Hello,

My 2007 ES350 is in NY and sometimes I don't use is for 2 months. Should I keep battery connected to maintenance charger or just disconnect the battery when car is not used?

 

My mechanic said trickle charger. Said disconnecting battery is hard on all the cars computer stuff.

 

The second part is a little hard to believe?

 

I'm not sure it's "hard" on the computers, but you would, of course, probably lose all your preferences and presets if the battery is disconnected for months. I would find that a real nuisance.

 

Battery maintenance charger get my vote here. Disconnecting battery means among lost of radio presets. ecu's will have to relearn all the driving parameters upon starting the vehicle which may take one or two start/stop cycles to optimize. Another important point is your battery life will be longer with a trickle charge connected.

 

Battery Tender is a good brand of trickle charger. Stops charging once it's up to voltage, which avoids shortening battery life.

 

This, make sure the "battery maintainer" has the ability to stop charging if it's full, don't just get a cheap one it will destroy your battery, may as well as doing nothing and just leave your car alone

 

You do not loose radio presets if battery disconnected. The only thing I have noticed is in nav settings is state borders announcement I have to turn off again. As for electronics the initial voltage spike is harder on parts than just leaving voltage there all the time. I have seen many times where capacitors can't handle it but they were probably close to end of life anyway. Don't worry about it and choose either way. I personally use the battery tender now. If it were for an extended period of time like over a month I would disconnect the battery and charge it when got back.

 

If you have an AGM battery, be sure and get a battery tender that is compatible with AGM battery charging. I agree that the battery tender is the better route. I found when I swapped my battery and with it disconnected for only 10 minutes or so, I lost the backup camera lines, I had to reset all of my windows and sunroof one touch opening, all of the seat settings were lost and I had to re-calibrate them and get them set for both my wife and myself. It was a pain and not recommended by me.

 

My 2020 ES300h UL doesn't loose any of those settings. Post October 2019 the 2020 used a completely different head unit and no telling what else. They apparently incorporated non volatile memory in a lot of the settings. As for the AGM battery which my car does not have and I check for replacement Costco comes up with the AGM. That's why I started a thread to see what others have replaced with and no replies. Charging has got to be different and from what I read previously it affects mpg if wrong battery is put in. This hybrid charges weird anyway as the auxiliary battery never fully charges even on long trips. There is a fine balance how the hybrid battery charges the auxiliary.

 

Craftsman CMXCESM162 has 2A maintenance mode. The charger is designed for fully automatic operation with auto voltage detection, multi-stage charging, etc. The CMXCESM162 also automatically selects the correct charge rate during charging and maintaining.

I have bought this Craftsman maintainer. Will this work as a good trickle charger? Looks like it stops charging when it reaches certain voltage.

 

Looks like a great choice. It stops charging when the battery is full and is compatible with AGM and all other 12V batteries.

 

The opposite is true, electronics wear out especially capacitors and power resistors.