FX Chrony External Battery

[Rimshot]

I decided to buy the FX chrony because tuning my Mrod and Impact M3 I felt I was just wasting lead shooting through my F1 chrony.. With the FX chrony I installed it on a CF tube and mounted it to the side rail on my M3. I have a teryx stock on my Mrod so I can use the rail on the bottom. This way I will not be changing my POI when taking it on and off and can tune for speed and accuracy at the same time or at least thats the plan.

I have a 18650 battery slot sanded down to slide into the tube. These batteries are 3.7 volt lit-ion and charge to 4.2 volts. My FX chrony draws about 14 ma before it connects and 82 ma. when connected. I ran it connected for over 4 1/2 hours continuous on just one battery but that was without shooting through and im guessing it draws more as it reads a projectile. Its winter in MN and I will not be able to shoot till spring.

I am curious if anyone knows the current draw under normal shooting conditions and how long a set of AAA batteries last you. I can always add another battery in the tube. 

Have a look any input welcome

Regards

 

[fe7565]

The chrono uses about 15-25mA when not connected to the phone. The radar sensor is off. When connected to the phone the radar sensor kicks in with about 40-50mA, so 70-80mA total. It does not use more when reading the projectiles (maybe 1-2mA) , the readings are sent continuously, even if blank.

 

[Rimshot]

Thanks fe7565

That answers my question on whether or not the current changes. So it looks like one battery will suit my needs just fine. 

 

[dannya1a]

get rid of the ultrafire battery. those are sketchy chinese units. get a good quality LG battery. don't believe the spec they say the ultrafire has. its way off.

 

[Rimshot]

Yep there are alot of fake mah. ratings out there. I would say anything rated over 3000 mah and weight less than 40 grams is probably a fake rating. I have seen them rated as high 11000 mah. which is impossible. I had these batteries and sockets leftover from other AAA 3 battery conversions.

 

[oaks1450]

Hey thanks for the inspiration Rimshot. I thought your idea was so good I decided to do something similar. I just got tired of changing and making sure I had batteries on hand for my FX chrony. So this is basically what I did.

I used a Streamlight USB rechargeable 18650 battery (2600 mah 5amp) and put it in a battery sled. Sanded the corners so it would fit in my 30mm tube.

Carefully took the chrony apart and figured out which leeds to solder to.

Powered it up to make sure it works. 4.16v is the max that this battery will charge up to. It is a couple of years old and was used in a high output flashlight. 

Figured out how I was going to route the wire and soldered it up. I also used a plastic block as a backstop. Once I figured out the length of that block I could guess where to dremel the hole for the mini USB port. Then I hot glued the block so the battery would line up.

Time to mount it up and try it out! Thanks again for the the inspiration!

 

[DaystateRebel]

That's a nice setup. One of these might let you get bit more run time from a 1S lipo

https://www.amazon.com/Comidox-Module-Voltage-Converter-0-9-5V/dp/B07L76KLRY/ref=sr_1_3?crid=1U9ULV81BFUMM&keywords=dc-dc+lipo+step+up+5v&qid=1645920449&sprefix=dc-dc+lipo+stepup+5v%2Caps%2C59&sr=8-3

Then again it might introduce some electrical noise and reduce the chrony's accuraccy

 

[oaks1450]

That's a nice setup. One of these might let you get bit more run time from a 1S lipo

https://www.amazon.com/Comidox-Module-Voltage-Converter-0-9-5V/dp/B07L76KLRY/ref=sr_1_3?crid=1U9ULV81BFUMM&keywords=dc-dc+lipo+step+up+5v&qid=1645920449&sprefix=dc-dc+lipo+stepup+5v%2Caps%2C59&sr=8-3

Then again it might introduce some electrical noise and reduce the chrony's accuraccy

Thanks for the comments. That looks interesting and easy enough to do. The fact the you said it could cause noise interference though scares me a little. Do you think it would actually make the battery last longer or just read 5v and 100% on the app?

 

[Rimshot]

oaks1450 glad you liked it.



DaystateRebel Interesting I can see how that might work. By using that module you will be running the battery down below the threshold that the chrony will operate at but the module will still be putting out 5 volts. I am curious what the trade off is. You could incorporate a switch and when the battery nears the lower end of the operating threshold engage the module and have 5 volts, like running on reserve.

I am going to look into this. I dont know about interference and will not be able to test for accuracy until it warms up here but I will be able to power it up and check run times, not that I need more run time I can pull the end cap off the tube and change the rechargeable battery faster than replacing the 3 AAA. But maybe the chrony likes to run above 4 volts than below.

 

[heavy-impact]

Voltage on a AAA battery is 1.5v full to 1.1v dead so the chrony should operate from 4.5v to 3.3v. Capacity for 3 AAA alkaline batteries in series in 900mah

Lithium Ion batteries with a bms operate from 4.2v full to 3v empty.

If you remove the AAA tray inside the chrony housing (cut it out or 3d print a new rear housing) you could put a 3ah 124050 lipo pack inside the case and add a usb charge port.

If you want to get fancy add a buck converter to raise voltage and a capacitor to clean up the output. Just remember the buck converter will waste some power since it's not 100% efficient and the on screen power meter will become useless. I'd skip the buck converter and run directly on battery voltage.

 

[Rimshot]

Ok I installed the voltage converter and heres what I found. With the 18650 battery at 3.9 volts the current draw without the converter was .085 ma. With the converter in the circuit the output voltage increased to 5 volts and the current draw increased to .230 ma. The current draw was basically nothing until the chrony was wired in.



So what does it all mean? Its a current hog and your better off without it.



Good Luck

 

[Greg_E]

I will add how I fixed my battery issues... I bought a 4 AAA box and wired it to the 5 volts on the circuit board. Since 4 alkaline AAA are going to be 6 volts (or more) I decided to just go with 4 NiMH cells. I was getting less than 2 hours and a lot of false/no readings with the 3 alkaline or 3 lithium AAA, now it works far better and no voltage dips when changing from idle to measure mode. Lots of ways you can do this, but it is best to give it a good solid 5 volts.



I ran this in measure mode for around 4 hours messing around in my office at work, finally got the voltage (fresh off the charger) down to 5.0 volts, the shown maximum voltage is only about 5.2 or 5.18. Fresh off the charger is probably not the best idea, charge the night before and let the batteries naturally come down a bit. Too much voltage could be a problem.



Why 5 volts? Because the real power hungry device is the transceiver, and looking it up says it wants 5 volts. And the easiest way for me was with NiMH cells so I can stop wasting money on AAA cells that only last for 2 hours.



And all that said, I still think I want a Labradar, but not ready to spend that much and there has been issues with smaller caliber pellets, not enough signal reflected back. Certainly can't blame the hardware for that issue.

 

[Rimshot]

I was able to use my sent up over the weekend. Three different shooting sessions over three days.. My FX Boss, Impact .30 cal M3 sniper, and .22 Marauder. Over 4 hours of total run time and more than 250 rounds and not one missed shot. I did have one shot register that I didnt shoot that was about 200 fps slower than the others. I have the minimum return set on 20% for what thats worth. I did not have to recharge the battery still reads over 4 volts but I did have to recharge my Iphone 5S.



Good Luck