CellPro Charge times?

[whaleboy]

What should I expect for charge times charging FP evolite 3s 2500 Lipos at 2C with a CellPro 4S and 10S? On the 4S, set to 2C, I've never had them charge in less than an hour... usually takes a little over an hour, putting between 1900 and 2000 mAh back in.

On the 10S, charging at 2C, using both the power leads and the balance taps, the same charge usually take a few minutes more, if not the same, as on the 4S.

I've been hearing others say they can charge similar batteries in 45 min at 1C, and in 30 min at 2C. Why are mine taking so long? Or is 1:00-1:15 normal at 2C for a 2500 battery?

Thanks

-David

[Jotto]

Maybe your power supply isn't capable of delivering enough current?

[whaleboy]

Originally Posted by Jotto

Maybe your power supply isn't capable of delivering enough current?

Its a 25 amp supply. Should be plenty?

Is there a difference to setting the charger at 1C vs 2.5 amps? It will go to 4 amps, but I have never seen it actually use that much while charging at 2C.

-David

[Howard Matos]

Originally Posted by whaleboy

What should I expect for charge times charging FP evolite 3s 2500 Lipos at 2C with a CellPro 4S and 10S? On the 4S, set to 2C, I've never had them charge in less than an hour... usually takes a little over an hour, putting between 1900 and 2000 mAh back in.

On the 10S, charging at 2C, using both the power leads and the balance taps, the same charge usually take a few minutes more, if not the same, as on the 4S.

I've been hearing others say they can charge similar batteries in 45 min at 1C, and in 30 min at 2C. Why are mine taking so long? Or is 1:00-1:15 normal at 2C for a 2500 battery?

Thanks

-David

Hi,

The charge time is actually longer (approximately 10%) when you have either charger set in an automatic mode (1C, 2C, and 3C). This will also vary on different manufacturers packs. If you want the fastest charge, set the chargers to a manual setting. For the Cellpro 4S, you can set it to 4.0 amps (this is the maximum output). If your 2500 mAh pack had 0 capacity remaining (3.1 volts per cell), it would charge in approximately 37.5 minutes. You can charge as fast as 3C with the 10S charger because of the higher output. If you were to set a manual charge rate of 7.5 amps (3C), it would only take 20 minutes to charge a completely discharged pack (3.1 volts per cell). I hope this helps.

[whaleboy]

Originally Posted by Howard Matos

Hi,

The charge time is actually longer (approximately 10%) when you have either charger set in an automatic mode (1C, 2C, and 3C). This will also vary on different manufacturers packs. If you want the fastest charge, set the chargers to a manual setting. For the Cellpro 4S, you can set it to 4.0 amps (this is the maximum output). If your 2500 mAh pack had 0 capacity remaining (3.1 volts per cell), it would charge in approximately 37.5 minutes. You can charge as fast as 3C with the 10S charger because of the higher output. If you were to set a manual charge rate of 7.5 amps (3C), it would only take 20 minutes to charge a completely discharged pack (3.1 volts per cell). I hope this helps.

Thanks, but I assume its best to limit the charge rate to 2C, or is it ok to go a little higher? I have some batteries that say not to charge higher than 1C, others say 2C.

-David

[Howard Matos]

Originally Posted by whaleboy

Thanks, but I assume its best to limit the charge rate to 2C, or is it ok to go a little higher? I have some batteries that say not to charge higher than 1C, others say 2C.

-David

Hi David,

This is true with their charger and their technology but ours is totally safe to charge up to 3C without any loss of life to your packs. The only requirement we have is that your packs have a minimum discharge rate of 12C.

[beeflyer2]

Since the 4S only goes up to 4A, the best you could do is 1.6C, not 2C. Still should take under an hour though.

If your pack is old and tired, it will take longer to charge. I have experienced this with FP and TP, but never with my Revolectrix packs!

[must289pwr]

You keep talking about the C charge setting but the cellpro tells you how many Amps you are charging at. Can you tell us how many Amps its pushing a couple min into the charge at 2C?

