12 volt battery well rusted out- Houston, we've got a problem

Yes! ...you are right. Mudguards, not mudflaps. Mine are missing....so salty winter tire spray coats battery well. You'd think with all the alleged 729 point checks during oil changes it might have been mentioned. Thanks!

 

Ya, salt on roads greatly accelerates rust process....and undissolved salt can strip undercoating as it kicks up and peppers undercarriage- sort of a slow "sand-blasting".
I tended to dismiss battery acid being culprit because no sign of leakage showed on battery, but it does look like that is what did it.....like bottom of pan just dissolved. But since I now know my mudguard is missing- I think that is likely cause....

 

Not flaps- my mistake ...mudguards. [see above] and these are certainly not ornamental. I would think leak from above- but checked it in rain- looked ok. Leaky battery acid theory seems possible to me.

 

It wouldn't start. Probably because I could not attach battery because well is rusted out. :~) I check my oil- never uses any. Keep in mind this 2004 only has 105K miles. My dads car....drove it sparingly. He bought a new Prius- claims 75 mpg.
I agree dealers just want foot traffic from oil changes. Last oil change they suggested I give them $500 because the rotors were rusty. (brakes work fine)
When I brought in the rusted battery clamp still bolted to a rusty chunk of the actual Prius body...(see original pic) ...I imagine that was foot traffic they were not too thrilled about. I should have paraded it through the showroom (maybe they might have given me a new Prius Prime w/ solar panels to go away?)...but I'm not quite that diabolical.

 

Thinking of scrapping plan A because I need my car. They tow during snow storm so next snow I get hit

Plan A may be scrapped, and I may go with Edthefox5 suggested tire well plan....for the time being. Winter just too hard to execute this. Besides, I get towed if I don't move car when snow storm hits.....
Plan A scrapped because rust more extensive on side towards tire well...camera did not show.

Plan C just emerged***: tape syran wrap to sides of well... Fill with insulation foam.... take hardened foam out....bring to sheet metal fabricator.........have him replicate (slightly shrunk) with lip over edge to rivet. It would be along the idea of those plastic inserts you get for the pans when you roll on paint- only sheet metal.
hhmmm

 

Man.....on top of everything, my city issued a snow parking ban tonight. I can only off road park, so they tow with no exceptions [$2-$300 total bill after hypothetical tow back] So.....considered hooking up new battery next to battery well, but no good- non of the cable hookups reach. So.....finally suspended new battery into battery well with 2 bungie cords attached from above. Good news is new battery works! [I was never 100% sure battery was the issue]
As far as getting a battery pan from junk yard, I'd have to cut it out of the car- and it's more than just bottom: inside vertical wall (can't see in pic) is 2/3 rusted out. And size is an issue- I'd want it slightly shrunk to be able to jam into bottom of pan from above. I think I'll cardboard template the bottom (to fabricate sheet metal bottom), with some portion of vertical side flaps to rivet. I'll also have two steel straps sandwiched between...and attached to... sheet metal and battery clamp assembly -these will run up sides, riveted to sheet metal...and on inside edge, bend horizontally over edge of lip - and rivet there. These for added strength. Also- I will possibly suspend battery clamp/ cradle from above in some fashion to relieve some of the battery weight, and also provide a "fabrication malfunction firewall" just in case. I'm thrilled new battery works! Had old one tested- zero charge. [7 years old] Two pics are 1) the well with bottom gone (as posted before) and 2) after I wire-wheeled rust out, applied Ospho to chemically neutralize rust, cleaned, and painted with gray Rustoleum.

 

So....a year and a half later....was having tires replaced [Atlas Force- highly recommend! $44 and quality rated by Consumer reports with $100-$150 tires -get em thru Walmart] and seeing my battery suspended on its bungee cord swing above the speeding road below reminded me to finish battery well repair. Latest plan. make a cardboard mock up of bottom of battery well, and have a sheet metal place fabricate a pan to rivet on (with a couple of supportive metal straps) The other pic is of rust. I have to deal with this. Once I figure out how to prop car up (dig a center trench?) I'll wire wheel out loose rust......wipe clean with alc rag......apply Ospho.....paint black rustoleum.....than apply the CRC lube from home depot.

 

Constructed the mockup of battery well correcting catastrophe. The two metal straps are rthe supportive key. (real ones will be unyielding/ substantial) . The sheet metal (cardboard in mockup) will replace missing prius metal on bottom of well and half of one side. I'll screw/ bolt all 4 ends of 2 metal straps in place- but that is just to hold them in place- not truly essential, as the last horizontal inch of all 4 metal straps/ bars will be resting/ supported on sold material. In other words, the weight of battery should keep it in place. That said, I'll screw/ bolt in place 4 ends of 2 bars.....likely rivet or screw vertical piece of sheet metal to still existing metal.