Voltage converter for 144V EV battery

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   I want to build a portable circular open air small party soundsystem of four or eight speakers for my converted EV with a 144V battery (nominal 120-166V).
Instead of doing 12V amplification (because 144V-12V converters are *pricy*), I want to look into using these DC amplifier modules (https://icepoweraudio.com/products/other/a-series/) and need a high-power voltage converter for them.

Two routes are possible here:

1) Use mixed ICEPOWER 1000A for bass and ICEPOWER 500A for mids/highs means they have an overlapping voltage input of 42–75V which is wider than the battery of 120-166V. So a buck converter with a fixed 2.5 ratio could be used here which would yield 48–66V.

2) I use only ICEPOWER 1000A modules for all speaker types and pay better attention to controlling the top speakers with the higher-powered amps. In this case the amp voltage would be as high as 120V, so a buck converter with a fixed 1.4 ratio could be used which would yield ca. 85–118V.

Here are the questions:

Which of the approaches sound better? Higher voltage for better amp efficiency? Obviously, in a battery powered system, efficiency is king.

The converters would need to be custom built, since nothing like this exists on the market. How difficult is it to build one for, say, 4kW? I don't have sufficient knowledge atm to make one. So I could either learn it or hire someone to make it. But who would accept such a job?

I understand that making such a converter isn't gonna be cheap, either. I'm exploring options.
Going all 12V poses no technical difficulties, but I want to explore what else is possible first.

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yanone Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 02 March 2006 Location: Germany Status: Offline Points: 9	Post Options Post Reply Quote yanone Report Post Thanks(0) Quote Reply Topic: Voltage converter for 144V EV battery Posted: 20 March 2022 at 7:00am
	I want to build a portable circular open air small party soundsystem of four or eight speakers for my converted EV with a 144V battery (nominal 120-166V). Instead of doing 12V amplification (because 144V-12V converters are pricy), I want to look into using these DC amplifier modules (https://icepoweraudio.com/products/other/a-series/) and need a high-power voltage converter for them. Two routes are possible here: 1) Use mixed ICEPOWER 1000A for bass and ICEPOWER 500A for mids/highs means they have an overlapping voltage input of 42–75V which is wider than the battery of 120-166V. So a buck converter with a fixed 2.5 ratio could be used here which would yield 48–66V. 2) I use only ICEPOWER 1000A modules for all speaker types and pay better attention to controlling the top speakers with the higher-powered amps. In this case the amp voltage would be as high as 120V, so a buck converter with a fixed 1.4 ratio could be used which would yield ca. 85–118V. Here are the questions: Which of the approaches sound better? Higher voltage for better amp efficiency? Obviously, in a battery powered system, efficiency is king. The converters would need to be custom built, since nothing like this exists on the market. How difficult is it to build one for, say, 4kW? I don't have sufficient knowledge atm to make one. So I could either learn it or hire someone to make it. But who would accept such a job? I understand that making such a converter isn't gonna be cheap, either. I'm exploring options. Going all 12V poses no technical difficulties, but I want to explore what else is possible first.

yanone Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 02 March 2006 Location: Germany Status: Offline Points: 9	Post Options Post Reply Quote yanone Report Post Thanks(0) Quote Reply Posted: 20 March 2022 at 7:25am
	Sorry, I made a mistake: ICEPOWER 1000A’s frequency response caps at 1kHz and is therefore not suited to power all speakers. So either two voltage converters need to be built to power the two amp types, or only the ICEPOWER 500A is used for all speaker types, with electric requirements of 1) staying in place unchanged.

carlosdelondres Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 21 June 2012 Location: London Status: Offline Points: 243	Post Options Post Reply Quote carlosdelondres Report Post Thanks(0) Quote Reply Posted: 20 March 2022 at 9:30am
	If your battery installation permits, could you not tap in the centre of the pack and create a +/- 72V power supply for something like the hypex ncore series, which run on up to +/- 98V?

yanone Members Profile Send Private Message Find Members Posts Add to Buddy List New Member Joined: 02 March 2006 Location: Germany Status: Offline Points: 9	Post Options Post Reply Quote yanone Report Post Thanks(0) Quote Reply Posted: 20 March 2022 at 10:48am
	Very interesting idea. Yes, I have access to the battery pack. But I lack a bit of understanding of what happens to the other battery modules. Do they simply all rebalance if I take energy out of a subset of them? In this approach I have almost completely free choice of amp modules, as I can freely combine any of the 10 battery modules that connected in series make up my battery pack. What's extremely elegant about this idea is that it saves me to have voltage converters altogether. And does this also go for battery charging? I have much trouble finding a 144V solar charge controller. Anything between 12V and 96V is a lot easier to source.

carlosdelondres Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 21 June 2012 Location: London Status: Offline Points: 243	Post Options Post Reply Quote carlosdelondres Report Post Thanks(0) Quote Reply Posted: 20 March 2022 at 1:41pm
	You won't be taking voltage out of a subset of the cells, just taking a different point in the string as zero volts. The load from driving speakers and amplifiers will be less than driving the vehicle motor so doubt it will have much impact on the pack balance. What is the spec of the battery? Yes it is hard to find inverters and charge controllers for high DC voltage systems. SMA sell some kit designed to work with higehr voltages. Or various chinese options of uncertain quality!