General advice and park mode issue

i have been looking at putting an AGM battery to replace the OEM in my car sometime soon.

i was reading some forums the other day and noticed that for my particular car, a late model ford mustang. Ford has some options to tell the BMS that you're using AGM battery vs the OEM (assuming flooded, havent even looked to verify).

the option has to be changed via obd2 port and some diagnostic software or a dealer should be able to do it. from my reading its not "required" if you switch to AGM battery, but the car supposedly handles charging and discharging a little differently, maybe a couple other things too?

if anyone has a late model vehicle (or even an older one with a lot of computers), and is switching to AGM battery. it may be worth it to check out some enthusiast forums to see if your car or cars BMS has similar functionality.
 
but the car supposedly handles charging and discharging a little differently, maybe a couple other things too?
It may be able to improve fuel efficiency or performance by turning the alternator off at times, eg when the engine power is wanted for acceleration in the knowledge that the AGM battery can be recharged quickly during engine braking.
 
There are optimum charging schemes for every battery type, but for automotive usage an AGM replacement of a LA will work fine as a drop-in as long as the charging system is working correctly. Maybe not perfect but good enough for you to take advantage of most of the differences AGM offers.

As an aside I am a somewhat old and knowledgable LiIon user. These demand a CC/CV charging scheme for safety, but some cheap devices just use CC and a charging time limit. I had an old pack wired 3S2P and the charger died the night before I needed it. Having little alternative on hand I tried a few different AC/DC wall warts tied directly to the pack's outputs watching very closely with meter and touching it frequently to monitor temps. Third try was lucky so I got through the crisis. Then I wondered whether I could just continue this as I couldn't afford the replacement charger at the time (and it's now out of production :(). So I tried again and in fact am still using the exact same set-up a few years later with no apparent loss to the battery capacity and no danger signs from the pack. I just got lucky with my junkbox pick- I'll admit that- but it does also go to show that perfect isn't absolutely necessary to get very good results. NOTE that I do NOT recommend anyone do this with LiIon cells or batteries, for if things do go wrong it can be a large disaster to your health and home.

Phil
 
If you do go for a replacement battery at some point, I recommend looking into getting an AGM battery if there is one that fits your car, even if it is not standard. AGM batteries generally cost more, but they also charge significantly faster, so you get longer record times from shorter journeys. They also don't object so much to regularly being half emptied, so can be good value if you use most of their lifetime before replacing your car.

I have just looked at the battery and it is a AGM, labels on the top just show the Mercedes part number
 
I have just looked at the battery and it is a AGM, labels on the top just show the Mercedes part number
Excellent, in that case you probably have a stop-start system and you can expect it to stop working due to low battery voltage most of the time, unless you have already disabled it as a lot of people seem to do!

With an AGM battery, using 11.8V cutoff is fine, should not cause problems starting even in cold weather.
 
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