Recovery; a First in 30yrs

[Martin73]

Where do people attach their Noco's to on the engine for the negative?
I get the positive in the fuse box but the Noco's have pretty short leads and can't reach the recommended negative point in the handbook

Are any of these points ok?

[philip42h]

5 minutes ago, Martin73 said:

Where do people attach their Noco's to on the engine for the negative?
I get the positive in the fuse box but the Noco's have pretty short leads and can't reach the recommended negative point in the handbook

Are any of these points ok?

I've never actually had to use the Noco Boost (yet, touch wood) but I use the RAV4 equivalent of the rightmost one in your picture to trickle charge the RAV4. That looks to be bare metal through to chassis metal which must do what is needed ... (And it works for me!)

[ernieb]

The PHEV has particular connection points that I believe are designed to protect the cars electronics.

[Hayzee]

2 hours ago, ernieb said:

The PHEV has particular connection points that I believe are designed to protect the cars electronics.

Unfortunately Ernie I don't think the negative cable on the Noco can reach the official connection point identified in the manual.

[tfc]

 

[tfc]

[ernieb]

10 hours ago, Hayzee said:

Unfortunately Ernie I don't think the negative cable on the Noco can reach the official connection point identified in the manual.

That’s a pain. 

[Nick72]

When I was having troubles prior to DCM update I kept the noco in the centre console. Otherwise you have a motorised boot that's difficult to open.

 

I then boost from under the bonnet. Short leads on the noco but they still reach fine to the positive point and the nut and bolt earth.

[TopGeek]

Having suffered a flat 12-volt Battery on my 6-week old Yaris Cross, due to mostly short journeys, I have just purchased a Yaber booster and was shocked to see how short the cables are. This seems to be common to all of the lithium booster packs. They are evidently designed for connection directly to the Battery.

The car has no suitable negative pole connection point close to the fusebox and the owner's manual only refers to jumper cables (as in the above video) with the negative clamp being attached to a point on the far side of the engine block.

The only solution I can think of is to use a single conventional booster cable to extend the negative lead of the booster pack - not the most elegant way to play with high current devices but it should work, handled carefully.

[Cyker]

The entire body of the car is 'negative', so you can connect the negative terminal to literally any unpainted metal part in the car; Nearby bolts that are sufficiently big or sufficiently sticky-outy bits of the engine block are usually good candidates.

The designated points are just considered safer locations, but they are not usually mandatory.

[TopGeek]

The problem with connecting to screw heads is that, even though they may appear to be at earth potential they don't necessarily make a good enough electrical connection to pass the high starting current and could overheat or cause sparking. It's much safer to connect to the engine block or a terminal designated for that purpose.

Also, if the negative clamp doesn't have a firm hold on a screw head it can easily slip off and risk causing sparks.

[Cyker]

Yeah, that's why I was saying the designated points were safer, but you don't have to use them and it is possible to use other surfaces. It could be a bit sketchy for starting a diesel engine, but with the hybrids especially, I would think the current draw is low enough it'd be less of an issue.

A certain amount of common sense should be used tho' - A big thick bolt head connected to a big chunky engine part would be far preferable to a tiny screw holding two thin bits of bodywork together!

 

[ColinB]

I would have thought that with a hybrid the current draw would be minimal, unlike an ICE, so the chassis connection wouldn't need to be perfect?

Colin

[Nick72]

On 5/11/2023 at 10:55 PM, TopGeek said:

The problem with connecting to screw heads is that, even though they may appear to be at earth potential they don't necessarily make a good enough electrical connection to pass the high starting current and could overheat or cause sparking. It's much safer to connect to the engine block or a terminal designated for that purpose.

Also, if the negative clamp doesn't have a firm hold on a screw head it can easily slip off and risk causing sparks.

From memory that's what's shown in the user manual for a front jump at least.

[Nick72]

On 5/11/2023 at 5:48 PM, TopGeek said:

Having suffered a flat 12-volt battery on my 6-week old Yaris Cross, due to mostly short journeys, I have just purchased a Yaber booster and was shocked to see how short the cables are. This seems to be common to all of the lithium booster packs. They are evidently designed for connection directly to the battery.

