Battery power supplies for the Regen

[sandyk]

That is what I wrote in my reply as well. This part of the reply is just me explaining that it is safe to charge while the USB Regen is connected.

 

You mentioned that the output voltage is cut off when the battery voltage drops down to 5.5V, but you haven't mentioned what the over voltage limit is. Obviously the charger's output voltage will need to somewhat over 7.2V to fully charge a 7.2V battery.

Personally, I wouldn't rely on a charger's over voltage limiter to protect something like a Regen.

If you really need to use the Regen while the battery is charging, it's better to buy 2 batteries that you can use alternately.

[Cornan]

You mentioned that the output voltage is cut off when the battery voltage drops down to 5.5V, but you haven't mentioned what the over voltage limit is. Obviously the charger's output voltage will need to somewhat over 7.2V to fully charge a 7.2V battery.

Personally, I wouldn't rely on a charger's over voltage limiter to protect something like a Regen.

If you really need to use the Regen while the battery is charging, it's better to buy 2 batteries that you can use alternately.

 

The over-voltage limit on this battery pack is 8,4V so it will perfectly safe.

 

IMO, the whole point of getting a battery pack with charger is that you can avoid constant battery changes. Ohwerwise it is very easy to just buy THIS

 

 

and THIS

 

 

and be done with it. However, that would mean contant monitoring of both high.voltage AND low-voltage plus the hassle of changing a pair of 18650´s while charging the other pair. I would personally prefer a battery pack with charger and day.

 

BTW. The battery pack is 7,4v...not 7,2v.

[Cornan]

Here is a good & easy to read link if you want to know the high-voltage vs low-voltage on a standard 3,7v Li-ion 18650: https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages

 

What this link tells you is that the nominal voltage of a 3,7v Li-ion with 2pcs in series (=2P2S) will be 7,4v, the low-voltage will be 6v and the high-voltage will be 8,4v. With 2P2S configuration the amperage will be the same as in a single battery. In my example above (post #27) 2pcs 3,7v/5300mAh batteries will give you 5,3A in a 2P2S configuration, will have a nominal voltage of 7,4v, will never drop below 6v (unless the battery cells gets damaged or fully discharged) and will never go higher than 8,4v (since it is not connected to a charger). Nothing of that will damage the USB Regen.

 

The low-voltage cut-off (5,5v) on the earlier posted 7,4v battery pack is just a precaution for battery cells damage and battery discharge and the high-voltage cut-off (8,4v) is just a precation when the battery is connected to a device to ensure that the charging voltage peaks do not exceed the maximum 8,4v which could damage the connected device.

 

I think I got the most important things covered there. If not please let me know!

[sandyk]

Cornan

There are just as many Li Ion batteries listed as 7.2V. If you do some research you will find that the basic voltage is stated to be 3.65V with 2 in series . 7.4V sounds more impressive than 7.2V though doesn't it, when it is actually more like 7.3V ?

This is like with a "9V" Ni MH battery where the actual voltage is more like 8.4V.

 

Lithium-ion

 

The nominal voltage of lithium-ion is 3.60V/cell. Some cell manufacturers mark their Li-ion as 3.70V/cell or higher.

This offers a marketing advantage because the higher voltage boosts the watt-hours on paper (voltage multiplied by current equals watts).

The 3.70V/cell rating also creates unfamiliar references of 11.1V and 14.8V when connecting three and four cells in series rather than the more familiar 10.80V and 14.40V respectively. Equipment manufacturers adhere to the nominal cell voltage of 3.60V for most Li-ion systems as a power source.

 

 

 

Battery Voltage Information – Battery University

[Cornan]

Cornan

There are just as many Li Ion batteries listed as 7.2V. If you do some research you will find that the basic voltage is actually 3.65V with 2 in series . 7.4V sounds more impressive than 7.2V though doesn't it, when it is actually more like 7.3V ?

This is like with a "9V" Ni MH battery where the actual voltage is more like 8.4V.

