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Revisiting the Tuna Power System kit TPS

 

Now that we have stable power at the campground again and I needed to finish up my projects as we are leaving FL this weekend, I decided to finish up my Tuna Power System Kit.

This kit is a central power distribution kit for all of my tuna can kits, it also will charge a sealed lead acid (SLA) battery with an 18-20 volt charging input. The kit is set up for wall warts outputting from 0.4 - 1.0 charging amps.

I don't follow instructions well, ask my teachers from grade school! I believe in populating data points wherever I can. Assembly was halted because I was missing three 1K ohm resistors out of four the kit claimed to need. Because our campground had no power for 36 hours and no internet, I could not attend the Buildathon live. However, after the power came back on and then became stable (they doubled the size of the transformer), I decided to finish my TPS kit.

I bought a box of Diodes, 1/4w, 1/2w, & 2w resistors assortment to cover for those missing parts. In my case, I was missing three 1K ohm 1/4w metal film resistors but was given three 3.3K ohm resistors by accident. In this case, I calculated that those would not work in the place of the missing parts.

Anyway, I finished the assembly and even made a couple of mods to add a digital voltmeter at both the Battery input and the solar input so I could determine charging potential.

I went to buy an SLA battery but found a cheap Chinese 6ah LIFEPO4 lithium battery instead. I wondered if it could be used in the TPS kit.

I plugged it in and the TPS kit sprung to life with 13.3 volts of output. I then plugged in a 20-watt solar panel that claims 20 volts open circuit and 18 volts at full 1.0 amp output!!!!? Since this was a little higher than Rex or Chuck intended (0.7 amp max), I removed the 1n4004 1.0 amp rectifier and replaced it with a 3.0-amp 1N5404 diode instead. The 20-watt solar panel sprung to life at 17.5-volts and with whispy clouds, I was measuring between 0.7 - 1.0 amps via my amp clamp meter on the solar plus input.

The green LED illuminated to show charging and the battery voltage slowly began rising. Once it got to 13.8 volts I thought, "Well, the charge regulation should kick in now!" But it didn't, it continued to climb to 14.0 volts, 14.1, 14.3, 14.5, and 14.6 volts ... whew! Suddenly it jumped to 20.5 volts!!!! Oh my!!!

Why is this? Well, the battery voltage continued to hover around 14.6 volts, but the BMS (Battery Management System)? detects the higher voltage that the charging circuit tries to ramp up to and it disconnects the charging to protect itself. The battery still provides a 14.6-volt output, but the charging circuit with a near-zero amperage sees an open circuit that matches the voltage input from the solar panel.

Now, this would not be good for a radio's sensitive input voltage, but since it was an open circuit voltage I put a load on it and the voltage came right down. I am not sure why the UC3906N IC circuit did not limit itself to 13.8 volts since that is what I would expect with an SLA battery. I moved the TPS kit over to the Explorer battery box that I did a video on and tomorrow I will repeat my experiment to see what happens when the 12AH of LIFEPO4 batteries are near full charge. Tonight the voltage only rose to 13.5 volts as the batteries were chugging along all day powering my 30-watt 12-volt DC soldering iron. I triple-checked my TPS kit and verified all resistors, two capacitors, IC, and voltage regulators were installed correctly and at the proper values. So aside from the 13.8-volt regulation voltage, I declare the kit to be a success.?

I have a 24-amp MPPT solar charge controller that I charge my Explorer box with so I don't really need the charging circuit of the TPS kit, but I did try out the USB charging circuit and it worked perfectly. I left my fingerprints?
on the VR1 heatsink as I was charging my Android phone on it, a load that was not in the design criteria I am sure ... but it worked magically!

Anyway, back to soldering. When I get to Illinois on April 4th I will start on my Sea Sprinte so my grandkids can see what Popi builds when I am off by myself!

Cheers,

Davey - KU9L


Inline image
 

Additional notes:

As the datasheet shows, the Overcharge RED LED glows when the voltage reaches 14.0 volts, but charging continues until the battery reaches 14.7 volts upon which the charge current tapers off. I think the RUB of me using a LIFEPO4 lithium battery is that the battery BMS charging will shut down the ability to charge typically above 14.6 volts which is why I suddenly saw ~20 volts from the battery reading. This may have confused the 3906N IC which was to start tapering off the charge current prior to going into the 3rd stage, Float at 13.9 volts. Tomorrow I will test this with my 12AH Explorer battery box to see if I get a similar result as I did with my single 6AH battery. Now that I know the states the datasheet targets I can better determine if it meets the specs. Generally, though, my LIFEPO4 solar charge controller may be a better option. I plan to use the TPS Kit stand-alone for POTA and charge the batteries separately.

