Battery over heating

So the 2008 Prius with 209,000 mile spat the dummy yesterday and had to be towed home. Had red triangle and service car light on. Little power and the HV battery fan flat out.

Disconnected the battery and that cleared the warnings, but the car started to surge when lifting off to coast at 30+ MPH. Drove for about 5 miles and symptoms returned. Reset the battery again and made it home.

Took the HV fan out and it was dirty. Just maybe that was it. The car drove ok for 15 miles after that so parked for the night.

Next day the car did about 100 miles and the battery too hot again. Stripped everything back so I could see teh fan working and it was.

So I have pulled the battery out and shall have a look over it tonight and see if there is any bad cells or corrosion on the copper tags.

The surging was not there last week and we have done 18,000 miles this past 6 months, so I am hopeful the battery has an issue I can fix.

 

The car was working fine the other day in 122f heat....

 

Thanks Jmack111, I did that last night and the car did work better for a while - but soon began to play up today.

I scanned for codes but there were none set. Yet!

 

Yes in AZ! The car is in bits now. Will check the battery cells tonight and see what they are reading. I have access to some second hand units if needed.

 

I have the battery out - but not at a work bench yet - waiting for the trolley to come home. The fan was dirty for sure.

I suspect there my be fluff n stuff within the battery case blocking air flow.

Over the past month I have noticed the bars going up n down a little quicker and it struggled through the mountain climbs we did 2 weekends in a row. So maybe a few cells have dropped performance and now just a little too much for it.

I hope tonight I can find something to point to this failure. Else put it back together and head off to Toyota for a scan readout.

 

The power is there once the 12v battery has been unplugged for a bit. Charging seems ok when braking up to the lights, but the car surges now when coasting along at 30+ mph - so I just did the on off the gas to avoid that issue.

Spoke to a bloke that rebuilds batteries and he offered the following: Clean fan (as you suggested) and then clean contacts on the battery, test all cells for volts. Get back to him after that.

 

So the"VVT" thingo is the surge issue? plus a poor performing battery I think I remember looking into that 10,000 miles ago. It was a valve or something and it had been replaced not so long ago. But the throttle body may need a good clean. So sort the battery first and then look under the hood!

 

Hmmm - will have a look for sure at this. Our Prius does about 1,000 miles per week now and could do with a MPG boost Cheers

 

Checked all the cells and they came up 7.8 for all 28.

So put the car back together in the morning and off to see if we can get any codes out of it.

 

Battery back in and 100 mile road test in 111F heat and not once did the battery play up. The car still surges at around 30mph coasting so will look under the bonnet tomorrow when the engine is cool enough to work on. The throttle body spring seemed free enough.

 

The car is on the road and has good tint as such - but is 5 years on the car now, so maybe a time to upgrade. I'm an Aussie living in AZ LOL and spat the dummy is a saying from where I come from that indicates the car is not behaving well - ie kids spits the dummy out when unhappy.