I tried my 12.3v / 2AH Lidl Parkside drill batteries. On FT8 I got ~1:15 HR each on my Xiegu G90 @ 10W. The battery protection cut it off around 9.5v on TX. On a weak 1AH SLA it was useless but still received even at 6.5v. The drill charger takes
Know doubt Pete you had inferior batteries. May I suggest using Panasonic 18650/3500mah, red in colour. I use the same type of set up, except I used a bridge rectifier. The starting voltage is anywhere between 16.8-16.6 volts. The rectifier drops the voltage to 15.4v for safe 818 operations. When the voltage drops to 14.6v, I remove the rectifier from the circuit and connect the batteries directly to the 818. This raises the voltage back up to 16 volts. No sense wasting precious voltage to the rectifier. I stop using the radio until voltage drops down to 11 volts. This set up gives me a solid 2:30 to 2:45 hours of operations at 6-5 watts. On the OzQRP DCT, I'll get 3:25 to 3:45 hours with no rectifier needed.
I use 3 x 18650 cells in a similar pack for the FT817. Voltage drops quickly after 1 hr or so. You need a good 18650 charger (which I already had) , and the battery case can be obtained from ebay/aliexpress. I connected mine to Anderson Powerpoles, you can use whatever. Cells were pulled from expired laptop batteries. It takes a bit of experimentation to find good ones. Two 3-packs still weight less than a larger SLA or LiPo pack. From a Price/weight/performance these are hard to beat.
Thanks. I tried 3 batteries but also found the voltage dropped quickly. The ideal is probably some sort of switching converter (low noise) to keep voltage at a constant 11 or 12 volts to deliver full power output with best efficiency.
@@vk3ye There are plenty of different buck regulators available. Only thing with that is you can't read the battery voltage directly on the radio so you have to be extra careful not to drain them below 2.6V or they're trashed. Most sources recommend no less than 3.2V since there are only a few mAh left at that point anyway.
@@vk3ye I just updated with a 4x18650 cell pack. Since it typically gives more than 16V (more than the 817 recommends) I created a small adapter with 2 IN5401 rectifying diodes in series on the positive wire. So when fully charged, add adapter to lower it to safe range, once voltage drops, remove it.
Thanks for sharing this video i have been looking at making some kind of battery pack for when I get my radio and the old jam jar accumulator cells battery while great for looking retro and being a good homebase battery would be impractical to lugg around but this wee combination looks perfect for pedestrian mobile up hills and the likes.
Thanks for the video. I would also check what's inside this "intellectual" charger. I've seen simple diode+resistor or similar circuits in such cheap products before...
Charge the batteries as a series pack with a "balancing" harness to equalize the cells. Then charge the pack to only 16 volts with a smart charger. I supposed the same could also be done to each cell individually using only a standard, inexpensive charger. Basic idea: Charge the cells such that the resting open circuit voltage of each cell is over 4.00 volts. Some capacity is lost but no voltage dropping scheme is needed.
@@G7VFY Yes. And when you're using 4 batteries by the time the FT817 drops out they are very near the end of their charge (even with the diode). 3 batteries might be a different story.
I tried my 12.3v / 2AH Lidl Parkside drill batteries. On FT8 I got ~1:15 HR each on my Xiegu G90 @ 10W. The battery protection cut it off around 9.5v on TX. On a weak 1AH SLA it was useless but still received even at 6.5v. The drill charger takes
Know doubt Pete you had inferior batteries. May I suggest using Panasonic 18650/3500mah, red in colour. I use the same type of set up, except I used a bridge rectifier. The starting voltage is anywhere between 16.8-16.6 volts. The rectifier drops the voltage to 15.4v for safe 818 operations. When the voltage drops to 14.6v, I remove the rectifier from the circuit and connect the batteries directly to the 818. This raises the voltage back up to 16 volts. No sense wasting precious voltage to the rectifier. I stop using the radio until voltage drops down to 11 volts. This set up gives me a solid 2:30 to 2:45 hours of operations at 6-5 watts. On the OzQRP DCT, I'll get 3:25 to 3:45 hours with no rectifier needed.
Love the channel! I was experimenting with 18650 batteries for my radios recently too. Was very helpful watching your test here.
I use 3 x 18650 cells in a similar pack for the FT817. Voltage drops quickly after 1 hr or so. You need a good 18650 charger (which I already had) , and the battery case can be obtained from ebay/aliexpress. I connected mine to Anderson Powerpoles, you can use whatever. Cells were pulled from expired laptop batteries. It takes a bit of experimentation to find good ones. Two 3-packs still weight less than a larger SLA or LiPo pack. From a Price/weight/performance these are hard to beat.
Thanks. I tried 3 batteries but also found the voltage dropped quickly. The ideal is probably some sort of switching converter (low noise) to keep voltage at a constant 11 or 12 volts to deliver full power output with best efficiency.
@@vk3ye There are plenty of different buck regulators available. Only thing with that is you can't read the battery voltage directly on the radio so you have to be extra careful not to drain them below 2.6V or they're trashed. Most sources recommend no less than 3.2V since there are only a few mAh left at that point anyway.
@@vk3ye I just updated with a 4x18650 cell pack. Since it typically gives more than 16V (more than the 817 recommends) I created a small adapter with 2 IN5401 rectifying diodes in series on the positive wire. So when fully charged, add adapter to lower it to safe range, once voltage drops, remove it.
This is what I will be doing. Enough diodes to drop the voltage down safe. Then a switch to bypass them.
Thanks your idea resolved my problem with my G90 16.5V. The diod will also provide polarity protection.
I had wondered about the cheap battery and charger combo with the FT817. Not bad for an afternoon outing.
Thanks for sharing
Fantastic video . And even fantastic books for a hamradio operator and book fiend/ collector. ☺
Thanks for sharing this video i have been looking at making some kind of battery pack for when I get my radio and the old jam jar accumulator cells battery while great for looking retro and being a good homebase battery would be impractical to lugg around but this wee combination looks perfect for pedestrian mobile up hills and the likes.
Thanks for the video. I would also check what's inside this "intellectual" charger. I've seen simple diode+resistor or similar circuits in such cheap products before...
Charge the batteries as a series pack with a "balancing" harness to equalize the cells. Then charge the pack to only 16 volts with a smart charger.
I supposed the same could also be done to each cell individually using only a standard, inexpensive charger.
Basic idea: Charge the cells such that the resting open circuit voltage of each cell is over 4.00 volts. Some capacity is lost but no voltage dropping scheme is needed.
Great video Peter. I love to see you try out some RC lipo batteries used for drones and other devices. They can generally be very energy dense.
pro tip : you can watch series at kaldroStream. Been using them for watching loads of movies during the lockdown.
@Rayan Cash yea, have been using KaldroStream for since december myself :)
@Rayan Cash Yup, have been using kaldroStream for since november myself =)
Peter, you can a small switch in parallel with the diode for when the battery voltage drops.
You could but when the battery voltage drops it drops quickly and you should stop using it. So there is probably little benefit.
@@vk3ye What do you lose 0.5 to 0.8v so, maybe...
@@G7VFY Yes. And when you're using 4 batteries by the time the FT817 drops out they are very near the end of their charge (even with the diode). 3 batteries might be a different story.
Wonder if you get more time out of those batteries if you made the diode removable.
How long did it take to charge the batteries the first time with USB, and how long did it take the second time with USB? Thanks
Can't remember. Am guessing 2 or 3 hours?
@@vk3ye Thanks
Thanks a lot for this video.
51
73
From DE
Li-Ion 3S pack used. Ok.
6:14 is our SES 8C2YOTA
Marvelous video
73' de YD2UWF