voltage limiter????

[ted655]

AGM batteries don't like over voltage charging. Is there a voltage limiter (made or bought) that can act as a warch dog in case a regulator goes nuts?
Thanks,

 

[Texasmark]

Re: voltage limiter????

Motorola and many other companies manufacture Zener Diodes which are solid state devices, designed to maintain a certain voltage (within a certain tolerance, under certain environmental conditions) across them as long as the applied voltage/current remains within their rated parameters. Other, more sophistocated voltage regulators, use microcircuits and transistors/FETs to do the same thing to a finer degree of tolerancing.

Before I went to all the trouble of involving some cluged up, sophistocated contraption, to keep something from happening.....having to bear the brunt of the cost, engineering, testing, evaluation, and reliability evaluation, I think I would ponder the chance of the problem happening in the first place and determining whether I am ready to accept the consequences, then applying that to the (total) cost for the preventive measure.

My experience in life has been such that a lot of hoop-la that I prepared for never happened; so I quit doing it and have lost nothing.

Good Luck,

Mark

 

[ted655]

Re: voltage limiter????

dIn other words, there is not a device already out there.
Given all the issues you mention, no, I dom't want that much effort. Thanks,

 

[Silvertip]

Re: voltage limiter????

You have one regulator in the system already. Adding another one doubles the chances of something going wrong. Yes -- adjustable regulators are available. Do a search for "adjustable DC voltage regulators". You will need one with the following characteristics: 1) Input voltage from 11 - 16 volts DC. 2) Output voltage adjustable from 12.6 to whatever the maximum charge rate is for your battery. 3) It must have a current rating that is equal to or greater than the maximum output of the engine alternator. Since we have no idea what engine you have we can't even guess what that value is. And just so you know, such a regulator will probably be at least equal to or greater than the cost of the battery you are trying to protect from damage that will likely never occur.

 

[bruceb58]

Re: voltage limiter????

You can buy power supply crowbar circuits but the down side is that it puts a short circuit to ground temporarily which would then pop an inline fuse.

Drawback is that your alternator would then blow because of no load.

A zener wouldn't work because the alternator would put too much current through it and blow it.

 

[Texasmark]

Re: voltage limiter????

Bruce, that's not true. You can size the zener accordingly............................Ever hear of a hockey puck and a heat sink.....water cooled if necessary?

Mark

 

[bruceb58]

Re: voltage limiter????

The problem would be that the alternators output would be at a higher voltage than that of the zener and the alternator will be trying to dump a ton of current through the zener since there is nothing that can limit the current.

We use zeners as overvoltage protection on our circuit boards. Typically, there is either a fuse that will blow or the power supply that is driving the board will crowbar or go into current limit mode and fault out until reset.

Alternators don't have these options so it would be a bad idea to use one here.

What have you found to be the largest wattage zener available?

 

[Texasmark]

Re: voltage limiter????

Bruce my man, I totally agree. We are on the same sheet of music. The guy asked and I answered. Didn't say that I agreed with my answer, just that I answered.

And I was wrong about Motorola (my buddy for so long) who, after all these years, apparently quit the component business (which they did a stellar job for me) are now into systems.

If you want a Hockey Puck Zener you will have to go to a company like www.SSDI-Power.com, out in your neck of the woods (California Company) and will have to have it custom built.

They built some really slick parts for us, but they were not zeners......but they will build them if you want them (love it...a company that is customer oriented)......we were in the high power energy switching business.......butttttt they will build you whatever you need in that business.....all you need is $$$$$. That's OK. We all run on $$$$. 8)

Have a good day man.

Mark

 

[ted655]

Re: voltage limiter????

It's a Yanaha 115. Optima bats don't last long at anything over 14 volts. I'm told the "alternator" on an outboard is really an induction ring on the flywheel and not that accurate a piece of equipment. My mechanic clains the voltage can run as high as 16+. A AGM killer. At $200+ a battery, I was just looking for some insurance. I find OB manufactures to be VERY propritary in their engineering. The aftermarket or new technoligy markets be damned. Belt & suspenders guys, thats all I was after, I truly wasn't trying to reinvent the wheel.

 

[Silvertip]

Re: voltage limiter????

Don't blame the marine industry in this case. Optima should be designing the battery for the application, not the other way around. How electricity is generated has nothing to do with its regulation which is a separate process. It's called a regulator and most higher horsepower engines have one. Have you actually used a digital voltmeter to check what the charging voltage is at the battery? If you are relying on the dash gauge you may be in for a surprise. After reading your first post again, I gather this entire thread is about the "possibility of failure" and not about your current charging voltage being too high so aren't we really beating a dead horse here?

 

[ted655]

Re: voltage limiter????

d Yes it is in "antisipation" of a problem. I always try to prevent rather than react. It's why I filter my gas through a Baha funnel & use a water seperator befor it goes into the bulb, amongst other precautions when I boat.
BUT, I'm not ome for Rube Goldberg contraptions, nor am I gadget fixated. If there's no way (or need) then so be it.
As for what Optima should or even can do, that's way above my pay scale. I figured it was the nature of AGMs to perform the way they do that did not allow an over voltage. I get that AGMs were invented to overcome the shortcomings of cell bats. Seems IF over voltage tolerence were possible, it would have been included. What do I know!
Guess I'll buy a DVM, cuz I was relying on the analog guage.
I have a bank of Optimas in my houseboat for the inverter but they are charged by a regulated solid state charger. Just looking for a pair of suspenders, thats all. Thanks.

 

[18rabbit]

Re: voltage limiter????

16+ volts is too much for any 12v application. Have Yamahappy fix that.

AGMs were invented to do away with the problem of battery acid on the ceiling of an airplane. Think: planes can fly loops, i.e. inverted.

Optima batteries are good for replacing. In the grand scheme of batteries it is at the bottom of AGM technology, and way way over-priced. Replace it with either a Cabelas branded AGM or even better a Dual Lightening Pro (also sold thru Cabelas).

Modern AGM batteries are as flexible about their charging profile as wet or flooded-cell batteries. You don’t need a tweaked charging scheme like a gel batt needs, and the new AGMs are ok with over voltage, to a point. 16+vdc is not acceptable for any 12v batt.

You don't need a voltage limiter; you need to fix the 16+vdc problem.

 

[Saskatoon2005]

Re: voltage limiter????

I have to agree with Silvertip, he seems to know exactly when what he is talking about when it comes to electronics, expecially marine electronics.

 

[MrBigStuff]

Re: voltage limiter????

And I was wrong about Motorola (my buddy for so long) who, after all these years, apparently quit the component business (which they did a stellar job for me) are now into systems.

Motorola Semiconductor is now Freescale: http://www.freescale.com/

If all the OP wants is an alarm, that's a fairly straightforward and simple solution. Let's face it, battery overvoltage isn't going to kill it for some time. Good chance of limping in to R&R at convenience.

If you're really concerned, why not carry a spare regulator and some hand tools?