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When I took my car in after the battery incident, I was first told that I wasn’t driving it enough, because of the mileage I had on it. I told the tech, “ Oh come on. You mean to tell me that Toyota has produced a vehicle that can’t sit in a garage for 3 days without bein driven or the battery will run down?” I then asked them if they thought their statement might be a little bogus. So they told me they would troubleshoot the car, at my cost, as there was nothing wrong with it. I said they needed to read the warranty information first, and if they chose to charge me, there was going to be big trouble. I finally got the firmware upgrade done, which fixed my issue, but I had to push for it. As I said previously, there was no discussion whatsoever about the upgrade, and I learned about it from other sources.

I had talked to Toyota corporate about the issue several times and got a blank answer, like nobody else had the problem. I installed a blue tooth battery monitor myself, because I was determined to get to the bottom of the issue, and could see I wasn’t going to get much help with it. I think the lawsuit is applicable. If you can’t rely on your vehicle to be ready and waiting for you, you might just as well save your money and not buy a new car.
I looked on Amazon at the Bluetooth battery monitors. There’s quite a few to choose from. Which one do you have? Do you know the current draw on it?
I’ve been considering the ones that have a shunt so I can monitor the parasitic current. I can’t figure out how accurate they are in the low milliamp range though. If this data is accurate and can be logged it would be helpful.
 

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I have the ANCEL BM300 monitor. It draws very little current. I can’t remember how much, but it’s a fraction. I used my muliti meter in series with the negative terminal to measure the parasitic current draw. I think it was less than 40 milliamp from memory. It’s been quite a while since I used it. I finally removed the battery monitor off the vehicle and installed in on my RV, as I seem to no longer need it on the RAV 4 since getting the firmware update a year or so ago.

I don’t know if I‘d go to that rouble of installing a meter with a shunt to measure parasitic current draw. Seems to me that if things are normal, there is very little draw. I’ve had my car sit for 6 days and checked the vcltage drop using the ANCEL blue tooth monitor and the voltage has still been well above 12 volts. The 12 foot battery is small, But you need ot bear in mind that it’s only there to drive the necessary circuits to power the vehicle before the hybrid system starts. So, there isn’t a lot of draw on it. Most of us, who have had the issue, have lost battery power overnight. That’s a pretty big current draw to do that. I think from memory, the battery is a 24 amp hour battery? So to flatten a battery overnight, you would be looking at close to 2 amps draw. That’s about what the communications system uses when it’s transmitting. The main thing you are interested in is battery voltage over time when the car is sitting in the garage.

Cheers
John
 
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