Recharge the 12v battery by a 5A battery charger

[KW Lexus]

Hi UX250 users, Yesterday by stupid mistake I made my 12v Battery flat and after jump start by AA the car run again but I was advised by gentleman from AA to recharge the 12v Battery by using a 5-6A Battery recharge from amazon. I buy one but like to ask members here: can I recharge the 12v Battery by connecting +ve clamp to the Red jump start terminal in fuse box under the hood and -ve clamp to unpainted metal point under the hood, Or I should clamp the 12v Battery +ve -ve terminal directly under the boot. Thanks.

 

 

 

 

[LenT]

If you have bought - or are buying - a modern smart trickle charger, it should come with detailed instructions and should be appropriate for your Battery type.

You can connect the charger leads directly to the Battery but there is a procedure to follow.

1.  Ensure the charger is switched off and disconnected from the mains.

2. Connect red lead to the + positive Battery terminal.

3. Connect the black lead to the - negative terminal.

4. Switch on the charger.

5.  When the Battery is fully charged, switch off the charger and disconnect it from the mains.

6.  Remove the leads from the Battery in the reverse order ie negative first and then the positive.

You don’t mention what make of charger you have - or are buying - but most will have an accessory charging lead available.  This consists of a short lead made of both red and black leads, with spade terminals at one end.  These connect directly to the appropriate Battery terminal.

The other end of the lead will have a plug connector.  This connects to a matching connector coming from the charger.  The method of use is that you position the lead from the Battery as far away from it as possible, with cable ties for example.  You can then plug the other end into the charger cable before switching it on - and without ever having to go back to the Battery.

I hope that has made it clear.  
PS.  If you haven’t yet bought your trickle charger, I can recommend the NOCO.

[ColinBarber]

6 hours ago, KW Lexus said:

can I recharge the 12v battery by connecting +ve clamp to the Red jump start terminal in fuse box under the hood and -ve clamp to unpainted metal point under the hood, Or I should clamp the 12v battery +ve -ve terminal directly under the boot.

Either method will work. I've always charged my UX using the jump terminals in the engine bay as it is more convenient.

[Herbie]

As has already been said, either way will work.

12V is 12V whether it's at the front, back, top or side of the car and all you're doing is piggy-backing a known good 12V source onto a dodgy 12V source, so no worries either way

[Don C]

11 hours ago, ColinBarber said:

Either method will work. I've always charged my UX using the jump terminals in the engine bay as it is more convenient.

Me too.  

[KW Lexus]

Thank you for helping and answering my query. Just one more: the 12v charger have a AGM Battery mode.  Is the UX250h 12v Battery AGM or standard one? Thanks

[ColinBarber]

Standard flooded type. 

[stepppy]

14 hours ago, KW Lexus said:

Thank you for helping and answering my query. Just one more: the 12v charger have a AGM battery mode.  Is the UX250h 12v battery AGM or standard one? Thanks

If it's a smart charger like mine, it should auto-detect the Battery type, but as Colin states it is standard flooded type.

[Malcolm Kemp]

Hi Ken. A few months ago I managed to flatten my 12v Battery by having the radio on for too long with the engine switched off, and like you, the AA got me going again. To ensure I didn't get caught out again I bought a Grepro jump starter which I keep in the car. It's a neat little unit and is very easy to use.

[KW Lexus]

thanks Malcolm

 

[KW Lexus]

thanks c and Stephen

[KW Lexus]

Hi, yesterday I bought a Lidi Ultimate Speed Car Battery Charger to recharge my 12v Battery and after 5 hours charging, the charger screen sill showing the voltage up and down from 12.5v to 13.5v and black to 12.5v, with charging level 2 to 3 then 4(full) and back to level 3 and then level 4 and level 3 again within minutes.  My question is: Is my Battery bad soon ( i can still turn on the car) ? Or the Lidi Battery charge is faulty ? OR it is normal to fluctuate between voltage and charge level when charging and become stable when FULLY charge? Thanks.

[LenT]

4 hours ago, KW Lexus said:

Hi, yesterday I bought a Lidi Ultimate Speed Car Battery Charger to recharge my 12v battery and after 5 hours charging, the charger screen sill showing the voltage up and down from 12.5v to 13.5v and black to 12.5v, with charging level 2 to 3 then 4(full) and back to level 3 and then level 4 and level 3 again within minutes.  My question is: Is my battery bad soon ( i can still turn on the car) ? Or the Lidi battery charge is faulty ? OR it is normal to fluctuate between voltage and charge level when charging and become stable when FULLY charge? Thanks.

Well, you’ve bought a trickle charger and you’ve connected it to a Battery that you say you flattened.  The charger will have circuits to control the charge rate as overcharging can potentially damage the plates.  So minor fluctuations may well occur - and different chargers may respond in different ways and have different systems for indicating charge rate and Battery voltage.

However, I would not say that five hours from dead flat is usually sufficient for a trickle charger to fully charge a dead flat Battery.

I use my trickle charger over night and that’s simply to maintain the Battery condition - not to restore from dead flat!  I would certainly expect the charge rate to stabilise at a low rate after an overnight charge, so I would be inclined to give it a few more hours - which you probably have already done!

If you’ve left it connected, it’s probably fine by now! 😊