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

Saturday, March 15, 2014

Re: [Electric Boats] Re: Electric Kayak

William,

We need to back up...

You need to come up with a target for how power (watts) you need, at what voltage, and how long of a run time you want.

For a Kayak, you may be looking at a much lower power application than the "big boys", and that could offer an interesting alternative.

For example, the Torqeedo Ultralight kayak motor operates on 400W. (this is just an example - as it looks like that motor includes a self contained motor)

At 400W, you could power it off a voltage boosting power supply:

http://www.amazon.com/gp/product/B00EQ1Y9N8/ref=oh_details_o02_s00_i00?ie=UTF8&psc=1

The above supply will convert 12V up to as high as 80V (I wouldn't go that high, but you could easily get 12V up to 24 or 48V), at up to 600W. Assuming a budget of 400W, you'd be ok.

Then, you could entertain a 12V battery bank instead of a 24V bank - this cuts the battery expense in half, at corresponding less Ah. CLEARLY, this isn't a "something for nothing" proposition - just an opportunity to save weight and initial cost.

400W at 12V is about 33A. If you bought a 100Ah LITHIUM battery pack, you should be able to get 2 hours of run time on a 12V, 100Ah pack.

Assuming 100Ah, 3V Li batteries from Thunderstruck at $143 each, you could get a bank of 12V for around $600 (plus/minus shipping / tax), and use a 12V charger (though you have to find one set up for Lithium), and only 30 pounds of battery weight. (A single 12V AGM battery will be at least twice that.)

Take this all with a grain of salt. I'm not an expert, and I haven't tried this technique yet. But on paper it should work...

Again - gets back to the original question: How much power do you need at what voltage for how long to be able to achieve your target goal?

John

From: Robert Lemke <robert-lemke@att.net>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Friday, March 14, 2014 4:40 PM
Subject: Re: [Electric Boats] Re: Electric Kayak

From: Robert Lemke <robert-lemke@att.net>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Friday, March 14, 2014 2:36 PM
Subject: Re: [Electric Boats] Re: Electric Kayak [1 Attachment]

[Attachment(s) from Robert Lemke included below]

I used to use AGM (Odyssey) batteries before the LiFePO4 price drop 2 years ago. Used them in both EVs and classic cars that aren't run much. Compared to flooded lead acid, they have a very low self discharge rate, plus as you mentioned no spills or corrosion. Since the LiFePO4 price drop, lithium is all I've used since. In a deep cycle application they are cheaper in the long run than any other battery available today. If treated well, not cycled deeper than 50% DOD, I would get 400 cycles from the expensive Odyssey batteries. The Winston LiFePO4 cells I'm using now have almost 400 cycles to 80% DOD and still have 17% more than their rated capacity. I expect a minimum of 2000 cycles.

Here is a link for these cells that is not Balqon. I purchased my from Balqon, but they are a bit flakey on delivery for any cell that isn't the 700 and 1000 a-hr cells. http://www.electriccarpartscompany.com/Batteries--Lithium-Prismatic_c_1.html

This picture is (2) 12 volt 100 a-hr banks I put together for the kayak, total of 8 cells.

Bob

From: oak <oak_box@yahoo.com>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Friday, March 14, 2014 1:12 PM
Subject: Re: [Electric Boats] Re: Electric Kayak

I'd be very curious about this too!

From the Balqon web site, they seem to be Out of stock on a bunch of stuff at any period in time.

They seem to be a LOT cheaper than other sources I've seen, and it's nice to be able to get a 12V package instead of having to bolt together a bunch of smaller cells. But.... if you can't easily and effectively access them (the company), or if they're out of stock for months at a time, it would make me reluctant to send a lot of $$ that way.

At the urging of someone else in this group, I took another look at AGM batteries.

They're HEAVY, but for the $$ seem to work out to be more cost effective than Li. They won't spill, and they take common, easy to find (and relatively inexpensive) chargers.

I bought a set of Deka AGM batteries for my boat, and am very anxious to get some data on how well they do!!!

From: William Branan <kayakbiker@gmail.com>
To: electricboats@yahoogroups.com
Sent: Friday, March 14, 2014 2:34 PM
Subject: [Electric Boats] Re: Electric Kayak

Is there a best most cost effective brand for a 12 volt lifepo4 battery the size of a group 24 or 27. I know of but have not seen Balqon.