Can I attach another battery, in parallel to my existing one, so my radio a) doesn't turn off when I start the engine, and b) there's more juice for the bass?

The problem I'm having is that the bass in the songs I listen to causes my headunit to cut out, due to the power drop.

Can I just add another battery somehow into the equation to be able to give it a bit more "oomph"?

I can't remember anything from Physics GCSE, so I don't have a clue!

You can, but you`ll have to fit a split charging relay or they end up running each other down in no time.

Have you tried wiring the head unit directly to the battery with thicker gauge wire? (fit a fuse at the battery end if you do)

Also consider a power cap for the sub amp.

What music do you listen to?

power cap won't give you more power, just store a tiny bit to smooth it out a little - have a look in ice section. My other halfs car won prizes in a local comp and a 2 farad power cap was one of them.. streight on ebay - junk .

I have had a sub in an uno for years witn no extra power only a standard battery and have never had the head unit cut out the lights dim to the long rolling DnB basslines but that's about it. what power are you using?

Mainly DnB/ Hip Hop... or anything else with lots of bass frequencies

Amp is not connected as it broke
I might diconnect my sub and see if I still have the power loss.

It happens more frequently if lights, fan, rear demist and wipers are on, for obvious reasons.

Louie - what do you mean by "What power are you using"?

A73 - I hadn't considered chopping in a thicker wire, bit reluctant to as it'll only be able to connect to the original thinner wire in the ISO wire gorup before the HU (if that makes sence). It'll be a thicker wire, all the way until the last point, which will be the standard thin wire.


Just so you know, I don't have an amp in the car at the moment, so Im not talking about the power getting to an amp.
Radio is connected as standard, but with rear speakers in the parcel shelf, and a sub connected to the +left and -right of the rear speaker feeds from the HU.

If your running your sub directly from the head units amp then you will get it cutting out as it overheats!

6x9`s are about the biggest speakers you want to run from the head unit, & even they can cause the amp to overheat.

The head unit wiring is shared & goes through the fuse box, the power will fluctuate more than if it was connected direct to the battery.

When I had a mega system in my old Uno I had a completely seperate electrical circuit for the entire system, including the head unit.

Thanks for the reply, I can assure you the HU is not overheating


When there is a loud bass note, it is as if there is not enough power getting fed into the radio, to keep up with the drain from the sub.

When there is a loud bass note, the radio cuts out, then instantly comes back on again.

I reckon forget about the second battery, that won't be the problem. If the engine starts, that means your battery can supply about 700 watts... (to the starter motor.) Head units have a power consumption of about 80-100 watts (at the most!)

It sounds like the headunit has a dodgy ground or power connection. People tend to forget that the ground is as important as the +12V supply. I reckon the reason the headunit is cutting out is that it's not getting a full 12V between its +12V and ground connections. Consider adding a fuse near the battery, a power wire into the car, and a ground wire to one of the steering column 10mm nuts.

Alternatively get out the multimeter and see if you can identify where the voltage drop is taking place... e.g. is the ground wire at 0.00V, or 'floating' up to something like 0.4V, and is the 12V wire at 13.8V, or something like 11.8V - check for a loose/dirty fuse, check any plugs you can find in the radio supply, things like that.

-Alex