www.iFourWinns.com

I know Volvo and other manufacturers warn against using deep cycle batteries for starting, due to the heavy current load that starters put on a battery. On the other hand, I only start my boat in pretty warm weather so the battery should be near peak power and the engine isn't overly hard to start. Has anyone actually had or heard of a problem using a deep cycle battery for a starting battery?

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"No Losses"

Deep cycle batteries have fewer and thicker plates. They are designed for a lower amp draw over a longer time frame. Starting batteries have more and thinner plates, allowing greater contact with the electolyte, thus quicker discharge/recharge and higher amp draw for shorter times. Therefore, using a deep cycle battery for starting would result in a higher power density (that is amps per sq in of plate area) and greater heating, cooking off the electrolyte, and reducing battery life. I spent 7 years maintaining batteries in critical back-up applications, and became well versed.

Read the info in the link below.

http://www.cabelas.com/cabelas/en/templ ... ieldguides

I only use Deep cycle for stereos, as fishermen use for trolling motors.

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Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.

So have two if you're concerned. I believe the new boats generally tend to have a dual-purpose sort of battery model. I can't recall which one at the moment. But if you've only got one battery you're not going to be able to restart the engine if you run it down. Like by leaving the radio running all afternoon, or a chartplotter (or all of the above). Many boats have batteries dedicated for starting only, one for each engine. Our 348 came with three; port and starboard engine and a 'system' battery for the accessories. I added a pair of 6V (in series for 12v) golf cart model batteries to the system circuit. No more low voltage issues even with all weekend use.

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-Bill Kearney, 2005 348 Vista

I have an old FW and the way the boat is wired I could not have a dedicated starting and cycling battery. I did use group 27 deep cycles for starting (had a pair of them and a switch) and running the bilge pump (moored boat, auto bilge switch), and they were fine for 5 seasons. Just replaced them with a pair of Deka group 27 dual purpose batteries, since they should meet my use needs better. With a boat on a mooring, you are always worried about water getting in either from storms or a leak. You need adequate power for a bilge pump at all times, and a starting only battery may not cut it.
Keep in mind my old boat is a carb and points+condenser engine, the cranking voltage needs are not what modern engines have so I'd follow what the engine manufacturer says.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

A pair of Interstate dual purpose group 27's here, and when the time comes to replace them I plan to use the same. Been very happy with them so far.

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Mike
2005 Four Winns 230/240
VP 5.7GXi/DP
1998 F-150 XLT
Boat Pic

Only use dual purpose or cranking for this.

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H210SS 6.2
F150 Platinum

Thanks for the information and feedback. I'll stick to dual purpose and won't worry too much.

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"No Losses"

Depends on the boat, but I would use a dedicated starting battery for starting. I have owned several boats and some did not fare well even with a dual purpose battery (slow cranking speed) while I had an old Chris Craft with that had been "converted" from 6 volts to run on 12 (actually means the starters were left unchanged but deemed to be strong enough for this) and it had the same group 27 deep cycle battery for 5 years until I sold the boat. The point is while the Chris did fine with the deep cycle battery (single battery for 2 engines to boot), I had trouble with dual purpose batteries in other boats. I now only use dedicated starting batteries for starting.

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van
2003 Four Winns 214 Funship

My '07 H200 came with a Dealer installed dual purpose Group 27 battery - 120 Minutes Deep Cycle, 185 Minute Reserve, 720 CCA. For my engine, Volvo calls for a dedicated starting battery with minimum 650 CCA and 135 minute reserve capacity. So far I've had zero problems, and did have some extended stereo use on the hook with the standard stereo (no amp). I'm sticking with the dual purpose this next season, although I am adding a second group 32 deep cycle battery for House systems and new Stereo Amp. I'll be using the Blue Sea Systems "Add a Battery" switch and ACR to isolate starting and house systems so there should be even less load on the starting battery, although more of a load on the 75A alternator keeping both batteries topped off.

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2007 Horizon 200
4.3L GXi/ SX 225 HP

It's my understanding, isolators are available that will only send alternator output to the second battery when the first has a full chage. Thus, no extra load.

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H210SS 6.2
F150 Platinum