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Technical Stop Start Story

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Technical Stop Start Story

jrkitching said:
I'd be interested to hear if any of those here who pay very close attention to their fuel economy have noticed an improvement after replacing a battery.
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I consider this heresay, but the last tank on my dead LA battery netted 40MPG, vs the previous tank of 50MPG with a best to date of 54MPG. This was a really dead battery that wouldn't start a car after only sitting for 15mins. Bump started it and got home but it wouldn't hold a charge at all.

Interestingly, the old LiFe's frankly awesome charge acceptance seemed to give the same MPG as a LA despite no S/S. However, it's very difficult to tease this out of the data as UFI is still being run in. Unfortunately UFI won't run on a Supercapacitor alone (even though a 4cyl will) so I might just call up Fiat and get a warranty battery this weekend.

The perfect system will be a Supercap, LiFe, isolator and a force S/S button. Should get my MPG into the 60's easily.
 
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UFI said:
I consider this heresay, but the last tank on my dead LA battery netted 40MPG, vs the previous tank of 50MPG with a best to date of 54MPG. This was a really dead battery that wouldn't start a car after only sitting for 15mins. Bump started it and got home but it wouldn't hold a charge at all.

The perfect system will be a Supercap, LiFe, isolator and a force S/S button. Should get my MPG into the 60's easily.
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Makes sense - again just an estimate but I'd reckon you'd lose 10-15% to the alternator in a worst case scenario. The hard limit is going to be whatever mpg you can get with the alternator drive disconnected.

That would make for an interesting cheap hybrid and I'd expect you could get reasonable range, at least in daylight. EV's are much better at managing energy than ICE vehicles and I'm sure you could make substantial gains in economy with conventional cars by applying EV energy management concepts to their design.

With more time and a better workshop, I reckon I could engineer a consistent 70mpg out of a 1.2 & this is certainly one of the ideas I'd try out. I'd also like to try out generating electrical power using waste heat from the engine & exhaust.
 
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I'm not really trying to take load off the alternator per se, just trying to eliminate the woefully inefficient LA battery. It makes no sense to burn petrol to charge a battery that's constantly loosing charge at such a high rate. The total capacity of the system will be about 3Ah.
 
UFI said:
I'm not really trying to take load off the alternator per se, just trying to eliminate the woefully inefficient LA battery. It makes no sense to burn petrol to charge a battery that's constantly loosing charge at such a high rate.
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Absolutely and it's why I keep going on about the economics of replacing batteries on efficiency grounds before reaching the end of their operational life. Fitting larger capacity batteries than standard just makes the problem worse.
 
jrkitching said:
Absolutely and it's why I keep going on about the economics of replacing batteries on efficiency grounds before reaching the end of their operational life. Fitting larger capacity batteries than standard just makes the problem worse.
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but jrkitching i had 2 batteries at 42ah die on me in 2 years! ive gone 52 ah and so far so good. is it my driving style start stop mainly and lights on with the iphone charging the problem?
 
I know obviously my car isn't s&s, but my battery is 5.5 years old from delivery and still does the job. The big problem is that an alternator can never charge as well as a good smart charger.
 
306maxi said:
I know obviously my car isn't s&s, but my battery is 5.5 years old from delivery and still does the job. The big problem is that an alternator can never charge as well as a good smart charger.
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so the alternator is rubbish then?
 
Super Uwe said:
Well fingers crossed it works.

I'm probably going to get our battery tested out in a few weeks in our 62 plate Punto. S/S hasn't worked for about two months now, but in all fairness the car pretty much does sub 5 mile journeys at the mo (which is not great, but if I don't need the car then I don't need it!).

I guess it's not out of the question either that the battery may have permanent damage as the car only did 1500 miles in the 12 months prior to me buying it.

Anyway, all I really care about is that the battery is fine for the winter. Couldn't care less whether S/S actually works or not.
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no 5 miles is plenty ss should work.
 
Most Easterly Pandas said:
No, alternator is designed to provide a surface charge, not a deep charge which some smart battery chargers do.
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Yes but let's assume no one has a smart battery charger. After all routine car maintenance does not call for charging the battery when left overnight with a third party charger given normal everyday use !
Basically i want to know why fiat has so many s/s issues and why ive had 2 battery failures in 3 years. There must be a reason.

Reasons could be, Fiat gave me dodgy batteries from new and replacement from dealer, alternator is a joke, or simply Fiat stock battery capacities are not up to the job for the car given the amount of electricity it consumes.
 
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ahmett said:
After all routine car maintenance does not call for charging the battery when left overnight with a third party charger given normal everyday use !
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You've hit the nail on the head, 100's out there without an issue with every day use ;)

Its those with a defective battery, or sitting with the radio and lights on for extended period of time while not driving etc that are having the issues - and this isn't normal every day use.
 
Most Easterly Pandas said:
You've hit the nail on the head, 100's out there without an issue with every day use ;)

Its those with a defective battery, or sitting with the radio and lights on for extended period of time while not driving etc that are having the issues - and this isn't normal every day use.
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yes but i consider my car usage normal everyday use and ive never had this issue with any other car. my tech did say that he felt Fiat stock battery capacities were a joke, which is why he recommended a higher capacity battery. (and no he didnt really make money from saying that as the price difference was no more than a tenner and he had both batteries in stock!)

and when i told the main dealer that the batteries they gave were a joke, he had a 'no comment' long silence as he couldnt answer my question for obvious reasons (that i was right)
 
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306maxi said:
I know obviously my car isn't s&s, but my battery is 5.5 years old from delivery and still does the job.
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If our's wasn't S/S I would think the battery would last at least 10years.

The battery itself is fine. It starts the car on a cold and frosty morning ........... what more do you want?

I want a car that works as it is designed. It's designed to S/S and therefore it should S/S properly. Hopefully ........ and all the indications and advice from here ........... is that the S/S will work perfectly when the new battery arrives.

What am I going to do with the "perfectly serviceable" old battery?
I ain't got a clue as yet, but I ain't chucking it out. :)

Regards,
Mick.
 
An interesting read:

http://www.thetruthaboutcars.com/2011/06/the-shocking-truth-about-start-stop-systems/
Yes, you just read that right: the current generation of stop-start systems lose half of their benefits after two weeks. Which means they’re great for juicing up scores on Europe’s urban-efficiency test, but they are as good as useless for the vast majority of the life of the vehicle
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Stop Start battery tester:

http://www.matson.com.au/product/826-start-stop-battery-tester-with-printer
 
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I personally couldn't give much of a toss about saving a tiny amount of fuel.

The benefit of S/S is that engines aren't pumping out gasses and smells when stationary in traffic.

As a keen cyclist, I'm very well aware engines, noise, and exhaust fumes ..... and I wish all vehicles had it.

TTFN,
Mick.
 
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