Got a Toyota Corolla E170 and it is only used for highway travels twice a month. Car has a tracker installed as well.

I want to give the battery (lead acid 46AH) a top up using battery charger (10A) after every week so that battery remains charged since ECU and Tracker use battery to keep information saved and tracking the vehicle. The charger has Three-phase charging modes, Constant current, Constant Voltage and float charge. Although battery isn't discharged, just want it to start the car every time I want it to.

I searched many questions but couldn't get an answer about the car components including ECU and Tracker. I don't want to lose ECU information or getting automatic calls from tracker company by disconnecting battery. Will charging without disconnecting battery damage ECU or tracker or any other component?

2 Answers 2


If you are using your charger on "float mode", you shouldn't have a problem leaving your vehicle battery charging indefinitely. The purpose of the float mode is not to charge the battery, but rather to maintain the battery. What does that mean? It means it won't overcharge it, nor allow it to go flat. It will keep it at the proper charge level without damaging any components in the vehicle.

An alternative option would be to get a maintainer type charger. They are relatively cheap and are designed to keep your battery topped up at all times while plugged in. Yes, that's pretty much the same as what the float mode on your battery charger is doing, however, there are some plusses to it. It's small and easily handled. Most of them also come with a permanent plug type connector which doesn't allow you to put the polarity the wrong way. There's a pigtail which connects to your vehicle. Plug the maintainer into it, then plug the maintainer in and you're golden. You can leave it plugged in until you are ready to run the vehicle. These are usually used to keep batteries topped up on motor homes and recreational vehicles, but will also do a fine job keeping your rarely used vehicle's battery in tip top shape.

  • What is the difference between RVs and recreational vehicles? I thought they were the same thing!
    – psmears
    Mar 10, 2023 at 23:09
  • @psmears - Recreational vehicles, as in ATV's and motorcycles ... however ... I see your point and you are correct, lol :o) I threw in a little bit of an edit there for yah. Mar 11, 2023 at 1:57
  • Ah, I see what you mean! Yes that's clearer, thanks :)
    – psmears
    Mar 11, 2023 at 15:55
  • The charger is automatically selecting the mode based on the charge condition of the battery.
    – Ali
    Mar 13, 2023 at 11:27
  • 1
    @Ali - 10A is pretty high for a maintenance purpose. I personally don't trust multi-purpose charges to not boil the battery. As "smart" as they are, they are pretty stupid. It could very easily decide the battery needs to be fully charged when it is already fully charged, causing damage to the battery. A purpose built maintainer is usually at 2A charge and will fluctuate how it is charging to ensure there is no damage done to the battery during maintenance operations. Mar 13, 2023 at 12:06

As long as the charger never takes the voltage much above approx 14 volts and you make sure you don’t accidentally connect the charger with the wrong polarity, then there should be no problem adding the charger.

While you are driving, the alternator is usually supplying around 14 volts to the vehicle to supply power to the electronics and charge the battery, so adding that voltage using the charger would be OK.

However, some fast chargers may supply a higher voltage to force a larger current into the battery. I wouldn’t recommend using one of those while the battery is connected to the vehicle.

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