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Align T-REX 600N 700N > Voltage Regulator: Align 2 in 1 or Fromeco?
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

Quote 

No voltage regulator requires you to run an in-line diode for the tail servo.
More Great Wisdom. Sheesh. Except for all the 6V ones.

Only problem with 5 cell and stepdown is you will be at a pretty high voltage for the first part of your pack. Stepdown diodes will typically drop .7V a few have two diodes inline and drop 1.4V.

You're on the right track, Rock. It's a little higher than I'd run a tail servo. The 1.4V drop is essentially the same as dropping a full cell to the tail. The $3.99 Align takes you half that far.

Mike
06-22-2007 Over year old.
 
 
Ace Dude
Elite Veteran
Location: USA

Quote 
More Great Wisdom. Sheesh. Except for all the 6V ones.

What happened, did you just realize that LiIon is safer than LiPo?

Perhaps if you actually understood what you're powering you would understand that no voltage regulator requires you to run an in-line diode for the tail servo.

The servo voltage requirements are servo dependent not regulator dependent. Thus, the servo, not the regulator, may require a device to provide the proper voltage to your T/R servo. In other words, you're modifying the voltage to the T/R servo to meet the requirements of the T/R servo.



06-23-2007 Over year old.
 
 
Ace Dude
Elite Veteran
Location: USA

Quote 
Can't get the high voltage to the cyclic servos with a 4 cell.

The Align 2 in 1 doesn't step the voltage down to the tail servo, so you have to do it with a diode.

And you really need the high voltage because? I doubt most folks can tell the difference between 5v and 6v.

If you're that concerned, just get the Arizona regulator and be done with it.



06-23-2007 Over year old.
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

LOL. Almost a nice save, Ace. Pretty obvious we are discussing servo requirements. But I'm done regardless. I think I've demonstrated more than a little understanding over the years I've been doing this thanks.

I stated up front Li-IONs with built in safety were safer than any raw chemistry. It gets removed on many if not most of the Li-Ion packs.

But it isn't really that hard to understand. Take a pile of gun powder and light it. You get a nice little flame. Take a similar pile of gun powder and put it in a plastic bag. The bag pops or melts and you get a nice little flame. Put it in a metal shell. You get a bomb. Simple.

Good Luck,

Mike
06-23-2007 Over year old.
 
 
Ace Dude
Elite Veteran
Location: USA

Quote 
But I'm done regardless.

That's probably best.

Quote 
I stated up front Li-IONs with built in safety were safer than any raw chemistry. It gets removed on many if not most of the Li-Ion packs.

You said "LiIon is NOT SAFER than LiPo.", not me. If you read the LiIon link I provided you would understand that the thermal runaway protection is an integral part of the cell, it's not external circuitry which is also available and typically used for balancing/over charge protection.

I'll take the metal shell with the internal thermal runaway protection and vents any day over the sealed poly bag without any internal protection.

I do have plenty of LiPos, I just don't use them for RX packs in my helis. I use them for flight packs and store them accordingly when not in use. There have been quite a few report of LiPos spontaneously catching fire. I'm not aware of any spontaneous LiIon cell fires.



06-23-2007 Over year old.
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

Quote 
LiIon is NOT SAFER than LiPo. When they vent it is far more violent. LiPo was developed to help deal with that (and other reasons). LiIons become safer when they have safety circuitry built in and dedicated chargers
Is what I said. If you haven't seen or heard of a Li Ion exploding you haven't looked hard enough. Pretty much all cells are designed with internal runaway protection including the bags on lipo's.

Anyway. Run what you want. People think Li Ion is safer and it can be. But as we use it it typically is not. The chemistry is derivative. Both explode quite nicely. The built Lipo's to help deal with the explosions. This was a primary design goal.

From your quote:
Quote 
Li Ion cells truly can explode as they are sealed in a metal can. They too have vents.
[snip]
Li Po cells also can vent if charged at too high a voltage. There is a narrow range of choice of the electrolyte for use in Lithium Ion cells. Remember that Li Po cells are a form of Li Ion; they derive their name from the fact that Li Po cells are housed in a plastic (polymer) envelope. If the envelope has a small Vee cut in the join line, that serves as a vent. The major difference with Li Po is that the envelope can swell when pressure builds to form the infamous “silver sausage”.

If a Li Ion cell suffers ignition, the vent cannot act quickly enough to prevent rapid pressure build up. When this happens, the can fails instantly and catastrophically just as it can in a Ni Cd/Ni MH if the vent does not function properly

LOL. You're good at sucking me in. Rock on. I need to unsubscribe so I quit replying.

Mike
06-23-2007 Over year old.
 
 
Ace Dude
Elite Veteran
Location: USA

Quote 
But I'm done regardless.

Obviously, a man of your word.

