UK Prius user here - yesterday I installed a Bosch S4 155 size battery (£46 from EuroCarParts) in my '06 Prius, replacing what looks like an OEM/original battery. The fit is perfect (size and terminals) - except for the vent tube. The Bosch battery has two vents, one at either end, with a plug to bung one of them up. However, the vent holes are too small. I'd estimate around 5-6mm rather than the needed ~8mm of the vent tube. I reckon it might be able to be filed down to fit, but I was just wondering what others have done with this/other 3rd-party batteries where the vent tube doesn't fit? Thanks
On the whole people don't buy batteries that don't have the correct vent hole. having said that I just purchased an Exide X60DPMF which is a calcium not AGM battery which doesn't have the correct size vent hole. However it is a fully sealed battery and doesn't need to vent. you should check whether yours is a fully sealed battery. If so you won't need to vent it. Usually batteries have two vent holes so you might need to block one hole while fitting the tube to the other if it is not a fully sealed battery.
Car electronic shop just did give me battery vent tube fittings and hoses and one did fit perfectly. Before battery was just installed without vent tube.
You have two options: Try and find a new elbow that will fit the new Bosch battery vent hole. File the existing elbow down a bit on the end so it fits your new battery. I did the latter when I fitted a Bosch S4 155.
Yes and it was even installed by Toyota dealer. Its Toyota brand battery but not for prius and its not AGM.
Often screen wash fittings work as vent tube adapters. Even the screen wash tubing can be used. The gas flow rate through the tube in the vast majority of cases is zero. It is only when the battery is charged at an excessively high rate "such as when the battery fails with a shorted cell" that it is likely to gas at all, and even then the flow rate is very small. If the battery gasses continuously it will dry out and become useless in a few days. John (Britprius)
Thanks for the answers - in the end I just shaved off the original adapter with a craft knife and shoved it in. I figured if I still have the car in 4/5 years when then battery needs replacing again then I'll get another Bosch so it'll fit anyway!
Hi Oxford. I was in a very similar situation to this about 15 months ago when I replaced my OEM battery with a cheaper alternative. Mine also had two vent holes (each end) and they were too small to plug in that elbow joint. I ended up moving the elbow joint down to the other end of the tube (where it goes though the floor pan) and just shoving the rubber tube straight into the side of the battery. It was a tight enough fit to stay in place without any problems. Here are some pictures of how it went: Finally replaced my 8.5 year old 12V battery! Non AGM??? | PriusChat
