I would like charging amps explained pls.
Posted by: "John Green" v_2jgree@operamail.com john_green1947
Date: Mon May 23, 2011 12:45 pm ((PDT))
Thanks, I got it. Great replies. Thanks for keeping it simple. I have to
make sure that I have a charge controller suited to the amps load
expected, am I correct?
I will have to wait and see what I end up with for a wind generator.
I am looking at a design called the Chispito, using a dc treadmill
motor, with 4 foot diameter blades.
I have a supplemental question, again regarding the
same/similar/relative subject, hence the retitling of the thread.
I prefer not to have max wind power generation all the time. It is a
liability issue, with blades whizzing around unattended achieving only
bearing wear once the batteries are fully charged.
I would like to have a secondary charging system, with very low amps
involved. Can I assume that I can manually switch the feed to the charge
controller (that will be selected/purchased for handling larger amp
loads) from a large windmill to a smaller one that will give a trickle
charge and will only be as dangerous as the average electric fan.
(maybe a solar panel might make sense, I hate the look of them, and my
room to mount them is almost non-existent, but I could maybe have it to
fold/stow when I am present and the larger wind power is running.)
My projected batteries will be low cost Walmart type marine or similar
so-called marine or floor cleaner batteries. I want to have no shore
dependency, expected initial boat use maybe 3 times a week.
I suppose I might be asking here, does a larger amp handling charge
controller consume power to a greater degree than a smaller one? ( I
don't want to end up consuming more power than the small windmill makes)
Maybe I can just use a diode to prevent the battery running the small
generator, in the same manner that the very low output solar panel
'battery maintainers' do? What happens if this ends up in overcharging?
Can I assume that if I choose a charge controller that is too low in
capacity, that the thing will just destroy itself?
The reasoning for asking this is that the easy way for me to go is to
spend a little extra, and get a charge controller that can handle larger
loads, but I would like to know if there are snags in doing that?
Again, I might be overthinking, I might just get a 'large' windmill
selected, and then I can experiment with the smaller one while taking up
rum drinking on sunset nights at anchor.
Thanks again,
John
..................................................
Hi all,
After having controllers explained a while back, and now agreeing that
they are the cats meow, the idea of pulsing dc instead of lower volt dc
to save battery drain is genius, so, it is time for attempting to
understand more things.
I have another major thing that I just cannot get my head around, and it
is the amps used when charging.
I understand amps when running something, and that a starter motor from
a car, for instance, has thicker wire in the windings, and will
therefore draw more amps than a heater blower motor or similar.
This seems to mean that the greater the load, the more amps get drawn,
and the shorter the battery charge will last. Simple.
Now, what about when charging?
I know that some car battery chargers have a select switch, for, say, a
2 amp trickle charge, or a ten amp regular charge.
Yet the battery is the same, so the same rules as for running something
FROM a battery, do not apply to when a battery is being charged. The
load is the same battery, so how the heck can the amps change? I can
understand that when the battery gets almost fully charged, then the
amps will decrease, as there is less load drawing the amps. And I can
understand that if a battery is extremely low in charge, it might tend
to suck more amps, so the charger meter will show a greater amount of
amps, then slowly get less amps drawing as the battery condition
improves. But my basic question is, how do the charging amps change at
the flick of a switch?
My reason for wanting to understand this is that I am collecting parts
to build a wind generator that will work in conjunction with the
electric motor and battery etc (that I am currently also gathering parts
for) in a boat. I know that if I rewind the generator armature with
thinner wire to get more turns onto it, that the power created is
proportional to the number of turns, assuming the rpm is the same. That
is, double the turns, double the volts. (But less amps are possible due
to the thinner wire).
The thing is, how thin can I go with the windings before the charging
load (that I cannot understand) is too great for the generator, and it
overheats? My understanding is that I need around 15 volts as a minimum
figure, then this would feed a charge controller, which then feeds about
13.7 volts to the 12v battery.
Or am I overthinking here, (like I have been known to before!) and the
charge controller will prevent anything frying?
Simple explanations appreciated.
Thanks,
John
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