Which batteries and why? How about LiFePO4 for DLG?

tai626 · Oct 21, 2009, 07:30 PM

I have been scratch my head for a while: which rx batteries for my first DLG?

I have flown RC for 3 years now and all powered: Glow and electric. I use exclusively NiCd and A123. No NiMH, no lipo and no primary batt, at all.

There is a good thread about NiMH, lipo and primary cells:

http://www.rcgroups.com/forums/showthread.php?t=1044988

NiCd is not option: 120mAh per 34g.

I have found some alternatives:
1-RCR123 600 mAh from K2: http://store.peakbattery.com/lfp123a...r-lithium.html

rcg review here: http://www.rcgroups.com/forums/showthread.php?t=868243
Pro:
LiFePO4;
No regulator needed.

cons:
heavy: 34g, at least;
DIY.

Edit:
according to this result: http://www.rcgroups.com/forums/showp...&postcount=118
I've chosen this LiFePO4 for my first dlg:
dlg: Topsky1;
Receiver: Hitec Electron 6;
Servos: Eflite S75 all around;
Batt: 2s K2 Energy 600 mAh rcr123a.

There are other lifepo4, cheaper but I would not consider on my airplane:
http://www.dealextreme.com/details.dx/sku.4419
(what??? 1000mAh!!! You right :-)

2-MAXIRACE HW 25C-330 mAh: http://www.maximus-racing.com/fr/330mah_-_20c.html
rcgroups review here: http://www.rcgroups.com/forums/showthread.php?t=1078049
Pro:
LiFePO4;
light.

Con:
Not available yet;
DIY.

3-Another LiFePO4: Hyperion...http://aircraft-world.com/shopexd.asp?id=6764

Part#HP-FG305-0850
TYPE: 2S 6.6V "flat"
Capacity: 850mAh
Max Current Continuous: 4.25A
Max Charge Rate (4C): 3.4A
L x W x H (mm): 54.5 x 29.5 x 15.4
Weight (g): 48.8

Pro: Available!
LiFePO4

Con:
Heavyyyy
size

Sooooo, Which batteries and why?

kcaldwel · Oct 21, 2009, 08:01 PM

Quote:

Originally Posted by tai626

I have found some alternatives:
1-RCR123 600 mAh from K2: http://store.peakbattery.com/lfp123a...r-lithium.html

rcg review here: http://www.rcgroups.com/forums/showthread.php?t=868243
Pro:
LiFePO4;
No regulator needed.

cons:
heavy: 34g, at least;
DIY.

Those K2 cells look interesting. I had tried some Tenergy LiFePo4 cells previously, with the intent of using them in a DLG. The capacity was less than half their spec though, so I returned them.

http://www.rcgroups.com/forums/showt...hlight=lifepo4

It looks like the K2 cells actually test to a reasonable mAh. I'm not sure there is any test numbers for the 600mAh cells there?

34g for 600mAh at 6V with no regulator, and no LiPo worries, would be OK with me.

Kevin

John255 · Oct 21, 2009, 08:02 PM

Tai,
Glad you started this thread. Should be interesting.

I'm still studying your links. Some look promising. Greater safety with high capacity would be welcome.

I've used primary cells for nearly five years and enjoy the advantages, but always leave the door open for something better.

http://www.rcgroups.com/forums/showthread.php?t=966437
Regards,
John255

tai626 · Oct 21, 2009, 08:11 PM

Quote:

Originally Posted by kcaldwel

Those K2 cells look interesting. I had tried some Tenergy LiFePo4 cells previously, with the intent of using them in a DLG. The capacity was less than half their spec though, so I returned them.

http://www.rcgroups.com/forums/showt...hlight=lifepo4

It looks like the K2 cells actually test to a reasonable mAh. I'm not sure there is any test numbers for the 600mAh cells there?

34g for 600mAh at 6V with no regulator, and no LiPo worries, would be OK with me.

Kevin

K2 is the second highest peak after Everest... Ops let's me rephrase it:
k2 is the second best after A123 :-) Since A123 can't be found smaller than 18650, I go to the second best. Still trying to search for its retailer. $10 shipping for 4 cells is not cheap...

tai626 · Oct 21, 2009, 08:19 PM

Quote:

Originally Posted by John255

Tai,
Glad you started this thread. Should be interesting.

I'm still studying your links. Some look promising. Greater safety with high capacity would be welcome.

I've used primary cells for nearly five years and enjoy the advantages, but always leave the door open for something better.

http://www.rcgroups.com/forums/showthread.php?t=966437
Regards,
John255

I am just looking for something different here. Not sure if it will work or not. That why your experience is valuable.

kcaldwel · Oct 21, 2009, 08:20 PM

Quote:

Originally Posted by tai626

K2 is the second highest peak after Everest... Ops let's me refrase it:
k2 is the second best after A123 :-) Since A123 can't be found smaller than 18650, I go to the second best. Still trying to search for its retailer. $10 shipping for 4 cells is not cheap...

