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Old Nov 27, 2006, 11:37 PM
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Queens, NY
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Optima lead acid and A123 batteries

I did some research on Optima lead acid batteries and found similarities toward A123Systems cell
Hgiher charge rate without overheating
Very low self discharge rate (they say it would hold charge for over a year)
very flat discharge rate at 1V higher voltage then normal lead batty
Extremaly high Cold Cranking Current
Sharp voltage pick when full
unspilable, shock resistant and long lasting

And it is old pesky Lead Acid

perfect for field use and around the house
You can run winch out of it and still have a power to charge your flying cells
Bought it in COSTCO for $142 + Tax on sale

recomended
ZM
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Old Nov 28, 2006, 02:12 AM
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Madrid (Spain)
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ZM,

A couple of comments...

-Pulsar is not protecting itself, is protecting the battery when stops putting current onto it at 15'3V. In fact this is a too high voltage for many of them, but not too bad to do this way.
I too have problems with this: if you use an old discharged one, she does not accept much charge before going up in voltage and then Pulsar stops discharging at high rate. If you do use a newer one, probably she will be healthy in charge and you go also quickly to this situation.
Their advise to use a big one (70Ah, I am using 40Ah ones as you are doing I think) is a good one, the problem is then minimized.

-As stated, the problem is to get a good big battery, both for use at home (discharging/cycling/testing with this charger), or at the field (to charge "big" packs, say 7s or 10s A123). I started looking for "good" batteries some weeks ago, and after much investigation...Optima are good, but not best if you do want good deep discharging.
Better are Exide Gel or Maxxima, and better yet Concorde Lifelong. Unfortunately, their are all US made and hard (or expensive) to have here in Europe. For you all there, keep an eye on the Lifelong ones. Really good, able to stand deep discharges many times, surprisingly light. And keep far from some of the Optima (yellow, specially red tops), marketed sometimes wrongly as "deep discharge". Try to deep discharge them a couple of times and see...

Btw, what a great charger is the Pulsar.
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Old Dec 06, 2006, 01:15 PM
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Hi again,

I was thinking on open a new thread about "fast charging of lipo packs" but as I will be exposing things that this charger does, maybe is better to discuss it here instead of opening new threads (wellcome Charles).

As it has been stated, one of the options Pulsar has is "Fast" when charging CC/CV chemicals. The manual is a bit unclear on what happens: talks about pulses being used... ??
Pulsar's own software do not show nothing strange when you do "fast" charge of lipo: just a CC curve that is followed by another short CC one after "peaking" at 4'2V/cell (or whatever you selected, as this can be changed on this charger's setup). So, if you do a 1C charge, you have your pack "fast charged" in a bit less than one hour; you do at 2C, you have it in less than 30 minutes... We will not start discussing now about 2C lipo charging right? The pack does it no problem and Temp rises around 5 to 7 Celsius (10F).
But Pulsar advises AGAINST using a balancer when "fast " is on. So the 2C thing is something to consider with a different approach than usual here if we want to be safe (I was using a couple of well-know well-balanced packs).
I put my Eagle-Tree on to show you all some graphs but... the graphs are a mess: the current pulses go up and down in a way that are unreadable. Tried differente "rates" (4, 8 and 10 per second) with same effects.
What I think the charger does? He charges CC all the way up to 4'2V/cell (pulsed current, not linear), then he send slower pulses of the same current amplitude for a short time (1 to 2 minutes max), short of "top off". The thing is, with pulse current, at the end of charge the voltage gets into te "over 4'2V/cell" region clearly, maybe not higher than 4'3V however.
I have to do more tests, and have useful graphs to be shown, but this explains why them do not want you to use a balancer in "fast" mode: you will burn it, or you will not have your battery fully charged (fully to 80-90% than lets the "fast" mode do this).
Seems a bit complicated when you can do a normal charge at 1 or 2C rate, and just stop when the charger enters the CV phase, and call this a "fast lipo charge" (E-Station 902 does this exactly). But this charger does so wonderful things that it let's me scratching my head... and off course the makers tell there is no harm done to the cells, etc etc.
Any opinions?
Josep
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Old Dec 06, 2006, 02:13 PM
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Some call the AF-109 a pulse charger due to the fact that in Stage one it cycles the charge current 50/50 off / on and then in stge three it cycles the current off and on staying on less and less until voltage stays at 4.2 per cell for 45 seconds(?) then stoped the charge.

