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Author Topic: 7.2v 6800 Ni-MH from Hong Kong  (Read 6355 times)

Bluechrisp

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7.2v 6800 Ni-MH from Hong Kong
« on: June 24, 2011, 09:50:14 PM »

Evening all,

I've been using these and others for awhile, the latest bought 2 for 27.00 post and P&P free, charge up to 8.3 volts their very good, no complaints from me.  :-))

CP
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DickyD

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #1 on: June 25, 2011, 08:44:16 AM »

Very good, are you going to let us know where you get them from ?
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essex2visuvesi

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #2 on: June 25, 2011, 09:04:48 AM »

yes please tell.... I could do with some for the boys RC cars
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ACTion

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #3 on: June 25, 2011, 09:32:43 AM »

Not wishing to be a wet blanket or to suggest that anyone has in any way been duped, but there are  some NiMH cells on the market from that area which are vastly over-described as far as their capacity is concerned. For example, unbranded AA cells advertised as 3800mAH and sold on 'a well-known Internet auction site' @ 3.99 each have been tested and the best that could be obtained was 720mAH. Sanyo are the acknowledged world leaders in battery technology of this type, and if they haven't yet managed to make AA NiMH cells higher than 2900 mAH then how can an anonymous (Chinese?) company make cells which are 33% more efficient?
I'd be interested to know if these particular cells - presumably Sub-C sized - have been tested and also what maximum current they are capable of supplying. The price alone makes me very suspicious........ Caveat emptor strikes again?
DM
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Netleyned

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Mankster

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #5 on: June 25, 2011, 11:42:13 AM »

Ah.. 3800mAH not 6800mAH! Thats pretty standard stuff. Around 12 a pack if you were to buy in the UK.

Netleyned

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malcolmfrary

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #7 on: June 25, 2011, 12:10:56 PM »

It has been noted in the past that Oriental amps are a lot smaller than ours for the purpose of putting overly optimistic numbers on ESCs.  The same philosophy could govern batteries.
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ACTion

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #8 on: June 25, 2011, 12:20:09 PM »

Ah.. 3800mAH not 6800mAH! Thats pretty standard stuff.
Not in AA size it isn't!
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Mankster

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #9 on: June 25, 2011, 12:25:40 PM »

Not in AA size it isn't!

Was refering to the original link posted by Netleyned which were for sub C cells.

ACTion

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #10 on: June 25, 2011, 01:58:00 PM »

Was refering to the original link posted by Netleyned which were for sub C cells.
Ah! So it were. My humblest apologies.
DM
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ben hall

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #11 on: June 25, 2011, 06:00:57 PM »

go to component shop good quality and cheap
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Bluechrisp

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #12 on: June 25, 2011, 07:50:29 PM »

Evening all,

All daily tasks completed, now to converse with fellow model boaters, I chose these as I wanted to pair these up so creating 14.7 volts and a long endurance (well lets find out later) with the Darke Horse on my Sea Queen, making sure I used Dave's P103 parallel Power Board... Having bought some from HK before and they keep performing, I bought some more, Low price no P&P. My choice as they say, it's a open market..  :-) They fit nicely between the prop shaft, I did look at others with higher capacity but they wouldn't have fitted.
 
Well tomorrow I'll be out on the pond and I'll see what they do in the Tsoaka, I'll try to do a kind of, sort of scientific test   %)   {-)   %% one of these 7.2V 6800 running twin Graupner 500e motors a via 2 Mtroniks 15 amp ESC, I'll even use the water pump as well  :-)). see what run time I get...