The car has no suitable negative pole connection point close to the fusebox and the owner's manual only refers to jumper cables (as in the above video) with the negative clamp being attached to a point on the far side of the engine block.

The only solution I can think of is to use a single conventional booster cable to extend the negative lead of the booster pack - not the most elegant way to play with high current devices but it should work, handled carefully.

Interestingly when my PHEV was fixed with the DCM update (it fails to shut down when you switch the engine off) the dealer told me they'd had a few hybrid Yaris with the same problem and all were fixed.

Definitely software for me.

[TopGeek]

3 hours ago, Nick72 said:

From memory that's what's shown in the user manual for a front jump at least.

The manual only shows an external Battery connect to the jumper contact and the engine block by conventional jumper cables. They don't mention lithium starter packs

[Cyker]

They are equivalent.

[tfc]

On 5/11/2023 at 10:55 PM, TopGeek said:

The problem with connecting to screw heads is that, even though they may appear to be at earth potential they don't necessarily make a good enough electrical connection to pass the high starting current and could overheat or cause sparking. It's much safer to connect to the engine block or a terminal designated for that purpose.

Also, if the negative clamp doesn't have a firm hold on a screw head it can easily slip off and risk causing sparks.

There should be no need to pass high current as your only supplying 12v and not cranking amps like a conventional ICE.

[TopGeek]

5 hours ago, tfc said:

There should be no need to pass high current as your only supplying 12v and not cranking amps like a conventional ICE.

We're in nebulous territory here because we don't know what current is drawn from the booster when the AGM Battery is flat. However, if the ICE starts up while the booster is still connected the cranking current will be shared between the Battery and the booster and could be considerably higher Again, we don't know what the relative loads will be. No doubt, laboratory testing has been done but I can't find anything on the Internet.

I just feel it is safer to only use designated electrical connection points.

[Cyker]

In the hybrids the 12v system isn't responsible for starting the engine/ICE like it is in normal cars so thankfully that's not a concern.

The main goal of the jump/booster pack is to supply 12v to power up the ECU and other computers long enough for the driver to get in and start the car, which then energizes the traction Battery contactors; Once that's done, the jump pack can be disconnected as the high voltage system kicks in and takes over 12v duty, and can crank the engine if it thinks it's needed without the booster pack being connected.

As you say, the designated points are safer and more recommended, but for people with T-Rex-Arm (i.e. too short) jumper cables, they can use alternative easier to reach points in a pinch without worry

 

[Yorkboy]

53 minutes ago, TopGeek said:

We're in nebulous territory here because we don't know what current is drawn from the booster when the AGM battery is flat. However, if the ICE starts up while the booster is still connected the cranking current will be shared between the battery and the booster and could be considerably higher Again, we don't know what the relative loads will be. No doubt, laboratory testing has been done but I can't find anything on the Internet.

I just feel it is safer to only use designated electrical connection points.

There is no starter motor as such, the ICE is started by the traction motor and therefore uses the high voltage system, not relying on the 12 volt system

[Nick72]

12V on the PHEV is mainly for the electronic systems, lights, locking motors, and motorised boot. No role in starting the ICE AFAIK. It's a tiny Battery.

[Nick72]

On 5/13/2023 at 5:22 PM, TopGeek said:

The manual only shows an external battery connect to the jumper contact and the engine block by conventional jumper cables. They don't mention lithium starter packs

It's in the manual somewhere or one of the side documents. Found it on a US forum a long while back but I can't find the thread now.

The bolt and nut heads are marked as '-ve' on the car. Shown here...

 

 

 

[TopGeek]

4 hours ago, Yorkboy said:

There is no starter motor as such, the ICE is started by the traction motor and therefore uses the high voltage system, not relying on the 12 volt system

Good info. Thanks for that.

[Derek.w]

On starting any hybrid the bigist draw of current is the electronic handbrake operation if its not a manual conventional type.

Just keep 12 volt Battery at 12.2 volts as it will start under this voltage but its also degrades at lower voltages.