Well, you could live in Canada, and pay $15 shipping, and then have UPS charge you $65 to bring your 4 cells across the border! If they won't ship USPS, I won't be getting any.

The Tenergy LiFePo4 cells are very cheap, and if they had even 500mAh capacity I would have been happy. They told me they had never had anyone complain before, but I had 6 cells I think, and they were all the same, about 300mAh. I'm not sure if I just got bad ones, but I never tried again.

http://www.batteryjunction.com/rc375reliba.html

Kevin

tai626 · Oct 21, 2009, 08:27 PM

How about I sent you via Usps? We can split the shipping...

John255 · Oct 21, 2009, 08:28 PM

Quote:

Originally Posted by kcaldwel

34g for 600mAh at 6V with no regulator, and no LiPo worries, would be OK with me. Kevin

Kevin,
How about 34g. 1500mA, 6V. no fire hazard, no regulator, no balancing, no expensive individual cell charger, and no charging?

http://www.kodak.com/eknec/documents...7ec/K123LA.pdf
Regards,
John255

kcaldwel · Oct 21, 2009, 08:51 PM

John,

I've seen your thread. I'm not really keen on primary batteries. I like rechargeables.

I haven't had any issues with my LiPos. They hold a charge very well and are ready even if I haven't charged them recently. I can fly for hours with no concerns on the 450mAh packs I have now. I charge them at low rates, in the plane. Despite that, there is always the lingering thoughts of potential problems from a short or something, and the added complexity and failure points with a regulator.

The LiFePo4 cells look very good, if they had their rated capacity.

Tai,

I've mailed K2 to see if they will ship USPS. If not, I may take you up on your offer of forwarding some. Thanks!

Kevin

robert14 · Oct 22, 2009, 03:11 AM

in the netherlands allmost everybody's uses the GP ni-mh cells. for a 350mah pack you come about 28 grams. enough to fly a twister with allmost no lead in the nose for the cog

tai626 · Oct 22, 2009, 03:32 AM

I haven't used NiMH as receiver pack. Do you peak charge at field? At what rate?
Is the loaded voltage good indication of the batt gauge?

Here is the comparison of NiMH and k2 LiFePO4:
http://www.rcgroups.com/forums/showthread.php?t=914941

tai626 · Oct 22, 2009, 03:57 AM

Kevin:
You may try this one also. $6.00 per cell and $4.50 shipping, from Hong Kong.
http://www.cpfmarketplace.com/mp/sho...d.php?t=125353

Nominal Voltage : 3.2V
Capacity : 500mAH
Lowest Discharge Voltage : 2.0V
Standard Charge : CC 250mA CV 3.6V
Cycle Life : > 500 cycles
Weight : 16.5g

tai626 · Oct 22, 2009, 07:27 AM

Is the charging rate important for DLG?

If it is, this lipo is a good candidate:
http://www.allerc.com/product_info.p...oducts_id=4503

2s 7.4v 450mAh 29g and it can be charged at 5c or over 2 amperes!!!

tai626 · Oct 22, 2009, 07:32 AM

Regarding charging rate:

LiFePO4: 0.5C

NiMH: 1C

Lipo: 5C!!!

I really miss A123 here...

Fly2High · Oct 22, 2009, 07:51 AM

Quote:

Originally Posted by robert14

in the netherlands allmost everybody's uses the GP ni-mh cells. for a 350mah pack you come about 28 grams. enough to fly a twister with allmost no lead in the nose for the cog

I had batteries Plus make myself and others a few and the popular consensus of the GP 1/2AAA is that they are great.

Unfortunately for me, they closed the local Batteries plus. They are a chain but the nearest one is in N. Jersey!

