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-   -   Maximum Charging Capacity (http://www.Wattflyer.com/forums/showthread.php?t=73527)

garyp1029 04-09-2014 01:03 AM

Maximum Charging Capacity
 
Still trying to sort this out . . . Am considering a new charger to replace the one that came with my Apprentice. The ICharger 106B+ has a maximum charging capacity of 250W; the Cellpro MultiPro 4 has 75W. My understanding is that my 3200 mah batteries should only be charged at about 3W. Am I correct in thinking that both chargers would take the SAME TIME to charge the batteries as my existing charger? If I contemplate never flying planes larger than the Parkzone/E-Flite/Electrifly Super Sportster types, what is the advantage of having a charger with max capacity of 150W or 250W??? What, indeed is the advantage of either of the above over my Apprentice charger (beyond the fact that it can only charge 2 or 3 cell batteries??? Thanks. Gary

xmech2k 04-09-2014 01:44 AM

A 3200mah battery would be charged at 3.2A at 1C charge rate. The 75w charger could charge your 3s battery at 75w/12.6v=5.9A. I used an 80w charger for a long time and it was fine for all my needs until I got a plane that takes a 6s battery. So unless you plan on parallel charging or getting really powerful planes soon, it'll probably work just fine for now.

To answer your charging time question, at 1c charge rate, you'd still be charging at 3.2A with either charger, so they will have similar charge times. But I think they will both be faster than the stock one. All batteries charged at 1c take about the same time to charge. When you have batteries that can charge at higher rates is when you can speed up the process.

xmech2k 04-09-2014 04:20 AM

Oh, forgot to mention. The other thing to speed up the process is parallel charging. That's where the 250w charger would be useful.

kyleservicetech 04-09-2014 05:10 AM

Quote:

Originally Posted by garyp1029 (Post 944930)
Still trying to sort this out . . . Am considering a new charger to replace the one that came with my Apprentice. The ICharger 106B+ has a maximum charging capacity of 250W; the Cellpro MultiPro 4 has 75W. My understanding is that my 3200 mah batteries should only be charged at about 3W. Am I correct in thinking that both chargers would take the SAME TIME to charge the batteries as my existing charger? If I contemplate never flying planes larger than the Parkzone/E-Flite/Electrifly Super Sportster types, what is the advantage of having a charger with max capacity of 150W or 250W??? What, indeed is the advantage of either of the above over my Apprentice charger (beyond the fact that it can only charge 2 or 3 cell batteries??? Thanks. Gary

Lets see:
Assuming a three cell 3200 Mah battery, you'd be charging at 3.2 Amps for "C" equals one. So, at three cells, and 4.2 Volts per cell, that's 12.6 Volts DC.

"C" and what it is
http://www.wattflyer.com/forums/showthread.php?t=65869


The charging watts would be volts times amps, or 12.6 Volts times 3.2 Amps, or Watts equals 40.32 Watts. If you're running a 4 cell or lower count LiPo, you'd be running well within range of a 75 Watt charger.

More important, is whether your charger has metering capabilities while charging. That would include showing the voltage on each cell, the voltage on all cells, the charging current programmed, the actual charging current during the charging process, and the total ampere hours put back into your LiPo battery.

There are a number of very good chargers out there. Most of my club members that have higher powered electric models are using the Cellpro line, including the Cellpro Multi4, the 10xP, the Powerlab 6, and for me, two of the Powerlab 8 chargers.

Those 1300 watt, high powered Cellpro chargers work very nicely when charging my models 12S2P A123 packs 15 amps per 6S2P pack. Warning here though. Charging at these high rates will be pulling some 50 Amps out of your 12 Volt battery. Doing 50 Amps out of a 120 Ampere deep cycle will kill that deep cycle battery in only a few months. Personal experience.

Harbor Freight Gasoline/Alternator Setup
http://www.wattflyer.com/forums/showthread.php?t=66066,

Yeah, flying giant scale electric models gets real complex, real fast.

JetPlaneFlyer 04-09-2014 06:47 AM

Bear in mind that virtually all new LiPos will have a safe recommended charge rate of at least 2c. So all the previous calcs, being based on 1c, are incorrect unless you want to deliberately charge slowly.

Also the Cellpro Multi4 is not a 75W charger, it's maximum output is 4Amps or 58Watts: http://www.revolectrix.com/m4_specs_tab.htm

2c on a 3200mAh LiPo is 6.4 Amps / 80.6Watts, so that significantly exceeds the Cellpro rating already. The iCharger has a 10A output so could charge at 'full speed'. What ultimatly limits both chargers when charging 3s LiPos isn't their power (Watts), but their maximum current output in Amps.

