Batteries and Recharge times... Starting problems... - Page 3 - Perth-WRX.com

dtrally · #21 17-10-2008, 12:31 AM

Did the Electrician test each cell with a hydrometer or just check the terminal voltage and load test?
Cell specific gravity although old school, messy and a little time consuming is still the best way to acurately test a battery. A hydrometer costs from as little as $2 to $30 for a Blue Point one and will tell you what's going on.

Rossco · #22 17-10-2008, 12:38 AM

Quote:

Originally Posted by slg

I think you'll find that battery technology hasn't changed too much over the years and that anything over 14.5V starts to over heat the battery and cause the electrolyte to "boil" off. I think you'll find that 'most' cars are actually 14.5V when tested with a quality meter.

All the common Bosch regs regulate to 14.8 volts......

A 'Proper' 4 stage charger will run up to 16v initially to de-sulfate the battery's plates.

It's high amperage that causes electrolyte boiling not high voltage (I.e too high a charge rate = high amps).

The biggest killer of batteries these days is under bonnet heat which transfers into the batteries cells, warping the plates, and eventually causing a short (dropped cell).

pete gopal · #23 17-10-2008, 11:33 AM

335 CCA sounds bit low to be honest, I'd go 520 next time you're buying a new battery.

Could it be dropping a cell from time to time? had that happen before. Check what your voltage is before cranking it, then get someone to crank it...shouldn't drop below 10.5V on the start. Just above 14V when running and above 13.5V with all the lights/amps (if you have any) on.

meatbag · #24 18-10-2008, 02:02 PM

To give you an idea on charging time, mine when flat the other week. left it on the trickle charger for about an hour to the point where it was JUST enough to start. only drove about 2 minutes down the road and it started up again fine. Had a look when i got back home, another 2 minute drive and it was reading 14.2 volts.

i dont think you're really going to need long country drives to fix the problem...

slg · #25 19-10-2008, 10:18 AM

Quote:

Originally Posted by LegacyRS

It's high amperage that causes electrolyte boiling not high voltage (I.e too high a charge rate = high amps).

The voltage is directly proportional to the Amps. The current will not flow if the voltage of the battery is more than the charge rate. The higher the voltage difference between the battery and the alternator then the more current will flow.
So by having a higher alternator output voltage, allowing more current to flow, more water will boil off...
I = A/E
I learnt that during my apprenticeship quite some ago, and haven't forgotten it, yet.

Rossco · #26 19-10-2008, 12:32 PM

My expensive ($1500) 4 stage charger for my deep cycle batteries (120 ah 12v) readily runs the initial charge stage @ 16 volts/500 mah for approx 1 hour (de-sulphation stage) and up to 70 amps during stage 2 (absorbtion stage) whilst holding constantant voltage @ 13.8 volts. cycle goes in to float @ 14.4v when fully charged.

These batteries drive a Min Kota trolling motor on my bass boat and are always fully flat after a tournament (under 1.2 volts per cell), they are into their 5th season now and still last 2 days of constant use with a 40 amp peak draw!

STi Tuned · #27 20-10-2008, 10:59 PM

Whow.. firstly that's an expensive assed charger, secondly that's an expensive assed charger.

I'm having some battery wow's recently, not driving the car during the week but it's just died in it's ass. I was planning to take it in for a service/test.. whatever.

When I use my $73 trickly charger it's good for about 3 days. Doesn't seem to be any other drains on it which would cause it to discharge.

Question
How long shoud an Yellow Top last?

Can you service them or just buy another?