1. Last February was getting "Electrical consumers switched off" warning on first start after a cold night (which indicated low battery charge). Car was on Merc maintenenace contract and eventually persuaded the service agent (Merce dealer) to supply new battery. So battery is ~6 months old genuine Merc part.
2. All okay since then up until ~4 weeks ago. Then started getting the same warning.
3. Then car failed to start one morning - starter motor turned for a second or so then nothing. Started okay on jump leads.
4. My journey to work is ~20 miles/45 minutes so plenty of time for starting charge taken out to be replaced.
5. Voltmeter on battery terminals (leads not disconnected) is >12v with engine off and ~14.2V with engine at idle. Drops to ~13.8V with high load consumers switched on (lights. heated rear window etc). Except in one case where meter showed <10V.
6. Car has failed to start last 3 mornings and yesterday evening after sitting in car park all day. Started okay on jump leads.
7. Meter on battery this morning, immediately after it failed to start, showed 12.4V.
8. Nothing is being left on overnight whilst engine is off. Lights are automatic (and I have had them on manual control anyway). Radio switches off automatically and I have been turing it off manually anyway.
9. No other warnings seen.
10. I have taken to Kwik Fit twice for battery check and they say nothing wrong with battery (according to their test meter) and charge from alternator appears okay.
11. I want to try some fault finding myself before risking open-ended investigation at dealer labour rates of ~£100/hour.
Questions:
(i) Clearly (I think) something is draining the battery whilst the engine is not running OR the battery is never getting fully charged. Any suggestions for fault finding?
(ii) I have a battery charger and thought would try putting battery on charge overnight or during the day whilst in the office. Is it (a) absolutely necessary or (b) advisable but not that necessary, to disconnect battery leads whilst charging.
2. All okay since then up until ~4 weeks ago. Then started getting the same warning.
3. Then car failed to start one morning - starter motor turned for a second or so then nothing. Started okay on jump leads.
4. My journey to work is ~20 miles/45 minutes so plenty of time for starting charge taken out to be replaced.
5. Voltmeter on battery terminals (leads not disconnected) is >12v with engine off and ~14.2V with engine at idle. Drops to ~13.8V with high load consumers switched on (lights. heated rear window etc). Except in one case where meter showed <10V.
6. Car has failed to start last 3 mornings and yesterday evening after sitting in car park all day. Started okay on jump leads.
7. Meter on battery this morning, immediately after it failed to start, showed 12.4V.
8. Nothing is being left on overnight whilst engine is off. Lights are automatic (and I have had them on manual control anyway). Radio switches off automatically and I have been turing it off manually anyway.
9. No other warnings seen.
10. I have taken to Kwik Fit twice for battery check and they say nothing wrong with battery (according to their test meter) and charge from alternator appears okay.
11. I want to try some fault finding myself before risking open-ended investigation at dealer labour rates of ~£100/hour.
Questions:
(i) Clearly (I think) something is draining the battery whilst the engine is not running OR the battery is never getting fully charged. Any suggestions for fault finding?
(ii) I have a battery charger and thought would try putting battery on charge overnight or during the day whilst in the office. Is it (a) absolutely necessary or (b) advisable but not that necessary, to disconnect battery leads whilst charging.