Dc power supply setup and top balancing question

[Lucky360]

Hey everyone while waiting for my batteries to arrive I need a game plan to top balance my batteries. I purchased 4 272ah batteries. I have a 10amp dc power supply. From reading several post I need to setup constant voltage and constant current. So this is my game plan. First thing I need to do is put the batteries in series add bms and charge to 14.6 volts at the 10 amps let the bms shut off charge current then put batteries in parallel and charge at 3.65 and 10 amps till current reads 0.

Step 1.series charge: put batteries in series install bms and set bms so it stops the charger at 14.6 volts. setup the constant voltage setting and constant current on the dc power supply. Short both leads together and set constant voltage to 14.6 and constant current to 0. Then connect leads to batteries turn on power supply adjust constant voltage 14.6 and turn constant current to 10 amps and wait till bms shuts off at 14.6 volts. Does this seem right?

Step 2. Top balance: Put batteries in parallel and do a top balance. First step is short leads together and set the constant voltage at 3.65 and the constant current at 0. Then connect leads to batteries turn on power supply and turn constant voltage to 3.65 and constant current to 10 amps and wait till cells reach 3.65 and then batteries are done top balancing, is this a correct way of top balancing?
One thing Iam not understanding is when I first setup the constant current and constant voltage setting by shorting the leads does does constant current need to be set at 0 current or can I or should I set it at a different setting?

 

[DThames]

Not answering your question about the power supply...but when you put the cells in parallel, any voltage difference will cause current to flow until they are equal. Connecting them in parallel while still at a low state of charge would make sense. Once in parallel, you could charge the larger "cell" to 3.65v (all exactly the same) then disconnect and put in series and they would be balanced at full charge.

Power supply, unless you know it can handle a short at full power, you might put a resister load on it, adjust to a reasonable current, then do the short (you will be limited to that previous current, which could be zero, and then adjust up to your desired level. I say this based on using those dumb little charging boards without markings or instructions. I set one up yesterday and "up" voltage was counter clockwise on a 10 turn pot and current was "up" clockwise. Some of those little boards say short is okay, others say load with a discharged battery. I normally set the voltage, Open circuit, then set the current limit, then test it and watch it like a hawk (while charging) until you know it is correct.

 

[DThames]

Are you aware of the thread about clamping them with a specific amount of force? I don't know about the brand you are getting but the Eve brand needs a clamping fixture to avoid swelling in the center of the large side, like considerable force. Preventing the swelling helps with longer cycle count life.

 

[Lucky360]

Are you aware of the thread about clamping them with a specific amount of force? I don't know about the brand you are getting but the Eve brand needs a clamping fixture to avoid swelling in the center of the large side, like considerable force. Preventing the swelling helps with longer cycle count life.

The cells I am getting are lishen cells.

 

[Gazoo]

Hey everyone while waiting for my batteries to arrive I need a game plan to top balance my batteries.

Here is what I would do since you only have 4 cells.

Set the voltage on the power supply to 3.65 volts. Make sure you have set the power supply to 3.65 volts before connecting to the cells.

When you connect the power supply to the cells it should be in CC mode. Most power supplies come with 18awg cables which is fine for higher voltages. I used 12awg with mine...10awg would be better. I soldered ring terminals on the side of the wires that connects to the cells, and fork connectors on the side that connects to the power supply. Banana plugs don't work well with the max current the power supply is capable of.

Make sure to check the battery voltage using a DMM at the cell terminals. They should all be the same if you do not have any bad connections. The voltage at the cells will be less that what is displayed on the power supply due to voltage drop. This is normal.

Depending on the SOC of your cells it will take apx. 2.5 days to complete the top balance. My 8 cells took 5 days. Make sure you are checking the voltage at the cells frequently towards the end of the charge. Towards the end of the charge the power supply should go into CV mode when the voltage displayed on the supply is 3.65 volts, and the amps displayed on the power supply will come down while the voltages of the cells will rise. If all is set up properly the voltage of the cells and the voltage on the power supply should be 3.65 volts, and the current displayed on the power supply should be zero or very close to it at the end of the charge.

I am not so sure charging in series and then charging in parallel would be as effective as first charging in parallel. I am very happy with my top balance. When my pack is finished charging there is only a .083 difference between the voltages when the highest cell is 3.65 volts. On the bottom it's a different story because I didn't bottom balance and that's only recommended for EV's. When discharging and the lowest cell reaches 2.50 volts, the highest cell is 3.00 volts...a .5 volt difference.

