Batteries really depleted overnight or is it a BMS problem?

[Partimewages]

Shunt monitoring equipment?

 

[Mcstiggens]

"smart charger" is a marketing term.

Do you still have a converter in your RV?

Yes, still have converter.

I just don't see how it could "bounce back" from 10V to 13V according to multiple sources in that short of time

 

[WindWizard]

that's a 10A charger. Assuming you have a 100ah battery, it will take a MINIMUM of 10 hours to fully charge the battery.

Charging for an hour only adds 10%.

He has 2 200 ah batteries. It will take a minimum of 40 hours to charge the batteries.

 

[Mcstiggens]

Has the

Shunt monitoring equipment?

factory Furrion shunt but should likely be recalibrated

 

[Mcstiggens]

He has 2 200 ah batteries. It will take a minimum of 40 hours to charge the batteries.

Well it sounds to me like my charger and all monitoring equipment are not accurate or something

 

[sunshine_eggo]

Which is precisely what I said. How could it show as charged in only an hour? I did charge for 10 hours during initial charge

This:

The interior battery indicator is wrong. The battery monitor/shunt is wrong. They must be configured properly to work with your batteries.

That configuration may also include how the monitors handle power loss. Some reset to 100%. Some behave differently.

As stated above, any % reported based solely on voltage is completely worthless in almost all cases. They are almost always targeted at lead-acid, and will report 100% for a LFP battery that's near empty.

I just don't see how it could "bounce back" from 10V to 13V according to multiple sources in that short of time

Because LFP voltage is very flat, when empty, it drops FAST. When full, it peaks fast. The act of charging also drives the voltage higher.

Well it sounds to me like my charger and all monitoring equipment are not accurate or something

10A charger for 400Ah of batteries = 400ah/10A = 40 hr charging.

Yes, still have converter.

Please link the brand and model.

99.99999999% chance your installed converter is a better charger for your LFP batteries than the 10A charger you linked especially when charging from generator.

 

[Partimewages]

Are you sure the Furrion is a shunt? I don't know but Furrion is the cheapest that any manufacturer can use. I would think it's probably voltage based and you will need a current based monitor.

 

[Mcstiggens]

This:



That configuration may also include how the monitors handle power loss. Some reset to 100%. Some behave differently.

As stated above, any % reported based solely on voltage is completely worthless in almost all cases. They are almost always targeted at lead-acid, and will report 100% for a LFP battery that's near empty.



Because LFP voltage is very flat, when empty, it drops FAST. When full, it peaks fast. The act of charging also drives the voltage higher.



10A charger for 400Ah of batteries = 400ah/10A = 40 hr charging.




Please link the brand and model.

99.99999999% chance your installed converter is a better charger for your LFP batteries than the 10A charger you linked especially when charging from generator.

WF-9855-AD Deck Mount Converter Charger – WFCO Technologies

WF-9855-AD Deck Mount Converter Charger: 55 AMP OUTPUT CURRENT The WF-9855-AD Converter includes the exclusive, Patent Pending Auto-Detect technology. This microprocessor-driven technology will recognize lithium-ion and lead-acid battery chemistries and adjust the charging profile to match the...

www.wfcotech.com

 

[Mcstiggens]

Are you sure the Furrion is a shunt? I don't know but Furrion is the cheapest that any manufacturer can use. I would think it's probably voltage based and you will need a current based monitor.

https://lci-support-doc.s3.amazonaws.com/furrion%20_off%20the%20grid/ccd-0005620.pdf

 

[Mcstiggens]

Are you sure the Furrion is a shunt? I don't know but Furrion is the cheapest that any manufacturer can use. I would think it's probably voltage based and you will need a current based monitor.

Well it appears that in order to calibrate it correctly, I must deplete the battery again.

 

[Mcstiggens]

Fixed, but often true in an RV due to shitty wiring and poor AC-DC converter behavior/models.



13.0V may be as low as 30% SoC.
13.1V may be as low as 40% SoC.

If the batteries don't have low-temp charging protection, charging at 29-30°F may damage them.

