AC / Li-ion Battery Power Supply: 24 V DC Output for DC Amplifiers

[TheBeerinator]

Ahh I did not use a direct upload. oops.

[Millstonemike]

Well I followed the advice in here and this is a picture of a quick test wiring I did. I later wrapped everything exposed in shrink tubing. It all works. Multimeter reads a solid 24v from the batteries. Can hotswap to AC charging and power while listening.

I only hooked in GND to the relay, and not VBAT-, and everything works fine it seems. I read in here that you need to connect both, but it works. Is there any reason why this would be bad?

I meant to post this earlier, but had to let my account get approved, and uhh kinda forgot. I had to navigate myself here after asking for support on the product page.

The pic is not showing.

[TheBeerinator]

Well I followed the advice in here and this is a picture of a quick test wiring I did. I later wrapped everything exposed in shrink tubing. It all works. Multimeter reads a solid 24v from the batteries. Can hotswap to AC charging and power while listening.

I only hooked in GND to the relay, and not VBAT-, and everything works fine it seems. I read in here that you need to connect both, but it works. Is there any reason why this would be bad?

I meant to post this earlier, but had to let my account get approved, and uhh kinda forgot. I had to navigate myself here after asking for support on the product page.

[Millstonemike]

Millstonemike,

I would have gladly posted sooner but I was on vacation and I am happy to say, listening to my project which works very well using the power arrangement in your design.

1) I recognize that your idea was conceptual.

2) I initially went with the 3 diode arrangement as suggested by the Sure update in post #7 largely because this diagram was given to me by PE Tech support.

I got a kit for a portable setup from PE and the assembly instructions allude to increasing the power for better performance.
Direct inquiry regarding this modification got me a copy of the Sure adjusted diagram and no further info.
Some crafty web searching got me to your initial thread on the concept and then to this thread for the updated design.

I may have over-rated my diodes, I went with SB1245's partly because I liked the idea of very low forward voltage loss.

I found that despite using a mechanical switch I had the same power oscillation as indicated in dmormerod's post about the relay.
Both sets of "Charging" LEDs flashed and the pulse was audible in the playback, I assume mostly because of the constant change in voltage to the amp.
Frankly, I didn't leave it plugged in long enough to measure for certainty.

A blocking diode added at BATT+ as you suggested in post #28 cured the pulse and I have not seen it since.

I have been using my set up on and off for a few weeks now and so far have seen no issues.
Charging works as expected and the added voltage under battery power provides a welcome boost in volume and performance.

I'm grateful for your design and even more so for your direct help.

Thanks again.
-Joose

Thanks. Great that it works. I like the Shockley diodes. Less voltage drop. I forget which amp you are using, but many have a reverse polarity protection diode in the DC input. For permanent installations, it's not necessary, just another voltage drop. I bypass them. as a rule. Adds a little extra headroom

[joosemcgee]

Millstonemike,

I would have gladly posted sooner but I was on vacation and I am happy to say, listening to my project which works very well using the power arrangement in your design.

1) I recognize that your idea was conceptual.

2) I initially went with the 3 diode arrangement as suggested by the Sure update in post #7 largely because this diagram was given to me by PE Tech support.

I got a kit for a portable setup from PE and the assembly instructions allude to increasing the power for better performance.
Direct inquiry regarding this modification got me a copy of the Sure adjusted diagram and no further info.
Some crafty web searching got me to your initial thread on the concept and then to this thread for the updated design.

I may have over-rated my diodes, I went with SB1245's partly because I liked the idea of very low forward voltage loss.

I found that despite using a mechanical switch I had the same power oscillation as indicated in dmormerod's post about the relay.
Both sets of "Charging" LEDs flashed and the pulse was audible in the playback, I assume mostly because of the constant change in voltage to the amp.
Frankly, I didn't leave it plugged in long enough to measure for certainty.

A blocking diode added at BATT+ as you suggested in post #28 cured the pulse and I have not seen it since.

I have been using my set up on and off for a few weeks now and so far have seen no issues.
Charging works as expected and the added voltage under battery power provides a welcome boost in volume and performance.

I'm grateful for your design and even more so for your direct help.

