Confused

gthomas

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Jun 13, 2020
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I swapped out a lithium battery for the existing house battery without replacing the WFCO 8735P. Before hooking it up I charged it to 90% thinking it stay there for a bit and then reduce down to about 75%. However it charged up to 100% and has stayed there.

I also downloaded the company’s preferred BMS app and I have no clue what any of this means other than SOC.

Any help would be greatly appreciated.
 

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The standard WFCO or Lithium capable WFCO converter will charge a lithium battery to near 100%. But the rate of charge is very, very slow (Low amps) Ours does. Ours is a WFCO 9855AD and is lithium capable (auto detect)but rarely goes into lithium charging mode.

The BMS pictures you attached looks the same as ours. On the first screen, the power and current indications will tell you how much power (watts) and current (amps)(positive or negative number) is going into or out of the battery. Example shut off your shore power and you will see the current (amps) number go negative, that's how much power is coming out of the battery to the RV. If you leave the shore power off for a little while, then turn it on, you will see the current (amps) number go positive. That's telling you the battery is charging, how many amps are going into the battery., You will see those numbers decrease as the battery gets closer to a full state of charge. Right now the current and power numbers at 0.00 are telling you no power or current is going into or out of the battery.


The other indicators tells you if the cells inside the battery are balanced. The protection indicator tells you if the battery has been shut off by the BMS (Battery Management System) maybe because the battery temp fell below 32*. The graphs are just fluff, they tell you what the battery has been doing over time periods.
 
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The standard WFCO or Lithium capable WFCO converter will charge a lithium battery to near 100%. But the rate of charge is very, very slow (Low amps) Ours does. Ours is a WFCO 9855 and is lithium capable but rarely goes into lithium charging mode.

The BMS pictures you attached looks the same as ours. On the first screen, the power and current indications will tell you how much power (watts) and current (amps)(positive or negative number) is going into or out of the battery. Example shut off your shore power and you will see the current (amps) number go negative, that's how much power is coming out of the battery to the RV. If you leave the shore power off for a little while, then turn it on, you will see the current (amps) number go positive. That's telling you the battery is charging, how many amps are going into the battery., You will see those numbers decrease as the battery gets closer to a full state of charge. Right now the current and power numbers at 0.00 are telling you no power or current is going into or out of the battery.


The other indicators tells you if the cells inside the battery are balanced. The protection indicator tells you if the battery has been shut off by the BMS (Battery Management System) maybe because the battery temp fell below 32*. The graphs are just fluff, they tell you what the battery has been doing over time periods.
Thanks, that helps a lot
 
A LiFePO cell is considered to be charged when the cell has 3.45V. Multiply that number times 4 (because there are four individual cells in the battery) and the result is 13.8V. Obviously, your charger will need to output more than 13.8V in order to be able to charge the battery in a timely fashion. Many of us have had issue with the WFCO chargers simply not working as designed. Many of us have switched to a different charger, and those that are made specifically for charging the LiFePO (better known as LFP battery). In my case, my WFCO would get me to just under 80% State of Charge (SOC) and that simply was not good enough for me.

And just as a reminder or a bit of info if you didn't already know. If you live in a climate where you winterize your camper, the LFP battery also needs a bit of attention. Most will have a low temperature cutoff so that it cannot be charged or attempted to be charged when the temperature of the battery is at 32°F or lower....make sure you have that on your battery and should/may be visible in the app. If you don't know for SURE that you have low temperature protection, simply disable any/all methods of charging or trying to charge the battery. That would of course include the converter/charger, solar, and even a connection to the tow vehicle. As far as storage levels (SOC), most LFP battery manufacturers will tell you to store it in the 40% to 60% SOC range if it is going to be stored for a month or more. Some will tell you to get it to 100% SOC and I will tell you, I disagree with that completely. There is really no good reason to store one at 100% SOC, and it just adds more stress to the cells in the battery. Hope all this helps a bit...
 
