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Author Topic: Li-ion 18650 4500mAh 3.7 volt batteries  (Read 2574 times)

coolbumble

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Li-ion 18650 4500mAh 3.7 volt batteries
« on: June 26, 2013, 08:11:33 pm »

Hi
Has anyone experience of using these Li-ion 18650 batteries? I have used Li-ion AA 3.7 volt in series to give 7.4 volt in a small Kilo and phone batteries in a revell U boat both worked fine.
I am building a Moebius 39 inch Seaview and thought I would try a pair of the Li-ion 18650 as again fitted in a battery holder gives 7.4 volt and 4500mAh  which fits nicely in the small WTC.
However on trials everything works ok but I run out of battery power in a few minutes. I believe
this model is reputed to run for 30 minutes on a Lipo 1300,mAh battery in the Caswell conversion and thought this would better the run time but NO.
I have tried other 18650 batteries and I have the correct charger.
I have no technical knowledge on batteries (is it that obvious?) so do I need to purchase a Lipo battery or ?
The hardware is a mini air pump 4 servos and two 280RS motors
advice welcome
My regards
Ian  :-))
Have tried loading photos without success To Big !!
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Mad_Mike

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #1 on: June 26, 2013, 09:44:58 pm »

what brand and where did you get yout batteries?
 
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coolbumble

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #2 on: June 26, 2013, 10:04:24 pm »

The batteries are UltraFire I got them from Hong Kong or China !
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Mad_Mike

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #3 on: June 26, 2013, 10:22:46 pm »

For starters chinese batteries state the mah higher on the lable than they're actual mah. For example if the battery says 3000 mah its in fact more closer to 1000mah.
When it comes to batteries buy the best you can afford. These genuine pansonics are 16 quid:
http://www.ebay.co.uk/itm/2x-Genuine-Panasonic-NCR18650A-Li-Ion-3100mAh-3-7V-Rechargeable-Lithium-Battery-/360682062455?pt=UK_ConsumerElectronics_Batteries_SM&hash=item53fa538277
They also state there maxium constant discharge is 6.2 amps and these quality batteries. You may find that the loading of your 2 motors 4 servos pump and radio is beyond that and if the mah rating is fake on your batteries you will get a few minutes.
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coolbumble

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #4 on: June 26, 2013, 10:37:13 pm »

 Hi Mike
Many thanks for your information 
As I stated I have similar hardware setup to Caswells WTC which uses a Lipo 1300mAh and reputedly runs for 30mins !! So I thought it should work but as you say possibly need better quality batteries I will try that
My regards
Ian
 
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Subculture

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #5 on: June 28, 2013, 06:43:17 pm »

The time given for 1300mAH batteries sounds fairly reasonable to me. genuine 4500mAh batteries should give you enough time to sail until you are thoroughly bored I would think.

Personally I find sufficient capacity to provide and hour of sailing time is usually adequate, but some keen folk may want more.

Snowwolflair

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #6 on: June 29, 2013, 08:35:04 pm »

For starters chinese batteries state the mah higher on the lable than they're actual mah. For example if the battery says 3000 mah its in fact more closer to 1000mah.
When it comes to batteries buy the best you can afford. These genuine pansonics are 16 quid:
http://www.ebay.co.uk/itm/2x-Genuine-Panasonic-NCR18650A-Li-Ion-3100mAh-3-7V-Rechargeable-Lithium-Battery-/360682062455?pt=UK_ConsumerElectronics_Batteries_SM&hash=item53fa538277
They also state there maxium constant discharge is 6.2 amps and these quality batteries. You may find that the loading of your 2 motors 4 servos pump and radio is beyond that and if the mah rating is fake on your batteries you will get a few minutes.




I think this is far too general.  I have bought batteries from the Far East for years and when I test them, which I always do, I have found them up to spec.  One caveat, if its obviously too cheap don't buy.
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Subculture

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #7 on: June 29, 2013, 10:09:41 pm »

I usually purchase my lipos from Hobbyking. They're great batteries, and they give a limited warranty, and the price is very fair.

essex2visuvesi

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #8 on: June 29, 2013, 10:25:58 pm »

I have bought lipos from many sources on ebay (most of which were way under the claimed specs) and agree with Subculture, Hobbyking is probably the best place for serviceable batteries at a wallet friendly price
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coolbumble

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #9 on: June 30, 2013, 12:38:05 am »

Thank you guys for all your valuable advice.
My query was brought about as I have bought AA and AAA rechargeable batteries from the east an had no problem it is the 18650's that I bought for the Seaview that have let me down.
Also  being non tech on batteries is there any difference in the performance of a Lipo and a
Li-ion of the same mAh?
I've now bought a Lipo 1300 mAh from a reliable source and also ordered a pair of 18650 Li-ion genuine Panasonic. It will be interesting to see how they both perform
Will keep you informed
My regards
Ian  :-))
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Mad_Mike

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #10 on: June 30, 2013, 09:40:26 am »

A lot of the chinese manufacturers dont have QC measures. Its basically the luck of the draw if you get a good battery or a bad one.
The current that your sub will be pulling will be higher than 18650's can actually supply, despite their claims.
 If they were genuine quality articles they will do what they say on the tin.
Li pos can supply a higher current than li ion. They both have their pros and cons
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Subculture

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Re: Li-ion 18650 4500mAh 3.7 volt batteries
« Reply #11 on: June 30, 2013, 07:13:13 pm »

A rule of thumb I use for lipos is to half the given 'c' rating. So for instance if a 1A pack is rated at 20C (or 20A current), then i would use that at a maximum of 10C.

The other thing I do, is to always bring lipos in well before they are due to cut off for low voltage. Lipos last longest if they are run between 20-80|% of their capacity. that's a tip from the 1:1 electric car boys.
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