Thanks again.
-Joose

[Millstonemike]

only from the batteries (and not switch to direct 24v as per the diagram above), can I simply connect the boards in series by connecting VBAT+ on board 1 to VBAT- on board 2? Do I need a diode? My end device is pulling 2.0a.

Need more info ...

[aliouindie]

only from the batteries (and not switch to direct 24v as per the diagram above), can I Redtube Beeg Spankbang simply connect the boards in series by connecting VBAT+ on board 1 to VBAT- on board 2? Do I need a diode? My end device is pulling 2.0a.

[Millstonemike]

Thanks very much for the reply, Millstonemike.
It's a big help.

Please post your results. I hope you realized that: (1) This was a theoretical design - I never built it; and (2) It was analyzed by Sure and their recommendation (diode) was incorporated into the schematic.

Another member was building it but never posted again. So I am interested in your results ...

[joosemcgee]

Thanks very much for the reply, Millstonemike.
It's a big help.

[Millstonemike]

I know this thread is a bit old but I could use a bit of clarification.

Am I correct in interpreting the diagram as showing the GND for charging and VBAT- wired together to make the indicated board (-)?

I know that GND and VBAT- should both be 0 VDC but they don't measure as contiguous connections in the board and I just want to confirm that connecting them together doesn't affect the charge circuit or protection in any way.

Thanks.
-Joose

Yes.

[joosemcgee]

I know this thread is a bit old but I could use a bit of clarification.

Am I correct in interpreting the diagram as showing the GND for charging and VBAT- wired together to make the indicated board (-)?

I know that GND and VBAT- should both be 0 VDC but they don't measure as contiguous connections in the board and I just want to confirm that connecting them together doesn't affect the charge circuit or protection in any way.

Thanks.
-Joose

[dmormerod]

Perhaps bad wiring is shorting the out the PS when the relay is activated. That will cause the switching PS to shut down, the relay will then release and the PS will recover. Then the relay will close again causing the short and the PS will shut down ... and the oscillations will continue.

Here's the pin by pin wiring for the relay - pin numbers in blue. If the wiring is correct, and the problem continues, then maybe another diode is needed as shown in blue. I seem to remember that the PS + cannot enter the BMM through Bat + (I thought I verified this during the design phase but can't specifically recall that).

I corrected the connections but still had the issue. I added the additional diode and that seems to have fixed it, so many thanks!

[dmormerod]

Perhaps bad wiring is shorting the out the PS when the relay is activated. That will cause the switching PS to shut down, the relay will then release and the PS will recover. Then the relay will close again causing the short and the PS will shut down ... and the oscillations will continue.

Here's the pin by pin wiring for the relay - pin numbers in blue. If the wiring is correct, and the problem continues, then maybe another diode is needed as shown in blue. I seem to remember that the PS + cannot enter the BMM through Bat + (I thought I verified this during the design phase but can't specifically recall that).

Thanks for all your help. I’ll try reconnecting based on your changes and let you know.

[Millstonemike]

Perhaps bad wiring is shorting the out the PS when the relay is activated. That will cause the switching PS to shut down, the relay will then release and the PS will recover. Then the relay will close again causing the short and the PS will shut down ... and the oscillations will continue.

Here's the pin by pin wiring for the relay - pin numbers in blue. If the wiring is correct, and the problem continues, then maybe another diode is needed as shown in blue. I seem to remember that the PS + cannot enter the BMM through Bat + (I thought I verified this during the design phase but can't specifically recall that).

[dmormerod]

I'm confused by your wiring explanation. Looking at the schematic, your number sequences should be aligned with the left side and right side, not the top and bottom.

In lieu of some esoteric problem with the relay, the oscillation when powered points to a coil wiring problem.

This is the schematic for your relay. The numbering is as if your looking at the relay's contacts (not over the top of the relay) You should have 8 contacts (any different and you were shipped the wrong part).

The two contacts at the bottom, their spades orientated different than the other 6, are the coil's contacts. Those would be connected to the PS + and -.. Verify that and we can move on solving the problem.

I was referring to the wiring schematic for the solution. What I realized is, if you look at the relay diagram, turn the relay 90 degrees clockwise and that's how I've wired it, when I should have probably turned it anti-clockwise. See my attached as to how I've currently wired it.