 

 

Battery Voltage Information – Battery University

 

Thanks for that Sandyk! I have actually read this page before...but that detail did´nt stick to my mind. Now it have. You live and you learn!

 

/Micael

[Mike Gillespie]

Has any one tried a 5V Bakoon BPS-02?

[Cornan]

Has any one tried a 5V Bakoon BPS-02?

Bakoon BPS-02 (5v), Kingrex uPower (7,5v), SOtM mBPS-d2s (9v) & Kingrex SLAP (12v) are some of the most interesting battery supplies around. The only one that works with USB Regen with or without USB powered DAC is the uPower. If your DAC do not require USB power (or handshake) you can choose which ever one you like. LPS-1 will work with all of them except BPS-02 but it would be an over-kill to choose any other than uPower.

I have'nt tried BPS-02...but have always wanted to!

[Cornan]

Here are pictures and links to all the mensioned batteries...just save you some valuable Google-time!

 

Kingrex SLAP! http://www.kingrex.com/products.php?c=6&s=9

 

 

Bakoon BPS-02 BPS-02 - Bakoon International Corp. (discontinued but still available at some local dealers)

 

 

SOtM mBPS-d2s SOtM - English | mBPS-d2s

 

Kingrex uPower http://www.kingrex.com/products.php?c=6&s=14

 

 

Here is a link to the CA thread for the coming Ultracap LPS-1 if someone have missed it: http://www.computeraudiophile.com/f27-uptone-audio-sponsored/mystery-revealed-uptone-audio-ultracap%99-linear-power-supply-1-a-28609/

[Guidof]

Bakoon BPS-02 (5v), Kingrex uPower (7,5v), SOtM mBPS-d2s (9v) & Kingrex SLAP (12v) are some of the most interesting battery supplies around. The only one that works with USB Regen with or without USB powered DAC is the uPower. If your DAC do not require USB power (or handshake) you can choose which ever one you like. LPS-1 will work with all of them except BPS-02 but it would be an over-kill to choose any other than uPower.

I have'nt tried BPS-02...but have always wanted to!

 

i used the SOtM battery PS with the REGEN and it worked just fine. I'm using it now with the Sonore microRendu and it works well with that too.

[Cornan]

i used the SOtM battery PS with the REGEN and it worked just fine. I'm using it now with the Sonore microRendu and it works well with that too.

Thanks Guodof! Reading about the SOtM again I realize that I got the specs wrong. It can deliver 6,5~8,4v not 9v. Should indeed be the perfect choise for USB Regen, microRendu and LPS-1.

[Qhwoeprktiyns]

Deleted

[MikeyFresh]

Thanks Guodof! Reading about the SOtM again I realize that I got the specs wrong. It can deliver 6,5~8,4v not 9v. Should indeed be the perfect choise for USB Regen, microRendu and LPS-1.

 

I think the SOtM battery is short in terms of the current required to energize the forthcoming LPS-1.

 

At the 6 to 9vdc output range of the SOtM battery, the LPS-1 will require between 2 - 2.5 amps of current, the SOtM battery only outputs 1.5 amps.

 

The SOtM battery specs:

 

Power output : 5.5mm x 2.5mm DC jack

- Battery output voltage : 6.5Vdc ~ 8.4Vdc

- Output voltage Range : 6Vdc ~ 9Vdc

- Current : 1.5 A

 

The low input voltage for the LPS-1 is stated as 7.5v, so that too looks like a bad match for the SOtM battery which will likely sag below that to 6 or 6.5v as it discharges.

[Cornan]

I think the SOtM battery is short in terms of the current required to energize the forthcoming LPS-1.

 

At the 6 to 9vdc output range of the SOtM battery, the LPS-1 will require between 2 - 2.5 amps of current, the SOtM battery only outputs 1.5 amps.

