Are there any class D amps like tpa3255 or better that can run directly from 48v to 60v DC solar house battery?

[jbl590]

I am running multiple 3x aiyima a07's off grid from my small RV size solar setup which uses a "48v" lipo battery bank (real voltage 50v to 60v)

Is there a way to make this more efficient without conversion loss from dc to ac and back to dc?

The whole reason I'm using these is because they're efficient on idle power draw, but they're not nearly as efficient as they could be if they would just input higher dc voltage directly.

I could also use more output power than the TPA3255 gives, if there is something else that can input higher voltage DC but has a similar low idle draw as the a07.

 

[lisgotan]

I am running multiple 3x aiyima a07's off grid from my small RV size solar setup which uses a "48v" lipo battery bank (real voltage 50v to 60v)

Is there a way to make this more efficient without conversion loss from dc to ac and back to dc?

The whole reason I'm using these is because they're efficient on idle power draw, but they're not nearly as efficient as they could be if they would just input higher dc voltage directly.

I could also use more output power than the TPA3255 gives, if there is something else that can input higher voltage DC but has a similar low idle draw as the a07.

I am not sure if the A07 could take in 50-60V without ny issue.

So, for this case, you best bet is a regulated DC-DC convertor. The converter will take it 50-60V and output 48V.

https://www.digikey.com/en/maker/blogs/introduction-to-dc-dc-converters#:~:text=DC%2DDC%20converters%20are%20high,input%20voltages%20and%20output%20currents.

 

[somebodyelse]

How low do you let the battery voltage go? Depending on the DC-DC converter type the input voltage may need to be higher than the output voltage by some margin, so you might need something a bit less than 48V on the output. That might also drop the idle power consumption a bit. If your speakers are 4R you don't really gain anything over 36V anyway from what I remember.

There may be amps that will operate up to 60V without a DC-DC converter, but they will have a very high power rating and probably more power consumption at idle / low output. A good DC-DC converter and an appropriately sized amp will probably be more efficient.

 

[jbl590]

I am not sure if the A07 could take in 50-60V without ny issue.

So, for this case, you best bet is a regulated DC-DC convertor. The converter will take it 50-60V and output 48V.

https://www.digikey.com/en/maker/blogs/introduction-to-dc-dc-converters#:~:text=DC%2DDC%20converters%20are%20high,input%20voltages%20and%20output%20currents.

Thanks
I just bought one of those buck converters to run 12v devices, but I cannot find specs on what the idle loss and conversion loss is on them.
I bought one of these cheapo things for 12v stuff: https://www.amazon.com/dp/B07RM1GHBC?ref=ppx_yo2ov_dt_b_product_details&th=1

I will have to buy a clamp on meter to tell what the idle draw is on it, unless someone already knows what the idle loss and overhead is on them.

It would just be nice if I could mod some parts in the a07's so there is no conversion loss or idle draw from a converter.

 

[jbl590]

How low do you let the battery voltage go? Depending on the DC-DC converter type the input voltage may need to be higher than the output voltage by some margin, so you might need something a bit less than 48V on the output. That might also drop the idle power consumption a bit. If your speakers are 4R you don't really gain anything over 36V anyway from what I remember.

There may be amps that will operate up to 60V without a DC-DC converter, but they will have a very high power rating and probably more power consumption at idle / low output. A good DC-DC converter and an appropriately sized amp will probably be more efficient.

The house battery never goes lower than around 48v, yes I think 36v would be good to drive the a07's with higher current available than what the stock power bricks can deliver.

I am currently using the stock 36v power bricks that came with the a07's and they are driving jbl 590 towers which are the most efficient towers I have tried, but if I push them too hard I do run into clipping on bass heavy stuff.

I have some klipsch rp8000f and some rp600m and some jbl 530 I need to try also to see if I can get more volume with less clipping but haven't had the chance yet. I can already run these pretty loud though so it hasn't been a priority, mostly going to be HT use where I hit that clipping wall. If I had a07's with crossover capability that could help, so I could shift some of that bass to the subs.

These a07 are so beautifully efficient I guess I will have to just cope with their limitations. The power they draw at idle is so far below any other option I tried I guess it'll have to live with their weaknesses.

I guess it was too much to hope for that maybe a few mods could be made to the a07 so it could take the house battery voltage directly.

 

[Jim Shaw]

Your DC to 120/60 AC converter is likely quite efficient, probably around 90-95%. More important, it provides a level of protection to your audio gear from switching and inductive spikes that could easily wipe out amp electronics.
If I were you, I'd continue to power your amps on 120vac and economize elsewhere if necessary.

