charged while the boat is running.

If you buy a decent quality battery charger that delivers over 10 amps and is capable of charging lead/acid batteries (i.e. Optimas), and leave it on there long enough to fully charge the batteries, you will have no problems.

I have a dual bank 20 amp onboard smart charger, cost $150. It charges my batteries fully in a couple of hours.

[toyotafreak]

You dual-bank charger is run by shore power, right Pete? Not the alternator; that's hooked up to the isolator, correct?

I wonder how many of them stereo gurus run two separate alternators. That'd be true independence, huh?

Hey Pete....don't be telling your minions about Grant's minions. You pimps gotta keep us in the dark about that. Nothin but love for you.

[Windy2]

There's an awful lot of stuff I don't understand above.  I can start researching it and learning and will start doing so this pm.  In the meantime, is there room for common ground (no pun intended) between you two?  The boat will get towed 4 hours to the lake and put in a manual lift once there.  It'll get used every weekend until the iceman cometh - at least if I have anything to do with it.  What it won't have is shore power.  It won't see Mr. AC/DC again until it gets towed home in six months - so I really want the batteries to be Ok.

[cyclone]

I would put in a second battery separated by an isolator, and I would not put in a big stereo system. Here is a relay type isolator, you can also use the stinger relay I referenced above.

http://www.yandina.com/c100Info.htm

I used a fancier one made by hellroaring, but it is probably overkill in your case.

I would use a large combination deep cell/starting battery for the second battery, as you probably are most concerned with being able to start the boat. I think I would also carry one of those jump starter packs, they are cheap and a lifesaver.

OR, put in an Optima Deep cell/starting battery as your only battery, and carry a jump start pack with you to the lake. That's probably all you really need. The extra batteries are really for running the stereo when parked. 

[toyotafreak]

Ditto what Pete said. If your current battery is a wet-cell battery and your new Blue-top fits, just replace the sucker outright and MAKE SURE you turn off the perko switch when you hoist her up.

With no drain on the Optima (perko switch rolled), you can leave it for a month and come back and it'll be only 1% weaker than you left it.

I run this setup (stock stereo) and have never been concerned about starting in the three years we've run the boat. Just a serious no brainer for me - turn off the battery switch when we get home, and next month when we pull it out, turn the key and whammo - a nearly fully-charged battery ready to roll.

Incidentally, my note about the Optimas being able to take a TON of charge very quickly is good because our alternators are just awesome. Once when the low voltage alarms had me concerned that the alternator might not be up to snuff, I took it out and a guy bench tested it up above 90 amps - that's a LOT of juice, and the Optima can take it all. In other words, that 1% you discharged while it was sitting on the lift is going to be restored in about a microsecond.

For safety's sake (with a stock sound system) you really have NOTHING to worry about. You'll probably have a harder time keeping your back up starting pack charged. I don't have one, but then again, at the first sign that my Blue-top is getting unreliable, I'll replace it.

If you're running amplifiers, then do what Pete said in his last post. 

[lesman01]

ditto what pete and freak said. There, now I feel smart.

[Windy2]

Ok - so I bought the Optima and pulled the OEM battery out and put it on the charger - took 3.5 days but its now good as gold.  Guess I now own a spare.  The Optima was a very tight fit - practically had to stand on it to push it into the tray - didn't want to trim all the rug off and a tight fit is better than a loose one.  By the way, once it slid into the tray (which is about 1" deep), I now have about 2" above it (above the top of the posts) to the bottom of the seat.

Like the suggestion about just turning the perko off but there are 4 sets of additional leads that bypass the perko.  Haven't been able to trace them down yet.  But absolutely nothing will turn on when the perko is off so they must be something secondary like the amp, the lube dispense & goodness knows what the others could be - those are the only two non-stock items on the boat.