R56 Mini - Trickle charge

R56 Mini - Trickle charge

Author
Discussion

peteblk

Original Poster:

6 posts

62 months

Wednesday 24th February 2021
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New to Pistonheads!

My R56 JCW needs to be put on a trickle charge as it's not getting much use. I've just bought a CTEK MXS 5.0 charger as this can do the 'stop start' batteries.

Is it OK to just attach the charger directly to the battery terminals on a mini and leave it? I've read that you need to check it's OK on certain cars.

Thanks in advance!

E-bmw

9,976 posts

159 months

Wednesday 24th February 2021
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Fit & ignore, the ctek will do whatever it needs to do without any issues.

un1eash

619 posts

147 months

Wednesday 24th February 2021
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Don't connect direct to the battery, use the battery terminal under the bonnet.

stevemcs

8,990 posts

100 months

Wednesday 24th February 2021
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I connect mine up direct to the battery and have never had any issues.

E-bmw

9,976 posts

159 months

Wednesday 24th February 2021
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It makes absolutely no difference which you use, they are all connected by wire.

un1eash

619 posts

147 months

Wednesday 24th February 2021
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If the cars equipped with an IBS I wouldn't connect a trickle charger direct to the battery.

Majorslow

1,197 posts

136 months

Friday 26th February 2021
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I have the same charger. I connect live(red) to the red terminal, and the black (neg) to a bolt head with difficulty down between the engine and fuse box.

You should ever use the neg terminal on the battery.

Select the "agm" setting on the charger if your battery is an AGM battery.

It works well on mine, and normally only takes about 15-20 hours to fully recharge and keep on float.

Mine has a front and rear dash cam as well as the alarm, and the cold weather and no use during lock down been helpful to keep it together (only done about 60 miles since last year

I have however connected the non clamp lead directly to the neg/live terminal for the short wires with the 10mm connectors to my MX5 and leave it connected 24/7 for when that requires a boost ( which is most of the time during the winter as it rarely comes out this time of the year) and never had an issue with it. I just leave the wiring in there where the heat will not melt the wires when engine is hot. Have done this for several years

The CTec charger is a brilliant bit of kit. Had mine for over 5 years now in almost constant use

tr7v8

7,306 posts

235 months

Friday 26th February 2021
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Just connect it direct to the battery absolutely no reason not too. The old reason for not doing it was sparks from connecting but these days A. the current is minimal & B. batteries don't gas these days as they are sealed. The low current means that there is no danger to the cars electronics either.

MDifficult

2,175 posts

192 months

Friday 26th February 2021
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Majorslow said:
I have the same charger. I connect live(red) to the red terminal, and the black (neg) to a bolt head with difficulty down between the engine and fuse box.

You should ever use the neg terminal on the battery.

Select the "agm" setting on the charger if your battery is an AGM battery.

It works well on mine, and normally only takes about 15-20 hours to fully recharge and keep on float.
THIS

I use the same charger on all three of my cars and all of the advice from Majorslow is correct.

E-bmw

9,976 posts

159 months

Friday 26th February 2021
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Majorslow said:
You should ever use the neg terminal on the battery.
OK, if it is that categorical, what are the reasons?

Scrump

22,940 posts

165 months

Friday 26th February 2021
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From the FAQs on the CTEK website:

5. The CTEK manual says: ”Connect the black clamp to the vehicle chassis remote from the fuel pipe and the battery". In the picture next to this, the black clamp is connected to the battery's negative pole. Which is correct?

When you use a CTEK charger, you can use both connections. The charger should be connected according to the vehicle user manual. If there are no other recommendations in the manual, the negative or black connector should be safely connected to the chassis.