Graph oa a 109 chargin a 3S A123 pack here.
Note I stoped the charge myself after approx. 45 sec. into stage 3.

http://www.rcgroups.com/forums/attac...mentid=1079592

Pulsed charging was a big deal for NiCads many years ago but most of the true experts felt that nothing was gained by it. They also felt like it really did not harm so it was just left to play itself out.
I have a very old TEKIN charger which used pulsed charge for SCE NiCads and it seemed to help that I really never did that much serious testing.
It would seem that pulse charging would help with breaking micro short down much the same as a very high current charge for a brief perio of time does. Problem is that once these short develop they will return very quickly.

I have never read any hard data on the over 4.3 volts per cell with LiPolys durning charging. 4.235 is the recomemded top but for what lengths of time?


A123 Racing states that their cells can be charged to 4.2 if they are not held there to long. I know the A123 cells hold no real capacity past 3.45 resting / 3.65 under charge and that imbalance gets very bad past 3.7 per cell.

Charles
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Old Dec 07, 2006, 03:50 AM
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Charles,

Mixed concepts here, AF109 looking at your graph is a pulse charger, but seems to be linear on most of the chargign process. Curious.

Pulsar is a pulsed charger, but it does have also the "reflex process" option, the thing Tekin made popular years ago. I too have (a couple) of Tekin chargers, the older A110 (? the first one with "power flex" that has two A settings from 0'5-4 and 1-8A if memory serves) and the less older BC112. This is a great unit that stills work good for me with NiMh and the occasional NiCD, you can feed him with up to 30V and charge up to this V (it does not have step-up converter, but does nicely step-down) and up to 10A, not a mean thing btw. This one has also the "power flex" option, usually know as "reflex" charging: negative pulses (discharging) are done between positive (harigng) ones, said to reduce "memory" efect on NiCD, and very discussed for NiMh, not to say Li chemicals (most say "useless or harmful", Pulsar makers say "do it it is better").

What puzzles me is the "fast" charging of lipos here, in fact, the "termination" of this mode. I have no idea of why and what he does, instead of just stopping at the end of CC stage: after this, instead of doing some CV, he "pulses" the pack a bit more, but only for a few seconds/minutes, so the mAh charged here are just a few.
This afternoon I will try the same thing on a A123 pack (this charger does have LiPh mode up to 3'65V/cell or whatever you want) and look if I can see something else than with lipos.
Josep
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Old Dec 09, 2006, 12:26 AM
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Gentlemen!
I got a little chat with Mr Krymski
It was too late to have answers to all your questions, but main thing he wants us to read manual several times. All these questions are covered in number of ways and might be hidden to give you direct respond to your concerns.
I read it again and again, both Polish and English version.
There is nothing missing in English version versus Polish one, but reading them both several times made me discover couple of things proving that Mr. Krymski is independent thinker setting algorithms of his Pulsar to the best of his knowledge regarding chemistry of the cells Pulsar is working on. His main focus was to deal with elevated charging current and employing tricks for further shortening of charging process.