 

[Gazoo]

Are you aware of the thread about clamping them with a specific amount of force? I don't know about the brand you are getting but the Eve brand needs a clamping fixture to avoid swelling in the center of the large side, like considerable force. Preventing the swelling helps with longer cycle count life.

I haven't been able to find anything related to that in the Lishen spec. sheet but I have not gone over it yet with a fine tooth comb since I have EVE cells. I will attach the spec sheet.

 

[Lucky360]

Here is what I would do since you only have 4 cells.

Set the voltage on the power supply to 3.65 volts. Make sure you have set the power supply to 3.65 volts before connecting to the cells.

When you connect the power supply to the cells it should be in CC mode. Most power supplies come with 18awg cables which is fine for higher voltages. I used 12awg with mine...10awg would be better. I soldered ring terminals on the side of the wires that connects to the cells, and fork connectors on the side that connects to the power supply. Banana plugs don't work well with the max current the power supply is capable of.

Make sure to check the battery voltage using a DMM at the cell terminals. They should all be the same if you do not have any bad connections. The voltage at the cells will be less that what is displayed on the power supply due to voltage drop. This is normal.

Depending on the SOC of your cells it will take apx. 2.5 days to complete the top balance. My 8 cells took 5 days. Make sure you are checking the voltage at the cells frequently towards the end of the charge. Towards the end of the charge the power supply should go into CV mode when the voltage displayed on the supply is 3.65 volts, and the amps displayed on the power supply will come down while the voltages of the cells will rise. If all is set up properly the voltage of the cells and the voltage on the power supply should be 3.65 volts, and the current displayed on the power supply should be zero or very close to it at the end of the charge.

I am not so sure charging in series and then charging in parallel would be as effective as first charging in parallel. I am very happy with my top balance. When my pack is finished charging there is only a .083 difference between the voltages when the highest cell is 3.65 volts. On the bottom it's a different story because I didn't bottom balance and that's only recommended for EV's. When discharging and the lowest cell reaches 2.50 volts, the highest cell is 3.00 volts...a .5 volt difference.

Thank you Gazoo, when I setup the the constant current by shorting the leads should I set the current at 0.00 or something else. The reason I suggested charging in series is because I read a couple posts saying it helps to speed up the process but if it might cause problems it’s not worth it.

 

[Gazoo]

Thank you Gazoo, when I setup the the constant current by shorting the leads should I set the current at 0.00 or something else. The reason I suggested charging in series is because I read a couple posts saying it helps to speed up the process but if it might cause problems it’s not worth it.

I don't know anything about shorting the leads.

Set the power supply to 3.65 volts and the current to 10 amps. Then connect the leads to the cells and be patient ...lol. Everything will be fine. You don't have to do it all at one time. You just want to make sure you are around to check the voltage of the cells when the power supply nears the end of charge. Some like doing this in steps. For example, set the supply to 3.40 volts at 10 amps then connect to the cells. Since the cells rise rapidly once they reach 3.40 volts it's a safeguard. Once this step is finished then proceed to charge to 3.65 volts.

 

[Lucky360]

So you did not preset the current limiting value? Sorry Iam just really confused I thought you had to do that.

 

[Gazoo]

So you did not preset the current limiting value? Sorry Iam just really confused I thought you had to do that.

I would suggest you watch Will's video concerning this. Everyone has slightly different methods and they all accomplish the same thing.

(269) How to Top Balance LiFePO4 Battery Cells Quickly (and why you need to do it) - YouTube

 

[GSXR1000]

Thank you Gazoo, when I setup the the constant current by shorting the leads should I set the current at 0.00 or something else. The reason I suggested charging in series is because I read a couple posts saying it helps to speed up the process but if it might cause problems it’s not worth it.

i THINK (mind you i am newbie to building batteries) but less things could go wrong if you don't charge in series. you know they are balanced if you only charge in parallel you know they will be right.. as far as speeding things up does it really matter if takes 1 or 4 days

 

[Lucky360]

This is what my manual says about the constant voltage and constant current setup. This is why Iam so confused. Thank you everybody for your help.

 

[LFP addict]

Can I use this "powersupply" for top balancing per cell ?( I have plenty tim
If I use a multimeter to be sure its giving 3.65volt it would charge the cell until it reaches 3.65 ?
I'm counting on 4-5amps ?

 

[Sanwizard]

Hey everyone while waiting for my batteries to arrive I need a game plan to top balance my batteries. I purchased 4 272ah batteries. I have a 10amp dc power supply. From reading several post I need to setup constant voltage and constant current. So this is my game plan. First thing I need to do is put the batteries in series add bms and charge to 14.6 volts at the 10 amps let the bms shut off charge current then put batteries in parallel and charge at 3.65 and 10 amps till current reads 0.

