Battery capacity tester... hmmm?

[WillyChang]

How would one of these things work?? [8)]

Hands up who thinks 99% of ppl who see this pic thinks you can just "plug it to your battery and it'll readout 'capacity' instantly".

Misleading? [:I][|)]

[terry.sc]

Err...do you really want to know how it works?[?]

I'm sure most people would figure it out, surely?[8)]

For those who don't know you plug in a charged pack, and when the capacity meter has finished discharging it you get the read out of the batteries capacity. Simple really.[]

[WillyChang]

Ahh, I've seen ppl switch their multimeters to the "AMPS" setting then poked the leads right onto the battery... [:0][:0][:0] (spectacular stuff)

Anyone actually got one of these "Battery Test Mater" here?

(mate 2 packs and get a 3rd one??[])

What's inside the black box?? []

Thoughts are:-

1) where does all the heat go?

2) what is cutoff point... for running the battery to 0V will of course show more "mAh" than cutting off earlier at 5.4V (0.9V/cell).

[DJTheo]

quote:Ahh, I've seen ppl switch their multimeters to the "AMPS" setting then poked the leads right onto the battery... (spectacular stuff)

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Poor smoking multimeters ad batts... [:0][8)][]

1) where does all the heat go?

Propably a big resistor with a cooler

2) what is cutoff point... for running the battery to 0V will of course show more "mAh" than cutting off earlier at 5.4V (0.9V/cell).

Definately around 0.9V/cell, the other doesnt make sense as capacity is defined till discharged voltage not 0V, could get more then...

[WillyChang]

quote:Originally posted by DJTheo

1) where does all the heat go?

Propably a big resistor with a cooler

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Not sure, you think its inbuilt Theo?

quote:2) what is cutoff point... for running the battery to 0V will of course show more "mAh" than cutting off earlier at 5.4V (0.9V/cell).

Definately around 0.9V/cell, the other doesnt make sense as capacity is defined till discharged voltage not 0V, could get more then...

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Ahh, but this pix was from an ad selling the *battery*.

Now I don't know about you, but I've been checking out the stickers on "matched" packs lately... and surprise surprise there's a whole heap of different 'standards'. Some discharge at 20A, others at 30A - lower = more "runtime". Some stop at 0.85V, others at 0.90V = moe "runtime". Lovely sales puffery... [}]

[DJTheo]

quote:Not sure, you think its inbuilt Theo?

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Maybe you connect an external cosumer like resistor or motor to it?

quote:Now I don't know about you, but I've been checking out the stickers on "matched" packs lately... and surprise surprise there's a whole heap of different 'standards'. Some discharge at 20A, others at 30A - lower = more "runtime". Some stop at 0.85V, others at 0.90V = moe "runtime". Lovely sales puffery...

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So true, like cheap stereos with stickers 400Watt PMPO which are often less than correct 5W RMS at 8Ohm and <0.01 % distortion [8)][][!]

[terry.sc]

quote:1) where does all the heat go?

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Looking at the picture the battery seems to be sitting on the top vents - keeps it nice and warm!

My battery charger has a discharger built in with a capacity readout. The charger has a bank of resistors in it to discharge at 10 amps, and has 2 fans mounted in the back to remove all the heat.

[mr_lister999.]

Ok guys, i havea similar one, just another make. (cs electronic)

You set the number of calles on the screen and the cut off voltage you want (0.9V normally) Press the button and away it goes. The heat is transfered to 2 large heatsinks, one on the top, one on the back. They get very hot on full charged 3300 packs! The display then says the capacity, average voltage and shows the voltage at each 100mah interval. It details everything you want to know about your pack.

When i compared my normal racing packs to brand new packs it shows why some of the racing guys are so fast on the same equipment. Around 1 volt difference under 20 amp load which is loads of speed lost. I discharged a brand new top spec 3300 pack and the results were fantastic, it showed you do get what you pay for! I ended up buying all new cells when i saw how bad they were.

(I also tried my old 7.2 hump battery, lets just say under 20 amp load it fell below cutoff level instantly when fully charged!)

[WillyChang]

Wow, nice!! [^]

How much is one of those things worth??

Given the price for a Turbo35 charger... can't be cheap! []

[mr_lister999.]

My one was £95 but you can get others cheaper but i wanted something nice. I looked at it i will use it for many years so a bit more money is worth it for a good result. You can even connect it to your pc with a modification they sell which displays full graphs and stats of your pack. True proffesional stuff. Those of you at snetterton are welsome to look at it if you want

[WillyChang]

Wow, only GBP95? That's not bad at all!! It looks great, here:

http://www.cs-electronic.com/CS-Produkte/C...p_check_pro.php

Hmm, the POWER CHECK motor dyno looks handy too. []

Arrgh... also the Robitronics. [][]

[terry.sc]

If you want a serious charger /discharger try http://www.users.zetnet.co.uk/pro-trak/

As used by Surikarn Chaidajsuriya, the touring world champion.

Prices start at £200, and it can even give you the capacity and voltage of individual cells without dismantling the pack.

[mr_lister999.]

quote:Wow, only GBP95? That's not bad at all!! It looks great, here:

http://www.cs-electronic.com/CS-Produkte/C...p_check_pro.php

Hmm, the POWER CHECK motor dyno looks handy too.

Arrgh... also the Robitronics.

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Thats the one willy, well done. I got a motor dyno from www.modeltech.co.uk. Fantastic little thing and about £82.99. Think its the cheapest dyno i have ever seen in the UK. Here it is:

http://www.rclab.rochenhost.com/catalog/images/e2009.gif

Their stuff is great plus free postage as well on orders over £10. Thats where i got my brushless motor from as well.