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-   -   LiFe or NiMh? (https://www.rcuniverse.com/forum/batteries-chargers-84/11639284-life-nimh.html)

Therapy 05-28-2017 07:15 AM

LiFe or NiMh?
 
Please help. So confused.
First the usual background. I am returning to the hobby after a 22 year absence. At that time, NiCd's were it and only it. Now there is multiple battery types to choose from.

Absolutely, in no way whatsoever will I go and burn my house down by purchasing LiPo's. Please please don't even try to mention it. NOT happening here. Not worth it.

So in collecting parts, I purchased NiMh packs for my receivers but now i'm not so sure. After reading a similar thread here, (but didn't want to hijack it) I read about LiFe batteries.

My question is, do these have the same fire hazard as LiPo's and how difficult is it to maintain them? (I admit that that even a common toaster is fire hazard)

Further, how do I load check these at the field. I was just getting ready to purchase Hangar 9 volt checker but stopped to be sure what direction I want to go. https://www.horizonhobby.com/digital...ltmeter-han171

Please respond to me as if I am very electronically challenged. I won't be offended.

Rodney 05-28-2017 07:27 AM

To answer all you questions here would take a long post. You best bet is to just query the net for "proper care of LiFe", or similar questions on Google; you will find a lot of good info; probably enough to keep your studying for hours. All types of batteries have their advantages/disadvantages and all "including NiCad" still have there place in the industry. If you have a Model airplane club near you, visit and you may learn a lot.

Therapy 05-28-2017 07:55 AM

I just joined a club but have not visited yet. Thank you.

I did find this great link though.
The A123 FAQ for Giant Scale and IMAC

Probably my main question is, fire hazard or not so much?

Rodney 05-28-2017 12:31 PM

Any battery is a possible fire source. If charged, they hold a lot of potential energy and if that is release suddenly (short circuit) there will be a lot of heat. What makes LiPo's a bit less tolerant of abuse is that they do not need an outside source for oxygen so can even burn under water: not likely but possible. Properly stored and cared for, LiPo's are as safe as Pb batteries.

Therapy 05-28-2017 12:41 PM

Agreed. But as stated in original post, I will not debate that. Wife says no LiPo's on our property. Happy wife, happy life.

Rv7garage 05-29-2017 05:45 PM

I've converted entirely to A123 packs for my planes, field box, etc. Love them!

warhwk 05-30-2017 11:03 AM

Therapy,
I continue to use NiCd and NiMh, although I am slowly switching over to LiFe. Perfectly fine to use if you understand their limitations. See this thread for more info.

http://www.rcuniverse.com/forum/batt...ate-batts.html

elmshoot 05-31-2017 02:04 PM

Go to Hang Time hobbies and read their discussion about LiFe batteries. Or google Red Schofield he is brilliant on hobby batteries. I have converted all my airplanes to LiFe. hobby King makes them and at about $4 a pack for the Zippy 700 Mah pack its a no brainer. The only caution is that if you have servos left over from your first foray into RC 20+ years ago you "might" run into a servo that doesn't like the extra voltage. I have some high end Helicopter servos from 20 years ago that get real nervous on the higher voltage but current production servos will be fine.
The Cellpro 4 is the perfect charger for these as you do all the charging through the balance plug and doesn't need the second chord to the pack.
You can't load check the batteries at the field, too flat of a discharge curve. Almost as safe as a 2 slice toaster.
Sparky

Therapy 05-31-2017 04:11 PM

Thanks for all the info! Great stuff.
I have decided to slowly switch my gear over to LiFe batts. I have 2 brand new NiMh packs to use until I get the hang of the LiFe requirements and get personally acquainted with a new charger.

All of my equipment is new. I sold all equipment 22 years ago when I got out of hobby. Absolutely everything. (idiot) Except for my Dremel. (idiot with potential for greatness! lol)

SwampFlier-RCU 06-08-2017 08:30 AM

On the high side, but the Hitec X4 PLus will take care of your charging needs for years to come
TowerHobbies.com | Hitec X4 Plus 4-Port AC/DC Multi-Charger/FREE USB Adapter Cable

Regards
Patrick

Therapy 06-08-2017 04:20 PM

What are the thoughts on this charger? Remember, I am not that versed on electronics. Seems like it will do it all. I don't need blazing fast charge times. I like this.

https://www.horizonhobby.com/helicop...harger-vnr0684

elmshoot 06-10-2017 08:06 AM

Every charger that (I have seen) is in the LiPo charging business require you to plug in the power leads AND the balance plug if you want to do Balanced charging. EXCEPT ONE.
Cell Pro 4 ..... I've been using it for 5 years and ONLY charge through the balance plug. It has presets for the LiFe 1100 and 2300 Mah balanced charging. If you choose you can program in any other setting.
I charge my 700 Zippy on the 1100 setting at 1 Amp.
Results count. I am the twice defending National Club 40 pylon racing Champion.
Simple is good!
Sparky

Therapy 06-10-2017 11:12 AM

Wow! That looks like a very versatile charger! And at a great price! Currently tops on my list. Thank you very much for your input.

