I carry the Costco "jump pack" in each car. It's a combination jumpstarter, area light, USB & 12V charger, and air compressor. The older one is in my wife's car and still works at five years old, although that's about as long as I expect one to last.

You must charge it every month; I have a battery maintenance routine that includes this. I cannot count how many self-saves and wow-that-was-easier-than-jumper-cables saves I have had with them.

I have one to extend the capacity of my ham rig battery. It does the job to some degree. I decided to refrain from using it for the car though.
IMHO it´s not worth the hassle. It needs a well lit place and it must be packed away for driving. If you decide to use one, make sure that it has a diode (which will cost you about 0.7V) in it to prevent reverse flow of current. Otherwise it may actually drain your battery.
It´s better to regularly check the the battery and replace it on time.

I noticed there ratings. With less then optimum angles, windscreen between it (huge loss of solar rays) and have less sun in winter, making them almost useless.

I always found electric everything rather annoying. I like the option to open my doors manually, put my parking brake on manually, put mine lights on manually, etc...

Lithium battery boosters are usefull and does not to be charged constantly (unlike the old style jumpstarters that uses AGM batteries), just once every few months. Probably does need to be replaced every few years, as lithium batteries do degrade.

If you drive a lot of short distances, the battery won't be charged properly. In that case, hook it up to a battery charger occasionally. Lots of new cars that are suppose to be very economical on fuel, charge there batteries very slowly or only in certain conditions. Especailly if you have those start-stop systems.

Mechanical door locks that work by a physical key are less prone to electrical failures.... or fob failures. Or fob battery failures.....

7 days to discharge a nearly new battery suggests an electrical leakage/load problem (glovebox light on? etc). (or maybe that's the load from listening for the fob to command the car to be unlocked????)

I used to park my car for a month at a time when in college so I'd lift the ground cable from the battery to ensure no discharge at all until I needed the car (but even this isn't adequate for several months at a time).

Until you get this car problem sorted I'd suggest doing the same if you can.

My modern Euro-sedan has a lot of loads in it. So much so that I believe the battery would be flat in 3 weeks. So it gets the top-up charger treatment when I won't be driving it for several days.

If I lived in severely a cold weather area where batteries died all the time, I'd have two. With an A/B switch controlling which battery was active. When you're on battery A, then battery B is totally disconnected, and vica versa. We used to have something like this on our ambulances back when I ran calls. I can't remember for sure if it was a total disconnect of the "off" battery or if it still could be charged by the alternator. A total disconnect would be best, if you could remember to use A one day, then B the next so that both batteries stayed charged. You'd also probably want to have a large capacitor hooked across the batteries to keep your car's clocks, etc. powered for the few milliseconds as you switched from A to B. Finding a place to mount a second battery could be problematic in a small car. In the trunk maybe? Mounting one in a truck or full size car might not be too much of an issue.

Most modern ambulances have dual batteries, but nowadays they don't often have an A/B/OFF selector, just an OFF/ON switch, usually with some kind of electronic load control and a charging management function.

There are some very compact batteries out there, but that seems like an expensive overkill. Something like this "battery saver" may be a better solution. It cuts off the all load from the battery when the voltage drops, saving cranking power for when you need it. All radio presets, etc. are preserved in it's memeory

https://www.amazon.com/PriorityStart-Vol...v+battery+saver

I haven't seen it on any other car, but one van I had a few years ago had a cutoff switch under the hood
that was a marine switch(will outlast the van! heavy duty switch made for rough weather/locations) , normally used on boats. (A mechanic acquaintance told me, and he had seen them used before also).
It might have been used because of cold or unknown battery drain,
OR it might have been a theft deterrent, I don't know which.

Ironically, I had to replace my Car Battery a few weeks ago - came out one morning and it was dead.

For a 2010 Ford Escape Limited -

With a brand new battery, it can sit about 14 days before I would run into a no-start condition. That's with the "truck" sitting in an insulated garage - in the summer.

I helped my son move to FT Worth at the end of July this year. The "truck" hauled a U-Haul trailer through 116F temperatures. It was HOT. It ran like a champ, and no issues but....


It was shortly after this trip is when I noticed that my stand-by time had dropped to 7 days (Battery about 4 years old). I purchased a plug-in Battery Maintainer that would keep the battery topped off without overcharging it. I wasn't driving the "truck" much, and it was sitting for weeks at a time. I did this so I wouldn't come out to a dead battery.

I took the "truck" for a vacation this October up around Michigan. No problems on the trip, but when I got home - after letting is sit for three days, I came out to a battery that had fallen to the point it would no longer start. I hadn't bothered to plug it in to the maintainer, as I was driving it throughout the week.

I think you start rolling the dice with any car battery over three years old, and your risk goes up as you approach the five year mark. Anything past five, and your just darn lucky IMHO.

Maybe I need to find better car batteries, but there's really only a few manufacturers of them these days - Johnson Controls, DEKA and Optima. Optima used to be great until they outsourced the manufacturing to Mexico I've heard.

I've read that it's Heat that actually kills batteries. You don't actually experience the damage until winter comes and the damage comes shows in a drop in CCA's.

I've started wrapping my batteries in Reflectix insulation to try to protect them from heat extremes. Not sure if it will actually make any difference, but it might.

I've never had much luck with the Solar Panels - at least not the little 1.5w 12v-24v ones I've tried to use. I like the small ones as I don't think you need a regulator. If you want something that would actually "charge" a battery, I think you need to get up into the 15w level of panels, and those I think you would want a battery regulator on. I think Battery Tender makes one, but for $100+ price tag, not sure I am that interested going that route.

The new LI-ION battery jumpers that some people have mentioned here I think are probably the best portable solutions right now. The old AGM ones are good, but you HAVE to charge them every 30 days or they will leave you disappointed (and stranded).

Manual Battery Turn Off Switches. Don't do this. Just don't. They don't make good connections, causing battery charging and starting failures when you least expect them. Cutting power to the car is also a great way to reset your car computers engine and transmission "knowledge". You can have some very interesting things happens while your cars computer and transmission "relearns" your driving habits and emission/spark-advance data.

Two possible issues:

1) Parasitic battery drains; clocks, radios, computers, alarms, etc--these are always on.

2) The alternator may be going out. If the alternator is not putting out enough amps, then the battery is not getting charged fully.

I recently had both of these things happen to my 1996 Explorer. I rarely drive it, so I had it on a battery maintainer. That worked for awhile, then it stuttered and died when I turned off the key after a trip. Replaced the battery per AAA's recommendation and it worked for a few more trips then died due to a bad alternator. So, I had to replace that too. Now all seems fine again.

Take away: It is probably a good idea to have both the battery and alternator checked at the beginning of winter. [I actually had done this just before they both went out, but that may have been either the shop's fault or a fluke].

Not sure how common this us in the US, but where i'm from a wintercheck at the dealer is generally free. Ok mine did ask people to donate €2 for charity, but did gave us as singing snowman... They check of fluids, batteries, tires, AC, wipers, etc. I can do most my self, but I don't have a proper battery tester and having somebody is check is far lazier.

You can use a multimeter to check of parasitic drain rather easily. Battery status and alternator status not so much. I mean yes, you can meassure the current and if the alternator is producing something. But not if it is on the way out but not that good anymore.

I'm happy to life in a moderate climate. I only replaced one battery in a car in my life. Preventive replacement as it was 12 years old, never did let me down and always started.