do you have to get a stop start battery if old one is stop start or can you use any 

They are not your standard run of the mill battery, AGM and the like , to deal with the additional stress SS puts on batteries. Some batteries also need coding to the car and in this case it may also be true. So buy with caution. 

For cars having Stop/start system the appropriate battery should be used (stop/start).

It's usually more Ah and has higher capacity.

But can you use another battery because my stop start doesn’t work anywaya

8 hours ago, Hecktor said:

But can you use another battery because my stop start doesn’t work anywaya

No.

 

A normal type battery can be fitted but will die quickly from the higher charging voltage being applied to it.

 

Thanks, AG Falco

If the stop start is disabled by disconnecting the sensing wire to the battery I thought that I read that the battery charging reverts to the normal 13.7v profile hence a normal battery can be safely used.

 

Or did I dream it?

If you disconnect the sensing wire attached to the negative terminal the battery control module will not know the SOC of the battery.

This can stop the Stop/Start mode and just leave the alternator on all the time.

But a Stop/Start alternator can run at a higher voltage which a normal lead acid battery can't cope with for long.

It is fine if the correct type of battery is installed.

 

Thanks, AG Falco

It was my understanding that it leaves the altenator on all the time but using a standard charging profile of 13.7 volts or whatever, yes it can run at a higher voltage but only when its commanded to which it wont be unless it knows the battery S.O.C.

2 hours ago, J.R. said:

It was my understanding that it leaves the altenator on all the time but using a standard charging profile of 13.7 volts or whatever, yes it can run at a higher voltage but only when its commanded to which it wont be unless it knows the battery S.O.C.

 

I think it does go to a default level but I can't confirm that level is 13.7V. I think it would work fine in a pinch if you needed to get the car away, but otherwise just buy the right battery and don't be a cheapskate.

 

 

Probably more like the 14.4v that my voltmeter shows after an engine start settling back down to 13.7ish.

 

For myself I am lucky that my vehicle was made just before the stop/startfoolery began, but if I ever end up owning one I will do the opposite to your advice, the system will be disabled immediately, I drove a car with it once for an hour in Lille and it put me off for life.

 

Wwhen the battery eventually needs replacing it will be with a decent Varta or Bosch (the same) AGM battery which will have a long and happy life with the charging system working in mode dégradé

Edited 22 October, 20205 yr by J.R.

10 hours ago, SuperbTWM said:

 

 just buy the right battery and don't be a cheapskate.

 

Not everyone is loaded... Some folk have to make compromises if possible where they can. Maybe the op needs to. Very hard times for some.

16 hours ago, AGFalco said:

If you disconnect the sensing wire attached to the negative terminal the battery control module will not know the SOC of the battery.

This can stop the Stop/Start mode and just leave the alternator on all the time.

But a Stop/Start alternator can run at a higher voltage which a normal lead acid battery can't cope with for long.

It is fine if the correct type of battery is installed.

 

Thanks, AG Falco

 

I'm sorry, but:

• It (the alternator, because the car electronics knows some more stuff, but doesn't usually use it, except in particular conditions) doesn't know the true state of charge of the battery. given a few tolerances and wiring offset, you can argue it would if it knew the temperature, but it doesn't know that (and it can vary throughout the battery, under dynamic conditions)
• For the cars that I know in detail, a start/stop alternator is the same as an ordinary alternator, it is just controlled differently. If anyone has a different part number for a stop/start alternator, please let me know, because then I will be better informed.
• The old trick for reverting 'smart charge' to 'old fashioned charge' was to remove the entire smart charge cable; this is designed to work, and should work in the face of Load Dumps, Field Decays, etc. ('should' rather than 'tested and guaranteed'). Removing fewer wires probably does work in the short term, but may not be reliable in transient conditions, as no one even checked out that it ought to work.
• From the dash controller (whatever it is called on these) there is a signal that can be used to tweak the alternator output, and this is used for the idiot 'micro-hybrid' mode (which saves fuel, but not so much as you'd notice, away from a lab fuel consumption test) as well as start stop

There are two types of battery certified for stop/start usage and those are EFB and AGM. EFB are a bit expensive and AGM are a lot expensive. AGM are good though, with about twice the number of rated stop/starts as EFB.

 

My view is that in non-stop/start mode a decent quality Lead Acid battery should be fine, slightly shorter life than in a non stop/start car, and that changing the set-up in the dash controller to 'Normal Lead Acid' will be fine, provided that you never switch stop/start on (if the system will even allow that, once you have set the system to 'Normal Lead Acid battery').

 

Don't try these tricks with the el-cheapo, cheapo batteries, available from some sources, though. That seems likely a recipe for dissatisfaction. They would have quite a high early failure rate, anyway, and this can only make that worse.

If you get a shorter life than with the Stop / Start battery given how short the life some on this forum get with OEM Stop / Start batteries as fitted by Skoda then that is really pretty crap IMO.

I'm used to getting, say, 7 years from a 5 year guaranteed battery. I know that by some people's standards that's a bit short, but my expectation is that it would be a few weeks or a month shorter in an s/s car that never used s/s (and exactly the same if the battery was appropriately programmed).

 

I did once do some 'back of a fag packet' calcs on s/s, based on Tiff Needel/fifth gears drive around a busy bit of Brum, and concluded that while you might save £100 per year on fuel, that shrank to more like £10 when you took the excess battery cost in to account.

 

I think that was based on petrol, which at the time, would have been around £1.40. I've got to suspect, by now, with cheaper fuel, you've got a negative saving! 

I think the idea is to save some paying the correct VED band for what the vehicles actually produce in emissions.