 

The SOtM battery specs:

 

Power output : 5.5mm x 2.5mm DC jack

- Battery output voltage : 6.5Vdc ~ 8.4Vdc

- Output voltage Range : 6Vdc ~ 9Vdc

- Current : 1.5 A

 

The low input voltage for the LPS-1 is stated as 7.5v, so that too looks like a bad match for the SOtM battery which will likely sag below that to 6 or 6.5v as it discharges.

 

Thanks MikeyFresh! Well, then it seems like my KingRex uPower with 7,5v/2,6A is not only the cheapest (approx GBP 150) but safest bet among the mensioned BPS for the Ultracap LPS-1...as long as you run it completely unconnected from the mains.

 

Bakoon have the same current as SOtM and KingRex SLAP! have voltage peaks up to 14v (LPS-1=max 12v).

[zilch0md]

Hi Cornan,

 

After some searching I have found a suitable battery pack for USB Regen for USD39,95 Lithium Ion Battery 7.4V 4400mAh

 

[ATTACH=CONFIG]26593[/ATTACH]

 

If you add this T-connector male to DC5.5/2.1mm DC plug for USD3,90 Male Dean (T-connector) to male 2.1mmx5.5mm DC barrel plug cable:Tools & Accessories,Cables - FPV Model: RC Plane, Multicopter, Quadcopter, FPV Goggles, FPV System and all things FPV.

 

[ATTACH=CONFIG]26594[/ATTACH]

 

you should have a pretty good & valuable battery pack for the USB Regen without soldering skills or the hassle of buying from China!

 

There's a potential problem with the PCM-equipped 7.4V battery pack linked, above. On the specifications page, it indicates that the built-in PCM (Protection Circuit Module) has a discharge cutoff voltage of 5.5V. That's obviously not the cut-off voltage for individual cells, as they will measure 4.2V when fully charged, so it's the cut-off voltage for the entire pack.

 

Problem: This is a 2S2P pack, so if the PCM is not going to stop the pack from discharging into a load until the sum of two cells in series is 5.5V, each cell could fall to an average of 2.75V per cell.

 

If a user allows this to happen, by nature of trusting the PCM instead of monitoring the voltage on his own to stop using the pack when it reaches 6.6V (3.3V per cell), having discharged from a maximum voltage of 8.4V (4.2V per cell), individual cells could go into phase reversal, suffering permanent damage, with the possibility of spontaneous combustion (not necessarily an explosion), but a fire just the same, with toxic soot getting spread about. Call a hazmat crew after you put out the fire. :-)

 

Ironically, at the top of main page for that same battery pack, the following warning is given:

 

 

Before you use or charge this battery you must read the Lithium Battery Saftety Instructions and Warnings document.

1. Do not charge or use batteries if the battery ...
   


1. is punctured or damaged
   
2. is bloated, expanded, swelling or otherwise deformed
   
3. has any cell with a voltage of 3.3v. This means less than 6.6v for a 2-cell/7.4v battery
   

 

[*]Do not charge batteries unattended. Monitor batteries during charging for popping, hissing, smoke, sparks or fire. Also monitor the battery for any swelling or other deformities. Disconnect the battery from your charger immediately.

[*]Do not charge batteries near flammable material. Charge batteries in a fireproof container. Do not charge batteries while they are in your robot

 

Do you see the disparity? They smartly warn us not to allow any one cell to drop below 3.3V - which is pretty much a standard warning for all LiPo batteries, although some people will say that 3.0V is the absolutely lowest you can go - and yet, going by the specifications, they contradict themselves by using a PCM that will allow a two-cell series voltage to fall to 5.5V (2.75V per cell) before it will shutdown.

 

I ruined a $100 6S LiPo pack once, by pushing the discharge all the way down to 3.0V per cell on each discharge cycle - and I was monitoring individual cell voltages during use, with an audible alarm that was set to go off if any one cell hit 3.0. The battery had only been cycled perhaps 7 or times, when a cell that had repeatedly reached 3.0V ahead of its siblings, decided to stop taking a charge. The pack started swelling when I put it on the charger. That was the end of that pack. So now, I stick to a 3.3V minimum per cell, religiously.

