DC current limiter

Jan 22, 2004 7 Replies

Is there a currrent limiter that can limit 12VDC to < 60 amps?



I have a situation with a deep cycle lead-acid battery where the 60 amp breaker trips when charging. I'd like to limit the current to reasonable levels and have continuous charging rather than spikes of > 60 amp current, breaker trips, resets, spikes, etc....


--Kamus


o__ | If you're old, eat right and ride a decent bike. ,>/'_ | Q. (_)\(_) | Usenet posting`

You can make a current limiter for any current. But, There is a voltage burden in doing so.

* | __O Thomas C. Sefranek WA1RHP@ARRL.net |_-\

to < 60 amps?

battery where the 60 amp

the current to reasonable

spikes of > 60 amp

What are the cause of the spikes, what is the peak value (if known) and how long do they last?

This is part of an RV charging system. There is a 60A breaker followed by a solenoid. When the engine is off, the solenoid is open and the starter battery is isloated from the RV battery.

The problem comes in when the RV battery is depleted and you start the engine to charge it. The solenoid closes and the engine starts to charge teh RV battery. The current is greater than 60 A, so the breaker trips. It resets autmatically, but trips again and again until a series of these short cycles charges the battery enough so that less than 60 amps is required for charging.

The problem is that some sort of breaker is needed; loads on RV batteries can be 100A or greater for short times (like when using a microwave) and you really want to isolate the car alternator from having to deal with loads like that.

A battery isolator introduces a voltage drop (0.7 V or so) so I'm trying to see if a current limiter of some sort exists that does not have a current drop like that.

--Kamus

o__ | If you're old, eat right and ride a decent bike. ,>/'_ | Q. (_)\(_) | Usenet posting`

Current drop like what? Did you confuse the voltage drop for a current drop? Current limiting is inherently a voltage drop!

In article , snipped-for-privacy@ARRL.NET mentioned...

He could put a low resistance across the breaker, say about 1 ohm. That would allow about a dozen amps to flow even when the breaker is tripped. What would make a cheap low resistance? Well, how 'bout a car headlamp? They're not expensive and they're easy to find. You might consider going to a junkyard to buy a sockete for it.

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Fat finger typo.

Well, yes. But I guess I'm looking for some sort of "intelligent" current limiter - one that gets out of the way if the current is less than 60 amps.

I've found a DC-DC charger that might work; I'll contact the manufacturer.

There are battery isolators that have almost no drop.. Here is one you might consider...

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Just do a google search and you will find others such as MasterVolt....Happy RVing.....Ross

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