<div dir="ltr"><div>I think this largely depends on the application for the batteries and mounting considerations. I don't have my copy of Busby immediately available, but I remember a lot of that discussion falling into the, "just enough to be dangerous" category. If you want good references for new research in this specific area the IEEE PES and VTS societies are very good references. On the whole you may find that a stratified architecture is best, but the general trend in applications like submarines is to achieve high thermal efficiency and prioritize specific power over specific energy. These considerations generally result in the selection of a supercapacitor (or ultracapacitor). If you need to achieve equivalent slow discharge rates you would just use a buck regulator. <br></div><div><br></div><div>I think in this case you have to really ask a couple questions first:</div><div>- How long do you want to run fully submerged?</div><div>- How much do you want to spend?</div><div>- What is your maximum dry weight or LDT?</div><div>- What is your maximum or minimum current draw?</div><div><br></div><div>The answers to these will be able to determine whether it makes sense to use conventional batteries or supercapacitors. Cost is really one of the biggest factors though, many systems that are built for long term sustainability are starting to center around stratified approaches using electrochemical fuel cells for the energy density and supercapacitors for the power density. Often these two can be balanced such that you achieve overall SWaP metrics ahead of any conventional battery.</div><div><br></div><div>Regards,</div><div>James</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jun 1, 2023 at 10:30 PM John Bussard via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Reading Busby and his discussion on the pros and cons of the battery types available at time of publication:<br>
<br>
Is there sufficient data as folks move forward in new sub designs re: newer battery types- Specifically Li ion? <br>
I’m guessing that given the safety hazards there aren’t sufficient advantages to using- lead acid batteries seem to serve the majority of desired profiles.<br>
<br>
Is this something that’s changing, or do folks expect to continue using old school batteries? <br>
<br>
Thanks for thoughts and history,<br>
John<br>
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