I noticed zero hum when using a tuna project from my batteries compared to the wall wart that makes tons of hum.

Davey - KU9L

Here is the info from the Data Sheet:

This?charger circuit diagram?is based on the?UC3906 battery charger controller?that contains all of the necessary circuitry to control the charge and hold cycle for sealed lead-acid batteries. The UC3906 battery charger circuit is specifically designed to provide the proper charging voltage and current determined by the temperature and state of charge of the battery.
The UC3906 battery charger circuit controller monitor and control both the output voltage and current of the charger through three separate charge states .
UC3906? has separate voltage loop and current limit amplifiers which regulate the output voltage and current levels in the charger by controlling the onboard driver.The charger circuit requires 18 to 22 volts DC input.? Three optical ( LED ) indicators show the charge state .? The UC3906 IC is configured to provide three charge states:
Bulk charge ¨C the charger operates in a constant-current charge mode until the battery reaches the programmed full-charge voltage.

Overcharge ¨C when the voltage reaches the programmed full-charge voltage, the charger switches to overcharge mode to ¡®top-off¡¯ the battery.
Float charge ¨C when the current decreases to the minimum overcharge current, the charger enters the float charge mode.
Voltage and current sense comparators are used to sense the battery condition and respond with logic inputs to the charge state logic.
How works these three states modes ?

If the battery voltage is between 10.2 and 12.2 volts? ( when charger is connected to the battery )? charging begins at the programmed bulk charge current and continues until the voltage rises to 14.0 volts. In this state mode only the power LED is illuminated .
When the voltage exceeds 14.0 volts, the overcharge LED illuminates (charger has entered in the overcharge mode) and charging continues. The charge current remains at the programmed bulk charge rate until the battery voltage reaches 14.7 volts.
When the battery voltage reaches 14.7 volts, the charging current begins to taper off.
When it decreases to 1/10 ?of the bulk charge current, the overcharge LED extinguishes and the float LED illuminates to indicate that the charger has entered the float charge mode (voltage is maintained at 13.9 volts ). ?The TIP transistor must be mounted on a heatsink , to prevent the damage of it cause of high temperature .



On Tuesday, March 28, 2023 at 07:38:00 PM EDT, David Knapp via groups.io <renewables@...> wrote:


Now that we have stable power at the campground again and I needed to finish up my projects as we are leaving FL this weekend, I decided to finish up my Tuna Power System Kit.

This kit is a central power distribution kit for all of my tuna can kits, it also will charge a sealed lead acid (SLA) battery with an 18-20 volt charging input. The kit is set up for wall warts outputting from 0.4 - 1.0 charging amps.

I don't follow instructions well, ask my teachers from grade school! I believe in populating data points wherever I can. Assembly was halted because I was missing three 1K ohm resistors out of four the kit claimed to need. Because our campground had no power for 36 hours and no internet, I could not attend the Buildathon live. However, after the power came back on and then became stable (they doubled the size of the transformer), I decided to finish my TPS kit.

I bought a box of Diodes, 1/4w, 1/2w, & 2w resistors assortment to cover for those missing parts. In my case, I was missing three 1K ohm 1/4w metal film resistors but was given three 3.3K ohm resistors by accident. In this case, I calculated that those would not work in the place of the missing parts.

Anyway, I finished the assembly and even made a couple of mods to add a digital voltmeter at both the Battery input and the solar input so I could determine charging potential.

I went to buy an SLA battery but found a cheap Chinese 6ah LIFEPO4 lithium battery instead. I wondered if it could be used in the TPS kit.

I plugged it in and the TPS kit sprung to life with 13.3 volts of output. I then plugged in a 20-watt solar panel that claims 20 volts open circuit and 18 volts at full 1.0 amp output!!!!? Since this was a little higher than Rex or Chuck intended (0.7 amp max), I removed the 1n4004 1.0 amp rectifier and replaced it with a 3.0-amp 1N5404 diode instead. The 20-watt solar panel sprung to life at 17.5-volts and with whispy clouds, I was measuring between 0.7 - 1.0 amps via my amp clamp meter on the solar plus input.

The green LED illuminated to show charging and the battery voltage slowly began rising. Once it got to 13.8 volts I thought, "Well, the charge regulation should kick in now!" But it didn't, it continued to climb to 14.0 volts, 14.1, 14.3, 14.5, and 14.6 volts ... whew! Suddenly it jumped to 20.5 volts!!!! Oh my!!!

Why is this? Well, the battery voltage continued to hover around 14.6 volts, but the BMS (Battery Management System)? detects the higher voltage that the charging circuit tries to ramp up to and it disconnects the charging to protect itself. The battery still provides a 14.6-volt output, but the charging circuit with a near-zero amperage sees an open circuit that matches the voltage input from the solar panel.