[Howard Matos]

Originally Posted by must289pwr

You keep talking about the C charge setting but the cellpro tells you how many Amps you are charging at. Can you tell us how many Amps its pushing a couple min into the charge at 2C?

Hi,

2C = 2 times the rated capacity of your pack. The charge current will vary from pack to pack with different capacities. If you have a 2000 mAh pack, and with the Cellpro set in the automatic mode at 2C, the charge current will go up to 4 amps. If you had a 1300 mAh pack with the same setting, the charge current will go to 2.6 amps. One thing to keep in mind is that when the charger is set in one of the automatic settings, you see will the charge current fluctuate up and down. It is normal for the current to even go above the settings for a few seconds. This will not hurt the pack or cells in any way.

[must289pwr]

I understand that....
I was asking what actual charge Amps Whaleboy was getting. He is trying to charge a 2500mah at 2C which should be around 5A. Since the cellpro 4s only does 4A max then it should be running about 4A. But if he is even only running at 4A then he should be fully charged in ~37.5 min. Apparently he is not getting the full 4A so i was asking what the acutal charge rate was a couple of min into the charge when it has rampped up to its full charge rate.

[whaleboy]

Originally Posted by must289pwr

I understand that....
I was asking what actual charge Amps Whaleboy was getting. He is trying to charge a 2500mah at 2C which should be around 5A. Since the cellpro 4s only does 4A max then it should be running about 4A. But if he is even only running at 4A then he should be fully charged in ~37.5 min. Apparently he is not getting the full 4A so i was asking what the acutal charge rate was a couple of min into the charge when it has rampped up to its full charge rate.

I'll have to periodically check over the course of the charge next time I charge, but its not 4A. This last round for the first 10 min it was less that 2A, then after 10 min or so I noticed it was a hair over 3A, but didn't check it again until the charge wasw almost complete, at which point it was under 1A.

I'll charge the next pack at 2C and log the charge rates, then kick it to the 4A setting for the one after that, and report back.

Thanks

-David

[must289pwr]

I am not sure exactly how it calculates the Amps for the set C rating (maybe internal resistance?) but it sounds like its not detecting it properly. Since the determined Amps would be MAH*C, but how the heck does it detect it.
I have a couple of packs that are fine, 2200mah that charge at just over 4A at 2C, but then I have another 2200mah that does about the same as yours and will start about 2.5A and peak around 3.5A during a 2C charge. So if it does determine the C rating by internal resistance then it sounds like it changes during the charging.

Although I could be totally wrong on the internal resistance thing. Would love to know if some one can answer that.

[Howard Matos]

Originally Posted by must289pwr

I am not sure exactly how it calculates the Amps for the set C rating (maybe internal resistance?) but it sounds like its not detecting it properly. Since the determined Amps would be MAH*C, but how the heck does it detect it.
I have a couple of packs that are fine, 2200mah that charge at just over 4A at 2C, but then I have another 2200mah that does about the same as yours and will start about 2.5A and peak around 3.5A during a 2C charge. So if it does determine the C rating by internal resistance then it sounds like it changes during the charging.

Although I could be totally wrong on the internal resistance thing. Would love to know if some one can answer that.

Hi,

Fuel Gauging technology for lithium batteries as implemented in the FMA Cellpro chargers is a great way to vastly simplify the charging process. In addition to supplying the customer with a fast approximation of how much capacity remains in his battery pack when connected to the charger, fuel gauging also allows the customer to select AUTO modes. This means it is simpler to initiate a charge. The customer does not need to know any details about the lithium battery pack he will be charging. He just needs to tell the charger whether he wants to charge at 1C, 2C, or 3C. We knew AUTO charge modes would be popular, but we had no idea that Fuel Gauging and AUTO modes would become the dominant method of using the chargers.

Fuel gauging is actually fairly simple in principal. The charger looks at the battery pack voltage as it charges and compares "where it is" to a known voltage-to-percent capacity table. In other words, if the battery is at "n" volts at any particular time, it has "y" % charge state.

