| T O P I C R E V I E W |
| kevinloh |
Posted - Oct 24 2003 : 03:18:36 AM
How long does it taked to charge a car battery rated 12V40Ah using a 12V 6A Transformer and what is the formula.
Thanx
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| 15 L A T E S T R E P L I E S (Newest First) |
| Kale |
Posted - Jan 25 2004 : 12:54:15 AM
There are chips that do a fast charge up to ~%80 of maximum and then slow to trickle for the remaining ~20% claiming that this is better for the battery. Is this true?
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| Aaron Cake |
Posted - Jan 21 2004 : 09:33:52 AM
It will charge the battery very quickly, but at the cost of cycle life. Of course, you shouldn't be cycling a car battery anyway, so it probably doesn't matter...
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| kevinloh |
Posted - Jan 19 2004 : 12:39:20 AM
I saw a 80A charger it cost US$279.00. Do you think it could charge a 40Ah car battery in less than an hour or will the battery boils like crazy?
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| Aaron Cake |
Posted - Nov 14 2003 : 09:15:51 AM
You know, a battery can be charged at any current as long as you can control the temperature. It's not recommended, but done all the time...I can charge the 20AH pack on my scooter in under an hour, but at that point, the batteries are uncomfortably hot so I have to let them cool befure I can use it. Electric drag racers use "dump packs" to recharge 50 or 100AH 300V packs in about 10 minutes.
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| Auterium |
Posted - Nov 13 2003 : 5:37:18 PM
One thing that u should get to know is that every car battery(no matter if it is lead acid or gel) is that htey charge from 2 to 6 amp/hr.
Only if the manufacturer of the battery says so, then the charging amperage should be different. As for what i know only the liquid carbon batteries can be charged over 6 amp/hr. Actually thet charge at 35 amp/hr.
Maybe the charger might be getting too hot because, as the battery can't take much more than certain amperage, the rest of it is transformed to heat.
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| Aaron Cake |
Posted - Nov 13 2003 : 10:34:54 AM
Filter capacitor just smooths the pulsing DC from the bridge rectifier into continuous DC.
As for the heat issue, you will have to be the judge.
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| kevinloh |
Posted - Nov 12 2003 : 7:22:53 PM
You mentioned a filter cpapacitor. What does the filter capacitor does? And the transformer is mounted on plastic I'm worried that it would melt if it is connected to a car battery.
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| Aaron Cake |
Posted - Nov 12 2003 : 2:52:48 PM
Proper chargers are a lot more sophisticated then an adapter. An "adapter" is generally just a transformer, bridge rectifier and small filter capacitor which outputs a voltage approximately close to it's rating. The voltage will be low during high load, and high during light load. Works reasonably well for charging lead-acid batteries if you manually monitor the state of charge.
Chargers are much more complicated supplies, that function as both constant current and constant voltage sources. They contain the charging algorithm for the type of battery which they are designed for. Most nowadays use microprocessors.
Charging other types of batteries gets more complicated, especially lithium-anything. Temp and current must be closely monitored, otherwise they burst into flame.
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| kevinloh |
Posted - Nov 10 2003 : 7:15:35 PM
Unfortununately, I can't find any picture of it even though I searched for google and yahoo. :( Sorry about that. It sells in here Brunei in 220Volts but it could be changed to 115V at a flck of a button. And why is it that there are two choices Adaptor and Charger Flick a switch to the left is for adaptor and to the right is adaptor. Aren't it all the same?
By the way are the charging times the same(using the same types of charger) for Ni-cd. Ni-Mh and Lithium Ion and Lithium Ion Polymer?
Edited by - kevinloh on Nov 10 2003 7:17:41 PM |
| Aaron Cake |
Posted - Nov 10 2003 : 09:37:07 AM
That sounds like a nice unit for the price....Do you know where I can look it up? I am interested in one (or several).
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| kevinloh |
Posted - Nov 08 2003 : 7:47:52 PM
There is one charger/adaptor that I wanted to buy it costs here BND$41.90 in US it is around $25 it has these specifications Adaptor and Charger with glass fuse protection. Variable 12V -24V. 12V 8000ma max 24V 4000mA max. Do you think this is a good charger? It says it can charge all types of car batteries, lead acid batteries and gel cells. I'm not quite sure of the name of the think but I think it is NEWSTAR. Any opinions are welcome.
Edited by - kevinloh on Nov 09 2003 7:47:46 PM |
| Kale |
Posted - Nov 05 2003 : 2:14:25 PM
That would depend on whether or not there is any limiting circuitry built into the adapter. Good ones have an overload protection system built into them that keeps them from melting themselves. Cheap ones often do not.
As for heat, if something is designed to run hot, then it's ok to do so, however electronics generally have longer lifespans if they are kept cool. As a result I like to use fans whenever practical.
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| kevinloh |
Posted - Nov 04 2003 : 7:49:58 PM
What if it was just a transformer or adaptor and not a charger, will it work too or it will it melt?
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| Aaron Cake |
Posted - Oct 31 2003 : 10:32:30 AM
A 2A charger [i]should[/b] have an internal current limit that prevents more then 2A from being drawn. That is probably why the transformer gets hot. I wouldn't worry too much, unless you start to smell something...
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| kevinloh |
Posted - Oct 30 2003 : 7:28:11 PM
Well that large current charger its ok its only warm but if I charge the battery using a charger say 2A it will get extremely hot. Do you think its alright to let stay that way? Could the windings in the transformer get melted and ruin the charger?
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