2.4V NimH battery charger development

Thread Starter

mishra87

Joined Jan 17, 2016
1,034
Dear All,

I want to develop NiMH battery charger for 2.4V (1.2V*2)/1100mAh battery.

So please suggest me the design criteria under below specifications-

1. What should be the charging mode NiMH battery i.e. CC or CV or CC-CV .
2. Could anybody suggest me the schematic and part number to be used.

Please find the attached detailed specifications -

Hope to hear you soon !!!

Mod edit: Converted .doc to PDF. Many members will not open a .doc file due to the threat of viruses.
 

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Thread Starter

mishra87

Joined Jan 17, 2016
1,034
Comments awaited !!

Specifications are attached.

Mod edit: Converted .doc to PDF. Many members will not open a .doc file due to the threat of viruses.
 

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Thread Starter

mishra87

Joined Jan 17, 2016
1,034
Take a look over at Battery University for the best charging strategy for your battery type. Then, find an IC designed to implement that strategy. It's cheaper and more effective than designing your own.
I have gone through battery university but I did not find recommended circuit or device.

Only explanation about NiMH battery is given.
 

BobTPH

Joined Jun 5, 2013
8,813
If you don't need fast charging, a trickle charger is simple to implement. Use a current source of C/20, in this case 55mA. You can use a 5V source (i.e. USB) and a 47 Ohm resistor. But it will take over 1 full day to charge from empty, or overnight to charge when half full. The good thing about this method is that it is safe to leave the battery in the charger after charging is complete because it is not enough current to damage the battery.

Bob
 

Thread Starter

mishra87

Joined Jan 17, 2016
1,034
If you don't need fast charging, a trickle charger is simple to implement. Use a current source of C/20, in this case 55mA. You can use a 5V source (i.e. USB) and a 47 Ohm resistor. But it will take over 1 full day to charge from empty, or overnight to charge when half full. The good thing about this method is that it is safe to leave the battery in the charger after charging is complete because it is not enough current to damage the battery.

Bob
Thanks for your reply.
I do not tricle charging.
I want to charging to be done by .5C method. .

For this could you recommend me something.
 

Thread Starter

mishra87

Joined Jan 17, 2016
1,034
I have divided this into two section
.
.
..
1. Universal input to 5V @1A SMPS
2. NiMH charger chip 2.4@500ma and CC configuration
3. Led indication for if load is connected and not connected. ..
4. When battery is fully charged load has to disconnect even if charger is connected

Please recommend me device as per above
 

wayneh

Joined Sep 9, 2010
17,496
Just to throw in an option, I always throw a LM339 comparator into my chargers. You can use one comparator to detect if anything is connected, another one or two for defined voltages across a shunt, to give an indication of charge current, and maybe the 4th for a warning light or to indicate which mode the charger is in (CV or CC).

Without reading the details of LTC4060, it probably covers some of these automatically.
 

Thread Starter

mishra87

Joined Jan 17, 2016
1,034
Are you blind?? Read post #5
Ltc4060
I have gone through LTC 4060.
That cost is to high. Usually we can get charger around 3 dollars.

To drive it from unversal input we need primary switcher and transformer and if we total cost one can not afford.

So please suggest me low cost solutions. .

Hope this will help...
 
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Thread Starter

mishra87

Joined Jan 17, 2016
1,034
So finally in post #11 we learn that there is a new specification – dirt cheap – and presumably for making a commercial product. :rolleyes:
I want to make it very clear that...

There's no point of using such a good word like " dirt cheap or blind "..

It's a knowledge sharing forum where one can share their experiences..and guides the needy.

It's not a commercial product.

We have got our electronic product like Digital pipette controller. This is battery operated instruments. For charging purposes of battery we have been giving readymade ( third party) charger to the customers which are very low cost effective. Now our aim is to develop our own charger and the cost should not be much more higher than our readymade charger. A bit higher will do.

Let's say we are spending 5$ to buy a charger and if we will spend 10$ in our own developed charger . So there's no point...!!!

That's why I am looking for low cost effective solutions.

I am a development engineer and not a management wings who only looks the how much extra cost.

Hope this help...!!!
 

wayneh

Joined Sep 9, 2010
17,496
My point was that design choices for a low-cost item to be sold commercially are very different than for the typical hobby project we see here in this forum. Letting people know the context of your question will get bet answers much sooner. I'm not picking on you, it's very common around here that we don't learn the real design parameters until the thread is pages long.
 

Thread Starter

mishra87

Joined Jan 17, 2016
1,034
I have selected Viper12 as a primary switcher which is very low cost effective. ..ĺ
And if we can get NiMH battery charger chip around same prices.

I want to develop isolated NiMH charger.
 

BobTPH

Joined Jun 5, 2013
8,813
It's not a commercial product.

We have got our electronic product like Digital pipette controller. This is battery operated instruments. For charging purposes of battery we have been giving readymade ( third party) charger to the customers which are very low cost effective. Now our aim is to develop our own charger and the cost should not be much more higher than our readymade charger. A bit higher will do.
If you have customers, it is a commercial product!

Unless you are selling a whole lot of them (10000?) you will not be able to make a charger cheaper than you can get on aliexpress.

Bob
 
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