AGM battery reliability

[Trigganometry]

I've made a previous post about my truck sitting for 2+ weeks and went to start it and the Batt was pretty much dead, charged it back and have been keeping it on a 1.5 amp trickle, (although i tested a 1.57 amp parasitic draw using the multimeter test.
So today i finally had some time to mess around with Forscan, I changed the batt charge % to 90,
messing around some more did the courtesy wipe to 2 seconds, the radio screen to the Ford Performance, ABS brake bleed, and a couple failed attempts to change the DRL's to the park/signal lights, a 'unsuccessful' screen popped up i think i need to make other DRL changes besides just the one i tried, like disable 'low beams'.
So i was inside the truck for maybe a half hour with ign on (doors shut no radio) and had to cycle off to on as directed by Forscan screen, when i finished i tried to start and all i got was a slow crank and no start. I removed the 1.5 amp trickle and hooked up my larger charger set to 10 amp then kicked it up to 55 amp start feature, it then started. I now have it on the 2 amp setting overnight.
So i want to see if the batt acts any different with the 90% charge setting.
Needles to say i was surprised how quick the batt drained down.
It's the original batt now 40 months old fwiw, i also have disconnected that ASS plug from the neg terminal.

When you say disconnected the ASS plug from terminal. At the battery you did this? If so you disabled the BMS system entirely. So at running it’s throwing full charge at battery unregulated I believe. With it on the BMS system is active and your BDYcm settings are active as well. You can disable ASS with Forscan BTW.

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[Muffin1]

Yes I disconnected' the plug at the battery neg term, thinking that might be causing the drain.
I'm open to be corrected if that's not a good thing to do, a little confused on that.

 

[Dereku]

It has to be the low charge. I have gotten a decade out of AGM batteries in the past. Forscan is probably in my future as well.

 

[dtech]

.

When you say disconnected the ASS plug from terminal. At the battery you did this? If so you disabled the BMS system entirely. So at running it’s throwing full charge at battery unregulated I believe. With it on the BMS system is active and your BDYcm settings are active as well. You can disable ASS with Forscan BTW.

If it's unregulated voltage you will fry the battery, disco the bms and the charging system uses the alternator's built in regulator , charging at 13.5 ~ 14.5 volts and keeping the battery at 100%. The bms will reduce the charging voltage based on what the bms soc setting is, someone mentioned monitoring the voltage at startup it should be higher with the bms then it will reduce somewhere in the 12 + volt range based on the bms sensing (takes a few mins for components to baseline). so in essence bms turns the charging system from fixed output into one of variable voltage. This lessens the load on the alternator thus saving some small amount of fuel and if one is using the ass allows for quick draw down cycles and charge back to full as the system sees 70% as a full charge with the bms setting. The end result of this can be reduction of battery life span. The end result of my disconnecting the bms will be a chain reaction with the battery exploding, then consuming the rest of the vehicle, its occupant and thus ending my posts on this board.
The bms is not rocket science, just turns the charging system into variable output and has a few other things like sensing to shut down various draws to preserve battery power, the time sensing thing to add additional voltage based on battery age - skeptical on the effectiveness of that one.

 

[dtech]

Yes I disconnected' the plug at the battery neg term, thinking that might be causing the drain.
I'm open to be corrected if that's not a good thing to do, a little confused on that.

it's what I've done I look at it as a sign of bravado, consider it a manly thing and display of virility to pump 100% charge into that battery, why settle for 80%, 90% or even 99.999% , life is short and battery life will be even shorter at 70% soc. I don't wake up every morning pondering what the proper soc setting is, just let it charge the batt at 100% , plus I am admittedly too lazy to mess with Forscan, well over a year now with bms disconnected and all is good. But if you are looking to limit/eliminate parasitic draws when car is not running discoing the bms won't accomplish that, however allowing your battery to be charged at 100% is going to lessen the impact of those parasitic draws on the overall battery power. With bms if the batt is 70% charged at shutdown those draws will result in less available power than a battery charged to 100% at shutdown.

 

[Friday yet?]

Don't even have my truck yet and already have a skull cramp from trying to understand and keep up with all of this AGM battery crap.

 

[AzScorpion]

Don't even have my truck yet and already have a skull cramp from trying to understand and keep up with all of this AGM battery crap.

Best thing to do is put it on a maintainer and keep it fully charged up. I never messed with Forscan but you could and set it to 90% like Trig has done. Other than that just drive it and have fun and dear God don't smell your oil!

 

[Friday yet?]

Best thing to do is put it on a maintainer and keep it fully charged up. I never messed with Forscan but you could and set it to 90% like Trig has done. Other than that just drive it and have fun and dear God don't smell your oil!

Yea. I think I see Forscan in my future.

Got to say, the idea of having to put a vehicle on the maintainer just blows my mind. It's not some hot rod that gets driven 3 times in the summer. Just nuts. When I get it, it may get driven daily, or it may get driven on the weekend only. Depends on the week. Just nuts to have to think about the battery.

