Battery Charging.

I own a 2007 Sonata, 3.3L auto.

I'm thinking of buying a CTEK CTE-MXS5.0 battery charger

I like their accessory which plugs into the cigar lighter. Very convenient and I don't have to disconnect any battery leads. I read reviews on charging this way and plenty of people seem to charge their batteries with no problems.

However, I need advise please. In the owners handbook, it states never to charge the battery with the leads connected.

Can somebody far knowledgeable than me on the subject please advise?

Reply to
nick
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You know that most vehicles nowadays turn off the cigar lighter plug when the key is off? I would not charge by leaving the key on. Disconnecting the cables makes sense when using a high power charger but I would not bother when using a low amp trickle charger. IMO, 50+ pound cost seems rather high, like about 10 times too much. I would pay about 7 pounds, at most.

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Reply to
Paul in Houston TX

Chinese trickle chargers are a dime a dozen. Nick's point is good. You have options: there are solar chargers, too. But the significant thing here is that for a cigarette lighter connection, you have to have the key on, and thus, there are other circuits that are engaged. This could, theoretically, not be such a good idea: the accessories, although probably with a low draw, could even out what the charger's putting out.

Therefore, what I'd do is to clip off the lighter plug and substitute alligator clips: connect the charger to the battery in the normal way, under the hood.

Richard

Reply to
Richard Steinfeld

If the key has to be turned to connect the lighter ionto the circuit, an alternative is a 12v power point for accessories that uses the same lighter plug and is on all the time without the key. So I guiess I can use that. My main aim is to find out whether I really need to disconnect the car battery. Looking at an earlier reply, the CTEK charges at max 5 amp which is not a great deal, so I'm wondering if other circuits would be safe.

Reply to
nick

I cannot definitively answer your disconnect question, however, no one else seems to worry about disconnecting the cables. In all my years of being a mech/tech and years of being on many automotive ng's you are the only person that has ever mentioned that. OTH, to be absolutely sure that no damage could ever occur to the electronics, then undo the cables and never use the cigar lighter plug to charge. IMO, using the cigar lighter plug is asking for trouble.

Reply to
Paul in Houston TX

The lighter outlet is fused at 10 amps so should be ok stuffing current back in at 5.0 amps. Will have to leave on Accessory. I,ve had a Ctek 7.0 amp charger on my camper for years and it seems a good quality unit. I,ve always connected the charger and then turned it on. Avoids ( or minimises) any sparks containing transients that can destroy semiconductors. Never had a problem. Guess its one of those 1 in a million things.

Reply to
John

Many thanks, I see lots of reviews where people don't disconnect, but then I read in my owners manual "Never attempt to charge the battery when the battery cables are connected". OK, you could say that answers the question, but I bet it says that in manuals where people don't disconnect. This is all it says on 2 pages. All the rest is about safety stuff, like don't drink the battery acid. Totally unhelpful. They could have explained the technical stuff a bit more. Where you say don't use the lighter socket, I do have just a 12v socket nearby of the same type of plug I could use? Doesn't need the key turned. It would save a lot of hassle.

Reply to
nick

I think that is a CYA message in case you connect a 5000 amp super charger that would blow out all the electronics. Takes away any warranty claims if you do so.

Reply to
Ed Pawlowski

I know in all my vehicles there is at least one power outlet that is non-switched. I purchased a $5 device that allows the plug in of a 9V battery into a power outlet and keeps the memories alive if/when the battery is disconnected. Might want to give that a try - they do work!

Reply to
r.mariotti

I'm answering from an American perspective, so your vehicle and your national requirements may be substantially different.

If I disconnect my battery, I'm going to zero out the computer's volatile memory. If I do this two weeks before a smog test, my car will flunk the test because not enough data will have been built up in the computer to satisfy the State of California.

I see no harm is connecting the charger directly across the battery with all the standard (non-running) loads in parallel. After all, in normal running, automobile charging circuits can put out some pretty dirty power and the various components aren't trashed as a result.

Many years ago, when I lived in a different part of the US with cold winters, I used to keep the car on a trickle charger every night during the winter. This helped a lot. If I recall correctly, I made up some sort of quick-connect arrangement so that I didn't have to raise the hood twice per day. People do this sort of thing in the American midwest, and I'll bet that it's commonplace in Canada. With today's cars, I don't think that the cigarette lighter approach will be practical.

Richard

Reply to
Richard Steinfeld

Ed's right. People put together instruction sheets who have no idea of what they're doing. How many times have you bought a little tiny device like an MP3 player with instructions that caution you with pictures of a TV falling on you from a rolling table?

Let's say that you're using a big hulking industrial-type quick charger that's capable of cranking the engine all by itself. Such a device could, in my mind, if poorly controlled, put an over-voltage across the battery that's capable of blowing out a few always-on devices. An example of something that's always on is the clock. The computer's memory is always on, but I'll bet that it's also protected against over-voltage. I think that this is it. A trickle charger just doesn't have enough "oomph" to do this sort of damage. I'd just connect it right across the battery terminals (or hot + and ground) without concern.

Richard

Reply to
Richard Steinfeld

Yes. In fact, I'm going to make up just this thing because I'm going to replace my battery soon, and I don't want to blow the volatile memory in the car's computer.

My Hyundai has no "always alive" power tap, so I'm going to make this up to go right across the battery cables using clips.

All it takes is a couple of clip leads soldered to the terminals off a dead 9v battery. The live battery will then clip onto the old terminals. Put across the old battery for a minute or so while disconnecting the big battery's leads shouldn't harm the little 9v battery: all we need for this sucker to do is to provide enough DC to keep the car's computer satisfied with that tiny trickle of juice. Then just put the new battery in the car, clamp on the large cables to the new battery, and disconnect the clip leads. I'll treat the 9v battery as disposable and toss it.

Richard

Reply to
Richard Steinfeld

Thanks for all the answers. My lighter and aux power outlets are switched by the ignition, so I agree these are not a suitable way to charge. I will fit the optional cable and feed it through.

As part of my investigations, having asked for more practical help here, I have had replies from the CTEK manufacturers and the UK suppliers.

You can leave your battery connectesd when you use CTEK chargers. No harm is done, If your car manufacturer have specific instructions, do always as the manufaturer recommends.

Best regards, CTEK

CTEK SWEDEN AB | ROSTUGNSVÄGEN 3, SE-776 70 VIKMANSHYTTAN, SWEDEN PHONE: +46 225 351 80FAX: +46 225 351 95 | WEB:

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EMAIL: snipped-for-privacy@ctek.com

THE SMARTEST BATTERY CHARGERS IN THE WORLD!

andThe MXS 5.0 will be fine in that case.All CTEK chargers have very low voltage and current ripple so, unlike conventional chargers, can be used on the vehicle without having to disconnect the battery. The only time we'd recommend disconnection is when using "RECOND" mode, but this should only be used on poor/failing batteries anyway.Kind RegardsThey needed to know the AH of the battery.The Owners Manual states MF 68AHCheers all.Nick

Reply to
nick

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