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Electronics => Electronics => Topic started by: Joker94 on March 29, 2010, 03:43:58 AM

Title: Building a Nimh battery charger
Post by: Joker94 on March 29, 2010, 03:43:58 AM

Hi every one

Is there a way to build a charger for a 6v 550 mAh. Is there a way i can, and possible another way to charge from a battery for my RC field box?

Thanks for your help

Joker94

PS. it cant be to expensive as i have just taken up RC planes and dont have much money left.

Title: Re: Building a Nimh battery charger
Post by: billhowl on March 29, 2010, 06:32:26 AM

Try this

(http://lh6.ggpht.com/_FdGFE8NBDgc/SshTR5qGeCI/AAAAAAAAA3s/8VfexEIqhHw/a_low_cost_universal_charger_circuit_diagram_for_nicd_nimh_batteries.GIF)
http://skemarangkaian.com/low-cost-universal-battery-charger-schematic/ (http://skemarangkaian.com/low-cost-universal-battery-charger-schematic/)
http://www.extremecircuits.net/2009/10/low-cost-universal-battery-charger.html (http://www.extremecircuits.net/2009/10/low-cost-universal-battery-charger.html)

Title: Re: Building a Nimh battery charger
Post by: Soeren on March 29, 2010, 12:06:00 PM

Hi.

I'd recommend MAX712 (http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1666), which has got dU/dT, time controlled and temperature controlled charge termination, so it can do fast charge and won't ruin your battery.

If you go with the simple one transistor circuit, you'll need a larger heat sink than shown, as it will dissipate up to 5.5W. C1 has no effect so can be left out. The side of R1 going to the collector should be moved to positive supply. The circuit has got no charge termination whatsoever, so will boil batteries if left unattended and you cannot safely charge batteries that isn't completely empty.
A grossly bad design which is just a constant current generator, so it shouldn't be called a charger at all. If you want to keep your batteries alive and well, stay clear of that circuit.

Title: Re: Building a Nimh battery charger
Post by: Razor Concepts on March 29, 2010, 12:34:17 PM

If you already are getting into RC airplanes, it would be wise to spend the money to get a multi chemistry charger for ~$50 USD. It is one of those investments that will last you years of use

Title: Re: Building a Nimh battery charger
Post by: billhowl on March 30, 2010, 08:41:55 AM

I'm using this for all my charging need.

Digital Balanced Li-Ion/LiPo/LiFe/NiCD/NiMH/Pb Battery Smart Charger and Discharger  USD$43.50
- NiCd/ NiMH battery cell count:1~15cells
- Ii-ion/ Polymer cell count:1~6 series
(http://www1.dealextreme.com/productimages/sku_15225_1.jpg)
http://www.dealextreme.com/details.dx/sku.15225 (http://www.dealextreme.com/details.dx/sku.15225)