[AllBlackBimmer]

So I finally got around to hooking up my CTEK 3300 Battery float charger... and my car needed it. Great product, quality construction, highly recommended.

Anyway... like many float charges, this came with a "permanent quick connection" ... bolts directly to the battery (under hood jumper posts) connection instead of having to use the alligator clips everytime... makes it just as easy as plugging in a cord.

(I am not getting into a "should just hook it up to the battery in the trunk" debate. It is well known you "should" hook it up under the hood at the jump points, even if some of you have it direct to the battery and don't have problems)

Anyway, are there any concerns with these wires getting too hot, or melting, or anything like that because it is an under hood connection. Obviously our cars run hot, and having a black car also adds to the heat. Not worried about it now, but once summer hits and it's 95 degrees outside, car baking in the sun, and then driving it... are there any chances these wires can get damaged?

See picture of wire routing, which seems to be a pretty typical routing/mounting... there is also a small 15a fuse encased in rubber/plastic that I don't want to get damaged.

God forbid these wires melt on me one day and cause a fire or something crazy.

Anyone have any long-use experience or know if there is a better location to route the wiring? I have it placed behind the windshield washer fill tube.

[IMG]20150122_182720 by AllBlackBimmer, on Flickr[/IMG]

[IMG]20150122_182731 by AllBlackBimmer, on Flickr[/IMG]

[IMG]20150122_182744 by AllBlackBimmer, on Flickr[/IMG]

[IMG]20150122_183317 by AllBlackBimmer, on Flickr[/IMG]

[John 070]

personally I use the alligator clips with the battery tender, and I put the negative to the strut tower. I don't like splicing anything in, especially when the device itself is in the $50 ballpark, would rather put up with the inconvenience....

[AllBlackBimmer]

Originally Posted by John 070

personally I use the alligator clips with the battery tender, and I put the negative to the strut tower. I don't like splicing anything in, especially when the device itself is in the $50 ballpark, would rather put up with the inconvenience....

nothing is spliced.
The CTEK, like others, actually comes with wires that have eyelet's so you can take the bolt off the battery post, slip it on, and re-bolt it.

The negative post just needed a 6mm (I think) bolt to attach.

So it is made to attach... I am just not sure if the heat of the engine will cause any issues... once it's nice out again, I will be driving my car on most days.

CTEK 3300 is also around the $50-60 range. the deltran battery tender is very comparable.

[AM330i]

The heat should not cause any issue for you, These wires should be able to handle a few hundred degrees before they start to melt. Just make sure they are not near any exhaust parts and you should be fine

[sy2767]

Originally Posted by AM330i

The heat should not cause any issue for you, These wires should be able to handle a few hundred degrees before they start to melt. Just make sure they are not near any exhaust parts and you should be fine

I agree, i have my BMW charger installed as you do and i have never had an issue or even worried about such a thing happening.

[I-4]

I bought a new Cetk and want to wire it with the connections supplied. Where exactly did you connect the positive terminal? I see you have bolted the negative directly to the post.

[Efthreeoh]

If you are worried about heat damage, then why not hook it up directly to the battery in the trunk.

[dmatre]

Connect under the hood because BMW recommends it that way. Connecting to the battery bypasses the IBS.

Don't know if it was related, but I used to connect direct to the battery. After about 2 months of driving (about once every third week) and charging, the battery failed completely (while driving). Car dead, key stuck, head/tail lights strobing like a disco.

It wasn't until after that incident that I researched & found BMW's advice in both the owners manual and their service manual.

It doesn't cost any more to do it right, so why go otherwise?

[AllBlackBimmer]

Originally Posted by I-4

I bought a new Cetk and want to wire it with the connections supplied. Where exactly did you connect the positive terminal? I see you have bolted the negative directly to the post.

On the positive jump post, which is under that red cap.

[AllBlackBimmer]

Originally Posted by Efthreeoh

If you are worried about heat damage, then why not hook it up directly to the battery in the trunk.

Because that is incorrect.
See post in Tia thread and search for others.

Long story short, you might be able to get away with direct to battery, but many, many people have had issues doing it direct.

Charge needs to go through the IBS.

Same reason why if you needed a jump start, you don't connect directly to the battery.

Good luck replacing fried electrical system on our cars.

These same people that connect direct to battery, are probably the same stubborn people who refuse to register their batteries to their cars. BMW (like all german cars) have complex and finicky electrical systems, so I will only do what the manufacturer states to do in these cases.

[ctuna]

Anybody have a schematic of the electrical system.
Because I am wondering how the IBS detects state of charge
and if it is wired in parallel or series with the rest of the car.
This might also explain those hard to jump the car situations
in which some claim the IBS stops you from starting it when
jumping with a low battery condition.

[Efthreeoh]

Originally Posted by AllBlackBimmer

Because that is incorrect.
See post in Tia thread and search for others.

Long story short, you might be able to get away with direct to battery, but many, many people have had issues doing it direct.

Charge needs to go through the IBS.

Same reason why if you needed a jump start, you don't connect directly to the battery.

Good luck replacing fried electrical system on our cars.

These same people that connect direct to battery, are probably the same stubborn people who refuse to register their batteries to their cars. BMW (like all german cars) have complex and finicky electrical systems, so I will only do what the manufacturer states to do in these cases.

I did check that the owner's manual states charge the battery from under the hood. It's not specific if that's for a high rate charger or a float charger. I can't see how a float charger at the terminals could damage the battery or electrical system. Maybe it could change the computer's charging scheme if the IBS sees a constant change in the state of the battery as the float charger exercises the battery. Charging from the hood probably prevents that. Anyway, the wires for the charger are not going to get damaged from engine heat.

[AllBlackBimmer]

Originally Posted by Efthreeoh

I did check that the owner's manual states charge the battery from under the hood. It's not specific if that's for a high rate charger or a float charger. I can't see how a float charger at the terminals could damage the battery or electrical system. Maybe it could change the computer's charging scheme if the IBS sees a constant change in the state of the battery as the float charger exercises the battery. Charging from the hood probably prevents that. Anyway, the wires for the charger are not going to get damaged from engine heat.

Yea, I know what you are saying, as regular chargers, and "float" chargers are different...

However, BMW re-brands the Deltran tender (and is now also re-branded the CTEKs) and if they are re-branding these units with the "BMW logo"... and are specifying to connect under the hood... then, I am in no way going to risk damage to my battery, the IBS, or my electrical system.

However, Ive read some posts that people have connected directly to the battery "for years" without problems... but, not willing to take that chance.

I highly recommend the CTEK units... the Deltrans are also good, but I feel like the CTEK is made with a little more quality... and the really high end cars all re-brand CTEK units (and charge 10x the price - porche, Lambor, Aston, etc)