[PSUBS-MAILIST] Power sources

Mon Jun 19 15:02:16 EDT 2023

 Roughly speaking lifepo is about half the weight of lead-acid.  I’m going to compensate that difference with lead. However, the physical size advantage will only come into play if you build from individual cells since most 12volt lifepo batteries on the market mimic traditional sized lead-acid batteries and therefore there would be no physical size advantage.  So you need to purchase individual cells, group them together into a battery, and then match a BMS to it for discharge and charging. 
An alternative would be to purchase a ready made battery (group 24 for example) and then strip the cells and BMS out of it to reduce the physical size.  

Jon

    On Sunday, June 18, 2023 at 01:49:40 PM EDT, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 Thanks JonHow do I pay for the stickers? What are the dimensions and weight of the Lifepro batteries and are you still using 4 per pod? Sounds like they are lighter? if so, how did you compensate for the weight difference?  What were the costs of each? 
Rick
On Sun, Jun 18, 2023 at 4:04 AM Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

 Rick, this is the primary reason I am switching to DIY lifepo batteries.  The K-boat battery pods make dealing with standard batteries difficult especially given their weight.  When I was with Dan Lance earlier this year he had a battery that did fit but only without the removable tray in the plans.  
I can send you stickers.  I’m out of town until mid week so will contact you then. 
Jon

    On Friday, June 16, 2023 at 02:29:59 PM EDT, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

 I had some difficulty in inserting my batteries the other day into the pods because of how close the battery lugs were to the wall of the pod. I had built an aluminum tray for the batteries to make it easy to install and remove them for maintenance and used 1/4" aluminum flat bar to fabricate them but I had to do away with the trays because of clearance issues and so even though that only bought me a 1/4" of an inch, I needed all the help I could get. It also helped in having the battery cables slide over the tops of the fill caps more easily when attached to the all thread that passes the power into the sub as they flex and bend when pushing it in after attaching. 
Anyone else that is building a K-350 have that same problem? I welded two pieces of SS angle in the pods for the trays to slide on and can't remove them and lower them as they were put in before I welded the ends on. As they go down, they come together being pipe so I couldn't of gone much lower with them and still have the horizontal room to fit the batteries. 
I also wanted to buy a couple of Psubs stickers that I have seen on other peoples boats and tried to do that on our web site but I didn't have any luck finding the store that would have them for sale. Any ideas?
Rick

On Fri, Jun 16, 2023 at 7:20 AM John Bussard via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Grateful for all the info here.  While I was vague and only stated “Li ion” I definitely have no fixed start point, so this is all good to learn about.  And certainly echo Busby that one needs to consider weight for ballast purposes as well.  I’ve spent most of my life around airplanes, so a slightly different approach to weight reveals itself, though CG management is a common theme here.
Thanks to all for the info and discussion.

On Jun 3, 2023, at 7:51 PM, Michael Holt via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
  I was sent some Waterways World magazines from 2020, a couple of years ago.  There are advertisements for electric power systems for canal boats.  They start with diesels tied to generators tied to batteries that drive 48VDC motors.  There appear to be versions that have no diesels involved, and the batteries are recharged from shore power.  In the UK, that's 230VAC.

 If anyone's interested, I'll dig out the magazines and make a list of the websites.

 Mike 
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