Which Battery is better?

Maine Sail · Jan 11, 2022

leo310 · Jan 11, 2022

Both attachment are the same by looking at the sku numbers.

leo310 · Jan 11, 2022

Now are you looking for a starter battery or house. If house amp hr is what you would be looking for not cranking or reserve. At 65 amp this would take about 5 hours to drain this battery using normal demands when sailing ie instr., freezer.

Tater · Jan 11, 2022

Andiamo 34 said:
How can you tell which battery is a better choice for your house batteries? One has more Reserve Capacity minutes, the other has more Amp Hours? Which is more important; Reserve Capacity or Amp Hours? See attached, how do you determine the best choice?

I have worked around battery banks for years. JMHO but, I think Reserve Capacity was invented to confuse the customer. Amp Hours has been used for many years to describe deep cycle batteries. I would go with Amp Hours and get the most bang for the buck.

Richard19068 · Jan 11, 2022

I'll probably say this improperly but Amp hour ratings can be based on different discharge rates e.g. 20 hour rate, 8 hour rate 15 hour rate. To compare one AH capacity to another without knowing the discharge rate can be misleading. Personally I would not buy a house battery based on AH capacity unless the battery showed what rate was used to calculate that capacity. The two fact sheets are obviously confusing and I probably wouldn't buy either one unless the manufacturer provided how the AH rating was determined. That said, if I was going to buy one of these two I would go with the one that weighs 59 pounds rather than 48 pounds. All other things being equal ( I know they rarely are) more lead should mean more capacity.

Maine Sail · Jan 11, 2022

Would not buy either of those batteries. Neither are deep cycle. Your money would be far better spent on Crown, Trojan or US Battery batteries..Read the article linked above. The DP in the group 29 signifies "dual purpose" and you Definitely do not want those as a house bank.
I have said this beforehand I will say this once again...Only buy batteries from the actual manufacturer not a company who slaps sticker on a box!!

Davidasailor26 · Jan 11, 2022

+1 for the link Maine posted.

Since you’re looking to increase your house bank size, what size are your existing house batteries? Ideally you want to add another battery as closely matched to that as possible for them to function together properly. In any case yeah definitely get real deep cycle batteries, not what’s being targeted for the auto market above.

Richard19068 · Jan 11, 2022

Andiamo 34 said:
.... got confused on which is more important RC or AHs

From Maine Sails article linked above:

Ampere Hours (Ah’s) and Reserve Capacity / Reserve Minutes (RC) are not one in the same nor are they interchangeable. You want to purchase house bank cycling batteries based on the Ampere Hour rating at the 20 hour rate not the Reserve Capacity or Reserve Minutes rating. If the battery does not have a 20 hour Ampere Hour rating it is generally best to simply walk away, or find out who actually made the battery.

Tally Ho · Jan 11, 2022

I don’t think I would buy either one, as stated above. Also, are you planning to add them to your existing bank? Usually not a good idea to add old and new batteries in the same bank.
You don’t say what is in your current bank...that might be helpful for us to know.

I had 2 group 27 “deep cycle” batteries on my boat. When they showed signs of weakness, I (finally) tried golf cart batteries. I bought 2) 6-volt Duracell GC batteries at Sam’s Club. 215 AH in the bank, very happy with them so far (just 1 season). Anchored out for 2 nights with plenty of juice. Right now, that is my only bank (no start battery yet). So I put some faith in those batteries. I monitored them closely and felt very comfortable with them.

jssailem · Jan 11, 2022

Hello again @Andiamo 34. Like with your question about transmission fluid, there is a bit to consider when selecting batteries to store your electric power. MaineSail's website Marine How To - DIY for Boaters - Marine How To is a terrific resource. It pulls back the curtain on the battery marketing.

I see you found batteries at AutoZone. They are not a manufacturer. They buy their batteries from a manufacturer to meet the price point of their customers. There customers are mostly guys who work on their own cars. Most often used cars that have been driven a lot of miles and need repairs. There battery needs are nothing like the battery needs you have for your boat.

I encourage you to read the link provided by MaineSail above. It will revel much of what has been posted in the replies.

There are a few conditions you need to think about as you consider this issue.

How long do you need your battery power to last between charges?
How much power (measured in AmpHours) do you expect the boat to use in a day?
How good is your recharging system?
Is your charging system designed compatible with your batteries?
Are you willing to consume batteries and just buy replacements frequently?
Will the batteries function with the DC systems you have on your boat?
How heavy are the batteries?
Will the batteries fit in the space I have in the boat?
Did the boat come with enough battery power for my needs?

These are just a few of the questions you need to consider as you decide what compromises you need to make to match your pocketbook and current resources.

I would not purchase either of the batteries offered by AutoZone for my boat. They do not have the proper design or capacity to meet my needs. About the only pro in their favor is they are a cheap price. Cheap price does not equal good value.

leo310 · Jan 11, 2022

Here's a chart that may help in what amp for your house bank may require. I currently have 4 GC batteries at 220 amp = 440 total but only can use 200 as I don't like to take them below 60%

leo310 · Jan 11, 2022

BTW I forgot to state I also have 335 watts if solar to help maintain charging of the batteries.

artboas · Jan 11, 2022

leo310 said:
Here's a chart that may help in what amp for your house bank may require. I currently have 4 GC batteries at 220 amp = 440 total but only can use 200 as I don't like to take them below 60%View attachment 201684

Ok, it’s pretty simple.
If you want the best bang for the buck, reliability, and ease of install go with Trojan or equivalent 6v AGM batteries (in series)
No need to overthink this.

Benny17441 · Jan 11, 2022

For House applications go with Marine Deep Cycle Batteries which are rated in Amp Hours (Ah). Starting Batteries are used for engine cranking and are rated in Cranking Amps. The term Reserve Capacity serves to compare one starting battery to another. The Starting Battery with the best reserve capacity will provide a cranking power of 25A for longer than one with a lesser Resrve Capacity. Starting Batteries and Deep Cycle batteries cannot be compared to one another as neither can fulfill the functions of the other and provide a long useful life. If you want to know what is the best battery of each type you also have to consider the Price and Terms of the Warranty.

Ward H · Jan 11, 2022

You already received very good advice. I'd just like to point out that auto starting batteries with CCA and Reserve ratings are not needed to start our small Diesel engines. Many people think that since the battery is used to start their diesel they need a battery labeled as a "starter" battery.
A deep cycle battery will easily start our small diesels and last longer doing so. Being deep cycle they can also act as a reserve battery for the house bank.

I bought two Duracell Deep Cycle 6V batteries (GC2) and wired them in series for 12 Volts. These are rated for 230Ahrs, much higher than a Gap 27 dual purpose battery.

justsomeguy · Jan 12, 2022

Benny17441 said:
Marine Deep Cycle Batteries

Any battery that doesn't overcapitalize it's features.

Which Battery is better?

.

Attachments

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.