 

[jbl590]

Your DC to 120/60 AC converter is likely quite efficient, probably around 90-95%. More important, it provides a level of protection to your audio gear from switching and inductive spikes that could easily wipe out amp electronics.
If I were you, I'd continue to power your amps on 120vac and economize elsewhere if necessary.

I currently use a growatt lvm3000es all in one that is reasonably efficient for what it is, (lower grade cheap chinese thing) but it's idle draw alone is 50 to 60w, just the idle draw alone equals a dozen a07's idle draw.

I bought more solar panels to double my array that I have to figure out where to put them, probably need to build a patio cover to make a place to mount them, and I bought a different inverter to try that is supposed to have 30w idle draw, and I've drastically reduced my power consumption everywhere I could, but I'm still not bringing in enough power during cloudy winter.

I have power to spare in summer just with the panels I have up now, I don't have to worry about saving power then at all, but the winter in oregon is brutal for solar output making me run half on a gas generator.

 

[Cars-N-Cans]

I would say the real thing here will be the inverters used. I don't know all that is available but getting one that can utilize the high battery voltage directly will ensure you have reasonably good efficiency if you don't already have it. Problem with running the amps directly off the batteries is that they will no longer be isolated from the rest of the electrical equipment in the home, which could cause issues. The stock offline supplies are galvanically isolated and well filtered, which serves to isolate the amplifier and limit things like ground loops and interference, not to mention destructive transients as was pointed out above. Also, for what its worth, the actual nominal power draw of an amplifier is quite low if its a class-D. The power is needed for the peaks, but the average output per channel will be something like maybe 10-20 watts during normal listening, and maybe substantially lower if its not something that's compressed like pop music. I would assume that with the stock power pack and its current limit the A07 amps have around 50-75Wrms per channel or so. An additional option is to use more efficient power packs, but the ones there are probably at least around 85-90% efficient already, and probably have only a watt or two of draw at idle. Probably not a lot of juice to be had for the squeeze involved.

Edit: Another thought if the inverter has a high idle draw you could use low voltage lighting so the inverter can be switched off when not needed. Easier said than done since additional wiring is needed and cheap LED lamps need modifying to work on the lower DC voltage, but in the winter the lights likely going to be on more than anything else. I would say the best option is to try and find ways to only have the inverter on when absolutely necessary if it draws a lot of power just sitting there.

 

[jbl590]

I would say the real thing here will be the inverters used. I don't know all that is available but getting one that can utilize the high battery voltage directly will ensure you have reasonably good efficiency if you don't already have it. Problem with running the amps directly off the batteries is that they will no longer be isolated from the rest of the electrical equipment in the home, which could cause issues. The stock offline supplies are galvanically isolated and well filtered, which serves to isolate the amplifier and limit things like ground loops and interference, not to mention destructive transients as was pointed out above. Also, for what its worth, the actual nominal power draw of an amplifier is quite low if its a class-D. The power is needed for the peaks, but the average output per channel will be something like maybe 10-20 watts during normal listening, and maybe substantially lower if its not something that's compressed like pop music. I would assume that with the stock power pack and its current limit the A07 amps have around 50-75Wrms per channel or so. An additional option is to use more efficient power packs, but the ones there are probably at least around 85-90% efficient already, and probably have only a watt or two of draw at idle. Probably not a lot of juice to be had for the squeeze involved.

Edit: Another thought if the inverter has a high idle draw you could use low voltage lighting so the inverter can be switched off when not needed. Easier said than done since additional wiring is needed and cheap LED lamps need modifying to work on the lower DC voltage, but in the winter the lights likely going to be on more than anything else. I would say the best option is to try and find ways to only have the inverter on when absolutely necessary if it draws a lot of power just sitting there.

Yes I'm setting up that 12v buck converter to run lights and a diesel parking heater, I'll have to search out the most efficient 12v led's haven't done that yet.

I don't run off the house wiring and I'm just in one room mainly and only heating one room, so I can do anything I want running automotive led lighting or whatever.

I need to find a couple 12v led lights with 100w equivalent output and long lifespan, that's like 1600 lumens or so if anyone has ideas. RV or car type would work.

 

[Jim Shaw]

I currently use a growatt lvm3000es all in one that is reasonably efficient for what it is, (lower grade cheap chinese thing) but it's idle draw alone is 50 to 60w, just the idle draw alone equals a dozen a07's idle draw.

I bought more solar panels to double my array that I have to figure out where to put them, probably need to build a patio cover to make a place to mount them, and I bought a different inverter to try that is supposed to have 30w idle draw, and I've drastically reduced my power consumption everywhere I could, but I'm still not bringing in enough power during cloudy winter.

