Batboard

Does anyone have a source for 12 volt DC hour-meters? I'd like to put one on the PTT circuit of a repeater trasmitter, to see how long it has been keyed up. I recall seeing one in a friends boat, which runs on 12 volts. I haven't checked any marine-type stores yet. Anyone have any sources?

Jonathan,

Look on ebay. Here is a sample item number: 3101361394

There doesn't seem to be one listed right now but there were twenty of these sold in the last month, so there may be more listed.

I am curious why these have the Motorola logo on them - maybe they were peripheral devices for the Coverage Plus system that Motorola sold to trucking companies.

Jonathan,

Also do a search on ebay under the words "Hobbs Meter".

These are used in Aviation quite a bit.

Eddie
N4UMJ

HI:

If you want a Brand New Motorola one
email me @ [email protected]

MS

The meters you've seen on boats are for a different purpose: they are to accumulate amp-hours drawn from a high-capacity, deep cycle battery bank while under load, and the amp-hours restored (after accounting for battery efficiency and Peukert's equation -- don't ask) while charging. For a single bank system, the standard is the "E-Meter," originally designed by Cruising Equipment Co. and now sold as the Link 10 from Xantrex. For multiple banks or combined metering and alternator regulation, metering and inverter control, or all three, they are called Link 1000 and Link 2000, also sold by Xantrex. These are available at competitive prices through West Marine.

If I understand the question, you just want to accumulate the "air time" of a repeater. The most straightforward way to do this would be to use a repeater controller that contains this feature, such as the Zetron 38M. (The feature was designed for billing by an FB6.) Alternatively, you could build a simple circuit that would tap the PTT line, and power an accumulating timer so long as PTT was low. None of the battery meters you've seen in boats is adapted for your project, and all are way too expensive.

just go down to your local heavy equipment or generator dealer and talk to the parts guys, most equipment is serviced on an hourly basis and has a 12v hour meter for tracking the time.

Just remember- most hour meters will log at least 1-3 minutes even if the power is applied to them for a half of a second.
You may get a very over-inflated reading over time.


You're better off using an "even timer", which will just counts every time 12V is applied. It just adds "1" every time voltage is applied. You can get time by multiplying the counts X average transmit time. Average transmit time is just the time that most transmissions last (about 15 sec.)

RKG wrote:The meters you've seen on boats are for a different purpose: they are to accumulate amp-hours drawn from a high-capacity, deep cycle battery bank while under load, and the amp-hours restored while charging.

Although it might be almost as entertaining as the battery charging thread, I don't want to start another flaming post war over Peukert's equation, Xantrex, Hehr Power Systems and/or Nigel Calder.

That being said...

RKG, you're going to have a helluva time convincing me that what you're talking about is the same thing Jonathan is talking about.

I've owned a fair number of boats, and the majority of the ones with motors larger than 40hp had hour meters. The current boat has two - one for each engine. They don't measure battery amp hours. Actually, they only keep a running tally on the amount of time the ignition switch is in the 'ON' position.

Why?

Simple. It's the easiest way to measure operating hours on the motor for warranty and service purposes. Just like on General Aviation aircraft. Usually, you can't fall back on the '3 months-3000 miles' routine for oil changes. Not many watercraft come equipped with an odometer...

You could be right; if it was a smaller motor boat, then it could well have been an ordinary Hobbs meter. Having just designed a 12V house system for a guy's boat, I may have had that sort of meter in mind when I read "hour meter."

Jonathan: you can find a simple Hobbs meter from West Marine. SKU 107573 is a 2-1/16" round form for $40 and SKU is a rectangular form for $45. Since these meters accumulate time while 12V is applied, you'll have to build a circuit that will pass 12V to the meter while the PTT line to the repeater is at ground, but that isn't all that hard to do.

ok, i am a meter freak, i admit it, i have eletric KWH meters, hour meters, water meters, cycle counters.....if anything has ever given me a thought as to gee i wonder how much that........ then it gets a meter. very interesting idea for a 12v hour meter on a transmitter, i need to do that now gonna put one on my syntor X base. that is easy.

anyway heres some advice on the types and designs of hour meters i have come across in my time with 12v analog hour meters. ok one big difference i have noticed among them is what i call "clicks" some hour meters will have to have power applied for 20-30 seconds before they click, the click is very important, those meters wont regester any time unless you get it to click. so if you talk for say, 18 seconds and it didnot use enough time, it would not increment. it is my expierence these types of meters are fairly cheap. yes they may keey accurate time if something is turned on for several minutes at a time, but not good for catching intermitnt TXing. i have found several MOTOROLA 12v hour meters click often, say every 8 seconds, wich is much better for catching and incrementing short transmissions. HAS THIS CONFUSED ANYONE?
some people may get concerned about reading what i have just typed ant think, OH OH OH!!!! you dont want to be getting an hour meter that clicks too fast..it will record time too fast. that is not the case, the internal workings of the hour meters compensate thier gears for the faster clicks, basically they are designed that way. the other one that i have that clicks fast is a motorola that just has the /\/\ and "electronic" on the front.

hmm could motorola be making quality hour meters in adition to quality radios?

i would personally stay away from buying a hour meter (or anything you can buy elsewhere for a boat) from a marine establishment, they rip you for a meter at 30-40$ i think the marine shops know that people shop in a marine store tend to have boats and lots of money, i would personally stick to ebay and fests. a correct hour meter at 20.00 is a fair deal for 20$ on ebay, and stock up when you are at hamfests, i usually see them for 10-15 at fests.

That is a good point. These meters do not record linearly, but in multiples of some defined time unit. If that unit is large enough (such as 1/10 of a hour, or 6 minutes), then any runtime of less than that unit will not be recorded, and any other runtime will be truncated to the next lowest increment. For the application for which they were designed, accumulating run time of a gas or diesel engine, that inaccuracy is OK. For what you have in mind, you may need a meter with a finer resolution.

to elaborate further, these 2 motorola hour meters i have, do say 1/10 but they click about every 8 or 10 seconds, it would still take the 6 minutes to increment the 1/10 but there is a smaller wheel with a white and black line that moves white/black/white/black every 8 or 10 seconds, it is located to the right of the 1/10hr digit.

We had to keep track of a freq. Tx problem one time,
and the radioShackScanner 2036 with the ctcss (PL)
board worked 100%.Each time the Pl of 100.0 Hz was used
it showed you the number on display of the tx times.
Great little device. ( Motorola does not make all great toys)

Check your local auto supply store. They would either have them or could get them.

From my experience with hour meters on our fire apparatus, I don't think the anolog click click rotating number wheel thing is really going to work very well. You may want to concider some kind of digital counter with an LCD display. Something like that would be accurate to the second.

any idea where i can find some of these digital hour meters? i have seen one on a CAT backhoe, it was really cool.

i would like to buy one.

TST, Grainger, Hobbs

Why not just hook up a relay and have it switch power to an electric clocK?

Tron

Tron wrote:Why not just hook up a relay and have it switch power to an electric clocK?

Tron

Ah, but isn't that limited by 12 hours on the average clock?