FX Radar Chronograph - LOVE IT, KInda'

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I have found Lithium rechargeable last significantly longer then NiMH, which may not even last through a moderate shooting session. Or... I’m buying the wrong NiMH batteries. 😊

I like the voice because sometimes the chrony doesn’t read a shot. I can then know to check the connection to Bluetooth.
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Where did you get 1.5v lithium rechargeable battery cells? I've never seen those. Thanks.
 
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Lithium rechargeables are great if you can get the voltage to work out, which usually requires a customization of some sort. The FX chronograph accepts 3x AAAs which places the max operating voltage at around 4.8V. Substituting 3x 10450 lithium cells would deliver a max of 12.6V which would very likely let the magic smoke out. A single 18650 mounted externally would be electrically compatible and deliver about 2x the run time of NiMH rechargeables. I'm tempted to do that with mine because it seems I'm always swapping batteries, and it annoys me they designed the battery cover to be secured with a screw straight into plastic. It would have cost less than a nickel to bed a hex nut into the housing, or really splurge and use a brass insert for a dime. That way it would have a proper machine screw that won't strip out.
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My educated guess (and somewhat verified by a more electronically knowledgable member) is that the FX Chronograph circuit board and associated chipset is really designed to operate at 5V. Because I have been using Panasonic Eneloop batteries (AA and AAA) for many years in everything in my house that wants 1.5v batteries, but still works fine on 1.2V Eneloop rechargeable NiMH cells, I did try using Eneloops in my FX Chrony. It was immediately clear that the FX Chrony really did need more voltage than any rechargeable AAA batteries I have heard of. So my idea is a simple one that many folks might like. If I use 4 aaa eneloops instead of only 3, then the voltage with freshly charged eneloops would start at about 5.1 or 5.2 volts and would settle down to 4.8V where it should hang in there for quite a long time before finally dropping off to 4V. A fairly simple way to implement this is by first buying a battery holder similar to this (I hope this picture works - haven't posted a pic before).

battery holder open.1630600678.jpg


Another pic of the same item showing it's measurements and the on/off switch.

battery holder measurements.1630600824.jpg


If you look at the measurements and compare to the FX Chrony, you will see that you could just velcro this battery holder to the back side of the FX Chrony without it blocking the Chrony's on/off switch and without it sticking out beyond the sides of the Chrony either.

So now all you have to do is make a hole into the Chrony's battery compartment and solder the two leads to the first and last battery terminals and do not ever put batteries in the Chrony's battery compartment again.

Sure, it will add a little weight to the Chrony, but that is what I am going to do as soon as my battery holder arrives.

I ordered mine from Amazon. If you do order this item or a similar one, be sure to get one that holds 4 AAA batteries. You can get them with a mechanical switch and without a switch, but I didn't see any without a switch that had a cover.

Just a grungy thought.
 
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If substituting a 4-cell Ni-MH pack, be advised the full charge voltage will be between 5.6 - 6.0V. If the FX chronograph has a processor or other semiconductors that are designed for 5V operation, a 20% overvoltage is potentially destructive. Most 5V parts will have an absolute maximum rating of 5.5V.

If you don’t have the means and experience to validate it yourself, the safe bet is one of the USB power banks. Nice regulated 5V supply for the price of a tin of pellets.
 
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If substituting a 4-cell Ni-MH pack, be advised the full charge voltage will be between 5.6 - 6.0V. If the FX chronograph has a processor or other semiconductors that are designed for 5V operation, a 20% overvoltage is potentially destructive. Most 5V parts will have an absolute maximum rating of 5.5V.

If you don’t have the means and experience to validate it yourself, the safe bet is one of the USB power banks. Nice regulated 5V supply for the price of a tin of pellets.
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Thanks for the heads-up about potential overvolting and trashing a $200 chrony.

I just now checked the no-load voltage of six AAA freshly charged eneloop battery cells. Results were 1.33V, 1.33v, 1.34v, 1.33v, 1.35v, 1.33v. So pretty much nuts on 1.33v per cell. 1.33v X 4 = 5.32v. Overvolt percentage = 5.32v / 5.00v = 1.064 = 6.4% over (assuming 5v is no overvoltage). I'm glad you made me check that so that I and others will see the actual measurements instead of just a grungy guess.

