T-Pain Is On A Boat: Re: [Electric Boats] Battery Box

Tuesday, March 22, 2011

Re: [Electric Boats] Battery Box

Thanks for your posts people.

My current boat had a flooded cell battery in it , located in the small cockpit.

I deciced that was a No No , so I replaced it with 2 AGM , a start battery , and a house battery , but it is set up so that I can start with either.

They are both big batteries , and I managed to get them in to a cupboard , down low and angled a bit , so the weight is used to advantage.Each battery was much bigger than the old battery I took out , so obviously , I noticed the weight.

But the difficulty is getting to the things , I doubt I could get them out of there without a real struggle.

But the electrical system is very good , set up by an electrician with a very good reputation within the commercial fishing industry.

I am still negotiating for my next boat , it is in another state , so I can't photograph what I have to work with.

But the boat at this time has a wet well , which will be closed off , and the batteries stored there.

So I should be able to get a straight lift , and maybe lift out with the aid of the boom.

Weight , within reason , can be used to advantage in the boat , its just setting up something I can handle myself.

Again , thanks for your posts . If I manage to get this boat , I'll keep the group informed.

Regards Rob J.

From: Sally Reuther <smreuther@gmail.com>
To: electricboats@yahoogroups.com
Cc: Arby bernt <arbybernt@yahoo.com>
Sent: Wed, 23 March, 2011 7:46:18 AM
Subject: Re: [Electric Boats] Battery Box

Rob,

I also have to agree with James, that having 4 batteries with less connections is a better way to go.

We have Northstar Energy 1's on our motor launch - the nice thing about these batteries is that the NSB's are a flat, wafer shape and can be mounted in any position except upside down. Here is the link to the specs:

http://www.energy1batteries.com/specs.html

Until I saw these batteries, and noticed their weight to size, I was wondering how in the world we would every fit those big, clunky batteries in the space we had. Battery manufacturers are coming out with a lot more shapes and sizes than previously available. There are more options out there than you might expect. And, a battery box to keep them dry and stable is always a good idea on a boat.

I agree with Eric too, lithium is the best choice when you need to be conscious of weight - if you can afford it. If not, the AGM's offer a very good alternative. There is new technology coming out all the time and eventually we will all benefit from the money being spent on battery technology.

Sally Reuther

Annapolis Hybrid Marine

On Tue, Mar 22, 2011 at 3:47 PM, Arby bernt <arbybernt@yahoo.com> wrote:

Flooded lead-acid batteries have a reservoir space on the bottom of the battery case, leading to a lower energy per cc. The reservoir provides space for lead-oxide which falls off the lead grids during the battery lifetime. The oxides would otherwise short the battery. This is why flooded batteries always seem to have a high center of gravity. AGMs physically trap the oxide on the electrodes such that it cannot mechanically separate. The energy per kg is very close, but the AGM's are a little denser, since no extra electrolyte is required to fill the reservoir.

Arby Bernt

AMeP

--- On Tue, 3/22/11, Eric <ewdysar@yahoo.com> wrote:

From: Eric <ewdysar@yahoo.com>

Subject: Re: [Electric Boats] Battery Box
To: electricboats@yahoogroups.com
Date: Tuesday, March 22, 2011, 8:13 AM

Rob,

It may seem that your AGM batteries are heavy, but all lead acid batteries (flooded, AGM, Gel) weigh about the same for the same rated capacity. Their weight to capacity ratios are typically within 5% for all of those types. However, because AGM has a deeper discharge duty cycle, it is easy to see that AGMs have a greater usable capacity for the weight. But even without a deeper discharge, AGM have a lower Peukert's exponent, meaning that under higher loads, they deliver more amp hours from the same amount of charge than flooded cells. So, AGM could actually be lighter for that same boating experience.

To significantly reduce your battery weight and size, the prismatic format of LiFePO4 batteries seem to be the most reasonable solution available today. There are acouple of people on this group that are already using these lithium cells, I think that most of them are CALB or Thundersky batteries.

Although I am a proponent of lithium cells for electric boats, cars and cordless tools, i believe that AGM probably represent the best compromise of cost and performance today.

Fair winds,
Eric
Marina del Rey, CA

--- In electricboats@yahoogroups.com, Rob Johnson <dopeydriver@...> wrote:
>
> Thanks for your post James.I take your point.
> I have AGM batteries in my current boat , yes , I'm impressed.
> But gee , they are bloody heavy.....
> Regards Rob J.
>
>
>
>
> ________________________________
> From: James Lambden <james@...>
> To: electricboats@yahoogroups.com
> Sent: Tue, 22 March, 2011 12:38:46 PM
> Subject: Re: [Electric Boats] Battery Box
>
>
>
> Rob,
>
> 12 volt batteries have half the connections.
>
> The whole system is dependent on each connection so less is more in this case.
>
> It is worth the extra money in life expectancy and amp hours available over time
> to buy AGM batteries.
>
> James
>
> www.propulsionmarine.com
>
>
>
>
>
>
> On Mar 21, 2011, at 6:27 PM, Rob wrote:
>
>
> >If I was to put a diesel hybrid setup in a 27 ft wooden boat , I'd like to site
> >the batteries , say 8 6 volt as low as possible in the boat .
> >I believe a sealed box , with positive ventilation would be appropriate.
> >Any comment ?.
> >Regards Rob J.
> >
> >
>