Trouble Charging an Anti-Gravity Battery

[mrjking2000]

My OEM battery was on its way out, so I picked up a 60ah anti-gravity battery to try out. charged it up with my 20 amp lithium charger and slapped it in the bronco almost 2 weeks ago.

what i'm noticing is the smart alternator in this bronco won't charge this battery. i've been driving around and never really seen the anti-gravity monitor tell me it's charging because the voltage is so high on these batteries.

i went into forscan today and shut the BMS off (changed from LIN to Not Availalbe) in an attempt to make this just a regular alternor, and while that worked beautifully on my test drive, as soon as I shut the bronco off I got a warning on the ford app that the bronco was in deep sleep due to low voltage.

it seems my shutting off the BMS config did get me my desired result to charge the battery correclty, but then no app/remote feature works anymore.

what am i missing? how can i lock this alternator to put out a fixed 14.7? is it even possible? i'd like to think it is.

unplugging the shunt on the negative post also puts the vehicle into 14.7 charge mode but throws a service charging system message on the dash.

thanks!!

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[mrjking2000]

looks like i found the problem. i did the non-forscan bms reset of 5 pulls on the high beam, brake 3 times. even though the battery light flashed that didn't actually reset the Battery Monitor.

I did the service procedure in forscan to reset it which took much longer, and holy cow you shoulda heard the alternator kick on! pulled the RPM down pretty good. my battery is now topped off and verified proper operation by watching forscan while driving. i didn't get pics of the 100 amps going into the battery as it would toggle faster than i could deal with holding my laptop and phone and pull over, but we got it.

this image shows a draw on the battery but it did cycle to a positive charge.

 

[swamp2]

So, if redoing this from the start, one has to do the controls sequence or that AND ForScan stuff?

 

[Brian_B]

I was looking at these but AG warns no more than 14.7 V and I don’t know how to keep the Bronco BMS from kicking up over 15V on high charge.

Not sure if the reset procedure you ran fixed that, or if the alternator tried to go that high but internal resistance on the LiIon battery is so low you just got that huge current inrush

Curious how it turns out though.

 

[mrjking2000]

I was looking at these but AG warns no more than 14.7 V and I don’t know how to keep the Bronco BMS from kicking up over 15V on high charge.

Not sure if the reset procedure you ran fixed that, or if the alternator tried to go that high but internal resistance on the LiIon battery is so low you just got that huge current inrush

Curious how it turns out though.

the vehicle dash may indicate 15.1 but the multimeter verifies at the battery it's seeing about .5 volts less than that. i will say though, once i ran the forscan service procedure to reset the BMS i have not seen it exceed 14.8 on the dash after an hour of driving around, and that translated to 14.2-14.4 on the antigravity battery monitor.

 

[mrjking2000]

So, if redoing this from the start, one has to do the controls sequence or that AND ForScan stuff?

looks like the process is charge your AG battery prior to install, install it, run the service procedure to reset BMS.

I also set the charge limit to 95% up from 80% in forscan and that seems to have helped when watching the charge cycles.

 

[Ape Factory]

Thanks for the writeup mrjking2000. Love Antigravity batteries. I was a customer first and then became a dealer for AG about five years ago . We install them on a lot of high end exotics with BMS as well and have run into similar issues but found fixes much like you did.

Generally the larger 80Ah batteries handle an active BMS without running into cutout. On some, when running a smaller amp hour, we either modify the coding or disconnect the BMS altogether. I never specify anything smaller than 60Ah with an active BMS and even then, we usually change the coding much like you did with Forscan.

I haven't looked into my own Bronco much but do plan on adding an H7 80Ah here soon. I was wondering if a simple disconnect would be easiest but you've answered that question. Some vehicles produce a dash light, others don't but do register an error code if you scan them. I do have Forscan so I'll try your method and report back.

AG batteries have internal circuitry that disconnects when it senses over 14.7V in order to protect the battery. I've run into this punching hard out of a corner at full throttle and it pretty much shut the car down momentarily. This was on a small 40Ah unit.

