Testing rectifier charge

[bowrider]

Hi there,
How do I test and what are the numbers for a good rectifier? Just need to know if I'm not gonna get my battery drained too fast...

 

[ezeke]

Re: Testing rectifier charge

You have an unregulated rectifier that may be able to maintain a charge if you run at a fairly good clip and don't run too many accessories on your battery. If the battery is a deep cycle dual purpose marine battery, you can expect that it will be showing around 13-15 volts on your voltage guage while you are running, depending on the charge and condition of the battery.

If you use your motor on an occasional basis, you should plan a method of maintaining the battery at a fully charged level. Trickle chargers of various kinds can fill the bill.

 

[R.Johnson]

Re: Testing rectifier charge

Dis-connect one battery cable, it does'nt matter which one. Place a volt meter in serie's with the cable, and the battery post. or other word's direct connection. If volt meter show's a reading , you have a drain, and will discharege battery. This is with key switch off. Dis connect component's until you find drain.

 

[bowrider]

Re: Testing rectifier charge

. If the battery is a deep cycle dual purpose marine battery, you can expect that it will be showing around 13-15 volts on your voltage guage while you are running, .

Well that's kinda where the problem is...I don't have a volt gauge! So I guess I just need to put a voltmeter on 2 poles with the motor on and see how much current it's giving right?

 

[bowrider]

Re: Testing rectifier charge

Dis-connect one battery cable, it does'nt matter which one. Place a volt meter in serie's with the cable, and the battery post. or other word's direct connection. If volt meter show's a reading , you have a drain, and will discharege battery. This is with key switch off. Dis connect component's until you find drain.

Thanks, I'll do this to make sure is not draining...wel in my case is easy because other than the lights, I don't have any other accessories! lol
But is simple enough to do it just in case...

 

[Seasport]

Re: Testing rectifier charge

Disconnecting the battery cable and putting a voltmeter in between the cable and battery terminal will not do anything. You can however do this with an ammeter to measure if you are getting any unwanted current draw which will drain your battery with the motor not running.

If I understand you right, you want to measure the charging current with the motor running. You can do this with an ammeter if you have one that will measure enough current. Most people don't and so if you just have a voltmeter you can measure the voltage across the battery with the motor running as ezeke says. If the voltage is greater than 13V you can be confident you are charging the battery - just like the volt meter in your car.

 

[bowrider]

Re: Testing rectifier charge

Yep...that's what I want to do. So this portable voltmenter don't measure OHMs as well? I have a fancy one but I can't remember.....I will try the volts measure thiugh....
Thanks everyone...

 

[teslaman]

Re: Testing rectifier charge

Whatever you do, do not stick an ammeter directly between the poles of the batt. This would subject the batt to zero impedance and blow the fuse in your meter.

Sparks may fly also!

 

[R.Johnson]

Re: Testing rectifier charge

Seasport: I thought he was looking for a drain on his battery. A drain from any source means a complete circuit. A volt meter in series with the battery will show this.

 

[wilde1j]

Re: Testing rectifier charge

Whatever you do, do not stick an ammeter directly between the poles of the batt. This would subject the batt to zero impedance and blow the fuse in your meter.

Sparks may fly also!

Not if the motor wasn't running, which is what RJ meant. You NEVER want to disconnect battery leads on a running motor, but we're looking for mA current leaks here, which will pull a battery down over time. To check a running motor for charging, just start the motor and measure the voltage across the battery terminals ... you should get 13.5 to 14 VDC if there is a working charging system.

 

[Seasport]

Re: Testing rectifier charge

We're talking about different things here. The voltage reading across the battery with the motor running will give you an indication of charging current.

If you're looking for a small drain on the battery, the normal way would be to connect an ammeter in series with the circuit by disconnecting a battery lead (with the motor not running of course) and inserting an ammeter into the circuit. A voltmeter has a very high internal resistance and if you insert that into the circuit like an ammeter then you will likely get no current flow at all and so no reading on the meter.

Of course never connect an ammeter directly across the battery. It should go in the circuit as RJ says.