LFP takes on more charge at lower voltage than lead acid, plus it seems to move much more slowly than lead acid voltage... staying mostly constant until the battery is nearly full.

As stated above, until you see voltage AT THE BATTERY terminals of 13.8V+, you're not fully charged. If the battery is resting at 13.4V after 5 minutes of sitting or under a very light load, you are likely at a high state of charge.

So if charging them at 29-30 can damage them, what about discharging them? I saw a rep from Battleborn say that LifePO4 batteries are good to -4 F before having issues FWIW. I thought that seems a little too cold in any case. It sound like, in addition to charging properly and calibrating monitoring equipment, that I should also mount the batteries in a warmer location, such as under the bed. They are currently inside the passthrough storage in the nose of the trailer. Enclosed but still close to ambient outdoor temps.

 

[Partimewages]

Well, you do have a current based system. While I'm not the smartest person in the room discharging batteries to 0 capacity seems like a bad idea and very time consuming especially with 400 amp hours of capacity.
This will need to be done to make sure your system is accurate.

 

[Mcstiggens]

Well, you do have a current based system. While I'm not the smartest person in the room discharging batteries to 0 capacity seems like a bad idea and very time consuming especially with 400 amp hours of capacity.
This will need to be done to make sure your system is accurate.

I thought so too.

 

[Q-Dog]

Just to be that guy, my AmpereTime/LiTime batteries came with a nicely done manual that went through proper setup and answered all of the questions/issues you seem to be having.

 

[Rocketman]

Since you are starting a boondock lifestyle- you may want to consider upgrading your battery monitor.

Look at a Victron BMV712 or Smartshunt.

Also, if you get the temperature monitoring cable and you use Victron mppt’s for your solar charge controllers - they can be setup so the solar will not charge until the battery is above _____F (user setable). This way you don’t have to rely on the battery bms for low temp protection from solar.

Lithium batteries can be discharged at something like -4F, but if you charge them below 32F you can destroy them. I like two way protection again destroying my battery when it is cold. (charger + bms).

I agree with the other posters that your batteries were draining and you were not charging them enough. Your charge sources are very slow charging.

If you decide to get an inverter- look at the inverter/chargers - I use a Victron Multiplus 12/3000. I can charge at like 90amps of 12v. Helps keep generator run time down.

Good luck on your adventure.

 

[Partimewages]

@Rocketman has the best answer for you!
You can't beat Victron for mobile applications.

 

[wme]

400ah of batteries will need at least 400w of solar at a minimum.

 

[sunshine_eggo]

WF-9855-AD Deck Mount Converter Charger – WFCO Technologies

WF-9855-AD Deck Mount Converter Charger: 55 AMP OUTPUT CURRENT The WF-9855-AD Converter includes the exclusive, Patent Pending Auto-Detect technology. This microprocessor-driven technology will recognize lithium-ion and lead-acid battery chemistries and adjust the charging profile to match the...

www.wfcotech.com

55A
should charge your batteries in as little as 8-10 hours.

"For lithium-ion Batteries, the multi-stage process ensures a safe operating voltage for all loads, replaces energy in the battery, and assures the lithium-ion cells inside the battery remain balanced."

Is there a reason you're not using this?

Voltage Output	Lead Acid – 13.2 – 14.4V DC Range, Lithium-Ion – 13.2 – 14.6 VDC, 13.6 – 14.6 VDC
Bulk Mode (Quick Charging Voltage)	14.4V DC (quick charging voltage)
Absorption Mode (Nominal Voltage)	13.6V DC (nominal voltage)
Float Mode (Trickle Charge Voltage)	13.2V DC (trickle charge voltage)

Looks like a great option to me.

Well it appears that in order to calibrate it correctly, I must deplete the battery again.

Looks like an Aili shunt - decent.

You don't have to. You can fully charge it, set Ah capacity in the shunt and then calibrate to 100%. should be pretty accurate after that.

So if charging them at 29-30 can damage them,

Yes.

what about discharging them?

Most are good down to -20°C discharge.

