Quite so, but what is the point of showing the input to the rectifier calibration, and what is the point of showing it at all, when the meter only has one function and is actually measuring.displaying the current flow to the battery?
surface rust
- Thread starter Munroast
- Start date
Quite so, but what is the point of showing the input to the rectifier calibration, and what is the point of showing it at all, when the meter only has one function and is actually measuring.displaying the current flow to the battery?
Sponsored Links
Maybe the input is superfluous but the DC output tells you how close to charged the battery is.
If it is still showing a full current then the battery really needs to stay on charge, if it has dropped a lot you may well have, say, an 80% charge which is probably okay.
- Joined
- 17 Aug 2010
- Messages
- 3,272
- Reaction score
- 802
- Country
Yes it does add up that the charger could be using 3 amps to deliver 2 amps to the battery, making it 66% efficient.
But as Harry says what is the reason to show this ? there is only one pointer and I suspect that is a measure of the output with a guess at input (as the machine ages I would expect it to become less efficient)
I appreciate the need to show output amps as it does show the state of charge (and very useful for what I'm doing) but the guess at input amps seems pointless (and literally is pointless)
But as Harry says what is the reason to show this ? there is only one pointer and I suspect that is a measure of the output with a guess at input (as the machine ages I would expect it to become less efficient)
I appreciate the need to show output amps as it does show the state of charge (and very useful for what I'm doing) but the guess at input amps seems pointless (and literally is pointless)
Sponsored Links
Your help wasn't invited, you volunteered it. Munroast is a regular and valued contributor, he didn't appear to be criticising you, or anyone apart from the designer/ manufacturer of the charger.
Oh yes it was. If you pose a question then you are inviting anyone to answer it.
Posting often does not make him incapable of being wrong / being unclear.
That is obviously not true. If it was I would not have read it that way.
You probably meant that you did not take it that way, which is a different matter.
I have read what he wrote five times and I still cannot see anything offensive in his comment, so I would suggest you are maybe seeking hurt where none was intended.
returning to the subject, I just remembered an easy trick to limit the current through a battery charger or other power source; for example if the job is overheating, or the electrodes accidentally touch, causing a short circuit, or, if electroplating, if you want to slow it down for a harder deposit.
you put an incandescent lightbulb, of the voltage the source provides, in series with the job. If you use, say, a 25Watt 12v bulb, then the max current that will flow is about 2 Amps, even if the electrodes are shorted. If the job has reasonable resistance, the voltage will be too low to light the bulb, so the resistance of the filament (being cold) will be much less than when it is white hot.
I learned this when constructing an arc-light with two pencils.
you put an incandescent lightbulb, of the voltage the source provides, in series with the job. If you use, say, a 25Watt 12v bulb, then the max current that will flow is about 2 Amps, even if the electrodes are shorted. If the job has reasonable resistance, the voltage will be too low to light the bulb, so the resistance of the filament (being cold) will be much less than when it is white hot.
I learned this when constructing an arc-light with two pencils.
I suggested a car headlamp bulb a while ago.
- Joined
- 17 Aug 2010
- Messages
- 3,272
- Reaction score
- 802
- Country
I have absolutely no idea why he took offence either, I think he was probably right and said that. I have went back and given him a "Like" hope that helps with his mental state.
although come to think of it - it can't be input amps and output amps. the currant at 240v will be 20x smaller than the currant at 12v. so even if the charger was 100% efficient. when output was 2 amps the input would be a tenth of an amp.
Last edited:
No, it is assumed to be a guess at the ac current flow out of the low voltage side of the transformer, into the rectifier - though why anyone might need to know that, is anyone's guess. The meter measures and indicates the raw dc fed to battery, but for some really strange reason they have seen fit to additionally indicate the likely current flow in the stage before.
Except you didn't actually say that. You said "Yes it does add up that the charger could be using 3 amps to deliver 2 amps to the battery, making it 66% efficient" which you maybe meant as agreement but is actually just a comment on the machine. Remember on the 'net there is no tone of voice or body language.
But you then went on to say "But as Harry says what is the reason to show this ?" which is clearly a question aimed at me.
If you meant that as a comment on the maker / designer then it would have been better if you had said that, e.g. 'Why would the make it like that?'.
My mental state is fine. When someone helps me I say thank you, I think that is only common courtesy. And, especially on the 'net, I try and make it clear what I am say and to whom.
A depressingly large %age of people on the 'net lack any manners and also take what is written to mean other than what it says. Which is what you, unintentionally, did.
That sad trait is present, thankfully to a lesser degree, on DIYNOT. But it is sufficiently common that I have stopped reading some sections because of the casual abuse that is given out.
Well a very likely answer to that is obvious but when I pointed out that the questions from you, and @Munroast, were not very helpful you said "Your help wasn't invited".
Was that really a helpful addition?
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
