the large currents would be very problematic.
Even at 100% efficiency a kilowatt would represent almost 500 amperes on the primary. A tiny bit of resistance becomes a huge power loss.
lead acid is a poor choice in my book. at any voltage
From: Ron <rlgravel@swbell.
To: electricboats@
Sent: Sun, August 1, 2010 12:54:41 PM
Subject: [Electric Boats] Re: Suitable batteries for watercraft? Wave of the future.
Hi Dan,
Not sure where the market is about to move, but I have a few ideas that might cause a major shift in direction.
The big choke hold on electric power is battery storage cost. For some new designs lead/acid can offer much more than energy storage. I am amazed that in all the years of L/A batteries the only major change (that I'm aware of) is the six pack style "Optima".
I'm not strong in electronics, but I think I understand that all increases in voltages have a well defined decrease in amperage and that losses are generally able to be shifted to more desirable areas based on design of motor or control charateristics.
One thing I'm trying to learn about, right now, is the practical limits of stepping up voltage with the use of electrical components. A single cell of a lead/acid battery is 2.1 volts, while amperage capacity is related to mass of lead and acid. Using a single cell and stepping voltage from 2.1 up to 120 volts is an increase of 57.1428 times, so the amp hour capacity would be divided by 57.1428. My question is how to dertrmine where the best control of losses will be, motor design or control circuits ?
My main thought in this is a single cell very high amp hour battery should offer far less problems in the life and maintaintance of said battery.
What would be better than a single cell mass of storage in the bottom of a boat. Now a change of battery design can make this (within reason) a battery that will require little or NO attention for as long as the boat is alive and can quite likely be moved to another vessel.
The big challenge will be, how much capacity can be sacrificed in exchange for less care and longer life of the storage unit. The typical thinking now, is how much energy can we pack in the smallest and lightest weight package ? this is almost completely reverse of what should be design direction in the marine market.
As stated earlier I have some radical ideas of how to build a battery as described and have some materials collected, just always seems like other things need to come first. Then there is the respect for sulfuric acid. Building the battery might not be nearly as much of a task as setting up a safe work area, so I keep thinking "one of these days"
Lets hear some feed back on stepping up voltage ???
Ron
--- In electricboats@
>
> Nickel-cadmium batteries have high density and are cheaper than Lithium-ion, but has more density. However, nickel-cadmium is easily recycled into new batteries, but Lithium-ion is not.
>
> Announced last year is a new Nickel-lithium battery that has 3.5 times the density of Lithium-ion.
>
> Nickel batteries are not allowed on all-electric automobiles, but can be used on hybrids.
>
> Does anyone know where the marine market is moving in regards to batteries?
>
