Battery Question

[FF654]

I'm looking to buy an Optima Blue Top Battery Model 31M to run the accessories on the boat.  Does anyone have any experience with these?  The stats are as follows:

Cold Cranking Amps    900                                                                                                                                                                           
Cranking Amps            1125


Reserve Capacity        155


Capacity (c/20 rate)     75


This battery will be hooked up via an isolator and will be used to run the electronics including a stereo system with two amplifiers.  I'd like to be able to sit for a while with the engine not running and listen to music.  There will be a separate battery for starting.  Any information would be appreciated.  Thanks.

[AndyDale]

Optima batteries are great. I don't have one on my boat, but the red top I have in my truck has performed flawlessly for four years now. It fires up my 6.0L V8 first time every time. One caveat is that I live in a mild climate. They are known for ruggedness and are popular with off roaders. I would be interested in hearing from anyone who owns one in a marine environment, especially their cold temperature performance

Andy

[Vuja De]

I use the Optima Blue Top AGM for my starting batteries.  Going on season number 3 with no problems.

I don't know how they would operate as a house battery though.  You might want to look for a true deep cycle battery for your house system depending on how many accesories you are running.

[Capt Ron]

I also recommend a deep cycle battery for your needs. Or even two deep cycle batteries wired in parallel (positive to positive, negative to negative). Stereos tend to suck a lot of amps and cranking batteries give it up too quickly.

[Dream 'Inn]

I agree, I would go with a deep cycle battery. (optima does make those as well if you desire to go with that brand).

[FF654]

I guess I was misinformed, I thought the group 31 Optima Blue was a deep cycle battery but was listed as dual use.  This is from the .pdf manual from Optima:

Physical Characteristics:
Plate Design: High purity lead-tin alloy. Wound cell configuration utilizing proprietary
SPIRALCELL® technology.
Electrolyte: Sulfuric acid, H2SO4
Case: Polypropylene
Color: Case: Light Gray
Cover: “OPTIMA” Blue
Group Size: BCI: 31
Standard Metric
Length:
Width:
Height:
Weight:
12.774”
6.529”
9.370”
59.8 lb
324.46 mm
165.84 mm
238.00 mm (Height at the top of terminals)
27.1 kg
Terminal Configuration: SAE / BCI automotive and 5/16”-18UNC-2A threaded stainless steel stud.
Performance Data:
Open Circuit Voltage (Fully charged): 13.1 volts
Internal Resistance (Fully charged): .0025 ohms
Capacity: 75 Ah (C/20)
Reserve Capacity: BCI: 155 minutes
(25 amp discharge, 80°F (26.7°C), to 10.5 volts cut-off)
Power:
CCA (BCI 0°F): 900 amps
MCA (BCI 32°F): 1125 amps
Recommended Charging:
The following charging methods are recommended to ensure a long battery life: (Always use a
voltage regulated charger with voltage limits set as described below.)
Model: D31M
These batteries are designed for starting and deep cycle applications and for use in vehicles
with large accessory loads.
Recommended Charging Information:
Alternator: 13.65 to 15.0 volts
Battery Charger (Constant Voltage): 13.8 to 15.0 volts; 10 amps maximum; 6-12 hours approximate
Float Charge: 13.2 to 13.8 volts; 1 amp maximum; (indefinite time at lower voltages)
Rapid Recharge: Maximum voltage 15.6 volts. No current limit as long as battery
(Constant voltage charger) temperature remains below 125°F (51.7°C). Charge until
current drops below 1 amp.
Cyclic or Series String Applications: 14.7 volts. No current limit as long as battery temperature
remains below 125°F (51.7°C). When current falls below 1 amp,
finish with 3 amp constant current for 1 hour.
All limits must be strictly adhered to.
Recharge Time: (example assuming 100% discharge – 10.5 volts)
Current Approximate time to 90% charge
100 amps
50 amps
25 amps
52 minutes
112 minutes
210 minutes
Recharge time will vary according to temperature and charger characteristics. When using
Constant Voltage chargers, amperage will taper down as the battery becomes recharged. When
amperage drops below 1 amp, the battery will be close to a full state of charge.
(All charge recommendations assume an average room temperature of 77°F (25°C).
Always wear safety glasses when working with batteries.
Always use a voltage regulated battery charger with limits set to the above ratings. Overcharging
can cause the safety valves to open and battery gases to escape, causing premature end of life.
These gases are flammable! You cannot replace water in sealed batteries that have been
overcharged. Any battery that becomes very hot while charging should be disconnected
immediately.
Not fully charging a battery can result in poor performance and a reduction in capacity.

[Capt Ron]

Go for it... Get two of them and you can last all weekend.

[Dream 'Inn]

If you are truly going to use it for deep cycle applications only, I'd go with a deep cycle.  If you are going to use it for starting as well, then go for it.  It sounds to me you would still be better off with a deep cycle.  On my current boat I use a pair of EverStart Deep cycles. We are on the boat every weekend in the summer, and more than half out on the hook.  Never an issue, going on my 4th season.  I fill with distilled water once a year.  So, in my book I'd spend less than $100 and put the deep cycle in on a switch.  Use it when anchored, then use the other to start.   Optimas are good batteries & I'm sure you'd be happy as well.  (I said happy, not happier)

[AndyDale]

Here's a great FAQ on deep cycle batteries. This is from a solar power dealer, but the info's good for marine and RV use also. Based on what I learned here I just bought two AGM batteries, one for the boat and one for the camper.

http://www.windsun.com/Batteries/Battery_FAQ.htm

Andy

[Dream 'Inn]

Here's a great FAQ on deep cycle batteries. This is from a solar power dealer, but the info's good for marine and RV use also. Based on what I learned here I just bought two AGM batteries, one for the boat and one for the camper.

http://www.windsun.com/Batteries/Battery_FAQ.htm

Andy

Yep, that's a good website.  I used it a few years ago when I replaced my batteries.  It's also posted in our library section.

If you have the money to spare and don't want to have to maintain your batteries (typically once a year putting distilled water in), then AGM is the way to go. 

[Vuja De]

Correct me if I'm wrong, but if you install one AGM, you have to switch all of your batteries to AGM.

This is because you have to switch your battery charger's settings to correctly charge the AGM type battery.

[AndyDale]

I think you may be thinking of "gel" batteries that cannot be fast charged without harm. AGM is not a gel battery. I don't think there's any issue with mixing AGM and the traditional flooded, or wet acid batteries.

Andy

[pepmyster]

I agree with Dream 'Inn.


If you are truly going to use it for deep cycle applications only, I'd go with a deep cycle.  If you are going to use it for starting as well, then go for it.  It sounds to me you would still be better off with a deep cycle.

Andrew

[FF654]

According to my research an Optima Blue is a true AGM battery using "Spiralcell Technology."  Here is a link confirming this:  http://www.optimabatteries.com/product_support/faqs.php

From the website:

Is Optima a Gel Battery?

A gel battery design is typically a modification of the standard lead-acid automotive or marine battery. A gelling agent is added to the electrolyte to reduce movement inside the battery case. Many gel batteries also use one way valves in place of open vents, which helps the normal internal gasses to recombine back into water in the battery, reducing gassing.

An OPTIMA battery is not a "gel" battery or regular flooded acid battery. An OPTIMA is a Spiralcell AGM battery.