Battery Charging

[viewsonic1]

May be obvious to seasoned Morris Minor owners, but can I charge the battery without removing the battery from the car and without disconnecting the leads? I used to do this years ago, but obviously with modern cars it is a big fat no; can the Minor take it?

[kennatt]

Never had a problem doing this, no different than a jump start,you're not getting confused re useing electical welders without disconnecting,but again I,ve never had a problem with this but many say you should to prevent diodes being damaged.

[lambrettalad]

Yo can but its safer off the car ,follow the usual safety precautions,as batteries can explode
this is good place to start ,Utube is full of it
https://www.youtube.com/watch?v=a-t2wszIQ5U

[IslipMinor]

Yes you can, just make sure that the charger is turned OFF before connecting to or disconnecting from the battery.

Spark(s) + gassing (newly charged) battery = exploding battery. I watched once as a single MIG spark arced gracefully across near the fork lift truck that had just come off charge - exit one 24-cell battery, but no other problem. An uncontained battery would have been much worse!

[bmcecosse]

Make sure you get the polarity correct - and as above -connect leads and then switch on......and switch off before removing leads. Why does it need charging?

[GBond]

If you don't use the car too frequently a trickle charger would be a good idea. These are small and just keep the battery topped up so there's no explosion danger and the car will always be ready to go when you are.

[viewsonic1]

It doesn't actually need charging, bmcecosse but I would like to get the correct information in place BEFORE I am caught short. At the moment, it is only an occasional weekend car. Many thanks for your reply and to all the other very useful MMOC members' replies to my query.

[bmcecosse]

A solar panel from Maplins works well - avoids need for mains connections, and keeps battery topped up nicely. Needs to be sited in good light obviously....... This works very well........ http://www.ebay.co.uk/itm/SOLAR-POWERED ... 2c76ec1fa8

[lambrettalad]

Times two for the above ^^^^^^

[blues2rock]

Old type battery chargers can cause sparks and if left 'on' too long will damage the battery. They also never actually fully charge the battery.

If you can, get a modern 'intelligent' charger that will not spark, is protected against reversed polarity and can be left connected and on indefinitely. Most come with an accessory lead and socket that you install on the battery and then you can easily connect the charger when required.

There are several different makes/types, you don't need a massive output for a minor battery, 6 amps is more than enough and the best of the bunch is CTEK. Forty or fifty pounds will get you a suitable one.

[bmcecosse]

Forty or fifty pounds..........geez..... Why would an 'old' charger not fully charge the battery ? Of course it does! I agree it's not clever to leave a 6 amp charger banging away into a battery - gassing up the cells. But most 'old' chargers have a selector switch - and you decide if you want fast or slow - or 'trickle' charge - perfectly satisfactory for the job - which should never need doing anyway. If you need to charge the battery on a reasonably regularly used car - the charging system (or the battery) needs investigation.

[blues2rock]

Old style chargers are limited to a maximum of 13.8 volts which is not enough to charge a 12 volt battery to 100%. Precisely why is to do with the chemistry of the battery, but was ok (ish) for the old style lead/acid batteries. Modern chargers can 'pulse' at 14.4 volts and can achieve 100% charge, varying both voltage and current to suit the battery type and state of charge.

Despite the fact that some of those old chargers had a high or low switch, the output is constant at the setting selected, and if left 'on' for too long will cause damage to the battery (and the electronics of a modern car if charged 'on the car').

The situation is further complicated with the arrival of the now common calcium batteries which are very susceptible to damage from overcharging.

Lastly some modern chargers are completely safe to charge on the vehicle so no worries about damaging the electronic components. Not much of a problem on a Minor unless it is fitted with an alternator.

But as always each to his own.

[bmcecosse]

Any old style chargers I have checked are good for about 18 volts on open circuit! Certainly not limited to 13.8 volts....how would they do that in an 'old' (ie non 'electronic') charger? But in any case - the additional voltage above about 13.8 is just a surface effect -and makes negligible contribution to the total charge held by a battery. As soon as it's used the volts will drop steeply - and then settle at a much lower supply figure for most of the battery life -falling away miserably of course near the end........

[blues2rock]

Interesting how you managed to measure a voltage on an open circuit ??????

I can't be bothered to argue the point but if anyone is interested just google battery charging technology or protocol or something similar and I'm sure all will be revealed.

[bmcecosse]

Easy - connect one lead of the DC meter to each terminal of the charger and switch it on... I can well see who is spreading the BS 'blues' - but I wasn't going to mention it! I never let the forums become personal. I've moved you to my 'naughty step'.. G'bye...

[kennatt]

[Ufudu]

The problem, very often with these types of discussions is that "it depends"...

As a student I had a number of "old style" chargers, and all are different. For example, the one BMC describes that has an 18V open circuit reading is most likely one with what is called a "loosely coupled" transformer.

A loosely coupled transformer acts as a sloppy voltage supply: when connected to a car battery that was low on charge the transformer would limit charge current. The disadvantage is that if you leave the charger on the battery the voltage would increase beyond what the battery could handle and damage it.

Other old style transformers (particularly the higher charge current types) did not have this characteristic but had a lower max voltage limitation.

All of these chargers suffer from a common problem; if left on too long may damage the battery by some degree. The rectifying circuit is a simple diode (bridge) rectifier that "pulses" the current into the battery. These pulses can result in voltage exceeding safe limits.

Modern "intelligent" chargers have a more stable & smooth voltage & current (more like the generator itself) but also should not be left on a charged battery for more than a day or so.

My non-expert view.

[bmcecosse]

Spot on Ufudu!

[rayofleamington]

Modern chargers can 'pulse' at 14.4 volts and can achieve 100% charge

REALLY modern chargers (e.g. search for CTEK ) can include a thermocouple at the crock clip end to measure the ambient temperature...
The actual max voltage at which a battery can go to without 'overcharging' is different between a hot day and a cold day.
Subject to the right temperature, anything up to 15v is fine.

As for damaging a modern car's electronics by charging on the car - I think that relates to 1980's cars.
Over the last 15 to 20 years most if not all electronic gizmos on cars have been designed to withstand 16v continuous and 24v for short period without damage.
Therefore if you've avoided a darwin-theory early demise, and attempted to jump start your 12v car with a 24 volt lorry you may actually get away with it
[However if it doesn't start quick you'll soon need a new starter motor and maybe other things... ]

and if that doesn't make you swap to another thread already... just wait for Lithium Ion batteries on a vehicle '12v' circuit (and maybe on a 48v stop start system etc..) as that chemistry is joining the market for cars' HV traction batteries as well.

Modern cars!! Who'd have em???

[MarkyB]

The worst thing I've heard on this subject is that coded batteries are coming in.
Another job that only the main dealer has the equipment to do and will charge accordingly no doubt