What would make the difference between the chargers bigger still is if you have more than one battery, and wish to charge them together in parallel (using a parallel charge board). If you were doing that then the desired charge rate will far exceed the rating of the Cellpro, so the iCharger will start saving lots of time. The amp limit (not power) of the chargers is what is limiting them on your 3s batteries, the iCharger has a 10A limit and the Cellpro only 4Amps, so the iCharger will parallel charge multiple 3s batteries in less than half the time of the Cellpro.

Actually if you are parallel charging more than two batteries you would benefit greatly from a charger with higher amp output than either of these two mentioned, the iCharger 206b perhaps (20Amp output)? Then you could really save some time.

fhhuber 04-09-2014 06:49 AM

Note.... There's some inefficiency in any charging process. Pushing that 3.2 amps at 12.6 volts might load the charger as high as 50 watts.
(3.2 amps is the max I can push into a 5000 mah 4S using a 50 watt "rated" charger I have)

It can be interesting putting a wattmeter between the charger and power source and another between charger and battery. They won't ever read the same watts.

JetPlaneFlyer 04-09-2014 07:29 AM

Quote:

Originally Posted by fhhuber (Post 944967)
Note.... There's some inefficiency in any charging process. Pushing that 3.2 amps at 12.6 volts might load the charger as high as 50 watts.
(3.2 amps is the max I can push into a 5000 mah 4S using a 50 watt "rated" charger I have)

It can be interesting putting a wattmeter between the charger and power source and another between charger and battery. They won't ever read the same watts.

Inefficiency doent come into it, the output watts is simply volts x amps at the output leads.

The efficiency losses occur in the internals of the charger between input and output (input power will be slightly higher than output due to efficiency losses), but the stated output rating of the chrger is at the output, not at the input..

The reason you can only charge at 3.2A is because you are charging a 4s battery (not 3s like the OP). 15.6v x 3.2A = 50W

kyleservicetech 04-09-2014 07:57 PM

Quote:

Originally Posted by JetPlaneFlyer (Post 944966)

Also the Cellpro Multi4 is not a 75W charger, it's maximum output is 4Amps or 58Watts: http://www.revolectrix.com/m4_specs_tab.htm


H'mmm
Must have gotten wrong information. Also thought the Cellpro Multi4 was 50 watts, but then found someplace that indicated 75 Watts.

Cellpro DOES list their Multi4 as a 50 watt unit.

kyleservicetech 04-09-2014 08:00 PM

Quote:

Originally Posted by fhhuber (Post 944967)
It can be interesting putting a wattmeter between the charger and power source and another between charger and battery. They won't ever read the same watts.

I've done that with my Cellpro Powerlab 8 chargers. The volts/amps/watts/ampere hours readings between the '8 charger, and my wattmeter are pretty close.

As for the best charger for your needs, IMHO, it's always wise to buy the best charger you can reasonably afford. Nothing worse than buying a charger, then finding out later on when you've gone to higher powered models, that you now have to buy another, higher powered charger.

JetPlaneFlyer 04-09-2014 08:21 PM

Quote:

Originally Posted by kyleservicetech (Post 945010)

Cellpro DOES list their Multi4 as a 50 watt unit.

They actually say '50W class' charger. The spec very clearly says 58W peak output.

kyleservicetech 04-10-2014 02:54 AM

Quote:

Originally Posted by JetPlaneFlyer (Post 945015)
They actually say '50W class' charger. The spec very clearly says 58W peak output.

Yup
Now is this a 50 watt charger, and if you push it to 58 watts, it gets a little hot?? :D :D :D

fhhuber 04-10-2014 04:48 AM

These modern chargers are pretty smart... even the cheap off-brands. They will self-limit current to prevent overheating and often have thermocouple sensors controlling the fans to reduce wasted energy when possible but still provide the cooling needed.