Using reflex
He suggest to use this function as a protection against high pressure build up and temperature rise when battery reaches its pick voltage. This is exactly what current balancers do to each cell. This function allows to carry high current to the last 2-3% of the capacity. I am not sure if the reflex is applied all the time or in the last minute of charging, but the thing is A123 2S1 is able to be charged in less then 15 minutes to 2164mAh every time, while normal charging gets to the 2210mAh level (50mA difference)
With the REFLEX On battery barely gets warm(30 degree C - the most) at 10A

What is interesting
( manual doesn't say about this phenomenon):
When REFLEX is ON
Cells are evenly balanced after charge to the last 5mV
If REFLEX is Off differences are much larger ( about 30mV)
I have tested 3 sets of 2S1 pairs and checked them for 3 times
next time I will check 4S1 packs again
This is something worthy to look at.
If REFLEX pulse is able to even the cells in the pack somehow we got the real winner here

balancer
Function FAST is not allowed to be used with balancers equipped with high voltage cut off switch. This is bad for charger as well is bad for cells ( there is no way back for Current under Reflex pulse anymore). We are talking here about high current charging to the last 3-5 seconds of the cycle
This is understandable
regular continuous discharge balancers are OK

PC Graph
Values on PC Graph are monitored every 3-5 seconds
What Charger is doing in between it remains mystery of the trade
If the clock of the PC graph is synchronized with Charger clock there is no way we can see what charger is doing in real time.
it seems like clever protection against cloning I believe


PS after almost two weeks with A123 cells and PULSAR my preffered way to charge them is FAST charging with REFLEX and top 3.65V restriction with highest Amperage available. It saves a lot of time and no much of the pay offs. 2165mA charged shows 2210mA discahrged ( It might be a difference in math there between charging and discharging), but pretty close every single time.

ZM
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Last edited by Smyk; Dec 09, 2006 at 06:59 AM.
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Old Dec 09, 2006, 03:25 AM
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... You experience charging "Fast" A123 cells is inline with Charles and others observations: after 3'65V/cell there is almost no mAh's (capacity) put into the packs. This is also why it is not harmful (short term) to have the A123 cells go up to 4'1 or 4'2 V/cell.
With Lipo however, "Fast" charging lets you with a bit undercharged packs, because you do not have the final CV part (almost).
Anyway an interesting and great charger, I am more than happy with it as stated, and still discovering his "tricks" (some fresh air, nice).
Josep
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Old Dec 09, 2006, 07:33 AM
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Quote:
Originally Posted by armengol
...With Lipo however, "Fast" charging lets you with a bit undercharged packs, because you do not have the final CV part (almost).
Anyway an interesting and great charger, I am more than happy with it as stated, and still discovering his "tricks" (some fresh air, nice).
Josep
I suspect that beside voltage limitation algorithm for FAST charging of LiPos
might be slightly different then for A123. My planes are big. I do not need them. I declare no input on LiPo.

ZM
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Old Aug 27, 2007, 01:12 PM
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PULSAR 2 has a new 2.10v upgraded software

Check PUSLAR 2.10v for details and links


ZM
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Old Aug 28, 2007, 02:41 AM
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I understand the only thing "new" on 2.10 is the capacity to use the "equalize" module/add on right?

Btw... "availability summer 2008" seems a bit far to me!

This said, I own one Pulsar 2 (besides some great other chargers from Schulze, Robbe, Graupner, Hobicco, eStation and others...) and I have to say it is the GEM of my collection.

Regards

Josep
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Old Aug 29, 2007, 06:21 AM
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Quote:
Originally Posted by armengol
I understand the only thing "new" on 2.10 is the capacity to use the "equalize" module/add on right?

Btw... "availability summer 2008" seems a bit far to me!

This said, I own one Pulsar 2 (besides some great other chargers from Schulze, Robbe, Graupner, Hobicco, eStation and others...) and I have to say it is the GEM of my collection.

Regards

Josep
Josep
2.10v
There is some minor changes how Pulsar handles NiMh cells
In this technology is lots of changes and seems like they do not fall in one basket anymore. They are still attractive in some applications

Yeh
I have recently changed the release time from fall to spring.
As always housing for gizmos like that creates biggest problem.
Stay tuned it might be worhty to wait

ZM
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Old Apr 15, 2008, 12:41 AM
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Balancer

http://www.rcgroups.com/forums/showt...12#post9566299



some you might find it interesting

cheers

ZM
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