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LiPo experiences


#1

During my Ardennes activation I tested my LiPo-packs for the first time.

It is super.

I bought two LiPo packs with 5Ah capacity with 4 cells (4S) = 14,8V , with 15C max. discharge current.
A low C is enough for radio, I do not need more than 15*5=65 Amperes I guess. Max. charge current is 2C, so you can charge them with 10 Amp in a ½ hour if you are in a hurry. ( Cells over 45C are sold also !!! )

More than 5000 mAH is relatively expensive. Better buy two instead.

This equipment is often sold in RC ( Remote Control ) shops, they sell RC- airplanes, cars etc.

I also bought a special charger with 12V DC/100-240 VAC input capable of safely charging almost every type of battery ( Pb, NiCd, NiMH, LiPo etc. ). You always need a special charger charging LiPo.

During use I monitor the voltage with a special monitor with visual and audio alarm. LiPo batteries may never be discharged below 2.75V.

I use a small plastic box for save storage. ( LiPo ,cell monitor and connector inside ), via a hole with a thick wire to the transmitter.

My FT-897D uses 13.8 VDC ±15 %, so with 4 cells (14,8V) I do not exceed the max. voltage.

My old lead ( Pb) battery 7Ah has a weight of 2660g, size 151 x 95 x 65 mm.
Lipo 14,8V 5Ah has a weight of 475 g, size 143 x 51 x32 mm.

Remember that the LiPo batteries can be very dangerous if used in the wrong way.

On the Internet there is a lot of info e.g.
http://prototalk.net/forums/showthread.php?t=22

My conclusion so far:
Weight and volume only 25 % of similar PB battery
Easy to charge and monitor
Nearly flat discharge curve
I guess the high end voltage ( 12,0V is save ) means constant output power until the end.

Price:
PB 12V 7AH more than 20 EURO, LiPo 14,8V 5AH abt. 33 EURO.

Pictures:
At my site: http://www.smitzeewolde.nl/index.php/2012/07/08/use-of-lipo-batteries/

I hope this info can be useful to you.

73 de Hans PA3FYG/P

*** I updated info on July 15 *******


#2

In reply to PA3FYG:
Hello Hans…
thank you for the detailled information…
Indeed the new battery technology is also useful for SOTA.

73 de Franz ON9CBQ


#3

In reply to PA3FYG:

Thanks Hans for your report. Am using a 4S1P 2400mAh LiPo from the same vendor for several years. Since my ATS-3B only draws 600mA, the fully charged battery covers many activations without being recharged.

A careful comparison of voltage ranges (LiPo, TRX) is recommended before deciding for a specific LiPo configuration. I went for a 4S and a low-drop 12V regulator because I can use the full LiPo capacity at constant TX power.

2 comments:

IMHO, a plastic box is not an adequate protection. My LiPo never ever leaves its “LP-GUARD” fireproof bag.

A fused cable between battery and load is a must, given the high current capability of the LiPo.

vy 73, Markus HB9BRJ


#4

In reply to HB9BRJ:

Tnx Markus for the reply,

Ur right about the plastic box, I get it out the fireproof bag during activation only.( to look at the meter )

I think most of the spectacular stories and YouTube movies are result of extreme use during RC. In normal use the danger is not so high.

Yes fuse is needed for sure.

73 de Hans PA3FYG


#5

In reply to PA3FYG:
HI HANS
YOU WILL NEED TO REDUCE THE FULL CHARGE VOLTAGE OF 16.8 V DOWN TO 13.8V.
IF YOU LOOK AT M6UXH PHOTOS YOU WILL SEE MY PLASTIC BOX WITH LI-PO + VOLTAGE REGULATOR .
COLIN G4UXH


#6

In reply to G4UXH:

TNX info Colin. I can not find ur picture.

Please more info abt the regulator.

I guess a bridge rectifier or one power diode can do the job also.

13,8V +15% is 15,9V.

When I have a full LiPo the LiPo alarm measures 16.50 V, on the FT897 display 16.4V. ( Recieving )

Please comments.

73 de Hans PA3FYG


#7

In reply to PA3FYG:

Have a look at this topic Hans.
http://live.sotawatch.org/reflector.php?topic=3844#

There may be other threads on the reflector as well as quite a few of us use LiPo batteries.

73, Gerald G4OIG


#8

In reply to G4OIG:
hi HANS
GO TO MORE PHOTOS M6UXH YOU WILL SEE THE BACK OF MY HEAD THE BEST (SIDE) UNDER FT 857 PLASTIC BOX WITH LI-PO + REG 2-POWER TRANSISTORS MOUNTED ON ALLOY BOX HEAT SINK SMALL CIRCUIT INSIDE.2 TRANSISTORS WILL HANDEL 10 AMPS RUNS QUITE HAPPY 20W -50W SHORT BURSTS AT 90W BUT GETS VERY HOT.

             73 COLIN G4UXH

#9

I Have been looking around on the new battery technology.
For the yaesu 817, a 3-cell Lipo will do the trick, but using a 857, the voltage should be betveen 11,8 and 15,8.