How dummy proof is it?

I will contact them regarding what type of connectors I will require to charge both NiMh and LiPo packs.

Rodney 06-12-2017 08:14 AM

I am also a fan of the FMA Cell Pro. Even though it will only charge through the balance connector (which limits the maximum charge current by the smaller size of the balance wires) it seems to give me the best results with my LiFe cells. Where I need faster charge rates I fall back to my Hitec chargers.

kdunlap 06-13-2017 02:32 PM

I run several LiFE packs for receivers and have good results. The main disadvantage is lower energy density and a low discharge rate. Neither of which should be a problem with a receiver pack. -Assuming of course you are not running a bunch of high draw digital servos on a crazy monster 3d machine. There you may need a LiPO. My advice is to just run cheap NiCDs on a cheap charger. The LiFE will add up. But I am going to say this as well. LiPO batteries are not inherently dangerous. People who don't monitor them while charging, use a cheap knock off charger, crash and reuse them are inherently dangerous. BTW you can short a LiFE receiver battery just as easily as a LiPO and burn your skin off. Don't get complacent just because it is a LiFE battery.

Also, just to follow up, LiFE do not have the same fire hazard as a LiPO. But they can short circuit and cook wires as effectively as LiPO and the short can cause the fire.

Therapy 06-14-2017 12:28 PM

Thank you both for your replies. I have decided to run the NiMh for receivers this year as they are brand new. Trying to find a LiFe pack for my T6J transmitter. But I now know enough from the responses here to purchase a decent charger to charge both type packs.

sirrom 06-15-2017 07:26 AM

I am going to mirror what everyone here has said. I have completely migrated all my planes to what is known as LiFe batteries and wherever possible I try and use TRUE A123 cells. Example my Jets all run A123 batteries except for 1 where I had to use LiFe packs for their size. My giant scale planes all run A123 cells for their durability, charge rate, and known for being an excellent cell. A123 cells are really a robust cell that can take up to a 10c charge if needed.
Also I will have to throw a nod to the CellPro line of chargers. I currently own the CellPro4 and two CellPro 10s'. All my giant scale planes have 3 packs in them with the cellpro4 and 10s going at the same time I can have a plane fully charged in about 20 mins. Most don't need that but just showing how reliable and versatile you can get with the cellpro chargers.
This is probably not where you are right now, but think about your purchases now as you move forward. I have the Hitec Charger as well, but really prefer my CellPro chargers more. Just make sure when you buy a charger look to the future of what you may need. I bought the CellPro4 before I was flying giant scale and charging one pack at a time isn't to bad when you only have 1 or 2 to charge, but a typical day of going flying for me and my son now is 2 Giant scale planes, a jet, and usually an electric plane or two. Also get your self a good clean power and high capacity power supply to run your charger(s). If you are charging 2 or 3 packs at 4amps each you will need a power supply to keep up.

patrick

mushia 06-16-2017 10:05 PM

I only know that most people here use Lipo Batteries. :o

Four Stroker 06-17-2017 04:48 AM

A few comments on charging through the balance lead on 2S LiFe. I use A123 2500 mAh packs on everything.

1) Any charger will do balance lead charging if you make a simple harness. Buy a 3-pin balance lead and two banana plugs, + to + and - to - and center balance tap direct to pack . Plug in both to charger. Put appropriate lead to pack. Be careful when you plug in this cable!

2) Balance lead charging will terminate prematurely because of the voltage loss in the cable . The voltage at the balance circuit is low due to voltage loss in the cable at some Amps - Ohms law stuff. Use a charger that ratchets down the charge rate - slow balance charge mode. But always use balance mode.

3) Crimps are not what they used to be - old man stuff. Back in the days of Kraft, RS, EK, etc. connectors were aerospace barrel crimps over tinned wire. Today you have commercial crap quality folded crimps over bare copper. Bare copper wire can oxidize on the shelf. The insulation can react with the copper - black wire syndrome. I have MEASURED voltage drops of 1 volt at 2.5 Amps in a big brand crimp. Why is this important ? If you are charging through the balance tap, which I always do, the charger will try to balance the pack (2S here) based on the voltage it sees. This can be off quite a bit because of crimps. The charger will then UNBALANCE your pack. For example, if one power lead + or - has a bad crimp and the other one doesn't, the charger will think the bad crimp cell is low and try to charge it up to the voltage of the other cell. Then it generally goes nuts and an hour later is still not done. I cut off all of the crimped balance plugs and replaced with Deans micro 3-pin soldered connections. Just saying that if you have a pack that won't balance charge through the balance lead, it is probably the crimped connector - charger cable OR pack.


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