Go Back  R/C Tech Forums > General Forums > Radio and Electronics
Revolectrix CellPro PowerLab 6 >

Revolectrix CellPro PowerLab 6

Revolectrix CellPro PowerLab 6

Old 03-24-2013, 08:30 PM
  #31  
Tech Master
iTrader: (39)
 
Join Date: Oct 2011
Location: Henderson, NV
Posts: 1,293
Trader Rating: 39 (100%+)
Default

Originally Posted by Dave H
Add all of the packs up, multiply by the desired charge rate. (Of course assuming all lipos are OK with a 2C charge rate, and fairly close in voltage before starting)

As long as you are using a proper parallel hookup including the balancing connections the controlled voltage of a lipo charge process will protect all of the lipos including the little one.

6Ah x 3packs + 1.2Ah = 19.2Ah
19.2Ah x 2C = 38.4 amp charge rate
I think you're off with this. You're asking the charger to divert a fair amount of electricity away from the small battery through the small balance wires. What would probably end up happening is that the charger can not transfer that much energy through those, so the entire charge rate will slow down to what the charger can flow through the balance wires (<2.5 amps if I remember correctly). If it were me, I'd charge the small pack separately and the other 3 at 36 amps in parallel.
ufoDziner is offline  
Old 03-25-2013, 04:26 AM
  #32  
Tech Champion
 
Join Date: Oct 2007
Posts: 7,342
Default

Originally Posted by ufoDziner
I think you're off with this. You're asking the charger to divert a fair amount of electricity away from the small battery through the small balance wires. What would probably end up happening is that the charger can not transfer that much energy through those, so the entire charge rate will slow down to what the charger can flow through the balance wires (<2.5 amps if I remember correctly). If it were me, I'd charge the small pack separately and the other 3 at 36 amps in parallel.
Well I'm certainly assuming the main leads are all attached, including the small pack. If so the current will mostly be on the main wires.

Are you thinking the current would be equally divided between the 4 packs, thus charging the small pack quicker? That can't happen due to the parallel connection, they will all be held to the same voltage by the parallel connection of the main wires. The current On the main wires will be divided appropriately during the charge.

Notice I mentioned the packs should be at a similar voltage before starting, as a practical matter it might be reasonable to speculate the smaller pack is used differently, and may not be at a similar state of discharge and thus voltage, if so that is a reasonable concern.

Also the packs should be in good condition and not have significant imbalance, otherwise that might cause some less than ideal results.
Dave H is offline  
Old 03-25-2013, 05:35 AM
  #33  
Tech Master
iTrader: (39)
 
Join Date: Oct 2011
Location: Henderson, NV
Posts: 1,293
Trader Rating: 39 (100%+)
Default

Originally Posted by Dave H
Well I'm certainly assuming the main leads are all attached, including the small pack. If so the current will mostly be on the main wires.

Are you thinking the current would be equally divided between the 4 packs, thus charging the small pack quicker? That can't happen due to the parallel connection, they will all be held to the same voltage by the parallel connection of the main wires. The current On the main wires will be divided appropriately during the charge.

Notice I mentioned the packs should be at a similar voltage before starting, as a practical matter it might be reasonable to speculate the smaller pack is used differently, and may not be at a similar state of discharge and thus voltage, if so that is a reasonable concern.

Also the packs should be in good condition and not have significant imbalance, otherwise that might cause some less than ideal results.

All of the main wires from a PowerLab are connected together unlike other chargers that have leads coming from separate places. This means that all of the power is coming equally to all connected packs and the parallel adapters spread the load as required, within reason. The difference in pack size is too much for the little wires to re-distribute.
ufoDziner is offline  
Old 03-25-2013, 11:07 AM
  #34  
Tech Champion
 
Join Date: Oct 2007
Posts: 7,342
Default

Originally Posted by ufoDziner
All of the main wires from a PowerLab are connected together unlike other chargers that have leads coming from separate places.
The PowerLab hooks up the same as most any lipo balancing charger. It has a pair of main wires (+ & -, some call them the discharge wires), and a balancer port. The hookup is not any different for a PowerLab than an iCharger, Hyperion, etc. (The non-relevant exception being some small chargers that only charge via the balance port)

This means that all of the power is coming equally to all connected packs and the parallel adapters spread the load as required, within reason.
In a parallel circuit the voltage of each paralleled path is the same. The power and current in each path are different if the paths have different properties, as is the case we are discussing. This is the key point.

