Battery not charging

[uncle_bob]

Hi

If the battery is fully discharged, you need to put 100A into it for an hour to get it charged.

The BMS in a *normal* lithium battery will shut off charge ( not throttle it, shut it off ) if the charge current it to high. The limit normally stated is a *disconnect* number.

Your converter / charger can put out some number of amps and it might do it over a range of voltages. When the current drain goes over that number of amps, the voltage comes down. This is what's called a constant current mode on a power supply.

If you drive higher voltage into a discharged battery, the Current into the battery will go up. With no BMS it will go way up. You might see 1,000 A at 11V or some other crazy number. With no BMS, the battery starts to smoke. With a normal BMS, the battery is cut off from charging.

If this or that gizmo suggests something other than this is going on, grab a multimeter. Put the probes on the post of the battery. See what the voltage at the battery really is. Put a clamp meter on the lead into the battery. See what the current actually is. Compare that to whatever your gizmo is telling you.

Bob

[Al and Missy]

Originally Posted by Jcondon

I give up. Y'all got this all figured out anyway.

I hadn't read your post about the BB BMS. So it doesn't manage the current, just turns the charge off at some level? Seems less than ideal.

[Jcondon]

Originally Posted by uncle_bob

Hi

If the battery is fully discharged, you need to put 100A into it for an hour to get it charged.

The BMS in a *normal* lithium battery will shut off charge ( not throttle it, shut it off ) if the charge current it to high. The limit normally stated is a *disconnect* number.

Your converter / charger can put out some number of amps and it might do it over a range of voltages. When the current drain goes over that number of amps, the voltage comes down. This is what's called a constant current mode on a power supply.

If you drive higher voltage into a discharged battery, the Current into the battery will go up. With no BMS it will go way up. You might see 1,000 A at 11V or some other crazy number. With no BMS, the battery starts to smoke. With a normal BMS, the battery is cut off from charging.

If this or that gizmo suggests something other than this is going on, grab a multimeter. Put the probes on the post of the battery. See what the voltage at the battery really is. Put a clamp meter on the lead into the battery. See what the current actually is. Compare that to whatever your gizmo is telling you.

Bob

So you are saying the Smart Lithiums that actually control the charging process of the batteries individually are abnormal? This is the way they all should be built. Allowing the converter to go to float voltage after 4 hours is silly.

[Jcondon]

If our goal is to help the OP troubleshoot his converter issue then we need to circle back to my original advice. Plugging in the converter should increase the voltage on the positive buss to 14.4 volts. If you have one of Uncle Bobs Normal Lithium’s you may have to disconnect a lead. When you did this before the voltage was all over the place. That is why I recommend a converter replacement. The rest of this is just background noise. Good Luck with your issue.

[richard5933]

Originally Posted by Jcondon

So you are saying the Smart Lithiums that actually control the charging process of the batteries individually are abnormal? This is the way they all should be built. Allowing the converter to go to float voltage after 4 hours is silly.

Not all converters automatically go to float after 4 hours. The Victron devices mostly have a smarter algorithm which calculates how long to stay at 14.X based on the amount of current flowing to the batteries. Once the current slows to a set point it will drop into float for the remainder of the charge. It is possible to configure them with a set length of time at 14.X if desired.

Originally Posted by Jcondon

If our goal is to help the OP troubleshoot his converter issue then we need to circle back to my original advice. Plugging in the converter should increase the voltage on the positive buss to 14.4 volts. If you have one of Uncle Bobs Normal Lithium’s you may have to disconnect a lead. When you did this before the voltage was all over the place. That is why I recommend a converter replacement. The rest of this is just background noise. Good Luck with your issue.

Thought we already went through this...whether or not one sees 14.4 volts on the positive buss will depend on which converter/charger is in use and which batteries are in use. The OP has already said that if he cuts power to his converter/charger it goes back to 14.4v, and that it will stay there for 4 hours. Sounds like his converter is working as designed.

[Jcondon]

Originally Posted by richard5933

Not all converters automatically go to float after 4 hours. The Victron devices mostly have a smarter algorithm which calculates how long to stay at 14.X based on the amount of current flowing to the batteries. Once the current slows to a set point it will drop into float for the remainder of the charge. It is possible to configure them with a set length of time at 14.X if desired.



Thought we already went through this...whether or not one sees 14.4 volts on the positive buss will depend on which converter/charger is in use and which batteries are in use. The OP has already said that if he cuts power to his converter/charger it goes back to 14.4v, and that it will stay there for 4 hours. Sounds like his converter is working as designed.

It sounds to me when the OP puts a load on that converter the voltage is swinging pretty wildly almost like it has a loose internal connection or something else happened when it was bouncing around inside the cavity enough to make the fuse fall out? It seems to me if the converter was working properly the batteries would not be dead?

[Jcondon]

If the charger is charging correctly why is the battery not charged?

[uncle_bob]

Originally Posted by Al and Missy

I hadn't read your post about the BB BMS. So it doesn't manage the current, just turns the charge off at some level? Seems less than ideal.

Hi

It's exactly what all my Renogy batteries do as well.

The problem is the heat. If you try to convert 14V down to 10V you generate a *lot* of heat. That's not what a BMS is designed to do. The converter charger is perfectly capable of doing the job. Why try and duplicate that? Converter chargers die due to playing with power, no reason to bring those reliability issues into a BMS .....

Bob

[uncle_bob]

Originally Posted by Jcondon

If the charger is charging correctly why is the battery not charged?

Hi

Well, without putting a multimeter on the battery posts and reading the voltage at the posts, we don't have the information required to begin working that out.

