Running ICE from Mains Power

[topcat1]

Morning all, I've spent a fair bit of time and money on my garage and in the finishing stages now. As my years of fancy/tacky head units and subs are behind me (in a car..) I thought I might use the garage as a bit of a throw back and create a bit of a wall install for my garage radio. I still have a JBL sub, amp and few other bits from several years back which I plan to use for a bit of fun.

I know there are different options for simple 12v PSU's but I can't see any of them working when powering anything more than a basic head unit. I have been thinking about buying a small AGM battery and hooking it up permanently to a small charger and running the system from it, the idea being the battery is effectively the damper with the charger keeping it topped up. Does this sound wise or feasible? I have suppliers for professional chargers and batteries etc as we use all this at work so I'm not worried about boiling a battery or anything like that.

I know the sensible choice is to just pop a home system in, but thought I'd explore the chance for something a bit more fun!

Cheers, TC

[Miserablegit]

As you are no doubt aware in-car hifi can pull a bit of current with being a 12v system. I’d be concerned that (from your description of your system) the current draw might interfere with the electronics in the chargers.

Might be a better idea to get a truck/tractor battery rather than a small capacity agm and run the stereo from battery power alone (removing any mains interference) - charging when finished?

Or get a classic, pipe the exhaust to the outside and use as a generator for the hi-fi and aircon etc 😂

[topcat1]

That was a concern, we use AGM batteries up to 260Ah so can put any size in but don't want the faff of having to charge after use etc. Online most recommendations are to use PC type PSUs but I am certain this wouldn't be any good when using an amp.

[Miserablegit]

If you hardwire the charger in then it’s as simple as flicking one switch to turn the hifi off and one switch to turn the charger on. Could even use a relay to only turn on the 12v hifi feed when the charger is off...

[Crackie]

topcat1 said:

Morning all, I've spent a fair bit of time and money on my garage and in the finishing stages now. As my years of fancy/tacky head units and subs are behind me (in a car..) I thought I might use the garage as a bit of a throw back and create a bit of a wall install for my garage radio. I still have a JBL sub, amp and few other bits from several years back which I plan to use for a bit of fun.

I know there are different options for simple 12v PSU's but I can't see any of them working when powering anything more than a basic head unit. I have been thinking about buying a small AGM battery and hooking it up permanently to a small charger and running the system from it, the idea being the battery is effectively the damper with the charger keeping it topped up. Does this sound wise or feasible? I have suppliers for professional chargers and batteries etc as we use all this at work so I'm not worried about boiling a battery or anything like that.

I know the sensible choice is to just pop a home system in, but thought I'd explore the chance for something a bit more fun!

Cheers, TC

A Meanwell PSU ( or similar ) should be a simple solution. https://www.meanwell.co.uk/

Select one of their 12V DC products, determine the total Wattage of the kit you have and add in a reasonable contingency for peaks rather than continuous power.

Meanwell have been in the PSU game for a very long time and have a great reputation.

https://www.powersuppliesonline.co.uk/rsp-320-12-3...

The usual caveats regarding working with mains electricity apply here. Hooking one of these up is no more complicated than wiring up a plug. Simply connect live , Neutral and Earth to the PSU and Negative & +12V to the relevant ICE gear.

IMPORTANT. Please be aware that the connections on the PSU will be exposed unless the unit is mounted in a suitable enclosure that prevents people / pets etc from accessing the terminals. This should be done by or at the very least inspected and verified safe by a qualified electrician.

Edited by Crackie on Saturday 30th January 17:42

[nyt]

Crackie said:

A Meanwell PSU ( or similar ) should be a simple solution. https://www.meanwell.co.uk/

Select one of their 12V DC products, determine the total Wattage of the kit you have and add in a reasonable contingency for peaks rather than continuous power.

Meanwell have been in the PSUgame for a very long time and have a great reputation.

https://www.powersuppliesonline.co.uk/rsp-320-12-3...

Meanwell are great power supplies. But pricey.

You could try a computer server power supply from ebay first.
Dirt cheap.
Lots of videos on youtube.
They may have noisy fans which may be an issue
.
Something like: https://www.ebay.co.uk/itm/HP-DL380-G6-ML350-G6-75...

[topcat1]

Thanks, we buy parts from Meanwell already so will have a look, I'm still sceptical as imagine there are huge spikes especially from an amp which in the intended situ would be dampened by the battery, but on the flip side I know huge sound systems are obviously mains powered albeit by purpose built systems. Its the size of the low voltage cable that makes me feel like mains will struggle but I do understand that it has 20 times the voltage thus a fraction of the current to deal with!

[jet_noise]

Miserablegit said:

If you hardwire the charger in then it’s as simple as flicking one switch to turn the hifi off and one switch to turn the charger on. Could even use a relay to only turn on the 12v hifi feed when the charger is off...

