Rectifiers, batteries (BEC's)
tks - 16/7/06 at 08:00 PM
I wanted to know a couple of things
Who uses a car battery in his BEC and how much ah?
Who uses a bike battery or similar and how much ah do they have?
Is it true that when the engine runs on idle the car doesn't charge??
Did anyone tried to hookup 2 rectifiers? to have more power amps output??
when mine is at idle i measure 12,9volts..
but when i give a blip on the throttle the rectifier dies battery drops to 12volts or worse...
and the rectifier gets 50degrees....
It doesn't look faulty of the fact that on idle it gives 12,9volts...
but it breaksdown when i ask to much amps...
its true that the battery is almost empty...
i use a 45ah car battery to big??
Tks
Wadders - 16/7/06 at 08:22 PM
Hi TKS
just had a similar problem, suspected the reg/rectifier was faulty, eventually traced it to a dirty corroded connector. have now hooked up the output
from the reg/rec directly to the battery + terminal and all is well. Bike batteries are fine BTW 14/ah is big enough, although i recently switched to
an odessey dry cell battery, which will hopefully last longer than the cheapo bike ones. So i would suggest you clean the battery terminals and wire
the reg/rec directly, then see what reading you get, should be about 14v at 4000rpm.
AL.
Originally posted by tks
I wanted to know a couple of things
Who uses a car battery in his BEC and how much ah?
Who uses a bike battery or similar and how much ah do they have?
Is it true that when the engine runs on idle the car doesn't charge??
Did anyone tried to hookup 2 rectifiers? to have more power amps output??
when mine is at idle i measure 12,9volts..
but when i give a blip on the throttle the rectifier dies battery drops to 12volts or worse...
and the rectifier gets 50degrees....
It doesn't look faulty of the fact that on idle it gives 12,9volts...
but it breaksdown when i ask to much amps...
its true that the battery is almost empty...
i use a 45ah car battery to big??
Tks
JoelP - 16/7/06 at 08:40 PM
hi alan.
did you work out the details about the diode to stop stuff frying when the regulator breaks? I couldnt follow it all! 
02GF74 - 17/7/06 at 02:48 PM
quote:
Originally posted by tks
Who uses a car battery in his BEC and how much ah?
Who uses a bike battery or similar and how much ah do they have?
Is it true that when the engine runs on idle the car doesn't charge??
Did anyone tried to hookup 2 rectifiers? to have more power amps output??
when mine is at idle i measure 12,9volts..
but when i give a blip on the throttle the rectifier dies battery drops to 12volts or worse...
and the rectifier gets 50degrees....
It doesn't look faulty of the fact that on idle it gives 12,9volts...
but it breaksdown when i ask to much amps...
its true that the battery is almost empty...
i use a 45ah car battery to big??
I'll try to answer your questions.
Car/bike batteries use lead acid cells; the ouput of each cell is 2.0 Vso the batteries are constructed to have 6 in series to give 12 V.
The battery chemistry is what determines the output of the alternator. There is an optimum voltage, typically around 14 V.
The alternator produces AC and this uses a rectifier to produce DC and then a vlotage regulator to keep the output at 14 V. There is some additional
sensing to limit the current going to the battery but that is also limited by the batter voltage.
Battery capacity varies according to the size of the battery and you determina how much you need by the load you put on it; mostly this is for
startiing t he engine. Too small won't turn the engine fast enough, too much may burn out the starter motor - and is wasteful. The huge load at
starting usually means the battery voltage drops so that limits the current going to the motor hance the need for ballasted coils. It is unlikley you
would damage the starter since jump starting using a second car or battery would be a no-no.
When you are driving, the alternator supplies the current for the lights, the battery is only needed for starting. If the battery is drained, the
alternator will charge it, the bigger capacity the longer it will take.
Depending in the alternator, the rpm at which is starts to charge varies, but typically is about 600 rpm, blip the throttle to 1,000 or so and it
should be charging for sure.
Not sure what you mean by using a second rectifier - you mean two alternators connected to gether?!!!NO, bad idea.
I don't think the problem is with the battery but souns like rectifier or voltage regulator problem.