How are you using your Lithium Bank while traveling?

[Saullman]

In all the years of having LifePo4 batteries, ive never worried about them being full.

Yes a full charge will get me to 14.6Vdc, but within a few hours they'll drop to their normal 13.2-13.6 vdc, they can stay that way for months on end with zero worries. Now with 1K watts of solar on our classic 33, the batteries no matter what SOC they are in they fill to 100% fairly fast. With the 12v fridge/freezer running 24/7 they will pull the batteries down some. But I will admit i always run my aldi heater utilizing electricity only, since it is easily replenishable. having 840 ah of LifePo4's does make boon docking for weeks on end gratifying.

[akarakos]

Just curious… some are saying they take their batteries to 100 pct. Some mention 70-80 pct. What is your voltage at 70 pct vs 100 pct?

[DCPAS]

Originally Posted by akarakos

Just curious… some are saying they take their batteries to 100 pct. Some mention 70-80 pct. What is your voltage at 70 pct vs 100 pct?

It's difficult to figure out state of charge by voltage. LiTime says 100% is 13.33, 75% is 13.3, and 50% is 13.15. Not much difference. I think most folks get state of charge from a smart shunt or from the battery's bluetooth app. My app gives me state of charge and voltage. The last reading I got was 99% for both with one at 13.6v and the other at 13.5v. Which isn't even consistent with the table I quoted above.

[mikeinca]

Originally Posted by Saullman

In all the years of having LifePo4 batteries, ive never worried about them being full.

Yes a full charge will get me to 14.6Vdc, but within a few hours they'll drop to their normal 13.2-13.6 vdc, they can stay that way for months on end with zero worries. Now with 1K watts of solar on our classic 33, the batteries no matter what SOC they are in they fill to 100% fairly fast. With the 12v fridge/freezer running 24/7 they will pull the batteries down some. But I will admit i always run my aldi heater utilizing electricity only, since it is easily replenishable. having 840 ah of LifePo4's does make boon docking for weeks on end gratifying.

FWIW and just to clarify, I don't worry about fully charging my batteries when in use while camping either. I do question keeping them constantly at 100% while in storage given that, anecdotal evidence aside, there is some information that this may not be good for them in the long run. Whatever.

[ITSNO60]

I store mine at 50-80% and for travel I fill them up just like the fuel tank. Like mentioned, there are probably more charge cycles than the average user will ever see before they just age out.

[richard5933]

Originally Posted by DCPAS

It's difficult to figure out state of charge by voltage. LiTime says 100% is 13.33, 75% is 13.3, and 50% is 13.15. Not much difference. I think most folks get state of charge from a smart shunt or from the battery's bluetooth app. My app gives me state of charge and voltage. The last reading I got was 99% for both with one at 13.6v and the other at 13.5v. Which isn't even consistent with the table I quoted above.

I agree - no was to get SOC from the voltage level. The voltage level of lithium batteries remains nearly level as they discharge and doesn't drop quickly like traditional lead-acid batteries do. Voltage drop from the wiring to/from the meter only complicates the readings.

Only accurate way to know SOC is with a shunt-based monitor.

[Saullman]

When they are fully charged, the battery voltage becomes 14.6V. It drops to 10 volts when fully discharged. The below 12V LiFePO4 battery voltage chart reveals how the voltage drops with respect to battery capacity.

[richard5933]

Originally Posted by Saullman

When they are fully charged, the battery voltage becomes 14.6V. It drops to 10 volts when fully discharged. The below 12V LiFePO4 battery voltage chart reveals how the voltage drops with respect to battery capacity.

Your chart pretty much shows what I said earlier...The voltage drop for lithium batteries is pretty much flat except for a few percentage at the beginning and at the end.

Lead acid batteries would have a pretty sloped line all the way down with much more constant dropping of voltage all along the graph.

[3OnOurWay]

Originally Posted by Saullman

When they are fully charged, the battery voltage becomes 14.6V. It drops to 10 volts when fully discharged. The below 12V LiFePO4 battery voltage chart reveals how the voltage drops with respect to battery capacity.

Thanks for posting. Helps illustrate SmartShunt value to understand use, minimize use, or justify use over a set SOC

[JeffKim]

A teensy-weensy correction. The charger will charge at 14.4V however the fully charged battery voltage depends on the brand, usually it's around 13.6V as stated by others here.

[uncle_bob]

Originally Posted by richard5933

Your chart pretty much shows what I said earlier...The voltage drop for lithium batteries is pretty much flat except for a few percentage at the beginning and at the end.

Lead acid batteries would have a pretty sloped line all the way down with much more constant dropping of voltage all along the graph.

Over the usable range lead acid goes from 12.6 to 12.0 volts at 70 F. Those voltages vary up to 0.6V over temperature.

LiFePO4 runs from 13.4 to below 12V over the usable range. They don’t vary much with temperature.

You need a shunt with both types of battery.

[richard5933]

Originally Posted by uncle_bob

Over the usable range lead acid goes from 12.6 to 12.0 volts at 70 F. Those voltages vary up to 0.6V over temperature.

LiFePO4 runs from 13.4 to below 12V over the usable range. They don’t vary much with temperature.

You need a shunt with both types of battery.

Correct, and I agree about the value of a shunt with both.

The voltage range on the lithium is as you say, but the difference is that for the majority of the cycle the voltage holds steady. There is an initial drop after charging, and then things hold steady for quite a while. It's not till the lithium batteries get in their lower end of useful capacity that the voltage starts to drop noticeably again. Look at the graph in post #27 and you'll see the long stretch of horizontal.

Lead acid batteries have a graph which show a noticeably diagonal line with the voltage dropping during the entire cycle and not just at the ends. This makes it possible to get a rough estimate of SOC using voltage.

[akarakos]

Another thought that was given to me by a certified technician was: If you want to get an voltage read out of what your batteries voltage “actually” is, check it when not connected to the tow vehicle or shore power.

[DCPAS]

Originally Posted by uncle_bob

You need a shunt with both types of battery.

Or batteries with a bluetooth app.

[steilkurve]

Originally Posted by Peter C

My three 100 amp hour BB10012 are over five years old. We just live our best lives and do not worry about regular discharge. I do pay attention to the state of charge when heading to a dry/boondocking location. They seem to be holding up very well and hopefully in a few years we will replace them with a couple of game changers or similar.


Note I live in Canada and leave the batteries in the trailer (they are under the bed) over the winter at 100% with roof solar connected.

I do the same. 500 AH of BBs under the bed. I let them be when in storage and solar tops them off eventually to 100%. It’s been 3 seasons of use and the full charge voltage hasn’t really budged. Maybe I’ll regret it someday but maintaining a lower state of charge, unlike in an EV, would be too much manipulation, at least for me.