Step 1.series charge: put batteries in series install bms and set bms so it stops the charger at 14.6 volts. setup the constant voltage setting and constant current on the dc power supply. Short both leads together and set constant voltage to 14.6 and constant current to 0. Then connect leads to batteries turn on power supply adjust constant voltage 14.6 and turn constant current to 10 amps and wait till bms shuts off at 14.6 volts. Does this seem right?

Step 2. Top balance: Put batteries in parallel and do a top balance. First step is short leads together and set the constant voltage at 3.65 and the constant current at 0. Then connect leads to batteries turn on power supply and turn constant voltage to 3.65 and constant current to 10 amps and wait till cells reach 3.65 and then batteries are done top balancing, is this a correct way of top balancing?
One thing Iam not understanding is when I first setup the constant current and constant voltage setting by shorting the leads does does constant current need to be set at 0 current or can I or should I set it at a different setting?

What am I missing with the current drop on these power supplies? Why would the supplied current drop using a power supply. The voltage and current are set, and should not vary. Are these special DC supplies on some way that they also act as chargers? The answers to questions on the moderate priced unit Will has links to specifically says the current will not drop.

 

[Gazoo]

What am I missing with the current drop on these power supplies? Why would the supplied current drop using a power supply. The voltage and current are set, and should not vary. Are these special DC supplies on some way that they also act as chargers? The answers to questions on the moderate priced unit Will has links to specifically says the current will not drop.

If you are referring to parallel top balancing the problem is the very low voltage we are dealing with. If using the step balancing method where one starts charging the cells at 3.4 volts the current will drop substantially. If one starts charging the cells at 3.65 volts then the current should remain at whatever the power supplies current rating is providing the cables are big enough to carry the current. I tried the step method and skipped it as it was going to take too much time.

For example, when parallel top balancing using a power supply set to 10 amps and 3.65 volts and then connected to the cells, the voltage will instantly drop and the current should remain at 10 amps, and the power supply will be in CC mode. There will be some voltage drop between the power supply and the cells and this is ok. The reading of the power supply's voltage and the voltage measurement at the cell will not match but will be close.

Once the upper knee of the cell is reached, the voltage will begin to increase and the current will begin to drop. When the voltage reading on the power supply reads 3.65 volts, the power supply will switch into CV mode. At this point the voltage will remain at 3.65 volts and the current will begin to drop. So both current and voltage will vary, and this is typically how a charger works.

 

[Sanwizard]

If you are referring to parallel top balancing the problem is the very low voltage we are dealing with. If using the step balancing method where one starts charging the cells at 3.4 volts the current will drop substantially. If one starts charging the cells at 3.65 volts then the current should remain at whatever the power supplies current rating is providing the cables are big enough to carry the current. I tried the step method and skipped it as it was going to take too much time.

For example, when parallel top balancing using a power supply set to 10 amps and 3.65 volts and then connected to the cells, the voltage will instantly drop and the current should remain at 10 amps, and the power supply will be in CC mode. There will be some voltage drop between the power supply and the cells and this is ok. The reading of the power supply's voltage and the voltage measurement at the cell will not match but will be close.

Once the upper knee of the cell is reached, the voltage will begin to increase and the current will begin to drop. When the voltage reading on the power supply reads 3.65 volts, the power supply will switch into CV mode. At this point the voltage will remain at 3.65 volts and the current will begin to drop. So both current and voltage will vary, and this is typically how a charger works.

Ok, so the power supply has to support CC and CV modes, or else the amp display will not show a drop as the cells reach the target voltage? Is that correct? If so, which power supplies support that? The cheap 30v 10a Will shows is out od stock, and the next 40a supply in his list indicates the amp and volt parameters will not change like a charger as the cells charge.

 

[Gazoo]

I am not in a position to recommend any power supplies except the one I used and it is the Riden RD6012. Since I bought mine Riden released the Riden RD6018. I bought the complete kit from Aliexpress.

If you take a look at Amazon you will find most if not all of the basic 10 amp power supplies like Will used support CC and CV.

 

[carbon60]

I am not in a position to recommend any power supplies except the one I used and it is the Riden RD6012. Since I bought mine Riden released the Riden RD6018. I bought the complete kit from Aliexpress.

I ordered an RD6018 kit a couple days ago. Planning on using it to setup the 16 Lishen cells I have coming. Glad to here it will work.

