LFP on Shore Power with Inverter/charger?

I'll be interested in the high draw items and length of time before the battery voltage/ inverter tags out with Si02.;

FWC wrote:
As we have discussed to death, even the "don't charge below freezing" caveat is really a soft limit, worse case you have fractional decrease in cycle life. To do and apples-to-apples comparison, lead acid also have a low temperature charge limit, and this is usually a hard limit - you try to charge below the freezing point and very bad things can happen.

Do provide a link.

That freeze point would be for a totally discharged battery? What sort of idiot are you that you would contemplate charging a frozen battery?

Itinerant1 wrote:
I'll be interested in the high draw items and length of time before the battery voltage/ inverter tags out with Si02.;

I tested for that in the TC to see if the one 100AH would run the inverter with MW draw like I bought it to do. Each set-up would act differently what with wiring and equipment, but The Trimetric showed a 65 amp draw fairly steady for about 35 -40 minutes roughly before the inverter quit due to low voltage.

Bounce back voltage soon after is 20% on the chart, but there is suspicion SOC would be higher if I had waited a day for a higher "resting " voltage.

The result I got matches the spec constant current discharge chart for 67 amps and 45 minutes to "end voltage" so at least that part came out right.

The problem is those tables don't say when your inverter will conk out, just what the "end voltage" is.

With the "flat" LFP voltage, you should be above inverter shut down farther along towards "end voltage" and you are already ahead of the game by having way higher voltages per SOC than the SiO2's.

Scroll down to the table on page 2

https://soneil.com/wp-content/uploads/2018/07/12-EFSM-100.pdf

It would interesting to see an LFP one to compare times per constant amps at selected high amps discharge. Anybody have a link to an LFP one?

Note the SiO2's IR is 6.5 mOhms, An ordinary AGM's is about 5 mOhms, and an LFP's is way low, so high draw is not all about IR, but could be a factor I suppose.

I disagree with PT suggesting SiO2 could be an alternative to LFP. I think they are two different animals, which each fitting certain scenarios. EG, the blurb says SiO2 caught on in Oz because of the high ambient temp they could be used at, and only later got noticed in North America. Whatever, no skin off my nose.

I ended up having to buy a second one with a changed scenario (DW moved the goalposts :) ) so if she had done that earlier I could have just got two AGMs for the job at hand. Oh well--now I am the proud owner of two SiO2s. Big warning there for LFP buyers! Get the scenario straight first unless you have deep pockets.

pianotuna wrote:
3 tons, Since SiO2 can handle a 243 amp draw from a single 100 amp-hour battery, I guess you are right. Li is a biplane. LOL!

Hey PT note, I didn’t say a Lear Jet ‘was better’ than a biplane, for acrobatics the biplane wins hands down...Similarly, for sub-zero weather and uber high discharge currents (if needed?) SiO2 kicks butt, but for a rapid 1C charge recovery and discharge rates, and nearly flat voltage curve (keeping inverters happy), I’ll board the Lear Jet...As I stated, both will get you where you want to go, but one need only imagine mental Debit and Asset columns for each battery type to arrive at what best meets their own RV habits... Were I in your shoes (snow shoes?), I’d likely warm up to SiO2, but LFP checks all my off-grid boxes, and packs lots of usable capacity within a lightweight compact footprint...

3 tons of harvest

I am not contemplating charging a frozen battery, and never suggested that, but thanks for calling me an idiot.

The point was that lead acid batteries also have a low temperature limit, and unlike lithium, if you try to charge below this limit you are apt to have a dangerous mess on your hands.

pianotuna wrote:


Do provide a link.

That freeze point would be for a totally discharged battery? What sort of idiot are you that you would contemplate charging a frozen battery?

OP here-- This thread ended at 0908 this morning and is now about Si02 vs LFP it seems. Whatever, but if folks want others to read that new discussion, many will probably miss it, having seen the OP question answered back at 0908.

Might be away to start a new thread on the new topic and transfer the posts since 0908 that apply to that new thread ? I don't know if that can be done. Or just carry on.

FWIW, SiO2 migrated into the discussion at 11:00 hrs, though (per past pattern) it’s not clear why...

3 tons

"Post not shown due to blocked member 3 tons. Click here to edit your blocked list."

That is what I see now. Such peace! The system works. On that, note if the one you block is the OP of a thread, that whole thread disappears, not just his posts. Anyone can block me too, if it will make him feel better :)

BFL13 wrote:
OP here-- This thread ended at 0908 this morning and is now about Si02 vs LFP it seems. Whatever, but if folks want others to read that new discussion, many will probably miss it, having seen the OP question answered back at 0908.

Might be away to start a new thread on the new topic and transfer the posts since 0908 that apply to that new thread ? I don't know if that can be done. Or just carry on.

It does seem that way. I wonder who would have brought up SiO2 in a discussion about lithium batteries and converters? :h

The question is not really that important, as the answer always seems to be 'SiO2'.

I'll help bring it back around some to LFP on solar power with inverter/ charger. ;)

Started this morning after breakfast (09:00) at 34% SoC by 14:00 at 99% SoC, charged by solar.

At 15:20+/- turned the air conditioner unit on for a 2 hour cooldown. Solar was contributing at the start 534 watts, at the end 223 watts.


Good enough for a couple hours when the sun finally dropped low enough and a breeze took over cooling. :)