[C320-list] Flooded vs. AGM batteries

[Warren Updike]

Wow! I thought I tended to be wordy. Still, good info for those in the throes of a battery decision. 

When I bought my last pair of 4Ds, I, too, did some investigation. The formula you cited gives an approximation of AH. I was originally told by a technician at Interstate that the SRM-4D is 195AH. Later, I got the following reply from another at Interstate: 
	Warren, 
	"The Ah (0f the SRM-4D) is actually 234ah per battery. Take the RC total, which is 390 x .6 = 234Ah. I sent you a copy of the RC with the ampere loads attached. The peukert is 1.19 see how this works for you. If you need anything else, drop me a line. 
	Thanks, Jeff Barron"

 As you know, the designation "4D" is a form factor and has nothing to do with what is inside. Most commercial 4D batteries are truck batteries intended for starting and deep cycle and so are a compromise of both purposes. The SRM-4D from Interstate is a "Deeper" cycle battery and hence the heavier weight, 120lbs. I've used them for 10 years and they work for me. We are cruisers and are out for weeks at a time. 

Another point made by R.C. Collins (Main Sail on catalinaowners.com) is that if you are using an Ah counter (battery monitor) and I am, it is prudent to adjust the AH setting in the monitor each year to compensate for the loss of capacity as the battery ages. He suggests reducing the AH by 5% after the first year, then by 3% each subsequent year; and, being sure to often synchronize your monitor with a known fully charged bank. 

Re. installation: Having bought my SRM-4Ds at our marina, they delivered them to the boat, on the hard or in the water. With a bad back, I can't lift them by myself; but, is easy with another person. All I do is lift them to the sole of the salon on a towel. Then, using a block and tackle rig hung from the boom (with a topping lift) I haul them out of the cabin onto the dock or down to the ground. The new ones come onboard the same way. Easy to do. Make sure no one is underneath. 

I don't think there is any question that wet cells are the best value the for house bank. They are fine for starting and house loads. That said, there are other reasons why people choose AGMs and I don't disparage their choice. But, for me, the wet cells do the job. Maintenance and monitoring are the keys to long battery life.

Warren and Pattie Updike
1994 C320 "Warr de Mar" #62

-----Original Message-----
From: Tim Westhoven [mailto:westhoven at wcnet.org] 
Sent: Thursday, July 03, 2014 5:13 PM
To: c320-list at lists.catalina320.com
Subject: [C320-list] Flooded vs. AGM batteries

Well, I finally made a decision after sweating details in between real
estate appointments this week. I received tons of help from many of our
great Catalina 320 Association members and I truly appreciate it. It was
like a dog chasing it's own tail-- so much information that I suffered from
paralysis by analysis, deciding, then changing my mind again and again! In
the end, I chose Interstate SRM-4D flooded batteries because they seemed to
be true deep cycle batteries and weighed 20 lbs heavier than most at 119
lbs, which somewhere in all the things I read said that meant more lead and
more recharge cycles in the long run.

What I learned:

   - Most motor boaters wanted to sell me smaller batteries because as they
   run, they charge them back up. I figured that with my fridge (it's got
   booze in it all season to keep cold), instruments, stereo and the
   occasional use of cabin lights while sailing, I need a big, deep cycle
   battery for house and a strong one for the engine, too. I want to stay on a
   mooring ball at Put-In-Bay and not sweat being able to keep my beer cold
   and getting my engine started.
   - AGMs need a strong charger to bring them back up full every time and I
   never really answered the question for real, but thought that if I brought
   her in to port late in the evening and wanted to sail early, then I would
   be taking it off charge before it was fully charged, which is bad for an
   AGM. I have a Zantrex 20 charger, but a safer bet would be a charger that
   does 30 amps. And then there's the question of what gauge wire from charger
   to batteries and the distance, which seemed to be pretty far. I read that
   they should be close together or you could cut the amperage by a few
   percent and, starting with just 20 to begin with, I thought it might be a
   problem. Flooded batteries don't have those questions to answer and if I
   did it wrong, there goes $1,000 - 1,200 for ruined AGMs.
   - Each battery maker seems to do all they can to obscure the specs so
   you'll just buy on name recognition, I guess. Interstate uses RC (Reserve
   Capacity) to determine how long the battery will last while drawing 25 amps
   at 80 degrees before dropping to 10.5 volts. (Don't even think about it if
   you've worked long hours, it will just give you a headache) Others use AH
   (Amp Hours), which is the measure of how many hours you can be on the hook
   drawing one amp. So to get a conversion from RC to AH, multiply RC by .4167.
   So my 390 RC Interstate is 162.5 AH. Not nearly as much as the AGMs I
   researched, but will work fine because of my boat's ability to recharge
   them and maybe not so much the AGM batteries. The Exide Nautilus was 250 RC
   or 104.17 AH. Lifeline AGMs have 210 AH, but they're stinkin' expensive and
   hard to acquire. And to confuse things more, the same Lifeline battery
   states the RC at 390, which doesn't follow the equation and instead, would
   infer that the AH was 162.5, just like the Interstate batteries I bought.
   Interstate doesn't say what the AH is, just the RC. For someone as OCD as
   me, this can bottle up my whole week trying to decipher.
   - Another frustrating this is trying to search for "4D marine
   battery" online. You get every battery category under the sun to wade
   through in order to find 4Ds, which are scarce because few use them, I
   would reckon. When you find them, many vendors don't publish the specs, so
   you don't have any idea what you're getting. Many dealers tried to sell
   heavy duty batteries, but the more I read, I really wanted the durability
   of the marine battery architecture to keep the guts together in rough seas.
   Also, I would encourage investigating the differences between starting
   batteries (lots of power up front, not so great in terms of staying power,
   like the tortoise and the hare), deep cycle batteries (for house power with
   cabin lights, fridge, instruments, they last longer with smaller draws of
   power) and truck batteries vs. marine batteries. If you are a sailor who
   doesn't have a lot of toys eating power, then you can probably get by with
   smaller, lighter batteries. But if you decide to add things, you'll want
   the power to go with them. My boat is my lake cottage and we use it as
   such.