Now, this would not be good for a radio's sensitive input voltage, but since it was an open circuit voltage I put a load on it and the voltage came right down. I am not sure why the UC3906N IC circuit did not limit itself to 13.8 volts since that is what I would expect with an SLA battery. I moved the TPS kit over to the Explorer battery box that I did a video on and tomorrow I will repeat my experiment to see what happens when the 12AH of LIFEPO4 batteries are near full charge. Tonight the voltage only rose to 13.5 volts as the batteries were chugging along all day powering my 30-watt 12-volt DC soldering iron. I triple-checked my TPS kit and verified all resistors, two capacitors, IC, and voltage regulators were installed correctly and at the proper values. So aside from the 13.8-volt regulation voltage, I declare the kit to be a success.?

I have a 24-amp MPPT solar charge controller that I charge my Explorer box with so I don't really need the charging circuit of the TPS kit, but I did try out the USB charging circuit and it worked perfectly. I left my fingerprints?
on the VR1 heatsink as I was charging my Android phone on it, a load that was not in the design criteria I am sure ... but it worked magically!

Anyway, back to soldering. When I get to Illinois on April 4th I will start on my Sea Sprinte so my grandkids can see what Popi builds when I am off by myself!

Cheers,

Davey - KU9L


Inline image
 

Today the 12 AH battery performed the same exact way, the LIFEPO4 battery BMS disconnects when it becomes full and the battery voltage becomes too high or is about to be overcharged.? No issues on my end, had I been using a radio, charging my cell phone (for HAMRS logger app), and other Two Tinned Tuna devices the small solar panel would have just extended my operating time rather than just filling up the battery.

Next, I will finish the Tuna Tunah project I already started. I think I assembled one in 2018 already, but it is in storage in Chicago.

Does anyone have a source for the mating Molex 4-pin connecter on the Tuna Power System Kit?? The first three I bought are too small or the wrong shape, do not rely on the photos on Amazon to be the exact item you need, just saying. I think the version I need might be related to computer floppy drive connector sizes, but I just want the mating connector with female pins so I can power my Penntek TR-35 QRP 4-band radio via the TPS kit. I need to power it and the Molex connector looked to be very convenient.

Davey - KU9L



On Tuesday, March 28, 2023 at 09:02:12 PM EDT, David Knapp via groups.io <renewables@...> wrote:


Additional notes:

As the datasheet shows, the Overcharge RED LED glows when the voltage reaches 14.0 volts, but charging continues until the battery reaches 14.7 volts upon which the charge current tapers off. I think the RUB of me using a LIFEPO4 lithium battery is that the battery BMS charging will shut down the ability to charge typically above 14.6 volts which is why I suddenly saw ~20 volts from the battery reading. This may have confused the 3906N IC which was to start tapering off the charge current prior to going into the 3rd stage, Float at 13.9 volts. Tomorrow I will test this with my 12AH Explorer battery box to see if I get a similar result as I did with my single 6AH battery. Now that I know the states the datasheet targets I can better determine if it meets the specs. Generally, though, my LIFEPO4 solar charge controller may be a better option. I plan to use the TPS Kit stand-alone for POTA and charge the batteries separately.

I noticed zero hum when using a tuna project from my batteries compared to the wall wart that makes tons of hum.

Davey - KU9L

Here is the info from the Data Sheet:

This?charger circuit diagram?is based on the?UC3906 battery charger controller?that contains all of the necessary circuitry to control the charge and hold cycle for sealed lead-acid batteries. The UC3906 battery charger circuit is specifically designed to provide the proper charging voltage and current determined by the temperature and state of charge of the battery.
The UC3906 battery charger circuit controller monitor and control both the output voltage and current of the charger through three separate charge states .
UC3906? has separate voltage loop and current limit amplifiers which regulate the output voltage and current levels in the charger by controlling the onboard driver.The charger circuit requires 18 to 22 volts DC input.? Three optical ( LED ) indicators show the charge state .? The UC3906 IC is configured to provide three charge states:
Bulk charge ¨C the charger operates in a constant-current charge mode until the battery reaches the programmed full-charge voltage.

Overcharge ¨C when the voltage reaches the programmed full-charge voltage, the charger switches to overcharge mode to ¡®top-off¡¯ the battery.
Float charge ¨C when the current decreases to the minimum overcharge current, the charger enters the float charge mode.
Voltage and current sense comparators are used to sense the battery condition and respond with logic inputs to the charge state logic.
How works these three states modes ?

