I'm using a $25 lawnmower battery for Prius 12v

Nope.

 

What's the cranking amps rating on the battery and did you have to adapt to non JIS battery terminals?

Posted via the PriusChat mobile app.

 

Is it properly connected to the vent tube to dump fumes overboard, so occupants don't breathe toxic fumes when something goes really haywire?

I haven't yet heard of any Prius occupants dying from battery-related hydrogen sulfide poisoning. The well publicized case of mother and daughter who died of that were in a fancier car model with inside-cabin battery. Most similar poisoning deaths are in lesser publicized industrial incidents, where the demographics of the deceased don't commonly make for tear-jerking headlines.

Spillage during overturns is another issue. Not fun inside the passenger cabin.

 

I could make the car run off D cell ever-ready's or 6 volt lantern batteries if I wanted to jerry rig it.

It's working for you only because you haven't run into a situation where it doesn't, yet. Then you'll be stuck and wondering if it was the right thing to do while paying $175 for a tow truck....

to each, their own....

 

ive done the same with the $19.99 Walmart special, if you want to be safe get an enclosed plastic battery box and drill a hole for the vent.

you should expect about 3 years life in that configuration, (if your lucky) they are cheap enough to replace every few years.

funny part is those batteries now come in AGM as well which should work much better

 

How many amp-hours do those lawnmower batteries have?

Cause for that prize here it looks like you could only get get a small one with something like 10Ah or less. That sound small enough that if the Prius would sit for a week or even less than that battery would be empty and it then couldn't start. And that's only if it would be fully charged to begging with. And it probably won't if your driving short trips.

 

that’s the price you pay for being cheap, when my cars are gonna sit I remove the positive cable.

Anyway
I use a lawnmower battery in my Insight, they vary in capacity but for $19.99, I’m willing to replace it every 2-3 years. Cheaper in the long run,
Penny wise and also pound wise

 

So it was about 10Ah? Insight probably uses less current from the battery when sitting as it doesn't have SKS?

It being cheaper in the long run really depends on if the capacity is enough for your use. If the lead acid (AGM or not) battery is stored with less than 50% charge it's going to age fast. And if it's allowed to get completely empty it will be bad a lot faster. To get that 3 years out of cheap battery it needs to be kept mostly full.

 

i think you're good, if you cannot afford a proper replacement