 

Unfortunately, the pack pictured above can't be monitored on a cell by cell basis, because it's not wired for a balanced charger. Both of its connectors use two-conductor connectors. A load only needs two conductors, of course, but the pictured "dumb" charger will charge each of the two banks of series-wired cells, together as a unit, not independently as a balanced charger would. So, there's yet another weakness built-in to this battery pack. Over time, in either one half of the pack or the other or in both halves, one cell in a series pair, could begin to exhibit a higher resistance to the charge current, such that by the time the two cells, together as a unit, reach the PCM-governed charge cut-off voltage of 8.4V, the stronger cell can actually be forced to exceed the safe maximum of 4.2V per cell - you'll be cooking that cell - while the weaker cell in a series pair is left behind at something less than 4.2V per cell.

 

Then, during repeated discharge/charge cycles, a snowball effect can take place, as the weaker cell is always sucked down to a lower voltage than its stronger sibling, leaving it all the more vulnerable to suffering damage from going below 3.3V while the other cell is still putting out something greater than that. (And that would be worse if you and/or the PCM allow the total voltage of the 2S pack to drop down to 5.5V before shutting it down.)

 

The fact that this battery pack is not wired for balanced charging is only compounded by the fact that its PCM allows the voltage of the pack as a whole to drop down to 5.5V. The two "oversights" will work together to shorten the useful life of the battery. Assuming the manufacturer actually knows what they're doing and that there are no errors in the published specifications, I would have to conclude that this pack is designed to fail after only a couple of dozen charge cycles - so that you'll toss it and buy another.

 

A battery pack wired for balance charging will have a two-conductor cable for discharging into a load, just like this battery pack, but it will have a JST connector for charging - similar to a small Molex connector, that has one conductor for each cell in the pack, plus a common ground wire. PCMs do not balance charge a pack internally, so the only way to keep the cells nicely matched throughout many usage cycles (500+), is to buy a balance charger and a battery pack that's made for balance charging.

 

That same vendor sells this 7.4V 4500 mAH 2S1P LiPo pack that's wired for balance charging (or monitoring the voltages of each cell during discharge through the separate two-conductor cable):

 



Tiger 7.4V 4500 MAH 30C LiPo Battery with T Plug

 

 

This photo shows a close-up of its JST connector - used for charging:

 



 

Three wires, not two - allowing each cell to be charged or monitored independently.

 

Here's an affordable ($16) balance charger for that pack:

 



Balance Charger for 7.4-11.1V 2-3S Cell Li-Po Battery

 

And here's a LiPo voltage alarm that I've used for several years (to monitor the aforementioned 6S packs I use to power a 24V TBI Millinea MG3 speaker amp for near-field monitors):

 



1-8S LiPo Battery Voltage Tester/Monitor

 

Just press the JST connector of a 7.4V, 2S pack onto the first three pins and it will start cycling through the cells to show the voltage of each, then the total voltage of the pack. In my experience, this alarm doesn't put any noise at all into your audio signal. (Which begs the question: How silent is a PCM that's equipped with a current-limiter?) You could leave it disconnected during play, re-attaching it occasionally throughout the discharge cycle, but that kind of defeats the purpose. Another feature of this alarm is that there's a little button which allows you to adjust the per-cell voltage at which it will alarm. I use do have mine set at 3.0V, but now I leave it at 3.3V. By the way, those little tweeter horns are ear-splittingly loud. They can be heard from the ground when mounted inside an airborne RC airplane or helicopter. I stuffed mine with some Play-Doh - I can still hear them when listening to music. :-)

 

Speaking of current limiting, this balance-wired battery pack, as with most of its kind, has no PCM and thus, has no current limiter. The specifications page for this battery says it has a maximum continuous discharge rating of 30C. A "C" rating can be converted to Amps (not milliamps) by dividing the pack's mAH rating by 1000, then multiply by the C rating.