Here's a post on the subject directly from Kurt Cook from Fromeco:

http://www.runryder.com/helicopter/...1/?p=2190334#RR

Here's some additional information on their website:

http://www.fromeco.org/instantKB/ar...45&cNode=1R3R8S

I'll quote it here for your convenience:

"As far as Thermal run away. Yes the Lithium Ion can thermally run away, but the circumstances needed to get to that point are pretty massive. In a normal everyday hobby envronment it is very very hard to get a Lithium Ion pack to run away. There are safety features that are built into every individual cell that must be over come. Lithium Poly do not have any of these safety features, this is why you always hear of them catching on fire, and not the Lithium Ions. Crushing Lithium Ions (like in a Vice Grip) or massive instantanious High VDC and Amperage like 20/20 will get them to thermally run away."

In case you missed the important part he said:

"There are safety features that are built into every individual cell that must be over come. Lithium Poly do not have any of these safety features, this is why you always hear of them catching on fire, and not the Lithium Ions."

Additionally, the text below is from the LG Chem Lithium Ion ICR18650 product specifications sheet. LG Chem is the brand of cell Fromeco is using in their Relion battery packs.

9. Safety Test

9.1 Abnormal Charge Test
Test method : Cells are discharged per 6.2, then charged at constant current of 6450mA and
constant voltage of 4.2V while tapering the charge current. Charging is continued
for 48 hours (Per UL1642).
Criteria : No rupture, No fire

9.2 External Short-circuiting Test
Test method : Cells are charged per 6.1, and the positive and negative terminal is connected by
a 100mΩ-wire for 1 hour (Per UL1642).
Criteria : No rupture, No fire

9.3 Overdischarge Test
Test method : Cells are discharged at constant current of 430mA to 250% of the minimum
capacity (Per UL1642).
Criteria : No rupture, No fire
PRODUCT SPECIFICATION
CONFIDENTIAL 6 (7)
Prepared Document No. Date Rev
LGCRP/BRI/BTC Yun, In Taeg LRB-PS-CY220 2003-01-13 0
Approved Description
LGCRP/BRI/BTC Kim, Soo Ryoung Lithium Ion ICR18650 S2 2200mAh

9.4 Nail Test
Test method : A nail (diameter : 2.5~5mm) is penetrated vertically through the center of cells
charged per 6.1 and left for 6 hours.
Criteria : No rupture, No fire

9.5 Heating Test
Test method : Cells are charged per 6.1 and heated in a circulating air oven at a rate of 5ºC per
minute to 150ºC. At 150ºC, oven is to remain for 10 minutes before test is
discontinued (Per UL1642).
Criteria : No rupture, No fire

9.6 Impact Test
Test method : Cells charged per 6.1 are impacted with their longitudinal axis parallel to the flat
surface and perpendicular to the longitudinal axis of the 15.8mm diameter bar
(Per UL1642).
Criteria : No rupture, No fire

9.7 Crush Test
Test method : Cells charged per 6.1 are crushed with their longitudinal axis parallel to the flat
surface of the crushing apparatus (Per UL1642).
Criteria : No rupture, No fire



06-23-2007 Over year old.
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

That is a great link, ACE. Haven't seen that one. Thanks.

Looks to me like the Fromeco cells are about as good as it gets from a li-ion for safety. At least according to the guy selling them. I wouldn't generalize that to all of them, and you can be sure he wouldn't either. Did you spot any mention of a PTC or layered matrix's in that data sheet? I didn't. You would think something that important would be in there. Perhaps it is shown somewhere else.

Hop on over to rcg and watch the explosions from the prismatics and other li-ions we used to screw with in the early days. Watch a laptop or cell phone explode.

There is a reason they looked for something safer and it certainly isn't because Li-Ion is 'safe'.

Kokam has lipo batts that pass all the same tests you listed above. Fred used to love to cite them. Pretty much boiler plate.

I see where you've gotten your opinion from any way.

Mike
06-23-2007 Over year old.
 
 
Ace Dude
Elite Veteran
Location: USA

Quote 
I see where you've gotten your opinion from any way.

Thanks!

Yes, it appears that all LiIon cells do not contain the same safety features. I was specifically referring to the cylindrical metal can ones and not the prismatic square ones, but it does appear that all the cylindrical ones may not contain the same safety features.

I only posted one section (the safety section) of the LG Chem spec sheet. The entire spec sheet can be found on the LG Chem website here:

http://www.lgchem.com/upload/chemPr.../icr18650s2.pdf

This is a bit old, but I can't find the latest spec sheet for the 2600Mah cells which (I believe) Fromeco is using in their current Relion battery packs. Notice the document is marked "Confidential" so maybe they're not posting the current spec sheets.

I'm a regular on RCG and have seen many of the explosions and fires. I can't say I've seen any LiIon metal can fires. All I've seen are LiPo fires.

LiIon is definitely not 100% safe, of course the same could be said for NiCd/NiMh as well, but from what I've read the metal can LiIon RX packs (e.g., Fromeco) are safer than LiPo.

I thought someone else besides Kokam had Lipo batteries that wouldn't catch fire (special chemical compound). Was is a specific version of Tanic or Apogee?

The good news is that the A123 cells do appear to be very safe. They may be a little large/heavy for our application, but I hear they're trying to produce them in a smaller size.

