Battery chargers.

[PaulJ2]

Maybe a question for Mex.
Stone dead 12 volt battery on my Prius. Gone for a week and door ajar causing dome light to drain battery.
Brought out 2 different battery chargers,neither one would put out any voltage. One an automatic 10 amp unit and the other 1.5 amp battery charger/maintainer unit.
Measured voltage at the dead battery was .3 volts.
I then drug out my 30+ year old 1 amp motorcycle manual charger. Worked fine! Is this some safety thing so you can't spark the two clamps together?
I guess they have to see a couple volts before they will operate.
Geeeez!

[camperdave]

MrWizard wrote:
'truck' ?

do you mean 'trunk' ?

auto correct spell check strikes again

yes, trunk. No autocorrect on my computer, and of course spell check is no use when you type the wrong word. Life goes on...

time2roll, agreed. Like on her car, it can go 15 or so miles in EV mode. The starter battery literally does nothing other than tell the computer it's ok to drive now. There should be a way to manually turn on the DCDC, in a similar way that we can combine the house and chassis batteries in a motorhome when it won't start.

[MrWizard]

'truck' ?

do you mean 'trunk' ?

auto correct spell check strikes again

[time2roll]

camperdave wrote:
It's good to keep the old dumb stuff around sometimes, for things like this. That's what I tell my wife about me anyway...

My wife's Ford Fusion hybrid wouldn't start a while back because of a dead starter battery. It amused me that there's 300v of lithium sitting in the truck, but the car wouldn't start because the lead acid battery under the hood was dead. She didn't find it amusing.

Getting to be a bigger issue with all the telemetrics that never shut down on these new cars.

Especially frustrating with the EVs that really need a deep cycle battery since zero need for the start surge.

I think the OP has the answer. Although I am surprised a dome light did it. Even my old 2001 F150 will cut all power at about 30 minutes if this is detected.

[camperdave]

It's good to keep the old dumb stuff around sometimes, for things like this. That's what I tell my wife about me anyway...

My wife's Ford Fusion hybrid wouldn't start a while back because of a dead starter battery. It amused me that there's 300v of lithium sitting in the truck, but the car wouldn't start because the lead acid battery under the hood was dead. She didn't find it amusing.

[LittleBill]

smart chargers need to see a minimum amount of voltage to turn on. usually because its a bit dangerous to charge a 100% dead battery

[2oldman]

I'd jump a known good battery to it, and try charging again.