I have power to spare in summer just with the panels I have up now, I don't have to worry about saving power then at all, but the winter in oregon is brutal for solar output making me run half on a gas generator.

I hear you. Another possibility might be to run another quite small inverter for low-power electronics and led lights at night -- one that has a much smaller idle draw current. I had no idea that idle current draw was so high on your present inverter. 50-60 watts is a lot.

Another alternative, but I don't know how practical, would be to use one of the 'uninterruptible' computer supplies for just the audio gear. For example, a 1000-watt-hr unit could power the A07 for several hours and just recharge itself when you turn the main inverter back on. This uninterruptible PS could also run your computer or iPad in an emergency.

Don't get me wrong... what you first wanted to do is possible, but protecting electronics from DC switching and inductive spikes is complex. An inverter provides those protections, built in. I wouldn't want to recommend a solution that might well have you replacing amps often. An amp damaged by power spikes is difficult to repair. Replacement might well be cheaper.

I feel your situation. Let us know how you solve it.
Regards,

 

[jbl590]

I hear you. Another possibility might be to run another quite small inverter for low-power electronics and led lights at night -- one that has a much smaller idle draw current. I had no idea that idle current draw was so high on your present inverter. 50-60 watts is a lot.

Another alternative, but I don't know how practical, would be to use one of the 'uninterruptible' computer supplies for just the audio gear. For example, a 1000-watt-hr unit could power the A07 for several hours and just recharge itself when you turn the main inverter back on. This uninterruptible PS could also run your computer or iPad in an emergency.

Don't get me wrong... what you first wanted to do is possible, but protecting electronics from DC switching and inductive spikes is complex. An inverter provides those protections, built in. I wouldn't want to recommend a solution that might well have you replacing amps often. An amp damaged by power spikes is difficult to repair. Replacement might well be cheaper.

I feel your situation. Let us know how you solve it.
Regards,

Yes I bought another inverter with a lower power draw to try that, just haven't installed it yet need to figure out the right fuse or breaker to put in front of it.

While I have some people with electronics knowledge here, do any you know what type of fuse I need to put in front of that 12v buck converter for 48-60v dc input?
The buck converter is 20amp at 12v output, 240w max.

I also need to know the right fuse or breaker to put in front of the new inverter, it's a 3000w output inverter with 6000w peak rating for a few seconds. 48 - 60v dc input 120v output.

I originally thought an automotive 12v fuse would work in front of the buck converter, but then when I went to buy one they say they're rated only up to 36v so now I'm not sure.

No idea what the right fuse or breaker is for the new inverter, the growatt I use now has a built in breaker so I didn't use a fuse or breaker on it's input, maybe I should have.
The batteries I'm using have built in over current protection in their BMS but they'll put out well over 100a at over 48v before that trips.

 

[Cars-N-Cans]

Yes I bought another inverter with a lower power draw to try that, just haven't installed it yet need to figure out the right fuse or breaker to put in front of it.

While I have some people with electronics knowledge here, do any you know what type of fuse I need to put in front of that 12v buck converter for 48-60v dc input?
The buck converter is 20amp at 12v output, 240w max.

I also need to know the right fuse or breaker to put in front of the new inverter, it's a 3000w output inverter with 6000w peak rating for a few seconds. 48 - 60v dc input 120v output.

I originally thought an automotive 12v fuse would work in front of the buck converter, but then when I went to buy one they say they're rated only up to 36v so now I'm not sure.

No idea what the right fuse or breaker is for the new inverter, the growatt I use now has a built in breaker so I didn't use a fuse or breaker on it's input, maybe I should have.
The batteries I'm using have built in over current protection in their BMS but they'll put out well over 100a at over 48v before that trips.

Is it the one you posted earlier? The fuse will need to be rated to handle the current draw at 48V since it will be higher.

For the lighting even yet another possibility to running point of use converters would be to run series strings of 4x 12V LED bulbs off the battery since you only use one room. They will likely need to be the type ballasted with resistors so the voltage splits fairly evenly and be able to handle the peak input of 15V at the top of the battery’s charge.

 

[orangezero]

Hello, I had some ideas if anyone still reads to here.

I share the concern of inverters inefficiencies and have considered using my big "house" lifepo4 battery to power some tpa3255 boards. I'm hooked to the grid so I have AC at my house, but getting "proper" DC power supplies at high voltages can get expensive. I knew there had to be some potential sound concerns with hooking an amp directly to the main battery, even with proper fuses. The cost of "proper" sine wave inverters can scare me. It seems to me devices like your growatt work really well if confined to their appropriate limitations and run well under spec. The marketing for my inverter always oddly added the 4kw at 110v and 4kw at 220v together and said "8kw total power" but I knew full well I was buying a 2-2.5kw inverter before the sine wave starts going crazy. I prefer the solution of having as many direct current devices as possible, and keep the inverter purchase from bankrupting me. If we look around, almost everything can be DC now and uses a wall wart.