Bob

[Jcondon]

Originally Posted by uncle_bob

Hi

Well, without putting a multimeter on the battery posts and reading the voltage at the posts, we don't have the information required to begin working that out.

Bob

Lets say we did put a voltmeter on those posts. What voltage should we expect? With the converter on.

[richard5933]

Originally Posted by Jcondon

Lets say we did put a voltmeter on those posts. What voltage should we expect? With the converter on.

It will depend on what type/brand of batteries and their state of charge.

A better test of the converter is to disconnect from the batteries and take a voltage reading from the outputs of the converter. That will tell you if the converter is producing enough voltage to charge.

[Jcondon]

Originally Posted by richard5933

It will depend on what type/brand of batteries and their state of charge.

A better test of the converter is to disconnect from the batteries and take a voltage reading from the outputs of the converter. That will tell you if the converter is producing enough voltage to charge.

That is what I would do. I would want to see 14.4 volts DC. And if not I would check for an AC component. I suspect there is an issue with rectification inside that converter. Maybe it's producing more AC than DC?

[Joey Joe]

Well hasn't this been a lively discussion!

Thank you all for your discussions. I think I have the problem solved. I disconnected my batteries and fully recharged them independently. Once I reconnected, I started seeing the gradual voltage drop again. Upon additional research, I realized my Victron SmartShunt settings were way off. I updated those settings yesterday and things have been going much better since then.

See my Victron data plots to see the results from a few tweaks to the SmartShunt settings...

[Jcondon]

Originally Posted by Joey Joe

Well hasn't this been a lively discussion!

Thank you all for your discussions. I think I have the problem solved. I disconnected my batteries and fully recharged them independently. Once I reconnected, I started seeing the gradual voltage drop again. Upon additional research, I realized my Victron SmartShunt settings were way off. I updated those settings yesterday and things have been going much better since then.

See my Victron data plots to see the results from a few tweaks to the SmartShunt settings...

That still doesn’t look good and the shunt would not do what this is doing. Do you have a decent digital voltmeter? If so measure the DC voltage on the positive buss or the converter terminals. Then switch the meter to AC and read again.

[Joey Joe]

Originally Posted by Jcondon

That still doesn’t look good and the shunt would not do what this is doing. Do you have a decent digital voltmeter? If so measure the DC voltage on the positive buss or the converter terminals. Then switch the meter to AC and read again.

Converter terminals have been steady 13.68 VDC when I’ve measured them previously. I haven’t measured AC, but that’s an interesting thought. I will try that too.

[Jcondon]

Originally Posted by Joey Joe

Converter terminals have been steady 13.68 VDC when I’ve measured them previously. I haven’t measured AC, but that’s an interesting thought. I will try that too.

The converter needs to output 14.4 volts to charge those Battle Borns. 13.68 Volts DC is not enough. Check the AC component of that output.

[Bunker]

I noticed with this converter and BB setup that I see 13.6 until the last couple percent of charge. Then it heads up towards 14.4.

I asked the dealer about it and they said that’s normal and the expected charge curve for this. Reading the BB material seems to indicate this works and is in the charge range for the batteries. Having said all that, it’s sure not what I expected to see or have read about other places, so I’m interested to see where this goes.

[Jcondon]

Originally Posted by Bunker

I noticed with this converter and BB setup that I see 13.6 until the last couple percent of charge. Then it heads up towards 14.4.

I asked the dealer about it and they said that’s normal and the expected charge curve for this. Reading the BB material seems to indicate this works and is in the charge range for the batteries. Having said all that, it’s sure not what I expected to see or have read about other places, so I’m interested to see where this goes.

Battle Born specs say 14.2 to 14.6 volts constant is preferred but since most converters in use include a float charge at 13.6 to 13.8 they say that is acceptable but not ideal. They do not want you to have to replace your converter even if you should. Your converter after the reset should go right to 14.4 if it is set up for lithium. https://m.youtube.com/watch?time_con...ature=emb_logo

[richard5933]

Originally Posted by Jcondon

Battle Born specs say 14.2 to 14.6 volts constant is preferred but since most converters in use include a float charge at 13.6 to 13.8 they say that is acceptable but not ideal. They do not want you to have to replace your converter even if you should. Your converter after the reset should go right to 14.4 if it is set up for lithium. https://m.youtube.com/watch?time_con...ature=emb_logo

Not sure where you're getting this information from, but it is not the recommendation from BB for their batteries. I've got two installed, and both the manual and my conversations with their support tech agree that the 14.2v-14.6v bulk/absorption phase is only to be 30 minutes per battery. After that it's either go to float or turn off the converter if the batteries are not being used. They do not recommend a constant 14.X voltage for their batteries from what I've seen and been told by them.

This is from page 4 of the manual:

• Bulk/Absorption: 14.2V - 14.6V
• Absorption Time: 30 minutes per battery (for parallel string)
• Float: 13.4V - 13.8V

[richard5933]

To put a finer point on this...

Both of my Victron devices use adaptive bulk charging, meaning that they will hold the output at 14.4v while until the batteries themselves reach 14.4v and stay there for the allotted time. This gives the batteries adequate time at the bulk/absorption voltage for them to do their internal balance, and then the Victron will go to float.

My 120v converter/charger (Progressive Dynamics) will go to 14.6v initially when turned on, and it will stay there for a maximum of 4 hours. But, if the batteries reach 14.6v themselves, the PD will stay at that voltage only for about an hour and then will drop to float of 13.6v.

Not all lithium batteries need or should have a constant-voltage charge.