Trickle charging - confusion over where to connect to

[MrM83]

Due to one issue or another I am wondering if I should try regularly trickle charging my T8.

Ive read reference on this forum on numerous occasions to not trickle charging the battery on the left hand side of the boot directly, and instead connecting to the terminal points under the bonnet.

Ive struggled to find any Volvo reference that supports this notion, on the contrary, the below link talks about the battery in the boot and in the same breath mentions trickle charging with no mention of needing to connect under the bonnet. Before I buy a CTEK lead to attach direct to the battery in the boot, can anyone inform me where the "must be trickle charged by connecting to bonnet terminals" message comes from?

https://www.volvocars.com/uk/support...a801515b6d74b8

Thanks

[sk546]

As per the link below which is aimed at jump starting but utilises the same principles for trickle charging the starter battery:
https://www.volvocars.com/uk/support...a801512a5a5c53

You need to charge in this manner so that the batteries (and electrical system) protection devices remain in the circuit and prevent any component damage should there be any voltage/current spikes during the procedure.

Hope that helps.

[nu11eaf]

This is from my D5 owners manual.
See paragraph under the pink warning box.
Screenshot_20240109-175539_Drive.jpg

[MrM83]

Originally Posted by sk546

As per the link below which is aimed at jump starting but utilises the same principles for trickle charging the starter battery:
https://www.volvocars.com/uk/support...a801512a5a5c53

You need to charge in this manner so that the batteries (and electrical system) protection devices remain in the circuit and prevent any component damage should there be any voltage/current spikes during the procedure.

Hope that helps.

Thanks, but this article doesn’t mention trickle charging explicitly like the one I linked to. Quoting from the link I posted:

“ In order to maintain the starter battery in good condition, it is recommended that there is at least 15 minutes driving/week or that the battery is connected to a battery charger with automatic trickle charging. A starter battery that is kept fully charged has a maximum service life.”

Seems strange to me given how explicitly it is mentioned in nu11eafs document for a D5. I can’t imagine T8’s are that different?

I interpret that as good to connect a trickle charger straight to the battery? I would expect a jump start or jump pack to be a different procedure…

[Clan]

Originally Posted by MrM83

Due to one issue or another I am wondering if I should try regularly trickle charging my T8.

Ive read reference on this forum on numerous occasions to not trickle charging the battery on the left hand side of the boot directly, and instead connecting to the terminal points under the bonnet.

Ive struggled to find any Volvo reference that supports this notion, on the contrary, the below link talks about the battery in the boot and in the same breath mentions trickle charging with no mention of needing to connect under the bonnet. Before I buy a CTEK lead to attach direct to the battery in the boot, can anyone inform me where the "must be trickle charged by connecting to bonnet terminals" message comes from?

https://www.volvocars.com/uk/support...a801515b6d74b8

Thanks

There is a battery monitor unit on the battery negative cable near the terminal end.. if you clip a charger across the battery terminals this Battery monitor will not measure the current flow It stores a lot of information . so that's why the charging negative lead has to go to the body of the car on the special terminal provided.. so that the charging current goes through the battery monitor and the data is stored.

[MrM83]

Thanks for the detail. I remain surprised Volvo aren't more explicit with warnings around not charging via main battery in light of the above.

[Clan]

Originally Posted by MrM83

Thanks for the detail. I remain surprised Volvo aren't more explicit with warnings around not charging via main battery in light of the above.

It's probably in the handbook actually, It isn't detrimental at all if you connect across the battery , the data will soon refresh and update over the next week and beyond.

[LRS]

I took the ‘trickle charger’ approach after suffering the dead car syndrome and so far, it has not dead-car’d again for a year. (My Volvo dealer said all the staff with company cars use a trickle charger to mitigate the extra drain on the 12v battery that these new AAOS systems are creating)

Look at this company CTEK for trickle chargers. I went for the MXS 5.0 UK. It’s important to set the charger to AGM mode as the 12v batteries in the Volvo are AGM type.

The trickle charger option is good for when the car is not being driven frequently or for short durations e.g., working from home. The problem may arise however, if and when you ever have to leave the car somewhere for an extended period of time e.g., airport car.

[LRS]

I took the ‘trickle charger’ approach after suffering the dead car syndrome and so far, it has not dead-car’d again for a year. (My Volvo dealer said all the staff with company cars use a trickle charger to mitigate the extra drain on the 12v battery that these new AAOS systems are creating)

Look at this company CTEK for trickle chargers. I went for the MXS 5.0 UK. It’s important to set the charger to AGM mode as the 12v batteries in the Volvo are AGM type.

The trickle charger option is good for when the car is not being driven frequently or for short durations e.g., working from home. The problem may arise however, if and when you ever have to leave the car somewhere for an extended period of time e.g., airport carpark.

[ian77]

Originally Posted by MrM83

Seems strange to me given how explicitly it is mentioned in nu11eafs document for a D5. I can’t imagine T8’s are that different?…

I think they are quite different. The D5 start stop has a starter battery in the boot that, as the name suggests, starts the car. It also has a support battery under the bonnet which powers the cars electrics whilst the stop start is active. The T8 has a starter battery in the boot but it’s not used for starting the engine, the hybrid battery does that. If there’s not enough charge in the 12v battery then the car won’t start. In theory the hybrid battery keeps the 12v battery topped up; I don’t believe the T8 has a support battery. That may account for the different guidance for different models.