Karnsy 05-03-2014 05:54 PM

Here's my question,,,,,,, is taking 100 minutes to charge a 2200mah 3s 30c 11.1v battery normal. I have a Hitec X4- 200w charger. The other day I was charging a battery and it timed out charging @ 90 minutes. I was charging it at 2.2

Each cell started from 3.71v. I know the charger came with a default setting of 120 minutes but I dropped it down to 90 thinking that should be enough. :confused:

kyleservicetech 05-03-2014 06:21 PM

Quote:

Originally Posted by Karnsy (Post 947196)
Here's my question,,,,,,, is taking 100 minutes to charge a 2200mah 3s 30c 11.1v battery normal. I have a Hitec X4- 200w charger. The other day I was charging a battery and it timed out charging @ 90 minutes. I was charging it at 2.2

Each cell started from 3.71v. I know the charger came with a default setting of 120 minutes but I dropped it down to 90 thinking that should be enough. :confused:


Do you have access to one of those wattmeters? If so, connect it between your charger and your battery and use it to check the accuracy of your chargers metering.

Keep in mind that those wattmeters are designed to read up to 50 amps or more, so may not be really accurate at currents of 2.2 Amps.

JetPlaneFlyer 05-03-2014 07:17 PM

Karnsy,

Most likely the battery is charged but the charger cant balance it. The usual cause if that is the case is that the battery is old and a cell is going down.

Karnsy 05-03-2014 10:17 PM

kyleservicetech, I do not have one of those meters. I do have a cell meter and sometimes what my charger says as an example is 4.20 the meter will say 4.19 or 4.18 but I figured that was not a big deal. I guess you might be right JetPlaneFlyer, should I up the timer to 100 minutes or call it good at 90 minutes ? or am I right and it is not going to make that much of a difference long term on the battery?.:cool:

JetPlaneFlyer 05-03-2014 10:31 PM

I'm note sure what options that charger gives you but you may be able to set a cut off voltage so that the charger calls it quits once the charge rate drops to a pre-set value. With my iCharegr i have it set to cut off one the charge current drops to 1/10th of the inital charge current. So if I set it at 5A the charger will stop once the current gets down to 0.5A. This does mean that the cells might not be as topped up and precisely balanced as they could be but it saves a lot of time and does the battery no harm at all. But not all chargers have the ability to make those sort of set-up adjustments.

You shouldn't have to wait anything like that long to charge, 90 minutes is already far too long. Try upping the current to 4.4Amps, which will give a 2c charge rate (almost all batteries these days are fine with that)

If a battery is timing out on balancing consistently then to be honest it's probably time for the battery to meet the trash can because it means that the resistance of the cells is so inconsistent that the balancer just cant get them voltage matched. Is the battery quite old and is it 'puffed' at all?

thepiper92 05-03-2014 11:21 PM

I set my charge to 3.5a usually on my IMAX B6ACT. akes 15 minutes for a 3s 1300 to charge, even less often as I usually don't drain a battery, often only go a bit more than half way through a pack. I balance charge fairly often. Charging is much slower. I have pushed charging to 4.2, but in the 3.5 range is good.

solentlife 05-04-2014 07:44 AM

Quote:

Originally Posted by garyp1029 (Post 944930)
Still trying to sort this out . . . Am considering a new charger to replace the one that came with my Apprentice. The ICharger 106B+ has a maximum charging capacity of 250W; the Cellpro MultiPro 4 has 75W. My understanding is that my 3200 mah batteries should only be charged at about 3W.

?? Suggest you recheck that ... Do you mean AMPS ? If the pack is 3S (11.1v) then 3W is incredibly low number. That is only just over 250mA rate.
Quote:

Am I correct in thinking that both chargers would take the SAME TIME to charge the batteries as my existing charger?
Only if you set the new chargers ay same rate as existing charger.
Quote:

If I contemplate never flying planes larger than the Parkzone/E-Flite/Electrifly Super Sportster types, what is the advantage of having a charger with max capacity of 150W or 250W???
Higher charge rates .. probably better information on screen ... and possibility to charge more than one battery at a time. The 250W charger particularly will enable you to charge multiple in good time.
Quote:

What, indeed is the advantage of either of the above over my Apprentice charger (beyond the fact that it can only charge 2 or 3 cell batteries??? Thanks. Gary

Any charger given with an RTF is usually a budget limited job .. any decent programmable charger is an instant improvement.

Why not google for the Owners manual for the proposed charger and readf up before buying ? That way - you get a better understanding of capability over what you have.

If the Apprentice charger is the basic 2 - 3 cell type with fixed output ... don't throw it away ... it does still have uses ... I have two and they can be used to sort out wayward packs slowly ! But that's not for today ..

