T-Pain Is On A Boat: Re: [Electric Boats] Lithium Battery sources?

Monday, January 20, 2014

Re: [Electric Boats] Lithium Battery sources?

John,

Your right, I screwed up the calculations. A 200 a-hr Winston cell gives in real life 220 a-hr, so 3.25 (cell voltage) X 220 (a-hr) = 715 w-hr X 16 (# of cells)=

11440 w-hr X 0.8 (80% DOD) = 9152 w-hr. At 5.1 mph that would be 2.61 hours @ 5.1 mph = 13.3 miles.

From all the other's and my testing, the Winston cells give 10%~20% more a-hr than their rating at a 1 C load.

So at 3.1 mph 9152/700=13.07 hours X 3.1 = 40.5 miles.

I bought mine from Balqon.

Bob

From: oak <oak_box@yahoo.com>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Monday, January 20, 2014 8:13 AM
Subject: [Electric Boats] Lithium Battery sources?

Bob,

Where do you get Winston cells?

I did a quick google search, looks like they're made in China. The graphic looks amazingly similar to what Balqon sells...

coincidence? :)

By the way - I'm a little confused by your calculations.

For the 5mph case, 200AH * 48V = 9600WH

Allow for 80%: 9600*.8 = 7680WH

At 3500W, that should (ideally) last over 2 hours, which should get me at least 10 miles, not 4.3

What am I missing?

I know my Lead batteries degrade MUCH faster at higher power usage, but I thought Li (with much lower Peukert) was a lot more linear.

MAIN QUESTION, though:

Aside from Balqon and ThunderStruck, who else is a good source for Lithium batteries?

John

From: Robert Lemke <robert-lemke@att.net>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Sunday, January 19, 2014 10:51 PM
Subject: Re: [Electric Boats] C-30 with Torqeedo 4.0R

John,

I'm using the Winston cells and through my testing Peukert is nil so your range at those speeds and draw for 80% DOD would be.....

3.1 mph 19.5 to 21.7 miles

4.1 mph 7.6 miles

5.0 mph 4.3 miles

Cost of 48 volt (52 volts) bank @ 200 a-hr $3520.

Bob

From: oak <oak_box@yahoo.com>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Sunday, January 19, 2014 8:21 PM
Subject: [Electric Boats] C-30 with Torqeedo 4.0R

I've mentioned a couple of times about having mounted a Torqeedo 4.0 outboard on my C-30.

I got a chance to go out today, since it was a really nice (winter) day - Sunny, and upper 60's.

Here's the data from my run:

I only have a small bank of AGM batteries, so I can't run at high speed for very long without the voltage dropping off quickly. However, I ran for a few minutes at several different speeds, and recorded:

700-780W => 3.1mph

2000W => 4.1mph

3500W => 5mph

I ran about an hour at around 700-800 watts, and only depleted the battery from an initial fully charged level of ~54V (which quickly dropped down to around 48V), down to 47V.

The Torqeedo isn't a replacement for my Atomic 4, but is sure is a LOT quieter. And if the prices of Li batteries would come down, or if I could win the lottery, I could see myself doing mostly electric if I could afford about a 200Ah bank at 48V... :)

Have fun!

John