Friends, Colleagues, Modellers.. was getting lots of requests to add a posting about a good battery charger, that can be made in an easy way, that must even a beginner can do.. but was tied up in some serious modeling project works, still busy, but i realizes that i am not living for to be tied up in a corporate like protocol.. so, turning to a parallel track, of my creativity, along with professional side.. so, by last two days i also started my own modeling works..

so, time to share this idea here, with all my proved experiences and materials that still working after years..

Tried several times to DIY a battery charger and balancer before I bought one a long time ago. But never got it working. Now I think, is the time, I should again get my hands dirty following this thread. I am eager to see the process.

Thanks Roopesh Sir for the effort.

Cheers...!

 

its sure.. here my effort is to help even a beginner, who do not have a clear idea in electronics.. here we are not using any deep formulas, fundas, complicated layouts, or complicated wirings, expensive components, but all simple, but effective..
we can use this unit as,
Battery charger: can recharge all types of batteries, from 1.2 volts to 12 volts in any Amperage..

Desk top Powersupply: can used as a desktop power supply unit, that can be used in electronic hobby as a variable power supply,by hobbyist..

Emergency light: with an inbuilt battery back up we can use this as an emergency lamp, at night, or in an emergency, with L E D strips, or by reflector lamp..

Music bed room lamp: for Couples can place at bed room with stereo music with music lights..!! (optional)..

Bring it onn, Roopesh Sir!!!

as a battery charger,
canb recharge any type batteries from 1.2 Volts, 500 mA to 12 Volts 7 Amps.. means can recharge from a glow starter, to an engine starter battery..
from NiCd, NiMh, SLA, and finally LiPoly.. we will add LIPoly system at last, as LiPoly battery is still not popular with us..
and we can control the recharge time up to us.. all manually..

For NiCD or NiMH battery, the most safest recharging current is 1:10...  means if we have a battery of 6 volts 1000 mA/h, the safst recharging current is 100 mA/H.. but a 50 mA/H current will be even more safest.. so, with provided circuit configuration, we can adjust the chraging current from 0 to any desired Amperagae, by turning the potentiometer..

some about batteries..
Even today, the selection of battery is still considered as a head ache..but, the Ni CD ( Nickel Cadmium ) batteries are one of the best bet for model making like some big cars , boats, ships etc.. it is very hard to damage the NiCD batteries, beacsue of it's deep discharge charecteristics.. NiCD batteries are stored as fully discharged.. so, to my experience, for ship, and car like modelling NiCD gives a better option.. modern generation NiCD batteries are even more good when compared to older versions.. cost is the second one criteria to consider.. a 1.2 Volt 2700 mA/H battery of NiCD costs Rs 30/- for each here, and lasting long.. some battery packs made by me are still working fine even after 4 years of hard use.. we can adjust the low cut off threshold of ESCs may be purchased or hand made to a very low level, because of the  deep discharge nature of battery..  terminal voltage of a NiCD battery discharged slowly than other batteries.. but weight will be an issue to compare.. but still this type battery is very suitable for ship and boat modelling, especially, a modeller with limited budget.. this one is also, self protected from deep discharging and reverse polarity charging in a battery packs, as found in NiMH batteries.. so, with a very limited money, we can make a very good value battery packs, for Car, Ship, Hover crafts and boat modelling.. this battery packs can be used in rail Road layouts, train sets, toys, TV remotes, clocks, and can be used in labs for experiments..works fine..

NiMH batteries are far better than in performance with NiCD batteries.. but extra care must be taken, about deep discharging of the battery.. self discharge is an other criteria with NiMH batteries.. so, while using NiMH batteries, we must make an arrangement to prevent over or deep discharge of battery pack.. when a battery pack deep discharges, one, or some of the cells will be reverse charged by the other batteries because of the nature of NiMH cells.. NiMH cells are much powerful than that of NiCD cells in same size.. the weight will be lesser than NiCD.. so, before LiPoly most used battery sets were NiMH.. still we can go with NiMH battery for our modelling..

 
Best of Luck
Sirji

SLA Battery.. this type of batteries are still in use widely in various applications.. emergency lamps, UPSs, various appliances, and can buy in 6 and 12 Volts from 700 mA/H to 12 Amps, and a 12 volts 1200 mA/H battery is the best for Car and Ship modelling.. still have to take care about too deep discharge.. but still value for money..

thank you Nehu..

so, before entering in to charger segment some more words..

this uint is not for am absend minded or lazy minded one.. this unit is full manual, but add the full auto version later.. full manual is because to retain the simplicty of total construction.. so, we must keep an eye while re charging the battery packs.. do not recharge any dented, punctured, sweeled battery packs..may damage or explodes..

this unit can be also used to charge the TX units with a 50 mA current..this unit is used in my applications by years.. so, if we use it properly this will helps us for years.. you can use any apropriate cabinet for this charger..

this one is also equipped with a discharger in need..

the charging circuit is based on simple Transistorized darlinton pair combination.. so it will last for years..

so what we need..? 

at first we need a transformer, in to 14-0-14 volts and 1000 or 1200 mA/H.  the transformer must be one with centre tapping..
for easy understanding, adding the real photographs keeping for beginners..

we need two TIP 3055 is inexpensive, popular, easily available, but can use any HD transistor to this class.. but i still prefer TIP 3055.. need two.. 22+22= 44 Rs/-

to make a Darlington pair, we need one SL 100 transistor..

keeping beginners in mind, adding the pin configurations.. of both transistors..

high Ampere diodes X 4 nos..any general purpose Diodes can be buy.. but make sure it can hold up to 6 amps at least.. or can used in double..

a cooling fan.. 2.5 inch or 3 inch fan is enough.. but can be also use a fan from burned SMPS from a computer..

10 Kilo Ohms potentio meter..  make sure to buy a best brand.. this one is the key of entire unit.. because the charging current is determined with this potentiometer..

collect a big good knob for the potentio meter..this will be more convenient to adjust the output with ease..

some L E Ds in various colours.. and 1 Kilo Ohms resistors for each L E Ds.. all resistors in 1/4 watts..

some switches.. make sure it all are good in quality.. select all switches for DC applications and in to 6 Amps 24 Volts DC.. these switches are easily available with car acssesory dealers.. in various shapes.. can buy according to you..

two numbers of electrolytic capacitors.. in to 2200 micro farad, or 4700 micro farad.. both works fine.. but 4700 micro farad gives more stability..

we need a multi meter like one this.. this one costs 120/-Rs here.. and works well.. will navigate through how to use and wire etc.. we can go with step by step assembling.. experts may feel laugh, but the step by step follow will be great helpful for a beginner..