Deep Cycle Battery not good for starting??

[airshot]

My cranking/house/electronics battery was a dual purpose deep cycle 600 CCA/750 MCA that I bought less than two years ago. The problem was that, by the end of the day on the water, the battery would struggle to start the motor. I figured it was because of too many starts followed by short runs to the next fishing spot. I assumed that the motors 10A charging system did very little charging of the deep cycle battery. I was curious if a regular cranking battery would be a better way to go. Also, I charged the battery after every trip and, sometimes load test it with my old analog meter. Assumed it was good, but on Sunday I check the cells with one of those turkey baster type gadgets and all of the cells measured on the very low end of FAIR. Apparently, these O'reiley's batteries (Super Start) only have a year warranty! SMH!

Were you using that battery for anything other than starting your motor ?

 

[phx5kegsman]

Aside from the motor, I'm running 2 fish finders. Also have running lights, bilge pump, dash lights and gauges on that battery

 

[dingbat]

My cranking/house/electronics battery was a dual purpose deep cycle 600 CCA/750 MCA that I bought less than two years ago. The problem was that, by the end of the day on the water, the battery would struggle to start the motor. I figured it was because of too many starts followed by short runs to the next fishing spot. I assumed that the motors 10A charging system did very little charging of the deep cycle battery.

The problem is not the battery, per se. The battery isn’t sized properly given your limited charge capability.

Ideally, you don’t want to use more than 50% of the battery’s capacity before being topped off again. Leaving them discharged after use significantly lowers life expectancy.

I was curious if a regular cranking battery would be a better way to go.

Deep cycles tolerate being deep discharged. Starting batteries, not so much

 

[cyclops222]

How many seconds of cranking do you have to do to start? Does the engine then stall ? And a restart is needed? how many times each day ?

 

[airshot]

Sounds like your asking your battery to handle to much draw. When a battery gets drawn down then only a partial recharge before being drawn down again is not healthy for the battery. Just starting your motor should not wear it down that much but then add the ff's and other accessories then consider your motor creates a low charge rate......all equals trouble. You have a couple options, first is to go with a bigger capacity battery, or move to using two batteries, one for engine starting only and a deep cycle for all acessories. When your done for the day, these batteries need to be fully recharged....as mentioned, leaving them in a partially discharged state only makes them weaker over time. The popular setup is a starting only battery for the motor....then what we call a house battery, a deep cycle battery to handle all the accessories, including radios, bilge pumps, lights and everything else. Then another battery or two if you run a trolling motor.
By using this method, the batteries will last longer and you will have spare power in an emergency by carrying a set of jumper cables. No matter what setup you choose, all batteries need to be fully charged before setting in storage. Even if your going out the next day, it is best to top them off for good health of the batteries.

 

[Mc Tool]

phx5kegman , It would pay to verify the accuracy of your hydrometer ( turkey baster ) some of them aint brilliant . I have 2 and the difference between them can turn a good looking battery into a not so good looking one . I got a bottle of demineralised water that had the specific gravity spec on the bottle ( cant remember what it was ) and used that to "gauge " the hydrometer.
Solar panel and charge controller .......cheap as off Temu . I leave the set up in my boat shed and have a simple plug that I remember to undo before taking boat out of shed ( most of the time ).
Admittedly my 4.2m / 35hp boat has only bilge pump , vhf radio and a Lowrance Hook 2 9ts and a huge battery 210a/h that came with the boat , works a treat

 

[Lou C]

I think if a deep cycle has enough CCA to crank the engine it should be fine.
BTW, people forget sometimes that bad starters that draw too much current and old corroded internally battery cables kill batteries. Bad cables also won't allow the alternator to fully charge the battery. I had far less issues with batteries after I changed the old Delco direct drive starter for a permanent magnet gear reduction starter and replaced the battery cables. The PMGR starters definitely draw less current than the old style.

 

[Chris1956]

Deep cycle batteries have softer plates than starting batteries. The soft plates allow the multiple deep discharge and recharge cycles and are not well suited to the high current draw needed by the starter motor. Will they work, sure, for a while, but a starting battery will last longer.

 

[Lou C]

So what about the so called dual purpose battery? I have used these myself for over 10 years with good results. Main concern is my is moored all season although covered. Still I want to make sure that the bilge pump had adequate pose in case water gets thru the cover which is kind of inevitable. So far they’ve worked fine…..Deka gp 27 dual purpose…..

 

[Buster53]

I’ve had 5 larger boats, 2 sailboats with small diesels and 3 motor yachts, all with big block V-8’s. All I have ever used have been deep cycle batteries. Never any issues.

 

[Mc Tool]

My battery says " Marine " on it . Apparently they handle the bouncing around better. this boat came with this huge battery but my previous trailer boats ( all around 16- 18' ) I have only ever used whatever was cheap at the time , never had an issue

 

[dingbat]

Will they work, sure, for a while, but a starting battery will last longer

Certainly not my experience.

Can you point to tech data to support your argument?

 

[Chris1956]

Sure, this is for RV's but the principles are the same.

Deep Cycle vs Dual Purpose

Let’s get into the difference between using a dual-purpose battery (commonly suggested by RV dealers), and true deep cycle batteries.

backcountrysolar.com

 

[cyclops222]

Did we all attend the 3 day Lead Acid Battery course ??
I did not.
If you get a good one ? No sweat.

 

[Mc Tool]

Certainly not my experience.

Can you point to tech data to support your argument?

I just found the following info , seems to make sense .

"A deep cycle battery's design and manufacturing process differs from conventional starting lead acid batteries that are found in any car. Deep cycle batteries contain less number of thicker sized lead plates that are designed to provide current for long periods of time. While a starting battery contains a larger quantity of thinner plates, which increases the total surface area to produce very high currents for short periods of time. Although using a conventional starting lead acid battery for cyclic applications will work fine in the short term, it will definitely fail in next to no time."

 

[Crosbyman]

Seems to me not being a battery specialist ... that the names on the batteries give us a good clue on their usefulness.

Marine starting batteries being destined to crank hard and occasionally
are best for "starting" . I have heard in the past that they have an improved internal design to sustain typical boating hardships like pounding and constant vibrations.

Deep cycle batteries are for low-modrate drain in day long use on trolling motors and misc accessories which does not stop them from occasional engine starts with a big & sudden amp dump but....that is not their design intent and may affect longevity ..

Marine starting & deep cycle batteries.... well an attempt to please everybody's needs but a compromise nonetheless.

I have used both starting and dual purpose batteries across 50 years of boating ... no problems with either when taken care of.

 

[phx5kegsman]

I ended up buying a 1000 MCA Marine Dual Purpose battery. I hope to be able to get on the water this weekend. I'll post how it goes. Thank You for all your input. I really appreciate it. This forum has helped me quite a bit in the last few years!

 

[cyclops222]

Hope you had a Load Test done and checked the Date Code on the battery.