Some claim to be able to recondition batteries. Sounds like some people have good results, some not.
The theory is somewhat sound, anyone had any experience? I've got a battery that simply loses charge over 1-2 weeks.
I've not had good results with commercial chargers that claim to recondition. I've had about a 50% hit rate with a custom-created desulphating circuit, returning 2 batteries to acceptable function. The other two were dead as a doornail and never recovered. Considering the cost of most replacement options it's bearly worth the effort and cost of new hardware. Last time I got a new battery it cost as much as a decent conditioning charger and came with a 4 year guarantee 🙂
Not really statistically usable but there ya go
This in your broken passat ? Wth the dodgy ecu ?
Yes they do recover batteries if not too far gone, it's still sounding like yours holds some kind of charge.
But if its a daily driver battery, not a specialist race batt etc, just replace it - far easier
if its 3 years of more sling it and get a new one , if its gone dry then topped up the plates would have buckled again sling it , just buy another btys last about 3 years.
Do you know it's the battery rather than, say, a drain problem or a charge problem?
if its 3 years of more sling it and get a new one , if its gone dry then topped up the plates would have buckled again sling it , just buy another btys last about 3 years.
Not sure that's really good advice. My fathers BMW only had one replacement battery in it's 22 years of life, the second got to the stage of not holding charge for more than a couple of days after 6 years, it was desulphated and topped up and worked fine again. We're far too throw-away these days. Sometimes it's needed, most of the time it's not.
The battery sat in my '91 celica currently was bought 10 years ago, still going fine after a desuph.
This in your broken passat ? Wth the dodgy ecu ?
Yes, but that's not the issue. Shortly after I replaced the battery it got fully drained a few times, and now (maybe 18 months later dunno) it just doesn't hold charge that well. It'll last a week and still start, but not 2.
I wouldn't want to bin anything that can be salvaged. After all, if I can spend £50 on a smart charger and it doubles the life of many £100 batteries, it's worth it.
There may have been a drain problem with a 3rd party radio, I've removed that now. Although I don't think there was.
I've also found plans for a desulfating circuit online which wouldn't be too expensive.
Left the thing on an overnight slow charge last night too - that's the first time I've done that, relying on long 2+ hour drives to recharge it before that, so it's a possibility this will help.
Do you know it's the battery rather than, say, a drain problem or a charge problem?
Last night, the voltage was dropping quite quickly when I had the multimeter on it.
I know you're all hanging on the edge of your seats, so here's an update:
Left the thing on slow charge for a good 24 hours, then took it off last night. Voltage dropped quickly after I removed the charger, as I'd expect, but this morning it was still 13.05V.
Sounds like the battery's not really at fault doesn't it?
trade in time ? or a real autospark whos not a cowboy
I'd have traded poor old Mol's Passatt in ages ago, but he likes taking a whipping off it 😉
Oh piss off you two. Just cos you can't be bothered to work out how to fix cars.
oh pull the other one molly you know fine well im perfectly happy fixing cars
how ever i have over time learned to cut my losses rather than keep throwing money at an unreliable car.
Throwing money at it? Only one thing went wrong with it. Caused by a poor crash repair it seems.
Seems the battery wasn't well enough charged by me, cos I was only fast charging it for 40 mins enough to start the car then driving a couple of hours, and only doing that every few weeks.
cTek charges are very good
ah sorry my mistake itll be an easy fix then .
so which was it ?ECU, EGR, trailer control module , brake lights , gear box being funky.
whys it taking so long? my mates nearly finished his cosworth 24v powered MK2 escort rally car from shell to runner in the time its taken to sort out your "poor crash repair"
1) Crash in Germany is the main suspect.
2) Possible improper repair, let water in the boot.
3) Water drips into 3rd party installed non VW trailer module, causes funny goings on re brake lights and engine not stopping.
4) Dodgy mechanic claims ECU is faulty and has it replaced (against advice of specialist, unknown to me)
5) ECU doesn't seem to be quite the right part as it doesn't know how to use the inlet manifold flap
6) Above issue causes EGR volume problem
7) ECU sees fault and puts gearbox into some sort of safe mode so it limits torque during shifts, causing crap shifts.
Points 5 to 7 are my ideas about what's wrong, point 7 itself is a bit of a hopeful stab in the dark tbh, but it's hard to explain any other way.
Voltage dropped quickly after I removed the charger, as I'd expect, but this morning it was still 13.05V.
real test is what happens when you put it under load
IME living off batteries[on a boat not eating them] it is big dumps of power and how they respond to that which lets you know that it is knackered.
Please laos note voltage drops when it is cold so most folk notice knackered batteries in winter
TBH I would just replace it tbh - go to an electrical car place and they will test it for you and even tell you the cause of the problem if any
They will be able to try if they think its worthwhile for a tenner or less if they like you
Well I'll see how I get on now having charged it fully. Tbh I'd rather charge it every few weeks than shell out another £100 right now.