My Citigo is 2016, it had to have the battery monitor, (the gizmo on the earth terminal of the battery),replaced in order for the stop start to work, that was about three years ago. It looks like it's gone again as the stop start doesn't work. In itself that's not a problem for me as I hate stop start. My question is whether the charging system works in a conventional way,is a regulator within the alternator. The battery voltage is 12.4 volts(not running) and 14.9 volts at 2000 rpm, this reading was just after starting.

Thanks for looking!

First reason for the stop/start to stop working is a low/poor battery.

Try charging the battery with the correct charger, connected up the correct way.

Then with the battery fully charged test the battery.

If it is a 2016 battery then it might be on the way out, but charge it first.

 

9 minutes ago, PETER COSGROVE said:

as I hate stop start.

Can you turn it off?

 

 

Thanks, AG Falco

I normally turn it off by the switch anyway, the last time it went the garage charged the battery for 24hrs, checked it, and the start stop didn't work! It turned out to be this battery monitor thing. More concerned whether the charging system is conventional, I can cope without start stop. Thanks

19 hours ago, PETER COSGROVE said:

More concerned whether the charging system is conventional

No.

Micro hybrid charging system if it is Stop / start.

 

Thanks, AG Falco

Thanks, well it's charging and starting ok, I'll keep my fingers crossed!

One last thing, does the unit on the battery have an effect other than on the stop/start? Thanks

Yes.

It measures the power going in and out of the battery.

From this the car will charge / or not charge the battery.

The alternator is NOT always charging the battery, it only works when the charging system wants it to.

 

Have you charged the battery yet?

 

Thanks, AG Falco

 

No,I think it needs a special charger,the car starts fine,the voltage at the battery when running shows 14.9 volts, when I had the stop start not work before, the advice given was initially what you have suggested. The car was just under 3 years old, they ended up changing the battery monitor on the negative terminal of the battery.

I will get a VW specialist to check it over,which is a bit of a waste as I don't like the stop start. It shows no signs of either under or over charging, so I remain confused lol.

33 minutes ago, PETER COSGROVE said:

so I remain confused lol.

 

On 08/04/2022 at 18:40, AGFalco said:

First reason for the stop/start to stop working is a low/poor battery.

Try charging the battery with the correct charger, connected up the correct way.

Then with the battery fully charged test the battery.

If it is a 2016 battery then it might be on the way out, but charge it first.

 

 

33 minutes ago, PETER COSGROVE said:

I don't like the stop start

Get it turned off permanently then.

Some people do this by disconnecting the black wire from the negative battery terminal.

DYOR first.

 

Thanks, AG Falco

 

All Up!s/etc have smart alternators, as far as I know, which come on and off to allow some regen braking (the alternator gets turned on when you decelerate, unless the battery is so low that it needs charging anyway).

 

The unit on the battery measures voltage, not power, and is used to decide whether the battery is OK for S/S as well as for regen braking.

 

S/S may not come on for several reasons - the usual one is poor battery condition, but also it won't come on if the ECU senses that engine is too cold, i.e. it depends on temp sensors working correctly.

 

A battery may indicate a fairly healthy voltage with zero or near-zero load - but it drops off a lot under even a slight load if the battery is in poor condition. The voltage under charge (from a charger system) is not really relevant as chargers normally control the output voltage and current presented to the battery.

 

Edited 21 May, 20224 yr by freemansteve

Thanks Steve, in the end I got the battery replaced,so thanks to the previous advice AG Falco and me getting over reluctantly replacing a battery that in the old days would be perfectly serviceable, so now a lot poorer but the S/S works

Edited 21 May, 20224 yr by PETER COSGROVE

The battery was going fail on you sooner or later!

Better changed with some fore-warning that not starting in the middle of nowhere, in the rain, with no mobile signal - as can happen according to sod's law