Recently, we have come up against a limitation to Fuel Gauging technology that we did not foresee. All of our research indicated that, within reason, all lithium batteries had very similar charge curves. It worked very well to have a single fuel lookup table stored in the charger. Actually, LiPo and A123 use two different tables. But in recent months, we have come to learn of newer, higher C batteries coming to market with substantially different voltage characteristics. Many of these are rated 30C or higher discharge. Also, we have learned that lower quality or aging batteries have substantially different voltage charge curves.

So what can happen? As noted in certain forum posts, the chargers might jump around on current during charge in AUTO modes. Charge current might go higher than expected for brief times. Fuel level percent displayed may not closely approximate the actual capacity remaining in certain batteries. Storage charge mode can also be affected as it uses fuel gauging to set the 1C charge rate.

Do not be concerned if the charger delivers higher current than expected to the battery pack during AUTO modes. The setting averages out over time. It will not stay at high currents for an entire charge and it will not damage your batteries.

The workaround is as follows: if you experience innaccurate fuel gauge readings or you witness the charge current jumping around on certain batteries, either during AUTO charge, or STORAGE charge, note which batteries are causing the problem. Stop using AUTO mode for those batteries. Instead, set the charge current manually. In manual charge modes, the charger does not have to calculate what the ideal charge current should be. It will not exceed the charge current limit you select.

[must289pwr]

Originally Posted by Howard Matos

Hi,

Fuel Gauging technology for lithium batteries as implemented in the FMA Cellpro chargers is a great way to vastly simplify the charging process. In addition to supplying the customer with a fast approximation of how much capacity remains in his battery pack when connected to the charger, fuel gauging also allows the customer to select AUTO modes. This means it is simpler to initiate a charge. The customer does not need to know any details about the lithium battery pack he will be charging. He just needs to tell the charger whether he wants to charge at 1C, 2C, or 3C. We knew AUTO charge modes would be popular, but we had no idea that Fuel Gauging and AUTO modes would become the dominant method of using the chargers.

Fuel gauging is actually fairly simple in principal. The charger looks at the battery pack voltage as it charges and compares "where it is" to a known voltage-to-percent capacity table. In other words, if the battery is at "n" volts at any particular time, it has "y" % charge state.

Recently, we have come up against a limitation to Fuel Gauging technology that we did not foresee. All of our research indicated that, within reason, all lithium batteries had very similar charge curves. It worked very well to have a single fuel lookup table stored in the charger. Actually, LiPo and A123 use two different tables. But in recent months, we have come to learn of newer, higher C batteries coming to market with substantially different voltage characteristics. Many of these are rated 30C or higher discharge. Also, we have learned that lower quality or aging batteries have substantially different voltage charge curves.

So what can happen? As noted in certain forum posts, the chargers might jump around on current during charge in AUTO modes. Charge current might go higher than expected for brief times. Fuel level percent displayed may not closely approximate the actual capacity remaining in certain batteries. Storage charge mode can also be affected as it uses fuel gauging to set the 1C charge rate.

Do not be concerned if the charger delivers higher current than expected to the battery pack during AUTO modes. The setting averages out over time. It will not stay at high currents for an entire charge and it will not damage your batteries.

The workaround is as follows: if you experience innaccurate fuel gauge readings or you witness the charge current jumping around on certain batteries, either during AUTO charge, or STORAGE charge, note which batteries are causing the problem. Stop using AUTO mode for those batteries. Instead, set the charge current manually. In manual charge modes, the charger does not have to calculate what the ideal charge current should be. It will not exceed the charge current limit you select.

Not exactly what I was asking.. I figured the fuel gauge was something like

(lowest desired V)/(Max V) * 100

So thats good to know but what I am asking is how it determines the auto charge current. Since the C rated current depends on the MAH of the pack.

(Auto Charge Amps) = MAH * C

How does it determine the MAH of a particular pack?

[Howard Matos]

Hi Mike,

All the computations are based off of the fuel gauge table.

[must289pwr]

I guess I just dont get what is on the fuel gauge table.

The voltage of a cell does not have anything to do with the MAH capacity of the pack. So what other than voltage is it comparing in the table that tells it the charge rate that it should be running in auto.