 

So, for this 4500 mAh pack, with a 30C rating, we get (4500 / 1000) * 30 = 135 Amps. No kidding! This LiPo pack can deliver a continuous current of 135 Amps, without overheating, until it is fully discharged (3.3V per cell), in roughly 2 minutes flat.) That's why they are used by RC racing hobbyists. (Don't short the wires!)

 

Do we need a current limiter for use with DC audio gear? Without naming names, I've been told by three different manufacturers that their DC-powered audio gear will not pull more current than it can use and that it's safe to use my RC LiPo batteries without a current limiter, but one of them joked that any dust bunnies that might fall across exposed power terminals could cause a momentary arc. Arcs across clean air require much higher voltages, even for short distances. :-)

 

I've used unlimited LiPo packs with multiple pieces of audio gear for several years - never having any problem related to their ability to dump a lot of current. But if you want to shop for larger capacity 7.4V LiPo packs that are wired for a balance charger, I would try to stick with 15C, 20C, 25C, or 30C. The really big packs can go as high as 65C.

 

Here's a brand of LiPo pack I like: GensAceUSA - High Performance LiPoly (Lithium Polymer) Batteries for RC Cars, Helicopters, Planes, Boats, Trucks, Crawlers

 

Mike

[Superdad]

Wow Mike, you ARE a battery geek!

 

And all those hazards and precautions--you just explained to everyone why I dislike batteries so much.

 

To each his own. Or, Live and Let Discharge…

[zilch0md]

Wow Mike, you ARE a battery geek!

 

And all those hazards and precautions--you just explained to everyone why I dislike batteries so much.

 

To each his own. Or, Live and Let Discharge…

 

LOL

 

I hear you. LiPo batteries can be dangerous when abused and, at the very least, a little inconvenient to properly maintain, depending on the charging and monitoring equipment you are using. Still, with a balance charger and an alarm, the actual effort required is minimal.

 

When the alarm goes off (as a cell reaches 3.3V), you swap the pack for one that's fully charged, putting the first one on the balance charger, having moved the alarm to the fresh battery. When not playing music, unplug the alarm from the active pack so that it doesn't slowly drain the pack (or sound off in the middle of the night.) That's it. Not so bad.

 

The toughest part is just selecting the right pack for the load - keeping in mind that the voltage can be as high as 4.2V per cell that is in series and that the pack must not be used once the voltage gets down to 3.3V per cell.

 

Given that these packs have no (noise-making) voltage regulators on their outputs, your appliance must be able to operate at both extremes of these voltage ranges (when setting an alarm to discontinue use at 3.3V per cell):

 

1S1P, 1S2P, 1S3P, etc., nominally rated and sold as 3.7V: 3.3V to 4.2V

 

2S1P, 2S2P, 2S3P, etc., nominally rated and sold as 7.4V: 6.6V to 8.4V

 

3S1P, 3S2P, 3S3P, etc., nominally rated and sold as 11.1V: 9.9V to 12.6V

 

4S1P, 4S2P, 4S3P, etc., nominally rated and sold as 14.8V: 13.2V to 16.8V

 

5S1P, 5S2P, 5S3P, etc., nominally rated and sold as 18.5V: 15.5V to 21.0V

 

6S1P, 6S2P, 6S3P, etc., nominally rated and sold as 22.2V: 19.8V to 25.2V

 

7S1P, 7S2P, 7S3P, etc., nominally rated and sold as 25.9V: 23.1V to 29.4V

 

 

If the bottom end of the voltage range is too low for your device, you can always set the monitoring alarm for a higher voltage, but looking at this typical discharge curve, you will lose a lot of play time if you set the alarm for a voltage any higher than about 3.6V per cell. This curve also reveals that you don't gain a lot of play time by setting the alarm at 3.0V instead of at the safer threshold of 3.3V.

