Ferrari California T battery charger with a battery

Never heard of a battery powered charger. Do you mean a booster like this?

https://no.co/gb150

 

Theoretically, you can hook up your car to an external battery (i.e. "power pack") in series and your car's circuits will drain that battery (as well as its battery) as you store the car. I'll have to verify this and in addition, I believe current flows from the higher voltage battery to the lower voltage battery... and then to your car's circuit. I believe this is why your battery tender/charger actually works... because it puts out a slightly higher voltage than your car's battery. So your battery gets charged. In effect, the smart battery tender/charger behaves like a variable voltage battery with infinite capacity. It detects the voltage of the target battery and adjusts its own output voltage so it won't send too much current, overheat the target battery.

I recall I read somewhere, actually several places, that this has been done before; hooking up a 2nd battery (of higher capacity) to a car to keep up the charge in the car's battery. Theoretically, you monitor the voltage of both batteries and when the 2nd battery starts to wane you swap in a 3rd battery and remove the 2nd battery to recharge at your leisure. It would be wise to have this idea checked out by a battery expert and if you do it, make sure the batteries are properly ventilated and monitored. Assuming your car's battery has been fully charged I suspect that at a comfortable 20-25°C ambient temperature, 13.5 - 13.6 V (see below) might be a good voltage level for the 2nd battery to supply a FLOAT charge. I would then swap in the 3rd battery when the 2nd battery starts to fall below 13V. I believe a properly-charged battery at 25°C (without active draw) should read 12.6 - 12.7V. You need to keep the 2nd battery above this level, at 25°C ambient temperature. OTOH, charging voltage has to be increased at higher ambient temperatures. So if your garage is very cold...

In effect, you act as the smart circuit in a smart tender/charger. Again, make sure you have this idea checked out by a battery expert before you try it.

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FWIW, this is one big reason why I swore off living in condos or apartments, ever. I am just not a commune kind of guy... too socialist for me. You end up having to appease people who don't care for cars or don't get why you need to hook up battery tenders. Some buildings don't even have an indoor car wash. Living in a flat simply doesn't go well with a car hobby.

 

You can plug your trickle charger into something like this. https://www.amazon.com/dp/B06WVDG9BS/ref=psdc_348967011_t3_B00D5RVMAM

When you drive the car you can top off this thing in your house.

 

Yes, that should work. Ideally, you should determine how long it takes to discharge as well as recharge but it should recharge fast enough so the car won't be off the tender too long. Nice suggestion!

In essence, this portable battery supplies AC current so you can attach and use the smart circuitry of your tender to monitor and control how much DC voltage is passed on to the car's battery.

 

Wouldn’t an extension cord from the house into the garage be simpler and much less expensive?

 

I'm about to take the plunge and get yeti (waiting for black friday deals) Has anyone actually used this before as a charging method for their F car?

As a condo resident this is my only choice if I want to top off the car battery every now and then.

 

How did the yeti work?