The connectors on old “non-smart” chargers can spark if the connectors touch each other, which could be dangerous if this happens near the battery. Keeping the connectors apart, and ensuring the positive connection point is as far away from the negative connection point as possible, will help to minimize any risk. If your vehicle has a BMS you cannot connect to the negative battery pole, the connection must be made to the earth or ground point, if you are in any doubt then connect to the nearest earth or ground point. Eyelets can be permanently connected to the battery as the charger is not usually attached to the eyelet cable when the cable is being connected, so there is no risk. The eyelet connections also give you enough time to check the correct attachment points.

Also, if the battery is disconnected or removed from the vehicle then both connections can be made directly to the battery terminal.

E-bmw

9,976 posts

159 months

Saturday 27th February 2021
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So , in other words you can do whatever you want/whatever is easiest.

SlimJim16v

6,116 posts

150 months

Saturday 27th February 2021
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E-bmw said:
So , in other words you can do whatever you want/whatever is easiest.
No.

Scrump said:
If your vehicle has a BMS you cannot connect to the negative battery pole, the connection must be made to the earth or ground point, if you are in any doubt then connect to the nearest earth or ground point.

E-bmw

9,976 posts

159 months

Saturday 27th February 2021
quotequote all
SlimJim16v said:
E-bmw said:
So , in other words you can do whatever you want/whatever is easiest.
No.

Scrump said:
If your vehicle has a BMS you cannot connect to the negative battery pole, the connection must be made to the earth or ground point, if you are in any doubt then connect to the nearest earth or ground point.
Now read the next sentence he quoted.

SlimJim16v

6,116 posts

150 months

Saturday 27th February 2021
quotequote all
Two different issues. The next sentence you're talking about is purely about sparks, I'm talking about the BMS issue.

There is an IBS module in the negative battery feed, which measures how much charge goes into it. If you bypass it the system doesn't know the correct state of the battery, so won't charge it correctly. If when charging you attach the negative lead to the chassis/engine, it goes through the IBS module, so the system works as designed.

As I understand it, it's usually only on cars with stop/start, so have an AGM battery. New batteries also need to be registered.

E-bmw

9,976 posts

159 months

Sunday 28th February 2021
quotequote all
SlimJim16v said:
There is an IBS module in the negative battery feed, which measures how much charge goes into it. If you bypass it the system doesn't know the correct state of the battery, so won't charge it correctly. If when charging you attach the negative lead to the chassis/engine, it goes through the IBS module, so the system works as designed.
https://bimmerscan.com/bmw-intelligent-battery-sensor-ibs/#:~:text=The%20BMW%20Intelligent%20Battery%20Sensor,to%20the%20negative%20battery%20terminal.&text=The%20IBS%20contains%20a%20micro,measurement%20from%20B%2B%20to%20Gnd

According to this it will still be able to measure battery condition as it measures voltage between B+ & gnd.

The only thing it will miss is the charge put into the battery when it is "by-passed" but then as it can measure the battery condition above it doesn't need to know about the additional charge.

Obviously it can't see the charge going into the battery when it is by-passed but then conversely it doesn't need to charge anyway, so won't.

Still not convinced.

Edited by E-bmw on Sunday 28th February 08:10

SlimJim16v

6,116 posts

150 months

Sunday 28th February 2021
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The correct way definitely works, the incorrect way may or may not work. Your choice.

peteblk

Original Poster:

6 posts

62 months

Monday 1st March 2021
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Many thanks for all the replies.

So, can you tell me where the nearest/best earth position is to attach the negative lead to?

The two cables aren't that long to it would have to be near the battery area.

Majorslow

1,197 posts

136 months

Monday 1st March 2021
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In my Mini it is between the engine and the thin black box. it is narrow, if you have large hands it is not easy to get it down to fix the clamp, but you will see a bolt/nut there.

I had to pull the two wires apart a little so it would reach down.

The comments above say to do it the proper way and why, short cuts can lead to .....short cuts smile

SHIFTY

924 posts

243 months

Monday 1st March 2021
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Can you not just plug into one of the 12v supply sockets on the car as I think that are all live even when ignition is off.