A LiFePO cell is considered to be charged when the cell has 3.45V. Multiply that number times 4 (because there are four individual cells in the battery) and the result is 13.8V. Obviously, your charger will need to output more than 13.8V in order to be able to charge the battery in a timely fashion. Many of us have had issue with the WFCO chargers simply not working as designed. Many of us have switched to a different charger, and those that are made specifically for charging the LiFePO (better known as LFP battery). In my case, my WFCO would get me to just under 80% State of Charge (SOC) and that simply was not good enough for me.

And just as a reminder or a bit of info if you didn't already know. If you live in a climate where you winterize your camper, the LFP battery also needs a bit of attention. Most will have a low temperature cutoff so that it cannot be charged or attempted to be charged when the temperature of the battery is at 32°F or lower....make sure you have that on your battery and should/may be visible in the app. If you don't know for SURE that you have low temperature protection, simply disable any/all methods of charging or trying to charge the battery. That would of course include the converter/charger, solar, and even a connection to the tow vehicle. As far as storage levels (SOC), most LFP battery manufacturers will tell you to store it in the 40% to 60% SOC range if it is going to be stored for a month or more. Some will tell you to get it to 100% SOC and I will tell you, I disagree with that completely. There is really no good reason to store one at 100% SOC, and it just adds more stress to the cells in the battery. Hope all this helps a bit...
Thanks, after a little over 2 days we have finally dropped to 99% SOC, 13.69 TotalVolt. We are in the TT year round in the Pacific Northwest which is why I switched batteries. 70+ percent of 100AH is better than 50% of 60AH when the campground power goes out. The battery has built-in low temp protection and it appears I can disconnect charging using the BMS app. I may put a heater on it.
 
Thanks, after a little over 2 days we have finally dropped to 99% SOC, 13.69 TotalVolt. We are in the TT year round in the Pacific Northwest which is why I switched batteries. 70+ percent of 100AH is better than 50% of 60AH when the campground power goes out. The battery has built-in low temp protection and it appears I can disconnect charging using the BMS app. I may put a heater on it.
A couple of things I will add in here as a response. If you are truly interest in an extremely accurate method of the battery SOC, and maybe you already know this....invest a bit of money in Victron BMV. Here is a link for the one that I use, and many others use... BMV-712 Smart - Victron Energy

These devices will monitor amps in and amps out of the battery. As you may or may not know, battery voltage is a terrible way to determine the SOC of a LFP battery because of their very flat charge/discharge curve. The difference of a few tenths of a volt can be the difference of say 40% SOC and 70% SOC. Sometimes the battery app and the battery's BMS is fairly accurate, sometimes not. One thing is certain though, using the battery voltage as an indicator is not even close to being accurate/reliable.

I have a homemade heated/insulated battery box for the battery that I DIY built, and I've never really used it except to test it out after I built it. I don't camp in cold weather, and I winterize my camper and leave the battery electrically disconnect at around a 50% state of charge.
 
A couple of things I will add in here as a response. If you are truly interest in an extremely accurate method of the battery SOC, and maybe you already know this....invest a bit of money in Victron BMV. Here is a link for the one that I use, and many others use... BMV-712 Smart - Victron Energy

These devices will monitor amps in and amps out of the battery. As you may or may not know, battery voltage is a terrible way to determine the SOC of a LFP battery because of their very flat charge/discharge curve. The difference of a few tenths of a volt can be the difference of say 40% SOC and 70% SOC. Sometimes the battery app and the battery's BMS is fairly accurate, sometimes not. One thing is certain though, using the battery voltage as an indicator is not even close to being accurate/reliable.

I have a homemade heated/insulated battery box for the battery that I DIY built, and I've never really used it except to test it out after I built it. I don't camp in cold weather, and I winterize my camper and leave the battery electrically disconnect at around a 50% state of charge.
Thanks, I’ll look into it
 
I think this is also a good shunt if you prefer a phone display...and on sale right now.
The one I linked to, the Victron 712 shunt has BlueTooth also and will display everything on the Victron app. I put the display in my baggage compartment within a few inches of my Converter/Charger, just because I had it. I normally use the phone app though when I'm setup and camping.

You can see most of it in this pic....on the side wall and the Converter/Charger mounted from the ceiling in the storage bay....
 

