Batteries once more

[trapper]

Try to put info together info on my next batterie purchase, realizing I am thrashing the subject but just need a couple of your ideas. Thinking about group 31 AGM using two Costco Energizer Dual Purpose. Should I consider trying to get a starting battery and a deep cycle battery instead. Seems to be limited access here on the island and would like to shop locally incase warranty issues appear. With these newer batteries in there any problem going with 2 deep cycle as they do appear to be able to start my F200 without issue.....but not sure over time and repeated try. Talk to me seasick....I know you are the guru!

 

[Doc Stressor]

Using a true deep cycle battery as a starting battery is not ideal even if it has sufficient cranking amps. If your engine turns over right away, you will be OK. But if it doesn't fire right up, the voltage will drop off rapidly with the high current draw. They aren't designed for high amperage usage and the surface of the plates might become damaged over time.

Dual-purpose batteries at best for boats in most cases. Electric trolling motors or powerful sound systems run with the engines off are exceptions where deep cycle batteries are appropriate. It's fine to use a deep cycle as a house battery as long as it is isolated from a cranking battery used for starting.

https://www.bestboatreport.com/using-a-deep-cycle-battery-for-starting-what-you-must-know/

 

[Hookup1]

I'm not familiar with the Costco AGM.

I'm using all Duracell Marine AGM's purchased at Sam's Club.

Group 34 43.10 lbs. 955 MCA 55 AH. $119.32
Group 24 52.40 lbs. 800 MCA 78 AH. Did not see availability at my store.
Group 27 61.55 lbs. 900 MCA 92 AH. $158.88
Group 31 67.35 lbs. 1,000 MCA 105 AH. $179.74

 

[trapper]

Thanks Doc and Hookup, My concern is the drag on batteries pulling prawn traps and raising 20 leads trolling. Been using Group 27 flooded but with the new battery configuration, have to almost turn the batteries upside down to get them in. Tough to find AGM in both starting and deep cycle here, will try and get one of each or dual purpose if that is all I can get. No Sams club here Hookup, but you certainly have the battery situation covered with 224 pounds of electric juice.

 

[Doc Stressor]

Your Scotty downriggers and their 2500 line pull draw just under 20 amps under full load. A single Group 31 AGM Energizer from Costco has a 200-minute reserve capacity at 25 amps. 50% capacity is the max you want to use for the longest battery life. So you could run either the downrigger or puller for 100 minutes without any problem. Of course, each time you run from spot to spot your 200 Honda is going to put out at least 30 amps of recharging power. So you really don't need a true deep cycle battery.

https://www.costco.ca/energizer-31m-marine-agm-battery-.product.100537376.html?langId=-24

 

[trapper]

Thanks Doc for your well explained, as usual, information. Up here in the rugged north (Island North) I can only get Group 31 dual purpose batteries at Costco. The one on your above info. does not indicate if it is a starting or deep cycle batteries. Still trying to find a Group 31 starter and deep cycle battery. As mentioned before I may have to go Costco dual purpose if that all I can find in the Group 31 AGM

 

[Doc Stressor]

The battery I linked to is a dual purpose. Any battery that is listed as Marine or RV is a dual purpose.

Are you looking for a group 31 starting battery AND a group 31 true deep cycle battery, both in AGM?

 

[trapper]

Doc, did not know that "any battery listed as Marine of RV is a dual purpose". Yes I am looking for, but not finding Group 31 starting and deep cycle . After getting your info re dual purpose batteries I am thinking to go that route. Wanted to purchase locally (Costco), so if there any warranty issues I can deal with them close to home. Thanks again!