This.

On the "mains won't hack it" point, and unless I'm due a parrot d'woosh on your understanding...
...it's the continuous watts that is the limit. 240V is reduced to 12 so currents on this LV side will be reduced by a factor of 20 in the HV (mains in this case).
There'll be losses of course but more or less

[Box Rocks]

I've done the same in my shed. An idea of using a headunit and some PC speakers a few years ago to now, currently running a couple of old Caliber amps off a sony head unit with 4 bookshelf speakers and a sub. Before the amps, I used to use a scalextric transformer, then a PC power supply. I then used a car battery hooked up to a 20w solar panel and charge controller. I have a digital volts and amp meter and I've seen it draw 8-9amps continuous. That's with it turned up loud mind. Someone then suggested an old xbox powerbrick power supply. They can handle over 15amps if you pick the right one, so I picked one up local for less than a tenner. Does the job perfectly. One thing I've noticed is than it holds the volts at exactly 12.0v no matter what volume / current draw.

[topcat1]

Cheers, so do you use a PSU directly powering the system i.e no battery in there?

On a separate note I've seen a couple of posts on various forums saying that sound quality won't be as good as with home audio stuff, whilst this may be true to a degree, is it anything noticeable? I can't ever say its been a problem in any of my cars!

[topcat1]

nyt said:

Meanwell are great power supplies. But pricey.

You could try a computer server power supply from ebay first.
Dirt cheap.
Lots of videos on youtube.
They may have noisy fans which may be an issue
.
Something like: https://www.ebay.co.uk/itm/HP-DL380-G6-ML350-G6-75...

I like the server PSU idea but given amps are usually connected by 10mm ish cable, how would this work as I gather these PSU's have several small outputs. Simply terminate them all to one stud and take power from there?

[nyt]

topcat1 said:

I like the server PSU idea but given amps are usually connected by 10mm ish cable, how would this work as I gather these PSU's have several small outputs. Simply terminate them all to one stud and take power from there?

Some power supplies come with single contacts for the + & - feeds. Otherwise common them up.


Loads os youtube advice, such as: https://www.youtube.com/watch?v=Mq322w_U2xU

[Crackie]

jet_noise said:

On the "mains won't hack it" point, and unless I'm due a parrot d'woosh on your understanding...
...it's the continuous watts that is the limit. 240V is reduced to 12 so currents on this LV side will be reduced by a factor of 20 in the HV (mains in this case).
There'll be losses of course but more or less

The currents on the LV side are higher not lower.

Power ( W ) is the product of Current ( I ) multiplied by Voltage ( V ). P= I x V

For a 100W stereo amp running on mains when the total power is 200W. Current is 200w/230v i.e 0.87 Amps

For a 100W stereo amp running on a 12v system when the total power is 200W. Current is 200w/12v i.e 16.6666' Amps

The example above is just to show the equation. In reality the current drawn by each option would be higher because of losses etc. The amps are 100% efficient etc.

Here is a link to a well known amp board supplier. It's simple 2 x 100w class T amplifier at the bottom of the page is a their suggested solution for the power supply.......another Meanwell in this case. https://store.sure-electronics.com/product/AA-AB32...

EDIT. - Forgot the link in the original post Added now.

Edited by Crackie on Sunday 31st January 14:26

[Crackie]

topcat1 said:

Thanks, we buy parts from Meanwell already so will have a look, I'm still sceptical as imagine there are huge spikes especially from an amp which in the intended situ would be dampened by the battery, but on the flip side I know huge sound systems are obviously mains powered albeit by purpose built systems. Its the size of the low voltage cable that makes me feel like mains will struggle but I do understand that it has 20 times the voltage thus a fraction of the current to deal with!

No need to be sceptical about the capability of these units, they deliver what their specification says. They are well designed and regulated........as post Box Rocks noted above, the supply will deliver a stable 12v without sagging, irrespective of the volume level and changing current being drawn.

[CubanPete]

Loads of industrial PSUs out there.

Something like this

https://www.ebay.co.uk/itm/201224928422

Is a 3d printer PSU and should have plenty of welly.

[topcat1]

Thanks, final question on this- i assume there will be a slight draw by the PSU when the stereo turned off, will this be a minimal amount or anything substantial? I think the amps will switch themselves off when the head unit is turned off but the HU will require power for memory unless they have a battery inside these days...

[jet_noise]

Crackie said:

jet_noise said:

On the "mains won't hack it" point, and unless I'm due a parrot d'woosh on your understanding...
...it's the continuous watts that is the limit. 240V is reduced to 12 so currents on this LV side will be reduced by a factor of 20 in the HV (mains in this case).
There'll be losses of course but more or less

The currents on the LV side are higher not lower.

<snip>.

That's what I said.
Not clearly though!