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What is the suitable rechargeable battery & battery charger for a small current?

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cyteh

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I'd designed a prototype which using the hydro to generate electricity.
The output generated is 7v and 17.33mA only and i wish to store the power generated.
May i noe any suitable battery and battery charger for this prototype?

Thanks :)
 

Re: What is the suitable rechargeable battery & battery charger for a small current?

For simple charger, you can use a LDO chip for it.
 
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Re: What is the suitable rechargeable battery & battery charger for a small current?

Hi,
You can use Ni-Cd or Ni-Mh as the current is small and you can find plenty of chargers online for this. You could also use 6v SLA battery. If you use a 6v battery, you could just connect the 7v to the 6v battery. I don't recommend using Li-ion here if you aren't sure if you can build an efficient Li-ion charger.

Hope this helps.
Tahmid.
 
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Re: What is the suitable rechargeable battery & battery charger for a small current?

Hi,

If it's a prototype having such low current output, you must use a simple-charger that requires very-low power to operate. If you can increase current capacity it will be easy. You should also consider efficiency of DC rectifying stage.

Find the possibility to use Li-Polymer batteries with MAXIM-Battery chargers.

Wish you success !
 
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Re: What is the suitable rechargeable battery & battery charger for a small current?

Tahmid said:
Hi,
You can use Ni-Cd or Ni-Mh as the current is small and you can find plenty of chargers online for this. You could also use 6v SLA battery. If you use a 6v battery, you could just connect the 7v to the 6v battery. I don't recommend using Li-ion here if you aren't sure if you can build an efficient Li-ion charger.

Hope this helps.
Tahmid.
Click to expand...

Thx Tahmid :)
From the internet, there are few type of 6v SLA battery which are 6v/4.2Ah, 6v/5.0Ah and 6v/12.0Ah.
May i noe how i'm gonna to choose?

---------- Post added at 17:01 ---------- Previous post was at 16:50 ----------
DineshSL said:
Hi,

If you can increase current capacity it will be easy. You should also consider efficiency of DC rectifying stage.

Find the possibility to use Li-Polymer batteries with MAXIM-Battery chargers.
Click to expand...
I'm thinking to increase the current as well but i had no idea on it. Is that the voltage will be effected once the current is increased since V=IR? so once the voltage drop, the battery could not charged up?
and sorry for you an easy question again. may i noe what is DC rectifying stage?

thx DineshSL :)

---------- Post added at 17:18 ---------- Previous post was at 17:01 ----------
leo_o2 said:
For simple charger, you can use a LDO chip for it.
Click to expand...

Leo,
is that LDO chip is just a voltage regulator? i can only regulate the voltage...how about the current?
thx :)
 

Re: What is the suitable rechargeable battery & battery charger for a small current?

Hi,
You have to choose the battery depending on your need. eg. For the 4.2Ah battery, you'll be charging it for (4.2/0.01733)*1.4 = 340 hours or so from full discharge to obtain an output of 4.2Ah. You probably wouldn't need that much. Likewise for a battery with larger current capacity, it'll take longer to charge but will provide backup for longer. I think 4.2Ah should be fine for your purpose.

Hope this helps.
Tahmid.
 
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Re: What is the suitable rechargeable battery & battery charger for a small current?

Hi,

cyteh said:
I'd designed a prototype which using the hydro to generate electricity.
The output generated is 7v and 17.33mA
Click to expand...

What is the power generator of your prototype-hydro ?
To increase current you have to change that power-generator.

DC rectifying means; AC to DC conversion. Necessity of this stage depends on type of your power-generator.

If you can't increase current and want to charge batteries within few hours; use low Ah Li-Polymer batteries.
 
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Re: What is the suitable rechargeable battery & battery charger for a small current?

Yes, LDO is just a voltage regulator. For very low current consumption, pls try XC6206. Typical current consumption is 1uA. You can find the datasheet: TOREX SEMICONDUCTOR LTD.

cyteh said:
Thx Tahmid :)
From the internet, there are few type of 6v SLA battery which are 6v/4.2Ah, 6v/5.0Ah and 6v/12.0Ah.
May i noe how i'm gonna to choose?

---------- Post added at 17:01 ---------- Previous post was at 16:50 ----------


I'm thinking to increase the current as well but i had no idea on it. Is that the voltage will be effected once the current is increased since V=IR? so once the voltage drop, the battery could not charged up?
and sorry for you an easy question again. may i noe what is DC rectifying stage?

thx DineshSL :)

---------- Post added at 17:18 ---------- Previous post was at 17:01 ----------



Leo,
is that LDO chip is just a voltage regulator? i can only regulate the voltage...how about the current?
thx :)
Click to expand...
 
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Re: What is the suitable rechargeable battery & battery charger for a small current?

Tahmid said:
(4.2/0.01733)*1.4 = 340 hours or so from full discharge to obtain an output of 4.2Ah.
Click to expand...
From the calculation, why need to multiply by 1.4 ?

Thx Tahmid :).

---------- Post added at 07:49 ---------- Previous post was at 07:45 ----------
DineshSL said:
Hi,



What is the power generator of your prototype-hydro ?
To increase current you have to change that power-generator.

DC rectifying means; AC to DC conversion. Necessity of this stage depends on type of your power-generator.

If you can't increase current and want to charge batteries within few hours; use low Ah Li-Polymer batteries.
Click to expand...

The power generator that i used is RS336-321. dc rectifying is not necessesary as it'll generate DC power.
Thx for ur information. :)
 

Re: What is the suitable rechargeable battery & battery charger for a small current?

Ok,

to cope with low output-current, you may try to find simple Constant-voltage-regulator based charger (ie. without intelligent mode; No current monitor+No indicators... Only to keep constant voltage over batteries)

Can you give link to your power generator-Datasheet ?.

Thank you,
 
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Re: What is the suitable rechargeable battery & battery charger for a small current?

From the calculation, why need to multiply by 1.4 ?
Click to expand...
Because nothing is 100% efficient. If you charge a battery at 1/10th its capacity, it's supposed to take 10 hours, but due to energy losses, it takes about 14 hours. Similarly, I've read, it takes about 1.4 times the time it would take with the specific charging current at 100% efficiency.

Hope this helps.
Tahmid.
 
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Re: What is the suitable rechargeable battery & battery charger for a small current?

This is the link for my power generator:
**broken link removed**

Thanks a lot.
 

Re: What is the suitable rechargeable battery & battery charger for a small current?

leo_o2 said:
Yes, LDO is just a voltage regulator. For very low current consumption, pls try XC6206. Typical current consumption is 1uA. You can find the datasheet: TOREX SEMICONDUCTOR LTD.
Click to expand...

Leo, is that means that i can direct connect the output generator to the LDO chip, then, it'll be able to charge up the bettery? LDO can act as a battry charger?

As what Tahmid said, current will only effect the charging periods. Hence, a small current would be fine as well. As for my project, it'll generate power once the water flow.
Thanks :)
 

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