Bremi 13.8V, 3A stabilised power supply BRS 27

[af024]

An 80s stabilised PSU, typically for CB radio use.

This is in a very poor state – extraordinarily grubby, paint missing, rusty, 1 x cover retaining screw missing etc, but remarkably it works. Its output voltage measures 13.85Vd.c. off load. I briefly loaded it with an 8.2R 50W resistor and it only dropped by approx. 0.05V. I don’t know whether this is typical of such a PSU, but that seems pretty impressive to me.

It’s just a shame that it’s in such poor condition.

Useful as a bench test PSU for car radios etc? Just don’t have it on show – it’ll become talk of the town if you do!

£4 to save it from being recycled?

[RichardGM]

I have been contemplating a 12 V UPS for a router. That PSU would seem an excellent way to keep a 12 V lead-acid battery on float charge, so please put me down to give it a home if no-one else is interested. But I do have alternative options, so if someone else is interested they can have it.

[Techman]

Remember they've got no crowbar protection and they blow up if you back feed them with a battery. Otherwise they're a good old power supply - I've got one identical. There's a story that they were banned from sale on safety grounds, due to not complying with our safety regulations.

[af024]

Hello RichardGM,

Thank you for your interest. If you'd like it, it's yours. I guess it could do with a good clean and a re-spray, but despite its awful appearance, it seems to work a treat.

It looks like it's just over 2kg (typical!), so if you'd like it posting, it puts it in Royal Mail's 'up to 10kg, Medium Parcel' category. According to their website that's £6.95. That's more than the item itself of course, oops. Isn't that always the way!

I'm happy to post it to you at cost if you'd still like to go ahead, unless you have a courier type arrangement that can be used?

If you'd like to go ahead, why not pop me a PM with your contact details and we'll take it from there?

Thank you, all the best,

Andy

[dragonser]

Hi,
I found a useful youtube video about this power supply. I typed in Bremi BRs27
it seems the early versions were 220 volt so over volted the internal caps, and didn't have an earth connection.
the later versions had an earth connection and were designed for 240 v ac...
it uses a lm723 in an odd case...
I hope the power supply can find a home !

[af024]

Interesting!
Well at least this one is earthed - I've just tested it. A sticker also claims that it's the 240Va.c. version. Mind you, I have no idea why it states 22V for the output voltage - all very bizarre when it's 13.8d.c.

[duncanlowe]

I know. Another 'me too' post. I have one that I used for years for testing any 12v stuff (as it was all kit that ran from a 12v battery with a charging system). It was initially used by my brother to power his CB in his bedroom (mine was in my car).

I now use a PSU with current limit for that work.

I wouldn't use it, as is for battery charging. As said it needs at least a reverse current protection, and probably some better current limiting to avoid excess charge current.

[Glowing Bits!]

Originally Posted by af024

Interesting!
Well at least this one is earthed - I've just tested it. A sticker also claims that it's the 240Va.c. version. Mind you, I have no idea why it states 22V for the output voltage - all very bizarre when it's 13.8d.c.

22V from the transformer itself is quite common, it allows for the regulator to have an easier life when on high loads such as 3A, otherwise the output would sag drastically on high loads.
It's worth noting that when the regulator fails short circuit, it tends to shove the full 22V out instead of the usual 13.8V.

[af024]

I hadn't realised that the sticker related to the internal transformer alone as opposed to the finished article. I was a bit quick to assume a typo! Stating 22V on it makes sense now Thank you.

[RichardGM]

I hadn't thought about the beast getting upset if connected to a battery. So, thank you, but I'll decline after all and go back to Plan A for my router UPS, which is to use an 18 V plug-in PSU, a diode, and an LM 338 adjustable regulator.

[Radio Wrangler]

This is a for sale thread, so we aren't supposed to be discussing it, but there is cause for a warning. That 22v is important. It's what the output will surge to should/if/when the regulator fails short circuit (the number one failure mode!)

People buy 13.8v powered radios, then they scrimp by buying the cheapest power supply they can find. Problem is should/when/if the power supply fails, it overvoltages pretty much ALL of the radio, taking out pretty much all the semiconductors.

The moral is that dirt cheap power supplies are only suited to powering radios you don't mind ditching. For anything better, you need a crowbar to protect the radio.

David

[duncanlowe]

Originally Posted by Radio Wrangler

This is a for sale thread, so we aren't supposed to be discussing it, but there is cause for a warning. That 22v is important. It's what the output will surge to should/if/when the regulator fails short circuit (the number one failure mode!)

People buy 13.8v powered radios, then they scrimp by buying the cheapest power supply they can find. Problem is should/when/if the power supply fails, it overvoltages pretty much ALL of the radio, taking out pretty much all the semiconductors.

The moral is that dirt cheap power supplies are only suited to powering radios you don't mind ditching. For anything better, you need a crowbar to protect the radio.

David

While that is true, you could consider that as the power supply overvolting is a recognised and relatively common problem, the radios ought to be designed to withstand it. It is possible as it's done in other industries.

[Glowing Bits!]

Originally Posted by Radio Wrangler

This is a for sale thread, so we aren't supposed to be discussing it, but there is cause for a warning. That 22v is important. It's what the output will surge to should/if/when the regulator fails short circuit (the number one failure mode!)

People buy 13.8v powered radios, then they scrimp by buying the cheapest power supply they can find. Problem is should/when/if the power supply fails, it overvoltages pretty much ALL of the radio, taking out pretty much all the semiconductors.

The moral is that dirt cheap power supplies are only suited to powering radios you don't mind ditching. For anything better, you need a crowbar to protect the radio.

David

That's pretty much what happened to mine one day, the radio would not key up or receive but luckily it caused no damage, most decent radios should be able to withstand it for a brief period.

[dragonser]

Hi,
if no one else would like the power supply, then I would, please. if it could be posted..

[af024]

Hello dragonser,

Thank you for your interest. If you'd like it then I'm happy to post it. I'll PM you.

Kind regards,

Andy

[af024]

Moderators, this PSU has now found a new home so this thread can now be closed. Thank you.