I have a 2010 Pruis with 30K miles. I make sure I drive it at least once a week or two for at least 20 minutes to keep the batteries charged, avoid flat spots on tires, rust off rotors, and circulate fluids.

For me, the risk of using a battery tender is not worth it. Driving the car is way better for the reasons I stated.

I am very conservative about introducing any external current to a Toyota hybrid from memory savers, jump packs, and battery tenders. I have had to replace a power ECU after a jump pack start. Perhaps it was related, perhaps not but if I don't have to introduce external current, I don't do it. JMO

https://support.toyota.com/s/article/Do-I-have-to-take-spe-7692?language=en_US

 

Just hook it up to the points in the engine compartment for jump starring the battery as shown in the owners manual. Just be sure to place the negative wire from the tender on the engine block connection, not anywhere near the ECU. You will be fine.

I often go on long, long, overseas trips and there is no way my RAV4 can be driven while I am gone, thus the battery tender route.

 

800 miles in two months is ample use to keep battery charged but if you want the added security of a battery tender then look for one with a set of permanent leads that attach to battery. This will allow you to simply plug and unplug charger as needed and will minimize chances of shorting something out. A smart charger is preferred as it will charge battery as needed rather than apply a constant current as a trickle charger will.

 

I really like Battery Tender and keep one of these attached to my '66 Mustang:

Battery Tender maintainer

You may also have to get the accessory cable Amazon lists to get the connection RobertB mentions.

 

i got a long lead (approx. 6ft) off of Amazon, and hooked it up to the 12 volt battery in the trunk. since i park on the left side of my garage, i wanted the lead to come out at the driver's side back hatch area. i plug my smart charger in when i'm done with work on Friday, and let it stay on the tender over the weekend, or if i'm on vacation or a long weekend, etc. works for me

 

Amazon.com: Battery Tender 021-0123 Junior 12V, 0.75A Battery Charger and Maintainer, Black/Green (021-0123) : Automotive

 

Not to complain (too much) but that one is rather anemic. This is the one I got: https://www.amazon.com/gp/product/B089GZV2PR/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

 

I, like Mark Skiver, got the Battery Tender extension and hooked it straight to the battery. Leave the set up in the spare tire space. Drop it through a back door when I charge up my RAV4 hybrid, every other month, just to be safe. Easy to do and it's there if I need it.

 

This is what I use. The slower the better when it comes to charging and maintaining batteries. If it works on my diesel that has 2 batteries, it will work on a RAV4. The .75 amp charger mentioned above is too small. It is more for motorcycle and ATV batteries. I have a couple of those too. Ignore the dirty engine bay. I haven't cleaned it up in a while.

Battery Tender®

Discover top-rated Battery Tender® chargers and maintainers. Shop our reliable, automatic battery chargers designed for cars, motorcycles, ATVs, boats, and more. Ensure long-lasting battery life with advanced technology from Battery Tender®. Fast shipping, industry-leading warranties, helpful...

www.batterytender.com

 

Did you ever figure out a solution? The last 2 years I have had an issue when we drop to around -40 where my battery needs to be replaced (under warranty fortunately) and the dealer always says to get a trickle charger installed. I live and work within close proximity and WFH sometimes so I dont really get the chance to drive around a lot especially when its so cold. Of course then the 1 time after I got a boost and actually drove for an hour, the battery still went kaput overnight.

I talked to a mechanic friend here though (experienced with Alberta winters) and he said its better to get a tender/maintainer since it will actually be able to read how much charge the car has instead of just always well..Trickle charging.. I have the same problem though, I am not sure how I could easily install it to the battery in the back and Im not sure if I can just hook it up to my terminal in the front.

 

Did you ever figure out a solution? The last 2 years I have had an issue when we drop to around -40 where my battery needs to be replaced (under warranty fortunately) and the dealer always says to get a trickle charger installed. I live and work within close proximity and WFH sometimes so I dont really get the chance to drive around a lot especially when its so cold. Of course then the 1 time after I got a boost and actually drove for an hour, the battery still went kaput overnight.

I talked to a mechanic friend here though (experienced with Alberta winters) and he said its better to get a tender/maintainer since it will actually be able to read how much charge the car has instead of just always well..Trickle charging.. I have the same problem though, I am not sure how I could easily install it to the battery in the back and Im not sure if I can just hook it up to my terminal in the front.

Your friend is right, you want a maintainer and not a trickle charger. The slower the better. I have a 1.25 amp charger that I leave on my diesel that has 2 batteries and it works fine. Actually just replaced them after 8 years. My wifes car is similar to your RAV4 with the battery in the back (trunk). I just hook it up to the battery connections under the hood with zero issues. Yours should work just fine doing it the same way too.

 

The battery tender should be connected directly to the battery. In the case of the hybrid, I would just run a line through one of the rear passenger windows and connect to the 12 volt in the rear. In my old Honda, I would attach it under the hood and there was still enough play with the electrical cord where I could easily shut the hood and keep the charger in there without issue.

 

It doesn't need to be connected directly to the battery. It can be connected to the battery points under the hood. I have been doing it that way for 20 years on my wifes car. The battery itself in her car is in the trunk. The battery in that car lasted ~14 years. I connect a tender to just one battery in my diesel and it keeps both batteries charged. It has 2 batteries. They lasted 8 years. You can easily run the power cord up from underneath the car and latch the hood. I did it for several months with my sons Camry while he was on deployment.