T-Pain Is On A Boat: Re: [Electric Boats] battery cost comparison

Tuesday, September 11, 2012

Re: [Electric Boats] battery cost comparison - now long term cost too.

- For what it's worth I hunted down an agent for these batteries ( http://www.elecsolbatteries.com/products/Carbon-Agm-Deep-Cycle-Series ) who has been installing Domestic (household) and Commercial (unmanned communication etc) Remote Area Power Systems in such cuddly places as the Atlantic coast of Ireland and Scotland for about 5-8 years and after a couple of meetings and a sizable purchase of Victron equipment he admitted that most AGM brands that have been around for a year or three you could change the labels and not really notice the difference (quality wise).

- I know that RAPS systems systems are not quite our application but they tend to be forgotten and only visited when something goes wrong, so their reliability is crucial.

- They are built into steel shipping containers with no insulation and are dropped on site as a complete tested unit, field commissioned, the doors closed and forgotten. They sit in howling winds, get covered/buried in snow, rained on a lot and on rare occasions get bloody hot from direct sunlight.

- He was initially skeptical of the "unlimited 7 year warranty" boast, and no they haven't been out there for 7 years yet, but after installing several hundred of them, he has had 3 fail, and all were replaced without a prior inspection, even though he did advise them that he thought it had been 90% discharged daily since week one!

- While he did say he thought they blew their own trumpet a bit, he had no real reason to doubt the product.

- His practical experience has led him to the simple maxim of, if you can size your back up so it doesn't see D.O.D below 50% then he can't see why unless he has a weight or space issue why he or anyone else would use anything but AGMs. They are cheap, easily purchased, have simple charging requirements and simply put, don't give trouble.

- He has had AGMs do well over 500 cycles but only at 50-60% D.O.D and he has had AGMs in service for 8 years (so far) but at less D.O.D.

- He has access to every battery type there is, and he's most definitely not a technophobe, and loves new products etc but he does work that must have the happiest combination of cost v reliability and after trying pretty much everything, he is adamant that if you can manage to keep 80% of your D.O.Ds to 50-60% 500 cycles and NEVER hit 80%+ D.O.D then AGMs are the best all round bet.

- I know there's a shit load of more promising, tempting and shiny things to chose e.g. Ultracapacitors BUT unless you're rich, crazy or just in from planet Zorb, let someone else do the bleeding edge research with something as important and expensive as batteries.

Hope that helps, Julian

On 7 September 2012 06:03, James Sizemore <james@deny.org> wrote:

The important question would not be has anyone cycled their lithium packs 2000 times, but has anyone killed their AGM pack with 500 cycles?
It really does not matter if the lithium cell have twice as many cycles or four time as mean cycles. As Lithium is only a third more expensive for the same useful power, if you have to replace your AGM pack once the Lithium would have been a better financial deal. If on the other hand you never have to replace the AGM pack it was a better deal.

Asking the right question will get us the right answer. So has anyone killed their AGM pack in a boat?
In a car the answer is obvious AGM banks will generally only last three years so Lithium is always the better financial option. In sail boats I would guess AGM may be a "good" option as 500 cycles will be rare for one owner. For power boats time will tell.

On Sep 6, 2012, at 5:13 PM, GNHBus@aol.com wrote:

To Eric's point,

Has anyone cycled any form of Lith Batts to 2000 cycles ?

Geo