I'll see what happens  O0

CP
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Bluechrisp

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #13 on: June 25, 2011, 07:57:18 PM »

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Netleyned

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #14 on: June 25, 2011, 08:04:41 PM »

It would be good to see the outcome
Run time with Tsekoa would give us all an idea how good they are


Ned
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essex2visuvesi

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #15 on: June 26, 2011, 07:34:39 AM »

Ive ordered some for the boys RC cars.
Currently they have Genuine Tamiya 1700 packs and some chinese 3800s

we get run times of about 6 mins on 17s and 10mins or the 38s

Ill report back when they arrive
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Bluechrisp

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #16 on: June 26, 2011, 01:37:41 PM »

Afternoon,

Just back from the pond, The 7.2v 6800 were charged upto or stopped charging at 8.3v on the Delta peak fast charger, The first battery went in, the Tsekoa was used  at full thottle on both engines for most of the time, except when drenching the wooden bridge, goes quite fast on 7.2 after 34 mins there was a real noticable difference in the speed and the twin water monitors all sprayed water abour 2 metres.

The pack was slightly warm as were the ESC's and engines, the voltage was down to 7.3V I don't have a amp meter, so couldn't measure that, the other pack lasted about the same amount of time with more fire fighting duies, the voltage was down to 7.2v. I can do science me!  :-))


I have used 6v 4.5a SLA they tend to last about 25 mins but no use of the water monitor.

In the next couple of weeks, we will use them on a Model Slipway Sentinal, this has the motors and set up as recommended on the site. so stay in touch!

So I leave you to make up your own concluesions.  O0


CP
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roycv

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #17 on: June 26, 2011, 07:23:29 PM »

Hi I bought some 3800 Ah cells a while back from Hong Kong and the seem to be about 2000 Ah  I had them in a Bobby with a brushless motor and the current (static) was just over 4 amps and the lasted about 30 mins.
Like someone said the China Amps are smaller but perfectly formed!
regards Roy
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Bluechrisp

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #18 on: June 28, 2011, 08:19:54 PM »

Hello,

Just doing some looking around like one does, it appears they use Japenese batts for their sticks/packs, is that good.  %)

CP
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john s 2

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #19 on: June 28, 2011, 08:28:32 PM »

Likely to be better than chinese. Every thing is built to a price Not everything made meets its spec. Downrated
computer chips end up in toasts washing machines etc. Less than perfect lcd screen end up in cheap tvs. Does
this happen to batterys that dont quite meet spec. Are they rebranded?.John. 
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Bluechrisp

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #20 on: June 29, 2011, 09:50:03 PM »

Hello John,

Yes your so right, i'll do some digging around. let you know what I find.  O0

CP
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BigA

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #21 on: June 30, 2011, 12:04:18 PM »

The Astec Models guy comments on some of the higher-capacity packs - it makes interesting reading!

http://www.astecmodels.co.uk/
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essex2visuvesi

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #22 on: August 29, 2011, 07:24:34 AM »

Ive ordered some for the boys RC cars.
Currently they have Genuine Tamiya 1700 packs and some chinese 3800s

we get run times of about 6 mins on 17s and 10mins or the 38s

Ill report back when they arrive

We did a quick comparison test using the boys RC cars

The 6800s gave a run time of around 15mins which they are happy with as thats about the attention span they have.  One thing we noticed tho was there is less drop off in power during the run.

They may not be true 6800Mah but the kids are happy and for the price so am I
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Bluechrisp

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #23 on: August 29, 2011, 10:43:29 PM »

Hi there,

So you got double on your other batts, What do you think, regards power and duration and how are you charging them? I'll be putting mine in to a twin electronize 543-23 motored USCG MLB, somewhen soon, I'll up date you.  O0

Cheers

CP
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essex2visuvesi

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Re: 7.2v 6800 Ni-MH from Hong Kong
« Reply #24 on: August 30, 2011, 07:01:59 AM »

Yes I'm happy with them and reccomend them for hobby use.... For the price they perform very well and as I said they seem to hold the power very well and certainly have more "Punch" than the standard tamiya racing packs.

Charging wise I use and genuine Imax B6 set to 1 to 1.5A, but the kids will also use the plug in wall wart type trickle chargers (when they remember lol)

I have never been a fan of fast charging batteries so tend to err on the side of caution when it comes to charging rates.
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