voltage regulator

What will the charging current be? For a trickle charge, you could use a simple low drop-out regulator. There are quite a few to choose from. Have a look at the data sheet for the LM2941 as an example of how it would work.

i forgot to mention it's 35 amp i need to have a constant 14.4 voltage going into the battery with or without load to keep the battery charge

Blake wrote:

Won't work.

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• Required crap appended to avoid restrictions imposed by brain +

• damaged idiots.

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• Server Response: '441 Posting Failed (Rejected by POST filter)', +

• Port: 119, Secure(SSL): No, Server Error: 441,

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• Error Number: 0x800CCCA9

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Once the battery reaches full charge, at around 14.4 volts, there is no way it can draw 35 amps from a 14.4 volt supply. So the question is, where does that 35 amp figure come from? It seems impossible that that is the charging current required. What you need is a charger that will switch to constant voltage when the battery is at or near full charge, or a commercially made regulator suitable for marine duty and your battery and engine. If you build your own, you need to figure out how to protect it from the environment - not necessarily an easy thing to do on a boat.

If you want correct advice here on how to build the thing, you need to post correct specifications, and that 35 amp figure at a constant 14.4 volts is impossible.

Ed

May I warn you that continous charge like you intend, is very bad for your battery? It will sulfate your plates. Better is, to charge until about 15 volts is reached, then wait until the voltage drops to about 12.4 to 12.8, to resume. These voltages depend on temperature. Some chagers have that protocol built in, called maintenance or hibernate charge. This protocol will also avoid boiling away your cell water. Google for Smart battery charger it shows lots of hits.

As I understand it, constant voltage charging is one of the preferred ways to charge lead acid batteries. The 14.4 volt figure does seem a bit on the high side (for a 12 volt battery) - around 13.8 volt is the figure I usually hear tossed around for a charger that operates 24/7. The slightly higher voltage might still be appropriate if the charger only operates intermittently.

A low dropout regulator capable of 35 amps isn't a trivial task. And as Ed points out, it may not be the best way. Do you have a specific reason for reinventing the charging system? The conventional way is the result of many decades of studying the problem. It's a pretty good approach.

Theres no reason to post a response if you don't want to supply any information about why you came to that conclusion. All you seem to do on this NG is waste bandwidth.

Up yours. The OP posts a nonsense request in incomprehensible language - and then 'remembers' more. His proposed charger won't work.

All you seem to do on this NG is waste bandwidth.

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+ Required crap appended to avoid restrictions imposed by brain   +
+ damaged idiots.
+
+ Server Response: \'441 Posting Failed (Rejected by POST filter)\', +
+ Port: 119, Secure(SSL): No, Server Error: 441,
+
+ Error Number: 0x800CCCA9
+
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"If these were woodworking newsgroups, their questions would be the equivalent of "What are the best kind of rocks to use to pound screws into fine furniture?" When someone tells them to use large chunks of granite, they are happy, but if you try to tell them about screwdrivers, they explode into a rage."

If I understand your question correctly, what you want is to build something like

This is called a shunt regulator (There are also other things called shunt regulators, which makes it hard to find this particular application in google searches)

note that your application is 2 phases (his is three)

This means you only need 4 diodes in the bridge (a normal bridge rectifer) And you only need 2 SCRs ... Having said all that, you are likely to have an easier time finding a used rectifier/regulator on Ebay than building one.

Look for ones for motorcycles, boats etc.

make sure they are 2 phase, and that they can handle the required amps

Make sure they are NOT for an alternator with a field coil, those regulate differently