2s Lifepo4 vs 5s NiMH

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2s Lifepo4 vs 5s NiMH

Postby carlossp » Wed Jan 16, 2013 5:46 pm

Dear all,

Is it safe to use 2s Lifepo4 in place of 5s NiMH?
The reason is I have a Futaba 6J transmitter that uses 5 NiMH and I would like to use a 2s Lifepo4 but I am not sure this will not cause damages to my TX.

Thanks for any comments.
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Re: 2s Lifepo4 vs 5s NiMH

Postby cynr100 » Thu Jan 17, 2013 2:01 am

A fully charged NiMH will test out at greater than the stated 6v and higher than a 2s LiFepo4 at 6.6v, if you have a multimeter test for yourself to alleviate any anxiety.
If you are concerned about the 0.6v stated difference I would recommend using a 2s A123 pack (good quality LiFe units at 3.3v).
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Re: 2s Lifepo4 vs 5s NiMH

Postby carlossp » Thu Jan 17, 2013 10:03 pm

Hi cynr100,

The 6J tx is design to work with 6V.
The 6J manual states that we can choose between 4AAA or 5NiMH.
I checked that 5 NiMH full charged can reach 7V for few time and a 2s Lifepo4 full charged can reach 7.2V.
Do you know what are the working (not nominal) voltage of 5NiMH and 2s Lifepo4?
I suppose both are around 6.6V but as I don't have any for testing I can't be sure the real value.

I know that it is a small difference but I don't know if this is a common tolerate difference for a Futaba TX 6J or it is advise to use a diode to reduce the excess of voltage?.

Thanks for your help.
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Re: 2s Lifepo4 vs 5s NiMH

Postby cynr100 » Fri Jan 18, 2013 4:52 am

If it was my radio I would give it a shot, but it is not and I would be forever regretting the demise of your Futaba on my roughhouse recommends.

Had a quick look at alternatives and would suggest this http://www.hobbyking.com/hobbyking/stor ... _Pack.html

and at 1/2 the price of the 2S LifePo4.
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Re: 2s Lifepo4 vs 5s NiMH

Postby carlossp » Fri Jan 18, 2013 6:48 pm

I just bought this battery
http://www.hobbyking.com/hobbyking/store/__23816__Turnigy_nano_tech_2100mAh_2S1P_20C_LiFePo4_Transmitter_Pack_Futaba_T14SG_.html
When it arrives I will try it first using a diode 1N4004 in series.
If I figure out that the diode is not necessary I will take it out.
I want play as safe as possible but if there is a possibility to move to a Life battery I will.
Thanks.
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Re: 2s Lifepo4 vs 5s NiMH

Postby cynr100 » Fri Jan 18, 2013 11:50 pm

Don't forget to let us know how it turns out, it all adds to the knowledge base of the forum.
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Re: 2s Lifepo4 vs 5s NiMH

Postby carlossp » Mon Mar 04, 2013 2:47 pm

Last week I decided to use the LiFePo4 I bought for use with my T6J.
http://www.hobbyking.com/hobbyking/stor ... 14SG_.html

The first time I turned the tx on, the voltage was 6.7v. After few minutes the voltage was 6.6v and at the end of the first flight the voltage droped to 6.5v.
Now, after 4 days of heavy use, the voltage is still 6.5v.

I am happy with the move.
I wanto to thank for the advise you all gave me.
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Re: 2s Lifepo4 vs 5s NiMH

Postby cynr100 » Mon Mar 04, 2013 8:17 pm

Happy that it worked out for you :D
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