Author Topic: Battery jump info and other possibilities  (Read 2614 times)

Terryp

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Battery jump info and other possibilities
« on: February 02, 2023, 05:32:58 PM »
Hi all

I pick up my xstar next month and started reading the manual. On the flat battery section it’s proving weird to my brain.

I have a battery booster and on my mk2 I connect to the + and - battery terminals, on the xstar it says to connect to the + but then shows connecting to something across the other side of the car, can anyone give my brain an understanding of the above please?

I also take it you cannot push start the xstar. Thank you

Marco1979

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Re: Battery jump info and other possibilities
« Reply #1 on: February 02, 2023, 06:28:14 PM »
The - of the battery is connected to the car’s mass. If you connect to any mass point (needs to be bare metal) it will work. Connecting to the battery might be more tricky in a practical point of view: enough room for the connector, very close to + which is a risk etc.

Push starting won’t work because without power the system cannot set up the electric motor to act as a generator and also a 80 kW motor might be difficult to rotate when connected…

Marco1979

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Re: Battery jump info and other possibilities
« Reply #2 on: February 02, 2023, 06:41:32 PM »
Small addition: the Mk4 uses the high voltage battery to power the starter motor. The 12V battery is to power the control systems to make that happen. So no high current needed from your booster, making safety (away from battery) prevail from less resistance.

Pine

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Re: Battery jump info and other possibilities
« Reply #3 on: February 02, 2023, 06:49:31 PM »
The negative cable from a battery charger should be connected to an earth point away from the battery, that is the norm now for any make of car.  If you connect directly across the battery you are bypassing the electronic battery management system and the ECU may not recognise that the battery has been charged. 

Kremmen

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Re: Battery jump info and other possibilities
« Reply #4 on: February 03, 2023, 04:50:37 AM »
I have my CTEK connected to the actual battery terminals, have done for about 15 months and never had any problems.

When I did have the negative connected to bodywork, first few months, it took a lot longer for the CTEK to turn green.
Let's be careful out there !

5thcivic

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Re: Battery jump info and other possibilities
« Reply #5 on: February 03, 2023, 01:36:51 PM »
This is an interesting topic which is difficult to find a definitive technical answer, even from a manufacturer. I too have  permanent cables attached to the battery on Jazz and E (and 5 Civics before this) and never had a problem charging when the car is off with intelligent micro controlled chargers.

I notice it is possible to get a very small spark when connecting crocodile clips (with the charger off naturally) and the far bodywork connection is the advice from when batteries had water top up tops and hydrogen could escape thus risk of that spark. With sealed batteries this is far less likely. Also jump start is a different scenario and here you are supposed to bypass the negative terminal sensor box on the battery to an engine bay bolt because of the large peak currents involved. But this does not apply to the E... or Jazz for that matter. The SAE connectors of permanent leads have the advantage of never sparking.

There is a school of thought that the car controller cannot recognise the state of charge of the battery after charging unless you have the negative sensor box in circuit when charging - i.e. negative to bodywork. I find this problematical, if the main micro system can tell the difference between 10 and 12V it should know the battery is in good condition after charging and run the approriate software routines accordingly.
But a definitive answer would still be welcome.
« Last Edit: February 03, 2023, 01:41:16 PM by 5thcivic »

Lord Voltermore

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Re: Battery jump info and other possibilities
« Reply #6 on: February 03, 2023, 02:52:14 PM »
I think  I have read somewhere that when connecting  jump leads  to a car battery its best to connect the negative terminal to the car bodywork or engine rather than  directly to the battery. Like 5thcivic says  its to reduce the chance of any spark igniting any battery gases.  The same may be true of connecting battery chargers. Any illustrations may show such precautions being taken.

I think the risk of gassing is minimal  with modern batteries and battery chargers, especially if you have leads pre wired.
« Last Edit: February 03, 2023, 02:53:47 PM by Lord Voltermore »
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Kremmen

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Re: Battery jump info and other possibilities
« Reply #7 on: February 03, 2023, 02:56:44 PM »
Yes, jump lead negative to body metal, I think body first then positive to battery, but trickle charger seems to be OK straight to battery.
Let's be careful out there !

Terryp

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Re: Battery jump info and other possibilities
« Reply #8 on: February 03, 2023, 03:46:18 PM »
In respect the CTEK charge units, do they still operate with its negative connection not physically on the battery?

One of the items I want to buy is a tracker that connects directly to the batteries + and - terminals, the tiny tracker then just sits on the battery, I’m now starting to wonder if anything on this battery would affect it. How’s things have moved on from years gone by.

Kremmen

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Re: Battery jump info and other possibilities
« Reply #9 on: February 03, 2023, 03:52:13 PM »
When I first got my Jazz I connected the ring terminals to the battery positive and a nearby suitable metal connector.

I was very surprised by how long it took for the CTEK to go green compared to my 9G Civic that was connected direct to both battery terminals so I moved the ring terminal negative direct to the battery and that took a few hours off the charge time so I've left it there.

I always plug the CTEK in after 2 weeks of non use so the battery discharge would be roughly the same.
Let's be careful out there !

nowster

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Re: Battery jump info and other possibilities
« Reply #10 on: February 03, 2023, 03:54:47 PM »
Positive is always connected first and disconnected last to avoid the chance of shorts, as all the exposed metalwork is "earth". It also lessens the potential of igniting any hydrogen escaping from the battery if the negative is connected to the engine block, well away from the battery.

R2D3

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Re: Battery jump info and other possibilities
« Reply #11 on: February 03, 2023, 04:01:22 PM »
The Honda Assist (AA) technician connected his jump leads directly to the battery terminals.  I presume he knew what he was doing.

Neil Ives

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Re: Battery jump info and other possibilities
« Reply #12 on: February 05, 2023, 06:46:37 PM »
If one were to connect a multimeter between the battery - ve and the car bodywork or engine and checked the resistance between them we might discover if there is a circuit between the two points. If there is no discernable resistance I do not see why a charger should not be connected across the battery. I suspect the instruction to put - ve to frame is to avoid battery gas ignition.
Neil Ives

5thcivic

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Re: Battery jump info and other possibilities
« Reply #13 on: February 07, 2023, 12:32:39 PM »
Unlikely to be a resistance, if significantly measureable then the peak currents in jump starting would be a problem and probably blow the sensor. More likely a shunt system measures voltage, current and probably temperature for info to the main controller. Most important for stop start systems where this sensor will tell the system whether to use the stop/start or not if the battery might not be poweful enough to guarantee a start.

John Ratsey

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Re: Battery jump info and other possibilities
« Reply #14 on: February 07, 2023, 07:34:30 PM »
One of the items I want to buy is a tracker that connects directly to the batteries + and - terminals, the tiny tracker then just sits on the battery, I’m now starting to wonder if anything on this battery would affect it. How’s things have moved on from years gone by.
Note that the vehicle has a built-in tracker provided you request the dealer to enable the telemetry. You can then see the vehicle location using the My Honda+ app.
2022 HR-V Elegance, previously 2020 Jazz Crosstar

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