Actually it can be a bad thing. Keeping a battery at 100% charge leaves no headroom for the battery and risks over-charging which is a bad thing. The BMS maintains the battery at 80% SOC normally although this can be changed using Forscan for example to 85% or a little more.
I agree! After 20 years of maintaining batteries, up to six at a time, you should not need to be on a tender/charger routinely. If you store for the winter, then it is definitely a good idea. If modern batteries are allowed to drain, they may never work properly again. Having said that, if I have a battery that doesn't charge the first time, I will often give it a boost charge multiple times and, in between, keep it on a trickle charge. I have had batteries take 4-5 days to complete a charge, and after that, they work fine. Another observation I have made is that problem batteries may only charge to 95% and not 100%. Glenn
Yes, a trickle charger (good one) will never maintain at 100% for the same reason the car doesn't. It will reach a 'float' stage where it allows the SOC to drop a little.
There is nothing wrong with doing what you do, but how do you know you have a parasitic drain if the battery is always charged? I am retired, so my Mustang isn't a daily driver and, because of the weather, often sits for a week or longer. I haven't as yet had any messages about the battery being low, but the Mustang has gone to sleep occasionally. Last week, I had it out and noticed the charge was at 13 volts. I called my wife and said I had to drive it to recharge it. She has no clue that 13 volts is fine, and I could have just put it on a trickle charge! I got to drive for another hour. Lucky me. Glenn
The smart alternator / BMS will charge at anything between 14.5v and 13v depending on the state of charge. Once it approaches 80% SOC you will see the voltage drop. In addition it tends to charge more on the over-run and less when accelerating for efficiency.
