Battery Charger V/Ah

Keeping you up are we?

Eh?!

|>Really, go with a 317 set up as a constant current source if you want it |>done right but don't want to go the $120 charger route. In a perfect |>world you should set up a charger with two 317s: First one to regulate |>the DC voltage to ~16V max317 and still have over 14.7V you want for charging> and the second one |>to limit current to the .8 amps you are looking for. It would only cost |>you a couple of bucks to do it that way.

For some reason, the Yamaha Shop Manual's instruction from GP is that (a constant current charger is not suitable for charging MF batteries) and conventional chargers may harm the MF battery as well....

Your explanation on the Voltage/Amperage was quite suitable as I have noticed and heard over and over again......so it must be true heh.....

I got tired of my Mickey Mouse wall wart charger taking forever to charge up the power pack on my 18V portable drill. I switched to a regulated 30V DC at 1.2 amps supply! The thing is at full charge I figure I have ~12V at 1.2 amps or 14 Watts of power going into the battery pack. I can tell when it has a full charge by how hot it is!

I mention this because as I said in another post, my 55 amp charger will cook a motorcycle battery even on its lowest setting.

It really wouldn't take much to make a charger superior to most of the junk on the market. Current limiting and voltage limiting of course, then add something like a PIC or AVR 8 pin microcontroller. You could have the thing put out pulsed DC at a couple of thousand Hz like some people reccomend for rejuvinating sufated batteries and during the off cycle check for the state of charge. A couple of LEDs could report status like possible shorted cells and state of charge.

I have seen a couple of web sites where people have rewound microwave over transformers to make cheap arc welders. I'm not really interested in that since I have both wire feed and oxy acetylene set ups. Maybe a s

50 amp home brew battery charger is in order.

Rick

Perfect way to knacker any battery. Properly looked after rechargeables can last for many many cycles. Overcharging them can damage them permanently in one go.

--
*Middle age is when work is a lot less fun - and fun a lot more work.

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

|>> The charging volts are not higher than 12.4 volts on any of the |>> chargers.... |>> |> Under voltage for charging -- even at trickle rates.

I use at least 13.5v+++

When using a DVM, were do you get your charging volt readings from, the standard DCVolt or the 12v Batt/Load setting, the difference in mine is about .5 volt....which makes a difference in topping up...to those 12v + incremental digits...

|>> The charging volts are not higher than 12.4 volts on any of the |>> chargers.... |>> |> Under voltage for charging -- even at trickle rates.

I use at least 13.5v+++

When using a DVM, were do you get your charging volt readings from, the standard DCVolt or the 12v Batt/Load setting, the difference in mine is about .5 volt....which makes a difference in topping up...to those 12v + incremental digits...

IIRC the Optimate battery conditioner settles back to 13.6V float charge, at this voltage the battery is maintained ready to go with minimal electrolyte loss due to gassing over a long soak charge time. Some batteries have a label "charging voltage not to exceed 14.4V", except for using a higher voltage to revive a deep discharged/sulphated battery, those two voltage limits serve as a good guide.

I think if you spelled this with two l's it wouldn't look so much like Walmart, which is the way I read it each time until this last one.

Besides the fact that wall-wart might not be a widespread term. And for that matter, not all little black plug-in boxes are "universal" or multi-voltage.

And you didn't use the word but while I'm at it, adaptor has its own problem in that one can adapt a lot more things than just voltages. (I don't even know how they chose that word. Changing to direct current and changing voltage don't seem like adaption to me.)

Little black box plug-in battery charger or replacer seems to be the words.

I haven't read much of the thread but I'm sure someone pointed out that the 16 volts drops quite a bit when it is actually charging something. At least with a cheap model. Doesn't that solve the problem?

P&M

If you are inclined to email me for some reason, remove NOPSAM :-)

Yes. When the packaging says that the current is limited near full charge, or that it declines as the item is charged, they imply that's because of special circuitry that their model has that others don't.

But is it not true that no circuitry is required to do this and none is included, and it's worked this way in all models since they first invented battery chargers?

If you are inclined to email me for some reason, remove NOPSAM :-)

On Tue, 27 May 2008 13:42:01 -0400, mm declaimed the following in alt.scooter:

Lead acid chargers have different concerns, but for comparison -- many of the cheap chargers for toy RC stuff (vs the "non-toy" RC stuff) are just rectified transformers built to limit the charge current to something like 1/10 the battery capacity.

The better chargers actually track both voltage and current... Many battery types will slowly increase in voltage until some peak point, and then /drop/ in voltage -- the chargers look for that drop to convert from forced-charge to float/trickle. (I've also got a charger for my radio gear that includes a thermocouple that looks for a sudden spike in battery pack temperature, I believe).

For lead-acid (about halfway down the page):

and charge controller chips

And some of the science:

Note that stage 2 would be 14.4V for a "12V" battery; stage 3 (float) is 13.5V {and my dung beetle at cruise only manages 13.9V on high beam and 13.7V on low-beam, +/-0.2V -- at idle at traffic signals the load on the battery drops it down

Dennis Lee Bieber wrote in news:j6adne9fdrFl_6HVnZ2dnUVZ_s snipped-for-privacy@earthlink.com:

most likely either a thermo-switch or a thermistor,not a thermocouple.

--
Jim Yanik
jyanik
at
kua.net

|>I haven't read much of the thread but I'm sure someone pointed out |>that the 16 volts drops quite a bit when it is actually charging |>something. At least with a cheap model. Doesn't that solve the |>problem?

In a 12v, 8amp, reg charge 10%= .8amp

Sure they all do that, and on the other hand if you use a constant charger with a 1-->>1.5 amp capacity, even a 9 volt charger will charge a

12v battery by borrowing ampsvolts usually till 13.5 then drops to regulated thermistor "overheat" setting..

I see the charger using up to an extra 5volts=1 amp if it borrows the whole 1 amp which is why a dedicated 9 volt with high amps will charge a higher volt less amp battery in the constant voltage system....

A 1.5 amp constant charger will charge the same battery as a constant (current) variable volt regulated automatic charger in the same amount of time.

The WalWart (Universal Charger) max .8 amp things would only amount to very low trickle charge of some .2amps and might take a very long time on a M/Cycle battery......it might take a week on some 10amp battery...

I figure try anything within common sense and it will work, maybe remember to look at the charging system as watts and the charger shouldn't over Watt the battery:

Automatic Charger MAX Quick Charge:

12v X 6amps=72watts

Small M/C battery:

12v X 8amps= 96watts

As long as the chargers watts don't overrate the battery's watts, your fairly safe but not too prudent......since a 10% battery amp is the best regular charge.....