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Monitoring while charging the battery


Reivax

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I found on ebay a cheap device that you can use to monitor how much power you put into your battery when charging.

http://www.ebay.com/itm/121939206655?

It shows current, tension, and accumulated power since the begining of the charge (1Wh here on the bottom right corner):

charge.jpg.72f06c1992e2e221b2e241e801768dcc.jpg

You'll need to add sockets to it and plug it between your charger and the wheel.

https://www.amazon.fr/16-3-broches-femelle-prise-lAviation/dp/B00GYUUK3W?ie=UTF8&*Version*=1&*entries*=0

20160204_190513.jpg.bc269a29aa531c663cba899c5efb97a5.jpg

 

 

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Thanx to Xavier for this tip! :)

I bought one, too, and use it with two GX16-3 male connectors for the input, so if I want, I can charge at 4A with two ordinary 2A chargers.

2016-04-09 14.08.45.jpg

2016-04-09 14.09.29.jpg

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Personally I'd still go with Hobby16's version, because it's not that much more expensive, comes ready-made with the connectors you want & he hand-calibrates them to something like +-10 (or was it 20?) millivolt-accuracy. The last part is pretty hard to do unless you have very precise multimeter (like a professional level Fluke, which probably costs several hundreds, if not more).

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13 minutes ago, esaj said:

The last part is pretty hard to do

and not very useful actually ;)

But yes, Hobby's version has more features, since you can also record the charging parameters on a PC.

But I like the display more on the one I found.

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34 minutes ago, dmethvin said:

Nice! I still prefer the Charge Doctor since it also offers auto-shutoff and has data logging for very little extra money. Still I might pick up one of these too, it's hard to go wrong at that price.

I agree! I use most of the time the real CD (in its double input version, too), with the auto-shutoff set at 0.5 A, at this time.


http://hobby16.neowp.fr/fr/2016/02/29/courant-de-charge/

CD_double1.jpg

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6 minutes ago, Reivax said:

and not very useful actually ;)

I beg to differ; as far as I know, the Wh-measurement must be done by sampling the voltage and current. The more precise the voltage-measurement, the more precise the Wh-reading. But, I don't know how precise those other devices are really, chances are that the difference isn't that big / meaningful. :P

In the end, for most users the actual watthour-amount may not be that meaningful anyway ;)

I have only the older Charge Doctor -version, which does just measurements, no auto-shutoff or such.

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4 minutes ago, esaj said:

But, I don't know how precise those other devices are really, chances are that the difference isn't that big / meaningful. :P

I did a test serializing this "Reivax tool", my CD v2 and my CD v1 for a same full charging, and the "wh" results was very similar for the first two tools, while noticely bigger for the original ChargeDoctor v1.

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12 minutes ago, esaj said:

chances are that the difference isn't that big / meaningful

exactly :)

12 minutes ago, esaj said:

I have only the older Charge Doctor -version, which does just measurements, no auto-shutoff or such.

Do not attempt to charge your battery with a charger that delivers more than 2A, you might kill the old Charge Doctor. Only the new one is intended for 4A or more.

(and of course it also depends on your battery)

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It may depend on the shunt they use to measure the current. Since all 3 are designed to work for different max currents, their shunt resistance might be different, and it therefore lowers the actual charging tension a little, but differently for each. It could explain part of the difference, and also, not all measuring devices are calibrated with the same precision, of course.

The CD V1 is a hack from an USB device, not primarily intended for currents above 3.5A and tensions above 7V, so may be it's less accurate because of that.

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