The difference in pack size is too much for the little wires to re-distribute.
The packs will not require re-distribution while charging, as the charge current distribution will be automatically achieved on the fly by the parallel connection. Does leave the issue of initial hookup, why I mentioned that packs should be at a similar voltage.


Worst case, some have tested configurations with significant voltage/charge state difference with different capacity packs (like 10:1). Even then the current spike when connecting wasn't terribly high and quite short in duration, with minimal wire & connection heating. Although not recommended for general practice just to be extra safe.

If that is not enough, the MPA (Multi-Port Safe Parallel Adapter) that Team Grid RC said he is using has fuses on every single connection, both balance and mains. Certainly the safest and most foolproof method of parallel charging.

Of course simply don’t try parallel charging if you are not comfortable with it. In many cases it is better to charge the packs singly as needed anyway due to the detrimental effects of lipos sitting at full charge. Personally I would probably only use it for something that had twin packs that always ran together.


And just for the benefit of anyone that might be reading this, do not try to parallel charge nickel type packs, ni-cads or ni-mh. For lithium, and lead acid (auto) batteries, parallel charging can be a useful tool in the appropriate situation.
Dave H is offline  
Old 03-25-2013, 11:36 AM
  #35  
Tech Master
iTrader: (39)
 
Join Date: Oct 2011
Location: Henderson, NV
Posts: 1,293
Trader Rating: 39 (100%+)
Default

Originally Posted by Dave H
The PowerLab hooks up the same as most any lipo balancing charger. It has a pair of main wires (+ & -, some call them the discharge wires), and a balancer port. The hookup is not any different for a PowerLab than an iCharger, Hyperion, etc. (The non-relevant exception being some small chargers that only charge via the balance port)


In a parallel circuit the voltage of each paralleled path is the same. The power and current in each path are different if the paths have different properties, as is the case we are discussing. This is the key point.


The packs will not require re-distribution while charging, as the charge current distribution will be automatically achieved on the fly by the parallel connection. Does leave the issue of initial hookup, why I mentioned that packs should be at a similar voltage.


Worst case, some have tested configurations with significant voltage/charge state difference with different capacity packs (like 10:1). Even then the current spike when connecting wasn't terribly high and quite short in duration, with minimal wire & connection heating. Although not recommended for general practice just to be extra safe.

If that is not enough, the MPA (Multi-Port Safe Parallel Adapter) that Team Grid RC said he is using has fuses on every single connection, both balance and mains. Certainly the safest and most foolproof method of parallel charging.

Of course simply don’t try parallel charging if you are not comfortable with it. In many cases it is better to charge the packs singly as needed anyway due to the detrimental effects of lipos sitting at full charge. Personally I would probably only use it for something that had twin packs that always ran together.


And just for the benefit of anyone that might be reading this, do not try to parallel charge nickel type packs, ni-cads or ni-mh. For lithium, and lead acid (auto) batteries, parallel charging can be a useful tool in the appropriate situation.
Here is an older post from the Tech Support of Revolectix.

Hi:

Just want to clarify one thing above. The Revoltectrix Safe Parallel Adapters as well as the MPA do offer some protection against over-amping vastly different capacity packs when connected in parallel; however, the standard non-parallel Revolectrix adapters do not, and the standard adapters should not be used for parallel charging in any case. In addition, the only way to assure packs will not be over-amped when using Safe Parallel Adapters or MPA is to plug the balance connectors in first, let the cell voltages of the parallel packs equalize for a brief time, then connect the main pack leads together. But you should not leave just the balance leads connected for too long because if the equalizing current is too high, the small balance wires may get hot. Then also realize, once you connect the main pack leads, there is no longer anything to slow the current between the packs. It's impossible to assign any times to the steps in the process because every situation will be different depending on how different the states of charge are on the packs connected in parallel.