 

 

Source: batteries - LiPoly Battery - When to stop draining? - Electrical Engineering Stack Exchange

 

If your device demands a fixed, regulated voltage, you can connect a battery pack with a range that fits the desired voltage, then supply the pack with an LPS that's regulated at the desired voltage for your device - a la JKenney and his Ciúnas DAC or the French-made Audiophonics PCM5102 DAC. Both of these DACs rely on internal LiPo batteries to filter noise coming from the regulated LPS. (I'm not so sure about that, but it might hold some merit.) The trick here is to select a battery pack where the desired voltage for your device (as regulated by the constantly connected, trickle-charging LPS), is as close as possible to 3.8V per cell - for the sake of the battery's longevity. (3.8V is the ideal long-term storage voltage of a LiPo cell.)

 

Mike

[mmerrill99]

LOL

...............

If your device demands a fixed, regulated voltage, you can connect a battery pack with a range that fits the desired voltage, then supply the pack with an LPS that's regulated at the desired voltage for your device - a la JKenney and his Ciúnas DAC or the French-made Audiophonics PCM5102 DAC. Both of these DACs rely on internal LiPo batteries to filter noise coming from the regulated LPS. (I'm not so sure about that, but it might hold some merit.) The trick here is to select a battery pack where the desired voltage for your device (as regulated by the constantly connected, trickle-charging LPS), is as close as possible to 3.8V per cell - for the sake of the battery's longevity. (3.8V is the ideal long-term storage voltage of a LiPo cell.)

 

Mike

AFAIK, Jkenney uses LiFePo4 batteries - a whole different ball game than LiPo batteries - no fire risk, very flat discharge curve (remains nominally at 3.3V throughout discharge) & are constantly trickle charged at 3.3V?

[zilch0md]

AFAIK, Jkenney uses LiFePo4 batteries - a whole different ball game than LiPo batteries - no fire risk, very flat discharge curve (remains nominally at 3.3V throughout discharge) & are constantly trickle charged at 3.3V?

 

Oh, that's right, but the concept is the same as I described - putting a battery pack between a trickle-charging LPS and your load to filter the LPS noise (if indeed this is effective).

 

But, yes, LiFePO4 batteries are more stable, "quieter" for audio purposes (or so I've read) and they do have a 3.3V nominal rating, instead of 3.7 for LiPo.

 

Here's a typical LiFePO4 18650 cell discharge curve.

(Note that not all 18650 cells use LiFePO4 chemistry):

 

[ATTACH=CONFIG]26778[/ATTACH]

 

Source: LiFePower4 -1100mAh - 18650 size - RC Groups

 

Better still, you can find LiFePO4 cells that are individually protected against excessive discharge. They are available in sizes other than 18650, too.

 

Mike

[zilch0md]

Having deluged this thread with perhaps too much information about the care and maintenance of batteries, and despite my comfort with using LiPo batteries, I've been pursuing mmerrill99's suggestion of using LiFePO4 batteries instead.

 

I've spent several hours looking for a convenient 6.4V LiFePO4 battery pack, where the individual cells in the series-wired pack are not simply protected, together as a unit, from excessive charge or discharge voltages, but are also kept in a balanced state, while charging with a simple, semi-intelligent, two-wire charger - again, with the understanding that balance charging can greatly extend the service life of the pack by avoiding the situation where one weak cell gets weaker still, eventually spoiling the entire pack.

 

There are lots of LiFePO4 packs that have built-in protection circuits, but very few of them include balance charging modules inside the pack itself.

 

This 6.4V 4500mAH LiFePO4 pack by Tenergy, a company that has a great reputation in the battery industry, appears to have everything we could want in terms of easy use, with proper self-management of its cells:

 

 

 

Tenergy LIFEPO4 6.4V 4.5Ah Pack - Item #31949

 

http://www.tenergy.com/31949

 

https://www.amazon.com/Tenergy-4-5Ah-LiFePO4-Rechargeable-Battery/dp/B00CPTCCPK

 

(This $39.99 Amazon price is a really good deal, as most places sell it for $69.99)

 

 

And here's the matching charger:

 

 

Tenergy 6.4V (2-Cell) Intelligent 1A LiFePO4 Battery Pack Charger - Item #01369

 

http://www.tenergy.com/01369

 

Amazon doesn't carry it. (Why not?)

