How do I know when my battery is sh***ed

[tiddy1]

I know was chilly this morning (-6 ish) but my battery did not stand a chance of starting the 7. Even though its always on tricle charge it never seems to be able to start the car. its a Hawker 680 so should have enough grunt to start the 2 litre duratec. so how can I tell if its past it?, its giving out 12 V and taking in 14 v

it seems to crank the car up to about 250 rpm but very briefly before it dies a death

 

also where is the cheapest place to get a new one, best price I have found is £95

 

Simon

[CageyH]

If it is showing 12v I suspect it is no longer useful.

I thought normal voltage was around 13.4 to 13.8v

 

Only dead fish go with the flow....!

[Stationary M25 Traveller]

Check the voltage while cranking ... how low does it fall then ?

 

Is that a wet or gel battery ? If a wet one, have you checked the liquid levels lately ? Check connections each end of all fat red and black cables, as any corrosion between connector and engine/chassis will produce a higher resistance.

 

 

[tiddy1]

Its a gel battery, how low would you expect the cranking voltage to be on a good/ bad battery?

I have done all the usual wiring and earthing checks but not having a known 'good' battery to compare with its hard to check

Simon

[peterg]

Right, a quick round up to know if you have a good battery:

 

With a multimeter and with everything switched off you want a minimum of 12v across the battery terminals and anything up to 13.7v is OK or to put it another way:

 

battery voltage............ % charge

12.6v or more.............. 100

12.4-12.6 .................... 75-100

12.2-12.4 .................... 50-75

11.7-12.0 .................... 0-25

< 11.7 ......................... it's fubarred

 

Turn the ignition on and try starting the car, if the battery voltage drops below 9vthen you either have a knackered battery or there is too much resistance so check connections/earths etc, if they are OK check the starter motor

 

The PC680 is sold by Powervamp Racing (Google or search this forum) and is now called the PVR25, ring them and speak to Ed Roller and tell him you belong to L7CGB and he'll sort you out free P&P although it will probably cost about the £95 you've got already...

 

 

[andy_h]

Sometimes when it's very cold temp outside, turning the headlights on and then try starting the car works. Don't ask me how I know this works, it just does alright 😬

 

 

White road legal 2.0 HPC VX race car - Now all shiney and new 😬

[Jason Plato]

could also be too much advance at cranking speed if it happens all the time ?

 

here is my Duratec R .... C7 TOP

Taffia joint AO with Al

 

[tiddy1]

Dave what cranking advance are you running?

 

Simon

[Sigmamark]

My Optimate charger tells me if the battery is good

[tiddy1]

just checked the cranking voltage and its about 8.4 v so does not look good

 

will check resistances

[Crudders]

Simon, I’ve managed to coax badly discharged lead acid batteries back to life in the past by connecting another good battery in parallel during charging, but this doesn’t seem to work with these new fangled compact gel types – they hold their charge well but if you let the voltage drop too far, they’re scrap. I’ve no idea where the threshold is but I do know it’s an expensive mistake as I managed it myself on a Powervamp 680.

 

The good news, if you find that you need a new battery, is that we have a bulk buy arrangement with Rally Design for their RMD Racing 25 battery. This is an equivalent spec to the Varley Red Top 25, Odyssey 680, Powervamp 680 etc. RD give us a discount for orders of 6 or more. The battery is cheap to begin with at £49.50 but exceptional value after bulk discount at £29.50 (plus VAT and carriage). See this thread for more details.

 

The batteries can either be despatched direct from Rally Design or I can collect them as I work nearby. That's only really an advantage if you attend any of the Kent area meets or can twist SM25T's arm for a gonads delivery.

 

Cruds

 

[tbird]

miss read that as twist SM25s Gonads, 😬

 

Tim

 

 

CSR 200 Aztec and Black

[Crudders]

You're very welcome to try that if you prefer 😬

 

Cruds

[Stationary M25 Traveller]

Ouch

 

 

[c7jhc]

Is the Rally Design RMD Racing 25 battery a straight swap for the Banner in an S3 Roadsport (no tray modification needed)?

[TomB]

here

 

This battery is the same as the Rally Design one, but cheaper and without the 'motorsport' label cost increase! This was discussed at the back end of the aborted buk buy thread - here

[c7jhc]

Thanks for this.

[Stationary M25 Traveller]

It will stand in place of the Banner, with a bit of wood next to it, to fill the clamp, as it is only half the thickness.