 

[GSXR1000]

why not to use supplies clips vs 10 guage wire

 

[Gazoo]

I ordered an RD6018 kit a couple days ago. Planning on using it to setup the 16 Lishen cells I have coming. Glad to here it will work.

It does but read the manual carefully... There are a ton of features. It can be used as a power supply or a charger. I used the charging function when I parallel top balanced my 8 cells.

 

[carbon60]

It does but read the manual carefully... There are a ton of features. It can be used as a power supply or a charger. I used the charging function when I parallel top balanced my 8 cells.

What’s the difference? Is charging what they call CV/CC?

 

[Gazoo]

I have not used it as a power supply. The reason I used the charging function is because I wanted to be able to sleep during the process and not have to babysit my cells. I figured since the Riden has over voltage protection why not? I did test it on another battery to make sure it would operate properly before I top balance my cells.

I was awake when the process completed and the charger shut off when the tail current read 100 ma's on the Riden. It performed flawlessly although I wish the tail current was adjustable. But so far it has performed great.

I will repeat what I posted in another thread if using a power supply. It applies here except when using the Riden as a charger the Riden will shut off when the current drops to 100ma's.

When parallel top balancing using a power supply set to 10 amps and 3.65 volts and then connected to the cells, the voltage will instantly drop and the current should remain at 10 amps, and the power supply will be in CC mode. There will be some voltage drop between the power supply and the cells and this is ok. The reading of the power supply's voltage and the voltage measurement at the cell will not match but will be close.

Once the upper knee of the cell is reached, the voltage will begin to increase and the current will begin to drop. When the voltage reading on the power supply reads 3.65 volts, the power supply will switch into CV mode. At this point the voltage will remain at 3.65 volts and the current will begin to drop. So both current and voltage will vary, and this is typically how a charger works.

 

[Sanwizard]

I ordered an RD6018 kit a couple days ago. Planning on using it to setup the 16 Lishen cells I have coming. Glad to here it will work.

I just finished putting my RD6018W together. This thing reminded me of the old Heathkit and radioshack kits. They should just sell it WITH the freaking PS and Case. If someone wants to swap out the PS, then fine, but sell me a product, not a science project! Especially for $200US

I noticed that the manual had the following warning:

1.4.2.1 Battery Charging Function Introduction Battery charging operation video：

After power-on, at battery related information display area, external temperature, capacity and energy will loop display. When there is output current: capacity, energy automatically accumulated, and automatically cleared after shutdown. The green terminal is connected to the positive pole of the battery, and the black terminal is connected to the negative pole of the battery. After the battery is correctly connected, the battery charging indicator turns red and the battery is connected. Press ON/OFF to start charging, the battery charging indicator turns green. When the actual output current is lower than 0.1A (10mA for RD6006), the output will be shut down automatically. Battery with protection board need to be charged with red and black terminals. The charging voltage and current should be set on your own. When the charging function is not in use, you can connect the green and black terminals with a cable to prevent interference with the battery detection terminal and accidentally turn off the output. It is strongly recommended to use the original charger to charge the battery. The charging function of this machine can only serve as a temporary replacement, not for long-term use. There is a risk of fire and explosion during the charging process. Non-professionals should not operate. (COMMON BATTERY VOLTAGE can be check in Appendix 2.)

Just thought you should know. I like the charging function, but it looks like they are wary of the duty cycle. I should have went with the Tekpower.

 

[Gazoo]

I read the warning and after testing it out several times I am confident the charge function works well. I just don't like the tail current cut off and wish it could be set higher. Even 500ma's would be much better.

I actually like the idea they sell the PS and case separately. It's good marketing because some people already have power supplies they can use with the head and have made their own cases. IMO.. for the DIY crowd it's great.

 

[Gazoo]

This thing reminded me of the old Heathkit and radioshack kits. They should just sell it WITH the freaking PS and Case. If someone wants to swap out the PS, then fine, but sell me a product, not a science project! Especially for $200US

I remember the Heathkit days very well. When I was a teen I built the mobile citizen band radio they offered back then and it actually worked. Later on in life I had two of the Heathkit Robots, Hero 1 and Hero Jr but I did not assemble them. Sadly I had to sell them.

I understand your frustration with the Riden. Hopefully when you begin to use it and learn about all of its features, you will see some value of it.

Regarding the battery charging feature, I forgot to say charging should always be monitored and observed no matter what charger one uses. On the other hand the Riden does have OV and OC protection. And that's a plus.