What about the LiFePO4?
according to the manual of mye charger, the have standard voltage of 3,3V, Max charge voltage cut off level 3,6V, and min discharge voltage cut off level 2,0V.
At 10% capacity the should be on about 3v pr cell.

So a 4p cell should start right under 14,2, standard voltage at 13,2, and be at 12v at 10% capacaity, then its time to go home…

The only problem, is that they dont seem to like cold weather, -20C, theyre just as usefull as a lead weight


#10

In reply to LA5XTA:

What about the LiFePO4?.. The only problem, is that they dont seem to like cold weather…

Well Erik, we all know and appreciate the benefits of LiFePO4 over LiPo in terms of voltage compatibility, safety, etc., but our wallets won’t open whenever we want to purchase them. :wink:

73, Gerald G4OIG


#11

In reply to G4OIG:
I know, like the buddiepole batteries.

But have a look at hobbyking, i have never tried these batteries, and cant say anything about the quality, but the price looks right.


#12

In reply to LA5XTA:
I do not know how the LiFePO4s of Hobbyking are, but I have purchased a Turnigy 3S1P LiPoly with 4000 mAh. Since February 2011 it has been working fine in about 40 activations. I am using it with a FT-817 and a mean activation uses 500 to 1000 mAh.

73 de Michael, DB7MM


#13

In reply to DB7MM:
Seems like the LiPo cells from HK gets good reviews, but not the LiFePO.


#14

In reply to LA5XTA:
My opinion, if you want power on the summit then you need LFP. If you want to save “significant” weight go with LCO. Li-Polymer is not a battery chemistry.

LFP is in fact much cheaper than LCO (LiPo) if you factor in life cycle!

Some figures:

         | LFP (LiFePo4) |  LCO (LiCoO2)

En. Density | 120Wh/Kg | 200Wh/Kg
Life | ~2000 cycle | ~500 cycle
Voltage | 3.2 | 3.7

I use LFP during my activations as I prefer to do VHF DX. However not so much DX so far :smiley: I think I need the available 50W on VHF from my 857, so I went with LFP. I have not used it below -10 C so far, where it suppose to loose half of its capacity.

Here are some readings:
http://batteryuniversity.com/learn/article/the_li_polymer_battery_substance_or_hype
http://batteryuniversity.com/learn/article/types_of_lithium_ion

Stay happy!
Peter


#15

In reply to HG1DUL:
Thanks!
To bad about the capacity of LFP in cold weather.


#16

In reply to HG1DUL:

My opinion, if you want power on the summit then you need LFP. If you
want to save “significant” weight go with LCO. Li-Polymer is
not a battery chemistry.
This is your very personal opinion. Cell phone producers with an output of 100’000 units a year do not share it.

LFP is in fact much cheaper than LCO (LiPo) if you factor in life
cycle!
Assuming 250 real cycles of a LiPo and the maximum of 25 activations I did last year I will be able to use it for 10 in words TEN years. Ok, 1000 cyles of a LiFePO4 will last me 40 years. Well, I hope I will be able to go for SOTA when I am 75 years old. Probably I will not be able to use the promised 2000 cyles being 115 years old by then. :wink:
Do not forget all Li-batteries degrade with life time independend from the number of cycles so the calculation above is not too serious.

Hobbyking prices:
ZIPPY Flightmax 4000mAh 3S1P 20C (DE Warehouse) 17.35 €
ZIPPY Flightmax 5000mAh 3S1P 30C (DE Warehouse) 29.79 €
ZIPPY Flightmax 4200mAh 4S1P 30C LiFePo4 Pack (DE Warehouse) 43.84 € (lower cell voltage requires one cell more)

I do not mind spending 25 € more for 4 LiPos than for one LiFePO4 during ten years while spending 2000 € for fuel in order to reach SOTA summits in the same time.

Of course this is all based on my personal way of doing SOTA. Activators working with 50 W and doing 100 activations a year will calcultate a differently.

73 de Michael, DB7MM


#17

In reply to all:

Thanks for all reply. Seems to be interesting subject.

I changed some info on my site and placed new pictures.

To reduce the voltage a bit I made an inserter with a diode in serial in the cable. As soon as the voltage droppes enough I can remove it. Better save than sorry.

I also made an insert with a fuse inside to be used if power wires are unfused.

I store my LiPo box in a LiPo bag, only take it out when I want to read the voltage onthe LiPo alarm.

More details on my site:http://www.smitzeewolde.nl/index.php/2012/07/08/use-of-lipo-batteries/

73 de Hans PA3FYG


#18

In reply to all:

Hi all,

Thanks for this good info. Presently I need much less power for my K1 :slight_smile: so I was able to buy Li-Ion pack (25 Euros including adapter and shipping)

http://www.409shop.com/409shop_product.php?id=104953

Although meant for low discharge currents it keeps on working great for my K1.

Cheers,

Wil