I saw a rep from Battleborn say that LifePO4 batteries are good to -4 F before having issues FWIW.

-4°F = -20°C

You didn't spend $ for battleborn. consult your battery specifications.

I thought that seems a little too cold in any case. It sound like, in addition to charging properly and calibrating monitoring equipment, that I should also mount the batteries in a warmer location, such as under the bed. They are currently inside the passthrough storage in the nose of the trailer. Enclosed but still close to ambient outdoor temps.

If the batteries don't have low temp charge protection, you should not charge them below freezing, or you will damage them causing permanent capacity loss.

Since you are starting a boondock lifestyle- you may want to consider upgrading your battery monitor.

Look at a Victron BMV712 or Smartshunt.

Meh. For LFP, the AiLi is mostly as good as Victron.

Also, if you get the temperature monitoring cable and you use Victron mppt’s for your solar charge controllers - they can be setup so the solar will not charge until the battery is above _____F (user setable). This way you don’t have to rely on the battery bms for low temp protection from solar.

A Victron Smart Battery Sense can also be used with Victron MPPT to provide direct voltage and battery temperature values for preventing charging at low temps.

400ah of batteries will need at least 400w of solar at a minimum.

I disagree with this completely. There is no battery size to PV relationship.

The amount of PV you have determines how much you can use per day.
The amount of battery storage you have determines how long you can go between charges.

There is a relationship between lead acid battery size and array size due to needed C charge rates, but it's not true for LFP.

Will 400W greatly help the OP? Youbetcha. Is there something about a 400ah battery that requires 400W? Not a thing.

 

[wme]

400w solar to 400ah of battery isn't like a hard rule, but more minimum common sense starting point. Reality is a 3x w to AH ratio is approaching reality for full timing
So even 400w ain't gonna get it but its going to be way better that 165w panel.

 

[Mcstiggens]

Just to be that guy, my AmpereTime/LiTime batteries came with a nicely done manual that went through proper setup and answered all of the questions/issues you seem to be

55A
should charge your batteries in as little as 8-10 hours.

"For lithium-ion Batteries, the multi-stage process ensures a safe operating voltage for all loads, replaces energy in the battery, and assures the lithium-ion cells inside the battery remain balanced."

Is there a reason you're not using this?

Voltage Output	Lead Acid – 13.2 – 14.4V DC Range, Lithium-Ion – 13.2 – 14.6 VDC, 13.6 – 14.6 VDC
Bulk Mode (Quick Charging Voltage)	14.4V DC (quick charging voltage)
Absorption Mode (Nominal Voltage)	13.6V DC (nominal voltage)
Float Mode (Trickle Charge Voltage)	13.2V DC (trickle charge voltage)

Looks like a great option to me.



Looks like an Aili shunt - decent.

You don't have to. You can fully charge it, set Ah capacity in the shunt and then calibrate to 100%. should be pretty accurate after that.



Yes.



Most are good down to -20°C discharge.



-4°F = -20°C

You didn't spend $ for battleborn. consult your battery specifications.



If the batteries don't have low temp charge protection, you should not charge them below freezing, or you will damage them causing permanent capacity loss.


Is there a reason you're not using this?



Meh. For LFP, the AiLi is mostly as good as Victron.



A Victron Smart Battery Sense can also be used with Victron MPPT to provide direct voltage and battery temperature values for preventing charging at low temps.



I disagree with this completely. There is no battery size to PV relationship.

The amount of PV you have determines how much you can use per day.
The amount of battery storage you have determines how long you can go between charges.

There is a relationship between lead acid battery size and array size due to needed C charge rates, but it's not true for LFP.

Will 400W greatly help the OP? Youbetcha. Is there something about a 400ah battery that requires 400W? Not a thing.

"Is there a reason you're not using this?"

Only because I'd have to run the genny for 8 hrs.

Unfortunately I could not find a 40+ amp charger locally that is not for starting a vehicle, thus, the 40 amp is only for 5 second bursts, not for continuous charging. The most I could find was 10amp continuous. I ordered a Li Time 40amp charger.