mark said:
hi, any body have or know of a schematic for a 10 amp lead acid charger
for car batteries ?
Basic requirements are a transformer and a rectum frier. You'll need
a hefty transformer (150VA at least) and a 50A bridge rectifier.
You'll probably find a schematic in the back of the DSE catalogue (if
they still print one).
You should also note that most commercial chargers only have around
half the claimed output -- ie a charger labelled 10A will output
around 5A. They apparently use some tricky electrical formula, like
multiplying the actual DC output by 2. The price tends to rise
exponentially if you want real amps (as does its capacity to boil
batteries dry).
something sorta basic , which keeps it on trickle charge, after its fully
charged ..
It's no longer basic if you want it regulated. Easiest and cheapest
way for only 12V use might be to to use Oatley's solar regulator kit
in conjunction with a rectified supply or basic charger. It's a very
nifty regulator circuit (costs around $30).
If it is only for a 12 volt battery you can probably buy a hefty
regulated DC supply for a lot less then a commercial charger. Wes
have a 13.8V 6A supply for around $100 (trade). Some adjustments will
be required -- not exactly rocket science but some basic knowledge
necessary.
Jaycar once offered a kit for a 6, 12 and 24V 10A regulated charger
from Silicon Chip, which they've since dropped. Price at the time was
around $200 for 6 and 12 volt or nearer $300 for 24V 10A (transformer
upgrade required). Alternatively you could use a smaller transformer
and limit the output to 8A. You can no doubt buy the reprint from SC
and source the necessary bits. It's a relatively complex project for
a beginner though. It also has a raw output of 50V or so which isn't
without risks for the unwary.
I've been using one for a number of years without serious complaint.
Price wise it was a bargain.
