LFP on Shore Power with Inverter/charger?

The idea with lithium is to provide a sufficient 'float' to support any loads that are present without the need to charge the batteries. A voltage of 13.3 - 13.4V will do just that - carry any loads without the batteries being discharged. You could also switch off the charger, but then you would be discharging the batteries, and would need to run them through bulk again sooner.

“ The only reason folks think lithium chemistries are more complicated is that they have come to accept all the requirements of lead acid as 'normal'. In an apples to apples comparison the care and feeding of lithium is far simpler, most folks just aren't familiar with it. ”

Exactly, Lithium (LFP) is happy with constant current and constant voltage, isn’t bothered by a float mode and there’s no need to equalize...This is about as basic as things can get and describes what a dedicated LiFePo4 charger does...The main caveat, don’t charge below freezing (discharging is ok).

3 tons

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.

FWC wrote:
The idea with lithium is to provide a sufficient 'float' to support any loads that are present without the need to charge the batteries. A voltage of 13.3 - 13.4V will do just that - carry any loads without the batteries being discharged. You could also switch off the charger, but then you would be discharging the batteries, and would need to run them through bulk again sooner.

It depends on how much load of course. Converters have 13.6v as "Normal", which is for when you are using the RV on shore power, and 13.2v is "Storage" for when it is not being used

The answer to the OP seems to be that if you have an inverter/charger on shore power with LFPs, you can set the voltage to 13.6 and be ok.

With a converter and LFPs you do have the choice of isolating the LFPs and running the RV on the converter

Yes 13.6V is fine.

If you were buying a new inverter/charger it would probably be wise to buy one of the better ones (like Victron) where you can configure it to your needs. Who knows what the next technological break through will be.

3 tons wrote:
“ The only reason folks think lithium chemistries are more complicated is that they have come to accept all the requirements of lead acid as 'normal'. In an apples to apples comparison the care and feeding of lithium is far simpler, most folks just aren't familiar with it. ”

Exactly, Lithium (LFP) is happy with constant current and constant voltage, isn’t bothered by a float mode and there’s no need to equalize...This is about as basic as things can get and describes what a dedicated LiFePo4 charger does...The main caveat, don’t charge below freezing (discharging is ok).

3 tons

And SiO2 are less problematic than Li, with even fewer hoops.

pianotuna wrote:

3 tons wrote:
“ The only reason folks think lithium chemistries are more complicated is that they have come to accept all the requirements of lead acid as 'normal'. In an apples to apples comparison the care and feeding of lithium is far simpler, most folks just aren't familiar with it. ”

Exactly, Lithium (LFP) is happy with constant current and constant voltage, isn’t bothered by a float mode and there’s no need to equalize...This is about as basic as things can get and describes what a dedicated LiFePo4 charger does...The main caveat, don’t charge below freezing (discharging is ok).

3 tons

And SiO2 are less problematic than Li, with even fewer hoops.

Well that seems to be the answer to the question that nobody asked :), but not a whole lot different than comparing a biplane to a Lear jet - either will get you where you want to go (lol).

3 tons, where ‘harvest rates’ and capacity matters...

pianotuna wrote:
And SiO2 are less problematic than Li, with even fewer hoops.

That would depend on the individual user needs.
For me SiO2 has only drawbacks.

time2roll,

After the summer when I get my SiO2, we should have a "shoot out"??? T'would be great fun!

We would have to limit charging to around 125 amps--as that's the maximum I can do.

I'll have uneven banks so I might well be able to come close to what ever capacity you will be making up.

I'd have to do my measurements in watt-hours based on the input to the Magnum inverter charger.

All this depends on covid unfortunately. At the moment travel is being discouraged *big time*.

I'd also love to know what the drawbacks you see concerning SiO2.

I see weight as a weakness--but I'll actually be going down from where I started, so that's a non issue for me personally.

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!