Starting Battery

Ken Juul · February 06, 2009, 11:33:57 AM

New batteries are on the spring project list. As well as a battery wiring update. I've got everybodies notes, still planning and referencing. One think I have decided is to move the starting battery to the aft cabin with it's own switch. It is probably going into the void under the settee. I know more power is better, but I think I might be space limited. What is the minimum CCA needed to reliably get the engine started?

Stu Jackson · February 06, 2009, 11:48:48 AM

CCAs for our small engines aren't really a limiting factor. Jim Moe's Electrical in Projects discusses it. We've been using a small 60ah start battery for years.

Steve Sayian · February 06, 2009, 12:02:16 PM

Ken,

Do you have an alternator with two output taps for the two battery banks, or do you use the battery selector switch as the isolator?

Steve

Jon Schneider · February 06, 2009, 12:08:19 PM

Ken, I went with an Optima AGM starting battery (red top). Fantastic product. Often available at a decent price at Sam's Club. No maintenance, which is important in the aft berth. My house bank is a wet cell bank, so I use a DuoCharge to charge the AGM from the house bank (the DuoCharge allows you to set the chemistry of the receiving battery). I love the set up. Also, moving the starting battery that close to the actual starter makes a huge difference (in addition to short-wiring the glow plugs).

PS: Ken, I know you know this, but for the benefit of everyone else, there are also terrific articles written on this subject which you can find in the electrical section of c34.org/wiki. Check out the articles by by Jim Moe, Mark Elkin, and John Gardner; all have great advice on setting up a starting battery.

Ron Hill · February 06, 2009, 02:09:13 PM

Ken : You can get a small Gp 24 starting battery - it might be 650 CCA. West Marine usually has a spring starting battery sale. Also if you have a Cabela's or Gander Mt. close to you, look at their batteries.

Stu Jackson · February 06, 2009, 02:09:59 PM

Steve, most alternators have only one output and it should run to the house bank. Use a separate switch, a combiner or echo charger or duo-charge to charge the reserve emergency (formerly known as the "start") bank. Don't use the 1-2-B switch for alternator output.

See: http://c34.org/bbs/index.php/topic,4623.0.html for starters, then do a search on 1-2-B switch to read more.

Kyle Ewing · February 06, 2009, 03:12:35 PM

Ken,

I used an Optima 34M-1050 (Blue top) in the aft cabin. Group 34 batteries are shorter (7.81") and fit fine under the aft birth near the shaft. Because they're sealed they can be "mounted in any orientation" per the literature so leveling isn't as important. I used the Blue Sea m-Series Mini Dual Circuit Plus (#6011) under the head sink and an Echo-charge to charge it.

Kyle Ewing
Donnybrook #1010

Ken Juul · February 08, 2009, 06:39:21 AM

I have a combiner for the charging side, PO installed, not sure of the make. Part of the reason I asked the question was my current starting battery has 650 CCA and sometimes barely cranks the engine. If that is enough, then it is either a tired battery, bad wires/connections or a combination. thanks for the inputs.

Craig Illman · February 08, 2009, 07:10:16 AM

Ken - You're correct, it's probably both. If you've never addressed the connections, they definitely need re-termination. Your boat is a bit older than mine. My lugs were minimally crimped on non-tinned wire. Check or redo both the postive and ground paths at every connection.

How old is the battery? I only expect seven years for my car batteries. Be careful mixing battery types with your combiner, unless you set your charger/regulator to the battery type with the lower charging thresholds.

Craig

Jon Schneider · February 08, 2009, 08:38:23 AM

Ken, the great thing about the Optima is something that Stu discovered for me last year when he was helping me with my re-wiring project. He discovered that the Optima AGM (as opposed to other AGMs) actually takes the same charge voltage as a standard flooded cell (14.6V), so, with the Optima, you don't have to worry about whether or not you're mixing chemistries, but you get all of the advantages of a no-maintenance, high-power AGM.

Stu Jackson · February 08, 2009, 09:45:04 AM

We "discovered" this by reading the regulator manual (gosh, did a guy say that?).

Ken, also with your combiner, check your manual and you should be able to put a shut off (toggle) switch in the ground wire to shut the combiner off so that you don't overcharge your brand new reserve emergency battery.

Mike Vaccaro · February 09, 2009, 02:01:41 PM

Ken,

I concur with the Optima recommendation for all the reasons noted. No issues with deep cycle (blue top), dual-use (yellow top) or starting (red top). Our engines don't demand too much from a battery mounted near the starter. If you're having issues with your ability to start, could also be the starter itself. Relatively straight forward to remove and rebuild, if required. 'Course, it's always important to fix the easiest thing first! Stick to your battery/wiring troubleshooting plan. We mounted our battery (Optima Deep Cycle) under the aft berth. We chose this flavor because it was available, i.e., it was part of the house bank when we bought the boat six years ago. I glassed a platform into the hull adjacent to the shaft log and used Igloo cooler mountings to brace the four corners (they match the radius on the Optima) and a battery strap around the platform. The wiring run to the alternator and starter is only about 24". The Optima's tolerate "standard" voltage as Jon noted--makes this straight forward if you have a lead acid house bank and an alternator with a built-in regulator. Any "out of sight, out of mind" mounting location merits a maintenance-free battery. We changed ours last summer simply because we didn't know how old it was or how badly it was abused before we bought the boat...

Cheers,

Mike

Ron Hill · February 15, 2009, 06:00:09 PM

As I mentioned about sales : West Marine has a sale till 1 March of a Gp 24 MCA 725, AGM battery for $149. A thought.

Stu Jackson · February 15, 2009, 08:20:48 PM

And as Jim Moe's electrical system article, among others, mentions, you could spend half of that at Sears for a simple automotive battery. Stay away form marine stores for ALL batteries.

If you're still having starting issues, start with the usual suspects: wiring connections and the grounds. Check the + connection at the battery switch, per John Nixon's suggestions. Basics...

Jon Schneider · February 15, 2009, 09:03:12 PM

Quote from: Stu Jackson on February 15, 2009, 08:20:48 PM
And as Jim Moe's electrical system article, among others, mentions, you could spend half of that at Sears for a simple automotive battery. Stay away form marine stores for ALL batteries.

But my reco for an Optima was based on its maintenance-free benefit, since the battery was going to be placed under the aft berth. The equivalent AGM from Sears is $189.99. I'm not sure if the WM battery is quite as good from CCA perspective, so I still think an Optima starting battery from a low-cost distributor such as Sam's Club (where I got mine for about $140) is the way to go. Unbelievable cranking power and zero maintenance. Plug n play compatibility with a flooded-cell bank for charging. Can't beat it.