12volts and charging a Roberts rechargeable radio

[FairweatherDave]

This will seem a bizarre question but our autistic son pushes us into strange situations! He loves listening to radio, and has several. The latest is a Roberts Blutune T2. It is portable and can run on mains or 4 A A batteries that can be recharged inside the radio.... the lead to the radio from the mains having a gizmo that converts 240v to 7.5v 2amps + ve.
The problem is that when on board my son hates seeing the display indicating the charge level is going down. He fears that towards the end of a trip it will have discharged and he will miss a favourite programme. So he won't listen to the radio say in the evening when we might want it on. So I would like to be able to use the boat battery via the cigar lighter socket. I do have an inverter I could use with the mains supply lead but read negative things about inverters. Should I do that or is there a simple lead out there on the market? I have looked but I am wary .... don't want to destroy the radio.
PS. Obvious solutions are to take a different radio or spare batteries..... but changing batteries is a faff, and the whole idea was to be green and use rechargeables, which aren't so cheap.
PS 2. You wouldn't believe how hard it is to persuade my son that it is okay to let the charge level get a bit low?

 

[Paulg25]

SHINA DC/DC converters Regulator Reducer 12V to 7.5V: Amazon.co.uk: Electronics

 

[AntarcticPilot]

SHINA DC/DC converters Regulator Reducer 12V to 7.5V: Amazon.co.uk: Electronics

There are many similar possibilities, including ones that have a selectable output voltage. Maplins (RIP!) used to have two or three that would do the job - also useful for running laptops from 12 v, and often more efficient than inverters.

 

[davidwf]

Alternative is an invertor and use the supplied fat plug,I am a bit of a fan of victron but naturally others are available Victron Sinewave invertor That way in the future it doesnt matter what radio he buys.

 

[GHA]

There are many similar possibilities, including ones that have a selectable output voltage. Maplins (RIP!) used to have two or three that would do the job - also useful for running laptops from 12 v, and often more efficient than inverters.

I've a load of those ones in the link stepping down to 5v, they work well, hold the voltage high even when pulling up near the rated current.

 

[Paulg25]

Alternative is an invertor and use the supplied fat plug,I am a bit of a fan of victron but naturally others are available Victron Sinewave invertor That way in the future it doesnt matter what radio he buys.

Going from 12v straight to 7.5v is most efficient.

 

[GHA]

Alternative is an invertor and use the supplied fat plug,I am a bit of a fan of victron but naturally others are available Victron Sinewave invertor That way in the future it doesnt matter what radio he buys.

Loads cheaper & much less power draw using a little buck converter like the one in the link.

 

[FairweatherDave]

Thanks folks.... the one in the link goes to 7.5 v 3amps....and the back of the radio says 2amps....does that matter?

 

[RichardS]

Thanks folks.... the one in the link goes to 7.5 v 3amps....and the back of the radio says 2amps....does that matter?

Nope ... that's even better.

Good luck with the radio. My Son's obsession is cars which is even more expensive.

Richard

 

[Paulg25]

Thanks folks.... the one in the link goes to 7.5 v 3amps....and the back of the radio says 2amps....does that matter?

No, not at all. As long as it is at least 2 amps it is good.

 

[Boater Sam]

No, the radio will only draw what it needs, the amp rating on the buck module is a maximum allowable load.