Oct 21, 2009, 07:30 PM	#1
tai626 Registered User Join Date: Mar 2008 Location: San Gabriel Valley, CA Posts: 559	Which batteries and why? How about LiFePO4 for DLG? I have been scratch my head for a while: which rx batteries for my first DLG? I have flown RC for 3 years now and all powered: Glow and electric. I use exclusively NiCd and A123. No NiMH, no lipo and no primary batt, at all. There is a good thread about NiMH, lipo and primary cells: http://www.rcgroups.com/forums/showthread.php?t=1044988 NiCd is not option: 120mAh per 34g. I have found some alternatives: 1-RCR123 600 mAh from K2: http://store.peakbattery.com/lfp123a...r-lithium.html rcg review here: http://www.rcgroups.com/forums/showthread.php?t=868243 Pro: LiFePO4; No regulator needed. cons: heavy: 34g, at least; DIY. Edit: according to this result: http://www.rcgroups.com/forums/showp...&postcount=118 I've chosen this LiFePO4 for my first dlg: dlg: Topsky1; Receiver: Hitec Electron 6; Servos: Eflite S75 all around; Batt: 2s K2 Energy 600 mAh rcr123a. There are other lifepo4, cheaper but I would not consider on my airplane: http://www.dealextreme.com/details.dx/sku.4419 (what??? 1000mAh!!! You right :-) 2-MAXIRACE HW 25C-330 mAh: http://www.maximus-racing.com/fr/330mah_-_20c.html rcgroups review here: http://www.rcgroups.com/forums/showthread.php?t=1078049 Pro: LiFePO4; light. Con: Not available yet; DIY. 3-Another LiFePO4: Hyperion...http://aircraft-world.com/shopexd.asp?id=6764 Part#HP-FG305-0850 TYPE: 2S 6.6V "flat" Capacity: 850mAh Max Current Continuous: 4.25A Max Charge Rate (4C): 3.4A L x W x H (mm): 54.5 x 29.5 x 15.4 Weight (g): 48.8 Pro: Available! LiFePO4 Con: Heavyyyy size Sooooo, Which batteries and why? Last edited by tai626; Nov 07, 2009 at 02:13 AM.

Oct 22, 2009, 03:32 AM	#11
tai626 Registered User Join Date: Mar 2008 Location: San Gabriel Valley, CA Posts: 559	I haven't used NiMH as receiver pack. Do you peak charge at field? At what rate? Is the loaded voltage good indication of the batt gauge? Here is the comparison of NiMH and k2 LiFePO4: http://www.rcgroups.com/forums/showthread.php?t=914941 Attached Thumbnails Comparing NiMH and K2 dischargig at 1C 41.0 KB · Views: 60 Last edited by tai626; Oct 22, 2009 at 07:04 AM.

Oct 22, 2009, 03:57 AM	#12
tai626 Registered User Join Date: Mar 2008 Location: San Gabriel Valley, CA Posts: 559	Kevin: You may try this one also. $6.00 per cell and $4.50 shipping, from Hong Kong. http://www.cpfmarketplace.com/mp/sho...d.php?t=125353 Nominal Voltage : 3.2V Capacity : 500mAH Lowest Discharge Voltage : 2.0V Standard Charge : CC 250mA CV 3.6V Cycle Life : > 500 cycles Weight : 16.5g Attached Thumbnails 56.5 KB · Views: 43 80.6 KB · Views: 41 Last edited by tai626; Oct 22, 2009 at 06:53 AM.

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Oct 21, 2009, 08:02 PM	#3
John255 Registered User Join Date: Dec 2000 Location: Pensacola, FL, USA Posts: 2,763	Tai, Glad you started this thread. Should be interesting. I'm still studying your links. Some look promising. Greater safety with high capacity would be welcome. I've used primary cells for nearly five years and enjoy the advantages, but always leave the door open for something better. http://www.rcgroups.com/forums/showthread.php?t=966437 Regards, John255

Oct 21, 2009, 08:27 PM	#7
tai626 Registered User Join Date: Mar 2008 Location: San Gabriel Valley, CA Posts: 559	How about I sent you via Usps? We can split the shipping...

Oct 21, 2009, 08:51 PM	#9
kcaldwel Kevin Caldwell Join Date: Jan 2007 Location: Courtenay, BC, Canada Posts: 1,082	John, I've seen your thread. I'm not really keen on primary batteries. I like rechargeables. I haven't had any issues with my LiPos. They hold a charge very well and are ready even if I haven't charged them recently. I can fly for hours with no concerns on the 450mAh packs I have now. I charge them at low rates, in the plane. Despite that, there is always the lingering thoughts of potential problems from a short or something, and the added complexity and failure points with a regulator. The LiFePo4 cells look very good, if they had their rated capacity. Tai, I've mailed K2 to see if they will ship USPS. If not, I may take you up on your offer of forwarding some. Thanks! Kevin

Oct 22, 2009, 03:11 AM	#10
robert14 Registered User Join Date: Aug 2008 Location: Emmen, Netherlands Posts: 64	in the netherlands allmost everybody's uses the GP ni-mh cells. for a 350mah pack you come about 28 grams. enough to fly a twister with allmost no lead in the nose for the cog

Oct 22, 2009, 07:27 AM	#13
tai626 Registered User Join Date: Mar 2008 Location: San Gabriel Valley, CA Posts: 559	Is the charging rate important for DLG? If it is, this lipo is a good candidate: http://www.allerc.com/product_info.p...oducts_id=4503 2s 7.4v 450mAh 29g and it can be charged at 5c or over 2 amperes!!!

Oct 22, 2009, 07:32 AM	#14
tai626 Registered User Join Date: Mar 2008 Location: San Gabriel Valley, CA Posts: 559	Regarding charging rate: LiFePO4: 0.5C NiMH: 1C Lipo: 5C!!! I really miss A123 here...