 

[AzScorpion]

Yea. I think I see Forscan in my future.

Got to say, the idea of having to put a vehicle on the maintainer just blows my mind. It's not some hot rod that gets driven 3 times in the summer. Just nuts. When I get it, it may get driven daily, or it may get driven on the weekend only. Depends on the week. Just nuts to have to think about the battery.

Yeah I have (had) the same notion too. The only thing I've ever put on maintainers where my motorcycle batteries when storing them for the winter. I've always had 2 vehicles one for work and another for fun. There were times I wouldn't drive my Vette for weeks even longer and never had any problems with the battery. But now there's so much tech on board draining them it's a good idea to hook them up especially if you're not driving it long distances or letting it sit more than a few days.

 

[RedlandRanger]

Yeah I have (had) the same notion too. The only thing I've ever put on maintainers where my motorcycle batteries when storing them for the winter. I've always had 2 vehicles one for work and another for fun. There were times I wouldn't drive my Vette for weeks even longer and never had any problems with the battery. But now there's so much tech on board draining them it's a good idea to hook them up especially if you're not driving it long distances or letting it sit more than a few days.

I think it is a good idea, but I drive mine typically 2-3 times a week (sometimes more, but usually not). I don't have it on a battery maintainer and I'm still on my original battery - April will be 4 years (currently at about 35k miles). So a maintainer is certainly not required if you drive it even somewhat regularly.

I keep my '73 Capri hooked up to a maintainer and that battery is 14 years old I think - it is certainly well over 10.

 

[AzScorpion]

I think it is a good idea, but I drive mine typically 2-3 times a week (sometimes more, but usually not). I don't have it on a battery maintainer and I'm still on my original battery - April will be 4 years (currently at about 35k miles).

So a maintainer is certainly not required if you drive it even somewhat regularly.

I keep my '73 Capri hooked up to a maintainer and that battery is 14 years old I think - it is certainly well over 10.

The only thing I'd add to the bolded part is driving it longer trips. I do drive it 2-3 times a week but most of mine are short trips (6-8 miles) so the battery never has time to fully charge. Then it sits again all day while I'm at work and another short trip back home. For me a maintainer seems like a necessity and since getting the new battery and doing this routine it's been good, so far.

 

[RedlandRanger]

The only thing I'd add to the bolded part is driving it longer trips. I do drive it 2-3 times a week but most of mine are short trips (6-8 miles) so the battery never has time to fully charge. Then it sits again all day while I'm at work and another short trip back home. For me a maintainer seems like a necessity and since getting the new battery and doing this routine it's been good, so far.

Fair point. I can't go anywhere without driving 12+ miles really. I'm not saying a maintainer is a BAD idea, just that it may not be required. I've certainly not needed one thus far. It certainly can't hurt. My brother ended up needing to put one on all his vehicles, but he doesn't drive a lot anymore, so that makes sense.

 

[Rp930]

I've made a previous post about my truck sitting for 2+ weeks and went to start it and the Batt was pretty much dead, charged it back and have been keeping it on a 1.5 amp trickle, (although i tested a 1.57 amp parasitic draw using the multimeter test.
So today i finally had some time to mess around with Forscan, I changed the batt charge % to 90,
messing around some more did the courtesy wipe to 2 seconds, the radio screen to the Ford Performance, ABS brake bleed, and a couple failed attempts to change the DRL's to the park/signal lights, a 'unsuccessful' screen popped up i think i need to make other DRL changes besides just the one i tried, like disable 'low beams'.
So i was inside the truck for maybe a half hour with ign on (doors shut no radio) and had to cycle off to on as directed by Forscan screen, when i finished i tried to start and all i got was a slow crank and no start. I removed the 1.5 amp trickle and hooked up my larger charger set to 10 amp then kicked it up to 55 amp start feature, it then started. I now have it on the 2 amp setting overnight.
So i want to see if the batt acts any different with the 90% charge setting.
Needles to say i was surprised how quick the batt drained down.
It's the original batt now 40 months old fwiw, i also have disconnected that ASS plug from the neg terminal.

The answer is simple. Replace the bad battery and plug the BMS sensor back in.

 

[Rp930]

It has to be the low charge. I have gotten a decade out of AGM batteries in the past. Forscan is probably in my future as well.

Or it could just be poor quality batteries. Or made to a cheap specification. There is no proof changing the charge will will increase battery life.

 

[Dr3wDrop]

Well something is wrong with my battery. First exterior touch locks were not working. Then later the same day as I was driving the locks cycled on their own 100+ times. Next day the reverse sonar noise only came from the front left pillar speaker. Going into Ford Dealer at 1p for diagnostic.

Ignore this is for a Toyota but I wonder if one of these would help?https://www.cascadia4x4.com/collect...-watt-hood-solar-panel?variant=35028822163608

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