LC500 Battery charging.

[AJ500]

The forums are awash with questions about charging the 12v Battery. There appear to be ,generally,different views as to whether we should connect up to the Battery direct or via the jump start connectors under the bonnet.The manual states use the latter but with all my previous cars I have put the ctek onto the Battery.This has been supported in some other forums as it bypasses the vehicles various wiring channels.

What are others doing with their LC?

[Herbie]

As I said in a different topic:

I'm not trying to come over as a 'know-it-all' because obviously, I don't, but I'm a time-served electrician by trade. When the factory closed down I became a telephone engineer on BT, and after a back injury LED to medical retirement I'm now self-employed doing computer repairs. I'm also a licenced radio ham and dabble in electronics as a hobby. I mention that, not to blow my own trumpet, but just to explain that I've been in and around the electrical/electronics fields for more than 40 years.

In my humble opinion (and this goes for both jump starting and charging), 12V is 12V.

It just doesn't matter whether it's at the front or the back, it's still 12V and all you're doing is piggybacking one 12V source onto another 12V source.

The only thing to worry about is to make sure you connect with the correct polarity.

Having said all that, you can't blame me if something does go awry 

[LexIS200Sport]

The logic of connecting to the jump start terminals as opposed to the Battery comes from a safety standpoint rather than an electrical one. And I think it really only matters for jump-starting and much less so for trickle-charging. 

The reasoning is that a flat Battery that needs jump starting is likely to produce hydrogen when charged from a high-current source such as a donor vehicle. The last thing you want is for potential sparks (from disconnecting the jump-start cable clamps) to ignite said hydrogen. That's why many an owners manual state that you connect the jump-start leads directly to the Battery terminals of the donor vehicle, but only to the positive terminal on the "victim" vehicle. The negative clamp should be connected to a good ground point as far away from the Battery as possible, and it should be the last clamp that you connect and the first clamp that you remove.

But I think this is really a non-issue for trickle charging a healthy 12V Battery.