12 volt battery question

I'm pretty sure that he had settled on leaving the car at home and asking a friend to start it occasionally.
Thus the somewhat different advice.

 

Unfortunate situation all around.
You just need to figure out some way to be SURE the new battery is fully charged before you leave it.
That means finding a small charger and a place to plug it in for several hours.......maybe as many as 12.
If you don't do that, it's a crap shoot whether even the new battery will survive 16 days.
But the odds are much better than with the old one.

 

It might be worth having a portable jumpstarter to throw in the car for trips like this.

 

Good catch.
An AGM battery won't suffer much from going flat occasionally.

CanyonKId: Just HAVING a driveway should allow you to fully charge the battery withing 24 hours of leaving, right ??
If you have a new battery and do that, it should NOT be a problem.

 

yes, that's what they're designed for.

 

I looked at the specifications on that one and they recommend charging it every three months - that would certainly suggest that 16 days wouldn't be a problem.

 

Even luckier, I'm self unemployed.

We go to extremes to avoid shelling out parking ransoms. Around Vancouver it's a pathetic cash grab. You have to pay to visit our parks now. The downtown is basically one big pay lot. Need to visit a hospital, yup: you're gonna pay.

Up here all the hospitals (except for Delta, where the mayor nixed hospital pay parking, kudos to her) are surrounded by big pay lots. And they sit half empty, while people, a lot of them sick/invalid, park beyond them, on city streets.

Can remember a couple of years back, visiting Waikiki beach. Parked a couple of blocks away from waterfront, no meters.

 

One would hope but the reality IS that many new battery sellers do NOT make sure that the ones going out the door are actually fully charged.
If you can be sure you get one that is fully charged, then yes.

But if this is a regular occurrence you are going to need a small charger anyway.

 

Why would they charge them when they are told they are 70% charged on the shelf?

 

Ideally:
They are supposed to periodically recharge them to maintain the shelf life AND service life. They typically slap the round stickers on them when they are recharged.
Lead acid batteries like to stay at 100% DoC. Anything less at length, and irreversible deterioration occurs.

In practice:
Most things are pretty forgiving and tolerant to abuse, and the world is so very random. My buddy's BIL has a 350K mi Tacoma with origianl drive train and he is a slacker in vehicle maintenance. So you do not always get back what you put in...

 

What ? Who's on first? "They" are nowhere to be found.

Because 70% is not good enough.

 

See page 49 of the owners manual. "the entry function (sks) is disabled in order to prevent the vehicle battery from discharging and the electronic key battery from depleting when the entry function has not been used for 5 days or more."
This is why a good battery can last longer than 16 days ladies and gentlemen.

 

It should theoretically last considerably longer than 16 days even without that feature. In rough numbers ... To half-deplete a healthy 40 AH battery should take 20 Ah. A couple of members here recently reported measuring vampire drain rates of around 15 mA. 20AH/.015=1333 hours=55.5 days. Others have reported 30 mA drain, which would allow only half a long, which is still over 16 days.

 

You are forgetting internal discharge.

 

If it is an AGM, that part is negligible.