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NiMh vs LiFe. What are the advantages and disadvantages?


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I use these at £12 a pop https://www.vapextech.co.uk/66v-1000mah-life-rechargeable-battery-vapextech

 

Well made reliable packs, nothing to do with Vapextech, just a satisfied customer.

 

I have bought £5 - £6 packs on eBay but they don't seem to be around at the moment.

 

I can't see what all the fuss is about with LiFe packs. They work and they work well. They don't self discharge like LSD cell's and they deliver the power unlike LSD's.

 

Fit them and fly them.

 

 

 

 

 

 

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Don, I am with you there. At an F3A comp. we may have had to have five ten min. flights on a 500 mA/hr DEAC when necessary. No chance to recharge either. A 700 Life would have been a godsend in those days and I often fly on one now.

People here seem to still be talking about discharging to 2.95V/cell as if they were Lipos. Forget it and simply do not bother with a discharge test at all since these are a different type of chemistry altogether. You will be surprised at how little you can get back in after several flights compared with NiMis of the same capacity.

 

Regarding HV servos, it is my guess that these simply have a regulator built in to take them down to a lower voltage since one of my models with four aileron servos has two HV and two normal. They all operate at the same speed.

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11 hours ago, Martin McIntosh said:

They self is discharge enough to worry a modeller after a week.

 

They lose between 1% and 2% charge in a week.

 

From a series of good tests found here: http://www.stefanv.com/electronics/sanyo_eneloop.html

 

Where the retention was measured up to a month (six month & year were predicted).

 

Time Period Charge Retention Charge Loss
Day 99.8% 0.2%
Week 98.7% 1.3%
Month 94.3% 5.7%
Six Months 70.2% 29.8%
Year 49.3% 50.7%

 

 

8 hours ago, Martin McIntosh said:

Forget it and simply do not bother with a discharge test at all since these are a different type of chemistry altogether.

 

Discharge to the right voltage for LiFe (2.5V I believe) and such a check will be perfectly valid.

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Sorry Nigel but I just do not believe those figures. On the many packs I have and had in the past I can usually get about 100mA/hr back in after a short break. I always leave them fully charged after use. I am probably simply being over cautious here but I do it for peace of mind and to ensure that a cell has not died, which has happened in the past.

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