Nigel

JetPlaneFlyer 05-04-2014 07:51 AM

Quote:

Originally Posted by thepiper92 (Post 947220)
I set my charge to 3.5a usually on my IMAX B6ACT. akes 15 minutes for a 3s 1300 to charge

You do appreciate that you are charging at 3c there don't you?.. That's ok for some batteries but not for all. I usually do 2c these days as it seems a good compromise between charge time and battery stress.

solentlife 05-04-2014 08:04 AM

Quote:

Originally Posted by Karnsy (Post 947196)
Here's my question,,,,,,, is taking 100 minutes to charge a 2200mah 3s 30c 11.1v battery normal. I have a Hitec X4- 200w charger. The other day I was charging a battery and it timed out charging @ 90 minutes. I was charging it at 2.2

Each cell started from 3.71v. I know the charger came with a default setting of 120 minutes but I dropped it down to 90 thinking that should be enough. :confused:

No need to change time default - that's a safety item for the charger and to stop you banging away at a pack.

120mins is normal and can be left alone ..

2.2A is in theory 1hour on a 2200 pack. (You should never need to put back 2200 ... if so - then pack is likely over-discharged and damaged). But in fact you will have different depending on how much balancing is required of the pack ... the more out of balance the cells are - the longer it will take ... particularly if one cell is getting 'tired' and its IR is increasing.

In theory a storage charge level pack should take significantly less that 1hour ... again as above.

I have various packs that run over the expected theoretical time ... I keep an eye on them ...

Nigel

fhhuber 05-04-2014 08:26 AM

You can have a good pack that somehow gets out of balance and the SLOW "balance by discharge while competing with the charger trying to fill the pack" balancing method (often at under 100 ma balance rate) can easily time out a balance charge MANY times before you get in balance.

2 basic answers to this issue:

1 Get a charger or balancer that will balance at a higher rate.
(Turnigy 420 balances by charging the low cell at up to 2 amps, accepts only 2 to 4 cell packs)

2 Make a lead so you can charge any one cell at a time through the balance plug and charge each cell individually to 4.20 v.

If the pack is good you shouldn't have to do "extreme balancing" often even if pushing the pack's current rating in your model.
High discharge rate is where I have seen the most need for this type balancing of a still good pack... and its rare.

solentlife 05-04-2014 09:55 AM

Quote:

Originally Posted by fhhuber (Post 947280)
You can have a good pack that somehow gets out of balance and the SLOW "balance by discharge while competing with the charger trying to fill the pack" balancing method (often at under 100 ma balance rate) can easily time out a balance charge MANY times before you get in balance.

2 basic answers to this issue:

1 Get a charger or balancer that will balance at a higher rate.
(Turnigy 420 balances by charging the low cell at up to 2 amps, accepts only 2 to 4 cell packs)

2 Make a lead so you can charge any one cell at a time through the balance plug and charge each cell individually to 4.20 v.

If the pack is good you shouldn't have to do "extreme balancing" often even if pushing the pack's current rating in your model.
High discharge rate is where I have seen the most need for this type balancing of a still good pack... and its rare.

Can you do me a favour ?

Can you tell that to "Julez" over on the 'Dark-side' ... RCG. I gave up explaining that in even the simplest terms to him ...

I know sometimes I talk crap ... we all do at times ... but that was just something else ...

Cheers
Nigel

Karnsy 05-04-2014 11:35 AM

So solentlife what I am getting from this is......

No need to change time default - that's a safety item for the charger and to stop you banging away at a pack. 120mins is normal and can be left alone .. 2.2A is in theory 1hour on a 2200 pack.

That the charger came defaulted at 120 mins auto stop charging and I could put it back to 120mins not a bad thing?

My charger is 50w per battery for a total of 200w.
I do charge my 2200 packs @ 2.2A and my 1800 @ 1.8A I thought that's what I should set it at.
Most of my batteries are one season or one year old have been taken care of and all look great,, no puffing or signs of abuse and all batteries are good quality.


can easily time out a balance charge MANY times before you get in balance

fhhuber ..........That makes me feel a little better Thanks !

JetPlaneFlyer 05-04-2014 05:04 PM

Karnsy,

Even at 1c (2.2A) charging the charge shouldn't take more than an hour. If it's consistently taking 90 minutes and failing to balance then something is amiss. Either the charger is not up to the job and/or the battery cells I.R are all over the place.

If it only occurs on certain batteries then those batteries are suspect. If it happens all the time on any battery then the charger isn't doing it's job. The balance circuit on those 50W chargers isn't very powerful but it should still do the job providing that the battery is in reasonable condition.

Having said that, if the cells come off with voltage on the cells close and they perform ok in flight then I guess you could put up with it.


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