Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
yeah, you really need some current limiting.... i use open frame linear supplies for charging batteries, and set the current limit at the recommended charging current of the battery (foldback current limiting is very useful), but then again, i have a few of those kicking around the workshop.... at least add a 10 ohm 5 watt resistor in series with the battery.... if you have a shorted or completely dead battery, you won't fry anything....
I finished building this charger today and did some testing:
I'm no electronic tech but I like to build circuits , etc ....
I'm using a 9v/2.2A -- 9v/2.2A transformer
I get 18v ac and 25v dc after full rectification.
1. on a "good" battery it pushed 14.2 v and about 2 amp.
I think if the transformer had a higher amperage it might charge at a higher amperage ?
2. on a "bad" battery it pushed 17v and about 1.6 amp.
on the bad battery: does that mean the voltage goes up because the battery is shorted inside ?
here is the link to the circuit: **broken link removed**
don't overcharge a good battery... hydrogen gas is emitted and can cause an explosion...
one of the signs of a bad battery is increased internal resistance, which might account for the lower current and higher voltage. max voltage applied to the battery terminals should be 14.2, not 24, so you need to regulate that output voltage. also make sure when you recharge a battery, to 1)open the vent caps. 2)do it in a well ventilated area, and 3) put the battery in an open container like a plastic tub to contain any acid spills (accidents do happen). monitor the battery. if you hear fizzing or see hydrogen bubbles, disconnect the charger immediately (unplug the charger from the wall, do not just disconnect the clips which can cause a spark at the battery).
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