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A LiFePO cell is considered to be charged when the cell has 3.45V. Multiply that number times 4 (because there are four individual cells in the battery) and the result is 13.8V. Obviously, your charger will need to output more than 13.8V in order to be able to charge the battery in a timely fashion. Many of us have had issue with the WFCO chargers simply not working as designed. Many of us have switched to a different charger, and those that are made specifically for charging the LiFePO (better known as LFP battery). In my case, my WFCO would get me to just under 80% State of Charge (SOC) and that simply was not good enough for me.

And just as a reminder or a bit of info if you didn't already know. If you live in a climate where you winterize your camper, the LFP battery also needs a bit of attention. Most will have a low temperature cutoff so that it cannot be charged or attempted to be charged when the temperature of the battery is at 32°F or lower....make sure you have that on your battery and should/may be visible in the app. If you don't know for SURE that you have low temperature protection, simply disable any/all methods of charging or trying to charge the battery. That would of course include the converter/charger, solar, and even a connection to the tow vehicle. As far as storage levels (SOC), most LFP battery manufacturers will tell you to store it in the 40% to 60% SOC range if it is going to be stored for a month or more. Some will tell you to get it to 100% SOC and I will tell you, I disagree with that completely. There is really no good reason to store one at 100% SOC, and it just adds more stress to the cells in the battery. Hope all this helps a bit...
No doubt you are accurate (you have way more knowledge/experience than I do) relating to 100% charge when storing and likely have read this from Battleborn:

"Unlike other LiFePO4 batteries that use prismatic cells, our batteries contain cylindrical cells. This means there is no worry of damaging the battery by fully charging or discharging it. Additionally, these cells are top-balancing, meaning once the batteries is fully charged the cells are balanced, this is why we recommend fully charging our batteries before storage. This way the cells are balanced during storage and fully charging the battery also allows the longest storage time."

They did not mention "simpler approach" and they do know that 50% produces longer battery life--if related mistakes are not made. I do as you do, 100% charge and then discharge to about 50% and hope that I do not make a related mistake.
 
Unlike other LiFePO4 batteries that use prismatic cells, our batteries contain cylindrical cells. This means there is no worry of damaging the battery by fully charging or discharging it.

I am no lithium battery expert but this statement is full of holes. Yes, I understand, it's not yours, it's Battle Born's. They sell batteries and they are trying to sell you why you should buy their batteries. They have to justify why they use round batteries vs square.

The way I see it is ALL lithium batteries will be ruined if over/undercharged. How they are made has nothing to do with it. Some will actually catch fire.

Because of this issue with damage/fire, lithium battery companies developed the BMS. As long as this component is working properly, you will never have an under/over charge situation. If you are a battery company that does not invest wisely in a good/robust BMS, you're just going to have a huge issue on hand, including fires.
 
I am no lithium battery expert but this statement is full of holes. Yes, I understand, it's not yours, it's Battle Born's. They sell batteries and they are trying to sell you why you should buy their batteries. They have to justify why they use round batteries vs square.

The way I see it is ALL lithium batteries will be ruined if over/undercharged. How they are made has nothing to do with it. Some will actually catch fire.

Because of this issue with damage/fire, lithium battery companies developed the BMS. As long as this component is working properly, you will never have an under/over charge situation. If you are a battery company that does not invest wisely in a good/robust BMS, you're just going to have a huge issue on hand, including fires.
I agree with you with the minor exception that when a battery is left connected and discharged or not recharged after use, until BMS shuts it off (by user misunderstanding or mistake) and then it is left uncharged for a VERY long period of time, the self-discharge will kill the battery. Unbalanced cells, again a user issue, will add insult to injury.

LFP, of course, are much less likely to have issues than LA. The BMS is going to save a lot of batteries!
 
Yes. The BMS would stop the discharge to prevent problems but that does not stop the self discharge that all batteries have.

I do know that BMS's are usually programmed to the safe side [I know I programmed mine that way]. They're programmed to stop the discharge well before damage. How long does this self discharge take before they are ruined? I do not know.

You are correct and something to think about, but my opinion is, it would be years before you would get from BMS low voltage shut off to major cell damage.

As a car mechanic, I know there are customers that do not maintain their vehicles properly and they pay in the long run.
 

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