Yes technically you're losing capacity but when you figure that with a standard lead acid is best to avoid discharge below 50% to prevent damage - the lithium actually gives you more USABLE capacity. Of course you have the lighter weight and higher charge rate of the lithium as additional advantages. Maine sailor did an article regarding the orientation of flooded cells on a sailboat. He showed how the heel can uncover cell plates depending on the fore/aft vs port/stbd orientation. He also found that all orientations were equally bad with either the 4D or 8D batteries (I can't recall which). The point is that that is another often overlooked advantage of AGM and lithium - they can't be damaged by uncovering the cell plates.
The biggest disadvantage of lithium for me is the upfront cost which includes converting all charge sources (shore charger, alternator, and solar) to lithium. Some of the manufacturers (Valance as just one example) have a BSM that makes it mimick a 12v lead acid so converting the charge sources is unnecessary. Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD Jul 28, 2022 15:36:53 Bill Coleman via CnC-List <cnc-list@cnc-list.com>: > Oh! > For some reason, I thought Ah were constant, regardless of voltage - I guess > maybe that is Kilowatts - > So with a 200 Ah Lifepo battery vs a 255 AGM, looks like I will lose some > capacity, unless that is made up with efficiency from the Lithium - . > Does that make sense? > > Thanks Joe. > > Bill Coleman > > On Wed, Jul 27, 2022 at 2:40 PM Della Barba, Joe via CnC-List > <cnc-list@cnc-list.com> wrote: >> >> A 100 AH 24 volt battery and a 200 AH 12 volt battery hold the same amount >> of power. >> >> Assuming they are using 100 AH cells, the 12 volt will have 2 sets of 4 in >> series in the case that are then in parallel and the 24 volt version will >> have all 8 in series. You could literally open the case and change a 12 to a >> 24 volt or back again, BMS issues aside. >> >> Don’t forget the lithium batteries in a standard-size case may not be using >> all the real estate inside that case either, it isn’t like lead-acid where a >> certain capacity means a certain size. >> >> >> >> */Joe Della Barba/* >> >> Coquina >> >> >> >> >> >> *From:* Bill Coleman via CnC-List <cnc-list@cnc-list.com> >> *Sent:* Wednesday, July 27, 2022 2:33 PM >> *To:* Stus-List <cnc-list@cnc-list.com> >> *Cc:* Bill Coleman <colt...@gmail.com> >> *Subject:* [EXTERNAL] Stus-List Re: Lithium Batteries >> >> >> >> These are confusing, they have a 24 V that looks similar in size to the >> lifeline 8D, but the 8D is 255 Ah, and the >> >> >> *_SOK 24V 100Ah LiFePO4 >> Battery[https://www.us.sokbattery.com/product-page/sok-24v-100ah-lifepo4-battery]_* >> >> >> >> is only 100 Ah - are they supposed to be equal, even with that disparity? >> >> >> >> Blil Coleman >> >> Entrada Erie PA >> >> >> >> On Tue, Jul 26, 2022 at 4:45 PM Joe Della Barba via CnC-List >> <cnc-list@cnc-list.com> wrote: >> >> I think I am going to get 2 of these: >> >> https://www.us.sokbattery.com/product-page/sok-12v100ah-lifepo4-battery >> >> >> >> Advantages I see: >> 1. >> Two of them means a dead BMS only takes half the bank offline, not 100% of your power. 2. >> They have heaters for the very rare times the cabin might be below freezing. 3. >> They have Bluetooth for access to the BMS. 4. >> I saved the best for last, if the BMS craps out or you just want a better one, just open it up and replace it! This is NOT possible with most batteries unless you cut them apart. 5. >> See 4, a dead cell can be replaced. >> >> >> >> Joe Della Barba >> >> Coquina C&C 35 MK I >> >> Kent Island MD USA >> >> >> >> >>