In case those of you with smart NiMH chargers who may have watched the charging voltage being applied to a NiMH just before your charger stops charging, you may have noticed that the applied voltage is around (close guess according to memory) 1.53v. This is not the voltage that the NiMH will have when it comes off the charger.

So I am going to do this simple mod when I get my battery holder and let you all know how it goes.

As nervoustrig pointed out, DO THIS AT YOUR OWN RISK !!!

grungy


 
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Rainy day update. I finally got around to altering mine. I took the easy way out and added a small DC socket for connecting up a USB battery pack:


There's already a spot on the board with a couple of pads to accept it and I found an old USB hub with a socket that matched up so I robbed it from there: 


Be advised they did not include steering diodes on the board...meaning if I have batteries installed and connect up the DC cable, the batteries will be getting charged in an uncontrolled manner. That's no bueno. Don't do it.

Side note, the battery pack I'm using needs a minimum load of 100mA to stay awake. The chronograph draws ~80mA so I soldered a 200 ohm 1/4W resistor across the cable to kick it over 100mA. Oh, the irony of throwing away over 20% to make this thing more useful.

With this done, I was able for the first time to use my FX chronograph with leisure and test several guns over the course of 2 hours and the battery pack's 4-bar gas gauge never budged. Even with the small one I'm using rated 4.8Ah, the available run time is on the order of 25 hours (allowing 15% for conversion losses). That will do nicely.
 
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Looks like they went from the Nordic 52832 Raytac modules to an actual bare Nordic chip. It’s cheaper by about $3 in larger quantities. I’m assuming they got FCC authorizations for the new set up. 

Although this is an older generation of Nordic chips (same as the one in the Raytac module) and not as energy-efficient as the 52840 which uses about 3mA vs 10mA, what’s really killing the battery is the 40 mA of the old 10Ghz HB100 microwave module. Even though they have it set up where it only gets energized when the app gets connected. 


One way for them to improve the energy use by about 20% if they wouldn’t be streaming constantly empty data from the Chrono to the app. Instead it would only send the data when a shot is fired. Even though, that’s not going to affect the energy use of the microwave module itself. 







 
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Two of my friends have the fx chronograph, I guess my impression of them has been rather mixed. We have had numerous issues with them not being able to read back numbers. 

I feel they are at least moderately overpriced. And I dont really like the fact that they dont work without a smart phone. I'm kind of a simple old school guy...

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I picked up this little fellow on ebay for 20 some odd bucks. It is truly phenomenal! Yes, it reads in meters per second, but I put a piece of tape on the top of mine in 5 meter per second increments and it gives me a very good and quick reference when I am tuning. And for 20 some odd bucks it just does an awesome job!

Sorry for posting negative, I'm truly glad there are people that like the fx model. My impressions of it however were less than favorable. 

And I'm kind of stingy with accessories like chronos and scopes and bipods...

I like to use the big bucks for the gun. Everything else is mega budget. Lol
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MoeHofer, I bought one of these cheap chinese chronys and I absolutely LOVE IT! I have an FX Radar chrony, but I don't trust it and, so far, it's just been a lot of frustration. I'll keep the FX, but I really don't know if it will get much use anymore. +1 for accuracy for offering up a great alternative chrony that is affordable and always works. Plus I know at what distance from the muzzle the cheap chrony is getting its readings from.

grungy
 
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MoeHofer, I bought one of these cheap chinese chronys and I absolutely LOVE IT! I have an FX Radar chrony, but I don't trust it and, so far, it's just been a lot of frustration. I'll keep the FX, but I really don't know if it will get much use anymore. +1 for accuracy for offering up a great alternative chrony that is affordable and always works. Plus I know at what distance from the muzzle the cheap chrony is getting its readings from.

grungy
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I have owned the cheap/inexpensive muzzle mount "velocity meter" for 2 years 4 months and it has never failed me.

Can't see spending more for a chrono for airguns. Mine was $33 from Amazon. Works flawlessly!
 
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