The solution i recall is to fit an auxiliary battery with increased capacity but they are reluctant to go down that path unless pressed by the customer in view of the cost to the company.

Not an auxiliary battery but a replacement battery which some say has an higher capacity whereas others say its the same capacity but a different make. It seems there was a bad batch of batteries fitted and its cars with these that have the issue. Toyota have been changing the batteries on cars affected but if the car is used everyday you would be unlikely to have an issue.

Ours has been left for just over a week twice with no issues, lets see what happens next week.

Quick question, where would you fit the auxiliary battery? The standard 12v battery is under the back seat along with the traction battery, no space there. No space under the bonnet either.

My hybrid is fitted with a Varta 345 LN1-MF 45Ah CCA 286A 12v battery.

I doubt if the CCA figure is important with a hybrid as the battery doesn't operate a high current starrer motor but is there a better battery (higher Ah?) to ultimately replace this battery and would something like an AGM battery help?

In a different car I always regarded a Varta as being an excellent battery. In my old 2003 diesel the original Varta lasted 12 years in my ownership and many more years afterwards when I sold it to a colleague.

PS thus far I've had no problems.

Edited by Big John on 14/05/2025 at 18:54

but is there a better battery (higher Ah?) to ultimately replace this battery and would something like an AGM battery help?

OEM spec battery should be fine unless you are very unlucky.

An AGM battery would be a bad idea if Toyota don't fit one, they charge at different voltages.

Why on earth do you want to spoil a perfectly OK car?

I wouldn't - I was just trying to see if anyone has "upgraded" such a 12v battery more for the benefit of others that have had a problem - eg I've spotted some mention use of a slightly higher Ah Yuasa conventional batteries elsewhere (54Ah v 45Ah).

I drive my car most days so I suspect I'm less likely to have an issue - fingers crossed.

One mistake with a car with Toyota hybrid gubbins is using Neutral for an extended period of time eg stuck in traffic. The car does not charge the 12v battery in this mode.

Edited by Big John on 14/05/2025 at 23:24