Did I see a post of yours where you are using A123 cells? I got a DeWalt 36v pack, but haven't had a chance to hack it up yet. Not sure what I'm going to use it for yet. I'm thinking a 40 sized plank or maybe to power my electric fuel pump.



06-23-2007 Over year old.
 
 
Ticidytoc
Senior Heliman
Location: Los Angeles, Ca.

Hes trying to suck you in again Mike, talking nice and all.
06-23-2007 Over year old.
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

Nah, Ace ain't that bad just likes to stir the pot occasionally.

Yeah I run A123's absolutely brilliant cells, imho. There is about a 30g weight difference to 2070 tpx for a 2s pack. I can live with that. They are WAY lighter than some of the monster Li packs guys think they need.

Now those babies are safe. I've charged mine at 30A. Pummelled them back down at 60A. Discharge to zero. Overcharge them safely to get done faster. You name it I've tested to try and kill them. They just spring back with no noticable effects.

40 size is where they come into their own. Anything over 4s and 400w or so and the form factor and small weight issue goes away.

Eventually someone will scoop their technology, and we'll get different sizes and price points. 1100mah supposedly in the works.

Tanic, Apogee, and now Duralite all have liMn lipos that are bulletproof safe. Slight weight penalty. Slight current advantage to the super lights.

Mike
06-23-2007 Over year old.
 
 
Ace Dude
Elite Veteran
Location: USA

Quote 
Ace ain't that bad just likes to stir the pot occasionally.

Man, I have been found out...my cover has been blown.

What the heck are you using to charge those puppies at 30A?



06-23-2007 Over year old.
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

Heh. Big Charger is ghetto lab power supply. 3 Large PC power supplies with the 5V rails series up for 15V for my 4s packs (you can safely overshoot the voltage a little. A123 does it themselves). 12V rails tied together for 10S. Just hook up the wattmeter, and let her rip

Day to day I often use a hacked 109, 8A wil get you out in under 15 minutes most of the time. With series charging, I can't begin to keep up with my flight packs most of the time.

Mike
06-24-2007 Over year old.
 
 
MJA
Key Veteran
Location: Cumbria-UK

Is the Align 2 in 1 the same thing as the Align 6A regulator
part RCE-B6X?
Does anyone know in what range the peak current draw would be,
with say your average 50 size heli useing a 9251/9256 and 3 digi 9252's plus a digital on the throttle,when all the control sticks are thrashed around ?

Also same for a 90 but with higher torque cyclic servo's?

Reason for asking is i have up until now used Duralite regulators but have just got some Align 6A regs , wondered if they would be upto the job on a 90 sized heli and generally how close to the max 6A it gets

I could measure the current draw myself but thought ball park figures for this sort of test would have been noted already somewhere.



Martin
06-24-2007 Over year old.
 
 
LDR
Senior Heliman
Location: Sarcoxie, MO

How many of you are actually using the 2in1? I would like to know if its working well, and how well its holding up.

Shakin like a dog... $hittin peach seeds
06-24-2007 Over year old.
 
 
cricket
Senior Heliman
Location: scottsdale az

works great.
06-24-2007 Over year old.
 
 
Ace Dude
Elite Veteran
Location: USA

Quote 
Heh. Big Charger is ghetto lab power supply. 3 Large PC power supplies with the 5V rails series up for 15V for my 4s packs (you can safely overshoot the voltage a little. A123 does it themselves). 12V rails tied together for 10S. Just hook up the wattmeter, and let her rip

Is that a current limiting power supply? Or does it rip at whatever current the power supplies can put out?



06-24-2007 Over year old.
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

Current is limited by the voltage differential between charger and cell. Initally I put a VERY large (300w) .8 ohm variable resistor inline to limit current. I slowly reduced it until I was comfortable with the current level. You really don't need it. My supply limits the current to around 60A (it cuts) If the cells have a normal depletion level (say 12V on a 4s pack) hooking them up raw will pull around 40A for a few seconds then the voltage rises in the cell so we sit around 27-30A for the bulk of the charge pushing 15V. To get more current you'd have to raise the voltage further. (which is what the cc supply would do)

They are a really neat cells in that the discharge curve is so steep on both ends. Voltage rise is immediate and very flat to limit current even with only a CV stage. The peak at the end also cuts current very quickly so there isn't a bunch of time wasted floating around waiting to get that last 5% in.

The charge model is closer to current limited CV than CCCV. We just let the current drop over time instead of keeping the voltage up to ram more. The flat curve means this keeps us pretty close to the CC model any way. They do get slightly warm when charged at these rates, A123 brags about 2 minute charges, but they also mention controlling temps at those levels.

I just like to know first hand what they are capable of. There really isn't a need to go to these extreme levels day to day. But if I KNOW they can charge safely over 40A. Then I can be moderate and feel pretty comfortable at 10A or 20A. It was a fun set of tests.

Mike
06-24-2007 Over year old.
 
 
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Align T-REX 600N 700N > Voltage Regulator: Align 2 in 1 or Fromeco?
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