If the battery voltage is between 10.2 and 12.2 volts? ( when charger is connected to the battery )? charging begins at the programmed bulk charge current and continues until the voltage rises to 14.0 volts. In this state mode only the power LED is illuminated .
When the voltage exceeds 14.0 volts, the overcharge LED illuminates (charger has entered in the overcharge mode) and charging continues. The charge current remains at the programmed bulk charge rate until the battery voltage reaches 14.7 volts.
When the battery voltage reaches 14.7 volts, the charging current begins to taper off.
When it decreases to 1/10 ?of the bulk charge current, the overcharge LED extinguishes and the float LED illuminates to indicate that the charger has entered the float charge mode (voltage is maintained at 13.9 volts ). ?The TIP transistor must be mounted on a heatsink , to prevent the damage of it cause of high temperature .



On Tuesday, March 28, 2023 at 07:38:00 PM EDT, David Knapp via groups.io <renewables@...> wrote:


Now that we have stable power at the campground again and I needed to finish up my projects as we are leaving FL this weekend, I decided to finish up my Tuna Power System Kit.

This kit is a central power distribution kit for all of my tuna can kits, it also will charge a sealed lead acid (SLA) battery with an 18-20 volt charging input. The kit is set up for wall warts outputting from 0.4 - 1.0 charging amps.

I don't follow instructions well, ask my teachers from grade school! I believe in populating data points wherever I can. Assembly was halted because I was missing three 1K ohm resistors out of four the kit claimed to need. Because our campground had no power for 36 hours and no internet, I could not attend the Buildathon live. However, after the power came back on and then became stable (they doubled the size of the transformer), I decided to finish my TPS kit.

I bought a box of Diodes, 1/4w, 1/2w, & 2w resistors assortment to cover for those missing parts. In my case, I was missing three 1K ohm 1/4w metal film resistors but was given three 3.3K ohm resistors by accident. In this case, I calculated that those would not work in the place of the missing parts.

Anyway, I finished the assembly and even made a couple of mods to add a digital voltmeter at both the Battery input and the solar input so I could determine charging potential.

I went to buy an SLA battery but found a cheap Chinese 6ah LIFEPO4 lithium battery instead. I wondered if it could be used in the TPS kit.

I plugged it in and the TPS kit sprung to life with 13.3 volts of output. I then plugged in a 20-watt solar panel that claims 20 volts open circuit and 18 volts at full 1.0 amp output!!!!? Since this was a little higher than Rex or Chuck intended (0.7 amp max), I removed the 1n4004 1.0 amp rectifier and replaced it with a 3.0-amp 1N5404 diode instead. The 20-watt solar panel sprung to life at 17.5-volts and with whispy clouds, I was measuring between 0.7 - 1.0 amps via my amp clamp meter on the solar plus input.

The green LED illuminated to show charging and the battery voltage slowly began rising. Once it got to 13.8 volts I thought, "Well, the charge regulation should kick in now!" But it didn't, it continued to climb to 14.0 volts, 14.1, 14.3, 14.5, and 14.6 volts ... whew! Suddenly it jumped to 20.5 volts!!!! Oh my!!!

Why is this? Well, the battery voltage continued to hover around 14.6 volts, but the BMS (Battery Management System)? detects the higher voltage that the charging circuit tries to ramp up to and it disconnects the charging to protect itself. The battery still provides a 14.6-volt output, but the charging circuit with a near-zero amperage sees an open circuit that matches the voltage input from the solar panel.

Now, this would not be good for a radio's sensitive input voltage, but since it was an open circuit voltage I put a load on it and the voltage came right down. I am not sure why the UC3906N IC circuit did not limit itself to 13.8 volts since that is what I would expect with an SLA battery. I moved the TPS kit over to the Explorer battery box that I did a video on and tomorrow I will repeat my experiment to see what happens when the 12AH of LIFEPO4 batteries are near full charge. Tonight the voltage only rose to 13.5 volts as the batteries were chugging along all day powering my 30-watt 12-volt DC soldering iron. I triple-checked my TPS kit and verified all resistors, two capacitors, IC, and voltage regulators were installed correctly and at the proper values. So aside from the 13.8-volt regulation voltage, I declare the kit to be a success.?

I have a 24-amp MPPT solar charge controller that I charge my Explorer box with so I don't really need the charging circuit of the TPS kit, but I did try out the USB charging circuit and it worked perfectly. I left my fingerprints?
on the VR1 heatsink as I was charging my Android phone on it, a load that was not in the design criteria I am sure ... but it worked magically!

Anyway, back to soldering. When I get to Illinois on April 4th I will start on my Sea Sprinte so my grandkids can see what Popi builds when I am off by myself!

Cheers,

Davey - KU9L


Inline image

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