 

Search Google Shopping: https://www.google.com/search?output=search&tbm=shop&q=tenergy+01369&oq=tenergy+01369

 

----

 

Here are some noteworthy specs for the battery:

 

Nominal Capacity: 4.6Ah (typ.), 4.5Ah (min.)

Nominal Voltage: 6.4V

Max. Discharge Current (Pulse): 8.0A

Discharge Method-Standard: 900mA

Max. Continuous Discharge: 5.0A

Discharge Cut-off Voltage: 4.6V

Battery Dimension: 70x47x101mm (It's about 4-inches tall)

 

I will add that, when fully charged, it can yield no more than 3.33V per cell or 6.67V, but will drop quickly to 3.2V per cell (6.4V) where it will stay throughout most of its discharge. The protection module will shut down the pack at 4.6V (2.3V per cell), but a USB Regen that has to provide 5V power to a DAC will fail before you can get down to 4.6V. If the USB Regen is not supplying 5V power to a DAC, then this battery will shut down before failing to satisfy the Regen's 3.3V regulator (which probably wants to see a little more than 3.3V, anyway, but probably doesn't need as much as 4.6V.)

 

So there you go... Now who wants to be first to give it a listen? :-)

 

By the way, you cannot combine these in series to achieve a higher voltage. If you want a different voltage, Tenergy has the following, similar products from which to choose:

 

Lithium Iron Phosphate

 

Mike

[Superdad]

 

This 6.4V 4500mAH LiFePO4 pack by Tenergy, a company that has a great reputation in the battery industry, appears to have everything we could want in terms of easy use, with proper self-management of its cells:

 

 

[ATTACH=CONFIG]26878[/ATTACH]

 

Tenergy LIFEPO4 6.4V 4.5Ah Pack - Item #31949

 

http://www.tenergy.com/31949

 

https://www.amazon.com/Tenergy-4-5Ah-LiFePO4-Rechargeable-Battery/dp/B00CPTCCPK

 

 

Very cool. Now you are getting somewhere Mike!

 

[Not that you will see me fall in love with batteries any time soon. I just can't love 'em the way you do. ]

[zilch0md]

Very cool. Now you are getting somewhere Mike!

 

[Not that you will see me fall in love with batteries any time soon. I just can't love 'em the way you do. ]

 

Thanks Alex!

 

Coming from you, I'll take that as an endorsement - of the approach at least, if not the specific product.

[watercourse]

Thank you zilch0md, this is very helpful!

[sandyk]

a USB Regen that has to provide 5V power to a DAC will fail before you can get down to 4.6V.

 

In fact, it will fail to remain in regulation after it drops below 5.3V which is well above the battery's cut off voltage.

[zilch0md]

In fact, it will fail to remain in regulation after it drops below 5.3V which is well above the battery's cut off voltage.

 

Thanks Alex. In the absence of any kind of voltage monitoring alarm, what would you expect a user to hear, while listening to music, when the USB Regen suddenly fails to get 5.3V? Would it just go immediately silent or do you think there might be a transition period, during which the sound quality starts to erode in some way?

[sandyk]

Thanks Alex. In the absence of any kind of voltage monitoring alarm, what would you expect a user to hear, while listening to music, when the USB Regen suddenly fails to get 5.3V? Would it just go immediately silent or do you think there might be a transition period, during which the sound quality starts to erode in some way?

 

I would expect the latter. Given the rating of the battery, perhaps one of the attached connected on the device side of a toggle switch etc, could be worthwhile ?

DC 0 100V 3 30V Digital LED CAR Voltmeter Gauge Voltage Panel Meter 2 3 Wire PRO | eBay