Consider this... a smaller, separate battery pack at the optimal voltage for the amp you have (someone said around 36v previously). No DC-DC converter needed. No inverter needed. You use the three A07 plugged in to the smaller battery when in use and then when it gets low, you unplug and use your main battery to recharge it. I do that with a few smaller battery packs. I ended up getting a charger often used for charging drone batteries and RC cars.

With this "separate battery idea" much depends on how often and how long you use the three A07. I'm curious how you are using them. I lost my 15yr old class D panasonic receiver recently and have been reading online about various ways to use things like several tpa3255 boards to make a 5.1 or 7.1 surround system with my pc. I see several advantages of having a separate battery: isolation, efficiency, simplicity, expandability. Some may find it a downside to have to plug and unplug things to recharge the battery, but the other electrical solutions seem overly complex to me.

Similar to inverters, these tpa3255 boards are often listed as 300w+300w, and often sold with 32v x 5a power supplies. I've read A07 power usage can be around 20-100w.

If you haven't purchased LEDS yet, you could consider the various lm561c led boards on ebay. There may be others now, but the more efficient ones were also 50-100% more expensive. DC-DC boards at 5a are pretty cheap and small.

Finally, I'm sure you know this already, but when I finally got less lazy and shifted my solar panels to a steeper angle in the winter, they do produce a bit more power. It was pretty interesting to see the bump in the graph. Your answer of "more panels" is almost always the correct answer

 

[Loathecliff]

I've been off-grid for twenty years, & I tried direct DC a long time ago. Great in theory but it's not a quiet world across those battery terminals.
The pulsing of the solar controller alone coming through the speakers was enough for me.
Edit:- I also thought one isolated battery was the way around that.....until the novelty wore off.

 

[Honu]

I am running multiple 3x aiyima a07's off grid from my small RV size solar setup which uses a "48v" lipo battery bank (real voltage 50v to 60v)

Is there a way to make this more efficient without conversion loss from dc to ac and back to dc?

The whole reason I'm using these is because they're efficient on idle power draw, but they're not nearly as efficient as they could be if they would just input higher dc voltage directly.

I could also use more output power than the TPA3255 gives, if there is something else that can input higher voltage DC but has a similar low idle draw as the a07.

We are on the same boat ... the best option out there : 48-60V => 36V DC-DC converter. 36V input prevent the3255 from overheating vs 48V... so it's better in any ways.

 

[Honu]

Thanks
I just bought one of those buck converters to run 12v devices, but I cannot find specs on what the idle loss and conversion loss is on them.
I bought one of these cheapo things for 12v stuff: https://www.amazon.com/dp/B07RM1GHBC?ref=ppx_yo2ov_dt_b_product_details&th=1

I will have to buy a clamp on meter to tell what the idle draw is on it, unless someone already knows what the idle loss and overhead is on them.

It would just be nice if I could mod some parts in the a07's so there is no conversion loss or idle draw from a converter.

Here we go for the 36V output, buy them on aliexpress, they cost like 20€ for a 10A output : https://a.aliexpress.com/_EGETNMh
No current load : 25mA for the 10A

 

[Honu]

I currently use a growatt lvm3000es all in one that is reasonably efficient for what it is, (lower grade cheap chinese thing) but it's idle draw alone is 50 to 60w, just the idle draw alone equals a dozen a07's idle draw.

I bought more solar panels to double my array that I have to figure out where to put them, probably need to build a patio cover to make a place to mount them, and I bought a different inverter to try that is supposed to have 30w idle draw, and I've drastically reduced my power consumption everywhere I could, but I'm still not bringing in enough power during cloudy winter.

I have power to spare in summer just with the panels I have up now, I don't have to worry about saving power then at all, but the winter in oregon is brutal for solar output making me run half on a gas generator.

I got a 5kW chinese all in one and it draw 45w idle which is 45*24 = 1kWh per DAY .. ! While my whole comsumption is 1.5kWh per day => since i got very low consumption, the inverter is responsible for 66% of our energy used.

 

[Honu]

I've been off-grid for twenty years, & I tried direct DC a long time ago. Great in theory but it's not a quiet world across those battery terminals.
The pulsing of the solar controller alone coming through the speakers was enough for me.
Edit:- I also thought one isolated battery was the way around that.....until the novelty wore off.

Maybe the DC-DC converter will filter those (40-60V => 36V)