Tim Marks


1200 vs. 6000 is vastly different. This wouldn't be safe to do IMO, which is based on the threads for this particular charger on various message boards. There is too much opportunity to over amp the smaller capacity pack.
ufoDziner is offline  
Old 03-25-2013, 06:44 PM
  #36  
Tech Champion
 
Join Date: Oct 2007
Posts: 7,342
Default

Originally Posted by ufoDziner
Here is an older post from the Tech Support of Revolectix.

Hi:

Just want to clarify one thing above. The Revoltectrix Safe Parallel Adapters as well as the MPA do offer some protection against over-amping vastly different capacity packs when connected in parallel; however, the standard non-parallel Revolectrix adapters do not, and the standard adapters should not be used for parallel charging in any case. In addition, the only way to assure packs will not be over-amped when using Safe Parallel Adapters or MPA is to plug the balance connectors in first, let the cell voltages of the parallel packs equalize for a brief time, then connect the main pack leads together. But you should not leave just the balance leads connected for too long because if the equalizing current is too high, the small balance wires may get hot. Then also realize, once you connect the main pack leads, there is no longer anything to slow the current between the packs. It's impossible to assign any times to the steps in the process because every situation will be different depending on how different the states of charge are on the packs connected in parallel.

Tim Marks


1200 vs. 6000 is vastly different. This wouldn't be safe to do IMO, which is based on the threads for this particular charger on various message boards. There is too much opportunity to over amp the smaller capacity pack.
We’re making progress, going from not even being able to parallel charge packs of different capacities, to being concerned about the equalization current during initial hook up. Excellent.

The initial equalization issue is why I mentioned in my initial post on the subject that packs should be “fairly close in voltage before starting” just to be on the safe side. Advice I repeated, including offering a scenario where that may not be the case.

Regarding the older post from Revolectrix, interesting that the current site and online manual don't appear to offer much concern in this area that I can find. Either to voltage / charge state or limitations in capacity difference. There is this comment:

* Li packs connected in parallel to the 6 available ports may have different capacities. Sum of all capacities = 1C.
MPA-XH User Guide

I certainly understand there will be considerable fear and uncertainly in any parallel charging thread, with good reason. Just as a newcomer to lipos should do some basic research, parallel charging shouldn’t be attempted without some basic understanding and proper precautions and diligence.

But there are also many posts with actual measurements and many many years of experience that address those concerns satisfactorily in my opinion. I could easily expand on this and explain why, but I’ve more than gone on enough already.

Again, I agree, of course no one should attempt anything they are not comfortable with, whether it be parallel charging, charging higher than 1C, etc.
Dave H is offline  
Old 03-25-2013, 07:29 PM
  #37  
Tech Addict
iTrader: (3)
 
Team Grid RC's Avatar
 
Join Date: Sep 2010
Posts: 644
Trader Rating: 3 (100%+)
Default

I never parallel charge packs that have that extreme capacity difference. Just hoping some was able to do it.

Maybe Tim can design a MPA board where it can accept packs that are extreme capacity along with high capacity packs, something like a special channel on the MPA, or a daughter board that plugs into the MPA to downgrade the current to it.

I have been using a separate charger to do low capacity packs which maybe the PowerLab could do in the future versions.
Team Grid RC is offline  
Old 07-17-2013, 11:26 AM
  #38  
ys
Tech Initiate
 
Join Date: Oct 2011
Posts: 47
Default

Hi everyone.
A newbie here, I dunno if i should compare but I'm considering a charger that would let me go far without any regrets. I'm looking at the Nosram Stealth Touch Evolution and the Cellpro Powerlab 6/Cellpro 10XP. Which is better? The Revolectrix ones are $100 cheaper though..
ys is offline  
Old 07-17-2013, 04:28 PM
  #39  
Tech Adept
 
REVOJohn's Avatar
 
Join Date: Dec 2011
Location: Singapore
Posts: 116
Default

my 2 cents worth.
just calculate the $/Watt of power and see which is better value, mind you all the other functionalities
REVOJohn is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.