Then to reduce the bill by Millions or Billions in Health Care and the penalties for not meeting Co2 reduction that the Governments signed up to.

We have had several cars come in with lead acid batteries fitted to stop/start cars.

These batteries have only lasted 6 months from when fitted new.

 

The cars had not been told about the change of battery type.

One Renault even killed an EFB when it should have been an AGM.

 

 

Thanks, AG Falco

I've been running a top of the range Yuasa AGM (stop-start) battery for the past year in an old car designed for a sealed lead acid battery. I'm hoping to get at least 10 years out of the AGM battery. I usually get 10 years out of SLA batteries, although I only start my engine a few times each week which does help battery life. Because this old car's charging system is designed for a SLA (Sealed Lead Acid) battery, I suspect that the AGM battery isn't being fully charged which I suspect in theory could reduce the life of the battery. SLA batteries don't like starting the engine when they are not fully charged as this degrades the battery quicker, but AGM batteries are more tolerant of starting the engine when not fully charged.

 

If you look at car battery manufacturers' websites you will see that SLA batteries might have a life of only 20,000 engine starts, whereas AGM batteries might be able to start a car engine 500,000 times, ie. 25 times the life of SLA batteries. However, age also degrades a battery not just the number of engine starts. These engine starts will be based on engines that start immediately, not engines that take a lot of turning over to start. Besides, my old car has always started instantly throughout its life.

 

I expect Bosch, Varta, and Yuasa car batteries are all similar quality. However, they all do different priced models which probably makes more difference than the brand. The more expensive models, should have higher CCA (Cold Cranking Amps) and/or have a longer life.

 

Edited 23 October, 20205 yr by Carlston

4 hours ago, Carlston said:

I suspect that the AGM battery isn't being fully charged

 

An AGM battery in a stop/start car will not be fully charged by design.

The car will want the battery to be charged up to a maximum of about 80%.

In normal driving the alternator won't be working, unless the battery has reached the minimum charged point.

This is so that when you brake the alternator will start to work and fast charge the battery.

Both EFB and AGM can withstand the faster / higher charging rates compared to normal lead acid batteries.

If the battery was already fully charged this would mean you cannot use the kinetic energy recovery system.

 

Batteries are not lasting as long as they used to on modern cars.

We think this is due to all the extra loads put on the batteries with all the modern electronics fitted to them.

 

Thanks, AG Falco

4 hours ago, Carlston said:

... I suspect that the AGM battery isn't being fully charged which I suspect in theory could reduce the life of the battery. 

 

 

Batteries don't get really  fully charged these days, unless by fully charged you mean 'as charged as it gets', rather than 'charged enough to give you the rated capacity'.

 

5 hours ago, Carlston said:

I expect Bosch, Varta, and Yuasa car batteries are all similar quality.

 

Bosch and Varta batteries are both made by Johnson Controls, so they are probably identical, if you choose the right variants. For Bosch/Varta, there are variants with different guarantee length, but I'm not sure everyone looks at that, rather than just saying 'it is a good brand, I'll buy it'.

1 hour ago, AGFalco said:

Batteries are not lasting as long as they used to on modern cars.

We think this is due to all the extra loads put on the batteries with all the modern electronics fitted to them.

That is a result if the charging strategies set up in the software and after this year, a dramatic shift in how vehicles are used. The batteries themselves from the top manufacturers are the best available but they are built to incredibly tight specifications and tested to more stringent durability requirements. OEM’s also have to remove the use of hazardous materials and get weight out of the vehicles as much as possible to achieve emissions targets. This just puts more pressure on getting efficient use out of the smallest batteries they can fit, as much as possible.

 

The batteries will last if they are looked after from the moment they are first fitted. They have to be protected from discharging and critically when they are in the dealer network from new 

 

 

^ Interesting and good info about reducing both weight and hazardous substance content by going smaller. 

All you tend to hear about is car manufacturers fitting smaller batteries to 'penny-pinch' but it seems there are other pressures too.

 

Do you @BigEjit know of a source of reliable freely available info about charging AGMs etc. optimally? Every time I look it up I seem to find more conflicting info. One site suggests that they must be protected from overcharge more so than conventional lead acids, and protected from heat by avoiding fitment in engine bays - https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm

Based on that it seems that poor lifetimes may be partly due to car manufacturers siting of these batteries near engines? 

7 hours ago, BigEjit said:

 OEM’s also have to remove the use of hazardous materials and get weight out of the vehicles as much as possible to achieve emissions targets. This just puts more pressure on getting efficient use out of the smallest batteries they can fit, as much as possible.

 

 

Lead? Lead is one of the densest metals and has been banned from everywhere else, because of its toxic potential. Weight is one of the advantages touted for Lead-Calcium (but I can't remember ever seeing the spec of a Lead-Calcium battery and thinking 'that's saved half a kilo', so there can't be that much in it, in practice),

 

That Lead is still allowed for car batteries is due to a deliberate exception in the EU Law. If they hadn't done that, we'd all have been scrabbling around for Lithium. and there probably isn't enough Lithium mining and purification capacity in the world,

 

Would have resulted in lighter batteries, though.

 

@Wino - I'll have a look at that Battery University page later. I have seen frankly dubious info from them before, so I am interested.

The last two paragraphs before the green/orange tables are what I was referencing mainly.

 

@Camlobe, can you give an example of this 'frankly dubious' content? (And your reasons for doubt)

 

Edited 24 October, 20205 yr by Wino

Vorsprung Durch Technik.

 

VW put their past behind them and go green and advance with technology. 

Only issue being they still use car batteries and the Software they procure and what you might get is a Courtesy Car you can rely on.

 

 

 

Blah, blah, blah...