chrony battery voltage effects readings?

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edfardos

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I'm seeing as much as a 200fps difference between a 9V and a 7V battery (when connected and Chrony turned on).

240grain44mag fps samples
19.0 2400 bat-low 1481 8x
19.0 2400 bat-good 1261 5x

23.0 H110 bat-low 1449 8x
23.0 H110 bat-good 1402 6x


I know a 7V battery should be tossed, but it read 9V when not connected, and I was shocked at the accuracy difference, plus the Chrony is supposed to display "Lb" if the input voltage is outside the usable range.

You guys seeing the same thing? I was thinking of getting a 11.1 lithium cell, and hooking it up to a 9V regulator just so I can get the same reading?

curiously,
-edfardos
 
Also look at the MA's (mega amps) on the battery. Not all batteries are created equal in this respect. For instance, rechargeable batteries produce lower MA's than alkalines do, and don't perform as well as alkaline.

And yes, I too have noticed my chrony will get hinky when the batt gets too low.

GS
 
My Chroney worked just fine with regular 9v batteries. It Hated the 223 round that I put through the display. My new one seems to be a little picky about the brand of battery
 
I just use a 12v as is. I see no difference between it & a 9v but a dead one causes all kinds on problems.
 
kingmt - that's what I wanted to hear! Are you talking car batterY? Lithium-3cell? Big pole of AA's?

so at 12V the results aren't slower than 9V?


thanks,
edfardos
 
23.0 H110 bat-low 1449 8x
23.0 H110 bat-good 1402 6x
Click to expand...

With a difference of only 47 fps, that's well within normal limits.

With 2400, a difference of almost 200 fps, ya, that very well could be a battery issue.
 
My chrony started giving off, yet consistent readings after the wind blew it over one day. I just use it to check for SD & ES moreso than actual velocity now. My drop can tell me what I need to know about velocity.
 
so I used it again yesterday, with the same "good" battery and it was 200fps high compared to the day before... For 20 shots of the same 44mag ammo.. It was also 200fps higher than the projected book value also. It seems like it has two modes: accurate and +200. Do you guys see this? Maybe its my technique? Perhaps its not completely unfolded?. I use a standard .223 load to see which mode its in now. Either 2600 or 2800. I'd like to figure out whyit changes modes.... Hmmm

edfardos
 
Also look at the MA's (mega amps) on the battery.
Click to expand...

That better be milli-amps (0.001 amps).

It should be abbreviated as 'mA' but advertising guys are not into accuracy.

No battery you could carry can produce 1,000,000 amps (that is what a mega-amp would be).

mA-hr is another useful number.

That is how many milli-amp hours the battery can produce and is a measure of how long it can power a load.

Every battery as a 'preferred' discharge rate (really designed into the battery) to maximize the power (mA-hours) it can deliver.
 
I'm guessing the ambient LIGHT conditions are having more of an effect on your Chrony than the battery.

When my battery starts getting low, I get random, crazy velocity readings. Like 200 fps for one shot, then 4000 fps for the next.

My Chrony works best on a completely overcast day, or in complete shade. Make sure the light conditions are the same from day to day when you test, if you can.

Also, make sure you are far enough away from the chrony that you are not getting muzzle blast or powder particles affecting the reading.

Make sure you shoot over the sensors at the same height EVERY time. Put a piece of tape on the vertical rods for the sky screens to give you a height reference. Make sure you are shooting level over the sensors, not angled up or down.

You can also make little cardboard "blinders" for the sensors so that they will only be exposed to light from directly above. Just make a little box about 1.5" high for each sensor and tape them over the sensors.
 
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