SailNet Community - View Single Post - Battery Sizing - am I crazy?
View Single Post
post #65 of Old 11-27-2012
Maine Sail
Senior Member
Maine Sail's Avatar
Join Date: Jan 2003
Location: Maine Coast
Posts: 6,412
Thanks: 22
Thanked 305 Times in 236 Posts
Rep Power: 18
Re: Battery Sizing - am I crazy?

Originally Posted by hellosailor View Post
Optima batteries are in a world of their own. They are made by JCI, who are a top maker. They are sprial-wound AGM batteries, and in theory that process makes them much cheaper to build than flat-plate batteries, and more vibration resistant. In practice, JCI charges about a 30-40% premium for them, and because you have round batteries in a rectangular case, you also get about 10% less capacity than a same-size flat plate battery.
And, no better warranty.

If AGM is the way you want to go, I'd go with flat-plate AGM batteries, get 10% more capacity at 30% less price. Last year...I think that was about $200? $230? for a G31 from various sources. Of course the price of lead seems to double almost weekly, for reasons that totally elude me.

And if your charging system can match the, consider gel batteries. Even the AGM-makers are now saying gel batteries will totally outperform AGMs in terms of charge cycles, if you can give them everything else they want.

But Optimas? Mainly, they've been branded very nicely. If JCI would just drop the price and raise the warranty, to match what they say about the technology...
It should be noted that JCI bought this brand from EnerSys who invented the Optima's. JCI does not manufacturer all their own batteries and many of the "brands" they have purchased. They still buy batteries from companies like US Battery in certain sizes and then private label them.

EnerSys sold the brand because they had a much better designed AGM in the Odyssey thin plate, pure lead battery. The Odyssey batteries are quite amazing in the current they can both take and deliver but still don't quite have the cycle life of a decent deep cycle flooded or GEL. I have personally watched a 400Ah bank of Odyssey batteries take 130A+ for nearly an hour or everything the alt could throw at them.. They would have taken more if we had it...

It should also be noted that the spiral cells cost you a lot more than 10% in Ah capacity if you compare case size for case size as in the group 31 batteries below..

A group 31 Optima Blue Top AGM is 75Ah
A group 31 Lifeline AGM is available in either 105Ah or 125Ah capacities
A group 31 Deka AGM is 105Ah
A group 31 Odyssey AGM is 100Ah
A group 31 Trojan wet cell is 130Ah
A group 31 US Battery wet cell is 130Ah
A group 31 Deka/West Marine/Sam's Club/NAPA wet cell is 105Ah

Even the absolute lowest Ah capacity flat plate batteries is has 25% more capacity than an Optima group 31 and the largest has 43% more capacity..... Big differences!!!

-Maine Sail / CS-36T

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Images In Posts Property of Compass Marine Inc.

Maine Sail is offline  
Quote Share with Facebook
For the best viewing experience please update your browser to Google Chrome