Ford and others use the higher charging voltage for AGM type batteries which charge faster than traditional lead acid batteries and can handle over 15V. But the AG batteries charge nearly twice as fast as AGM and at a lower voltage so there are definite benefits there.

But glad you got it working, will definitely help others who install them in the future.

AG does have deep cycle batteries but they don't have the cranking amps of their regular automotive line. The 40Ah automotive battery has no problem turning over a V12. It's pretty amazing. The deep cycles have about 1/4 of the cranking amps unfortunately but would be great as a second battery to power everything else.

The first time I lifted an AG battery off the ground, I grabbed the handle with two hands and hoisted it up so hard I almost hit myself in the forehead. It's that light. I saved 45 pounds over the OEM battery.

 

[Brian_B]

There is a toggle in Forscan for Battery type - I don’t know what the options are or what it does off the top of my head but may be pertinent here.

Also good info about the 40Ah and active BMS

 

[Ape Factory]

I think with all the electronics on the Bronco, it'd be better to go with the 80Ah. It's a bit more but should be worth it. The 40 and 60 do have enough cranking amps but the reserve power is going to be greater on the 80Ah for running accessories with the engine off.

We use an H7 case size and that maxes out at 80Ah.

 

[Brian_B]

I think with all the electronics on the Bronco, it'd be better to go with the 80Ah. It's a bit more but should be worth it.

More is always better than less.

In my case, I was thinking - 40Ah would probably be enough. The only thing I run with the engine off is Starlink, and that I have on a 30min power point timer.

20W for 30 min, is like... 1AH, give or take. And then enough juice to crank the engine afterwards. 40Ah would have plenty of capacity to swing that.

I do have an audio amp and a winch, but all of that only runs with the engine.

But, if 40Ah doesn't play nicely with the BMS, then it doesn't work. There's also the fact that 40Ah I could find in stock, but 60/80's were all backordered at the sites I saw.

 

[Ape Factory]

You'd need to code in the 40Ah like mrujking2000 did, then it would work. It'd have more than enough cranking amps (like 1200 off the top of my head) to stat the Bronco.

If we can get away running an H6 case size (same width as H7), the 60ah units are in stock. Sent you a PM.

 

[Ape Factory]

Ok I went and popped my hood. At least on the Braptor, it'll need to be an H7 to make it easy. You could block in an H6 but I'm not sure how much play the positive and negative harnesses have. So easy button is to stay with the same size. It's mounted by all three dimensions.

 

[dgorsett]

Ok I went and popped my hood. At least on the Braptor, it'll need to be an H7 to make it easy. You could block in an H6 but I'm not sure how much play the positive and negative harnesses have. So easy button is to stay with the same size. It's mounted by all three dimensions.

Not AG related, but I stayed with the H6 on my plain Jane BB for the same (inverse? ) reasons.

 

[mrjking2000]

You'd need to code in the 40Ah like mrujking2000 did, then it would work. It'd have more than enough cranking amps (like 1200 off the top of my head) to stat the Bronco.

If we can get away running an H6 case size (same width as H7), the 60ah units are in stock. Sent you a PM.

I am running a 60 AH battery, it's still a tad bit odd on how it charges but it's much happier after changing the charge percentage to 95% and doing that BMS reset.

I also have a 50 AH lithium battery in my rear end for running things while "off-grid" per say and the voltage on the AG battery is so high now that my DC-DC charger never turns off.

have you experimented with bumping the charge profile to 100% state of charge in forscan? i'm curious if that will force the alternator into 14.4/14.7 all the time. watching the alternator turn on and off while driving around it looks to put about 100 amps into the lithium battery in bursts, but the AG manual says not to chage over 20 amps. so i'm assuming they've accounted for this and the random 100 amp bursts for a few seconds are ok.

 

[mrjking2000]

There is a toggle in Forscan for Battery type - I don’t know what the options are or what it does off the top of my head but may be pertinent here.

Also good info about the 40Ah and active BMS

unfortunately your two options are AGM or flooded. nothing for lithium yet,

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