In the end, I liked what I read about the marine construction of the case
and plates in the Interstate battery and the fact that I could go pick the
damn things up later the same day in Sandusky for $220 each plus $50
deposit, which I will get back when I buck them back to the store.

I stopped at Home Depot and got a furniture dolly for $20 because I didn't
know if anyone at the dock would have a cart I could borrow. This thing is
a wooden rectangle covered with carpet on two sides with four wheels. It's
about four inches tall, so I loaded both batteries on it and crawl-walked
the thing down the long dock to my boat on the end. They are heavy, but not
that heavy. I slung the first up over the rail and on the deck, then
stepped it down on the cockpit seat, then the floor. I opened up the gang
way and stepped on the bottom step and heaved it up on the threshold, then
to the top step, then the floor in front of the battery compartment. I had
removed the table and all cushions and got everything cleared out of the
way.

The old batteries were already carted out in the reverse order previously.
There were puddles of acid in the bottom of the battery compartment, so I
had to be careful getting the old ones out, setting them on old towels as I
bounced them along the exit route. That's a pretty important point, because
along the way, there are wooden steps that I imagine could be damaged by
sulphuric acid. I had prepared a baking soda solution in a cheap sprayer I
bought at Walmart. A quart of water and a few tablespoons of baking soda
dissolved in it. I used that to clean off the terminals of the old
batteries and then to clean everything that ended up with acid on it,
including the floor and battery compartments. You'll end up with a white
haze and think you've dissolved your fiberglass boat lining, but it's just
residual baking soda dried in place. Wipe it off and rinse a bit if need
be.

The Interstate batteries had both a standard lead post and a bolt post,
which helped me eliminate the new terminals I bought at Walmart to replace
the old posts-- purchased before I bought the batteries because I didn't
know the old batteries were toast yet. It's a nice feature to be able to go
directly from the wire to the battery with no intermediate terminal to
become loose. The new batteries are about a quarter inch shorter than the
old ones, but a tad longer. Now I have to custom fit a piece of wood
between the hold-downs and the battery to make sure it holds securely in
place.

Hate the bleeding bastards, but wet batteries eliminated questions and took
away potential anxiety of ruining AGMs through ignorance. I've got enough
to worry about, my boat just went in the water last week!

Hope this helps a bit for future 320 battery buyers in our helpful group.
Warren Updike got me to re-consider wet batteries to begin with, then
Warren Pandy at Catalina backed up that idea, then my buddy Paul Rickman,
Affinity's previous owner and perpetual caregiver, re-sold the idea again.
Man, that guy knows this boat like the back of his hand! And thanks again to
everyone else I didn't mention specifically for the tips.

*Tim Westhoven, *
*​Affinity*

 *Herl's Harbor*

*2263 N.E. Catawba*

*Port Clinton, Ohio 43452*

*419-409-1000 mobile*

westhoven at wcnet.org
<https://mail.google.com/mail/?view=cm&fs=1&tf=1&to=westhoven@wcnet.org>


*​Life is for those who live it!*