AGM fully discharged

[Dave Mazone]

I did a STUPID! I pulled the break-away plug on the brakes and let it set a few days. I came back to a FULLY discharged set of batteries.

Anyone got a non-technical explanation of how to recharge these, or do I need to take it to a battery shop?

[topgun2]

OUCH!🤢

[John E Davies]

Well, the odds are that they are wrecked, but it is worth trying to salvage them, a charger with a “reconditioning” feature might possible revive them, unfortunately with four (?) batteries, the odds are high that at least one is irredeemable, so you may end up replacing them all, so that one bad unit won’t discharge the others….

i have a 6 amp C-Tek charger that I used successfully on my truck when I left a dome light on for several weeks over the summer, the battery appears to be fine now, but it may prove to be toast once the winter chill sets in… I did disconnect the leads when charging, to protect the vehicle systems from the higher voltage.  This charger is way too small for your big storage batteries, it might be best to talk to a local shop.

CTEK (56-353) MULTI US 7002 12-Volt Battery Charger,Black

Keep in mind a retail shop will be eager to sell you new batteries rather than fixing your old buggered ones. Maybe an auto-electric repair service would be more productive. Good luck, I bet you said a lot of bad words. I sure did.

John Davies

Spokane WA

 

[John Dorrer]

All it takes is one time to damage them. You need to get them charged and have a battery place do a load test.  How old are they? IMO I would be surprised if they aren't toast. Hope that isn't the case. I have seen many cases were AGM's were run down to 11.8 and damaged.

[Steph and Dud B]

Also check all your brake wiring and brake operation. I've heard of SOB trailer owners having melted wires and/or damaged brake magnets from this scenario. 

[SeaDawg]

Your batteries are pretty new, so you do have a good chance of "bringing them back to life." 

We are successful with that with our friend's jeep, who left his 12v fridge plugged in all night, got down to 10. 8 or so. He's still using same battery,  4 years later.

Give it a try. You have nothing to lose, everything to gain.

[John E Davies]

Battle Borns are on sale big time, maybe your toasted batteries are a sign from above that you should upgrade to lithiums now…. They will survive abuse much better than ye olde fashioned lead acid boat anchors…

BB Black Friday sales

I have never heard of even one owner that switched to lithiums who regretted it afterwards. Maybe you should add some 21st Century tech to your electrical system.

John Davies

Spokane WA

 

[Dave Mazone]

Well, thank you all for your input. Unfortunarely, most of it leans towards a very expensive lesson! I will try to redeem first. Wish me luck. PS: it's a 2022 model.

[SeaDawg]

Try, slow charge, and let us know.

I have my fingers 🤞 crossed for you. Good luck.

[SeaDawg]

Battleborn is inexpensive right now, relatively,  but I'm not sure we're ready to make the break. 

Well see how the old agms survive the winter.

And,then, decide.

[Rivernerd]

7 hours ago, Dave Mazone said:

I will try to redeem first. Wish me luck. PS: it's a 2022 model.

Then, as John Davies suggests, invest in a high-quality (ergo more expensive) lead acid battery charger that has a "repair" or "desulfate" feature.

I have had good luck with NOCO Genius chargers.  They are small but effective.  Below is a link to a 10A version for $79.96 that includes a Repair feature for deeply discharged lead/acid or AGM batteries.   If your AGMs are 6V, it can be set to 6V as well as 12V.

https://www.amazon.com/NOCO-GENIUS10-Fully-Automatic-Temperature-Compensation/dp/B07W3QT226

In your shoes, I would invest the $80 to see if the batteries can be salvaged.  Your 400+Ah battery bank will take several days to recharge with this charger, even if it can be saved.  After the charger has done its job, verify voltage of each battery with a multimeter, at least twice, before concluding that you have "dodged a bullet."

Even if you can't save the batteries, a NOCO Genius charger is handy to have around just for maintaining automotive lead/acid batteries.

Good luck!  And, please report your results.

[Ronbrink]

8 hours ago, Rivernerd said:

Even if you can't save the batteries, a NOCO Genius charger is handy to have around just for maintaining automotive lead/acid batteries.

Agree, my NOCO 10 has served me well for over three years on all kinds of batteries, even on recent upgrades to LFPs.

[John E Davies]

10 hours ago, Rivernerd said:

 

I have had good luck with NOCO Genius chargers.  They are small but effective.  Below is a link to a 10A version for $79.96 that includes a Repair feature for deeply discharged lead/acid or AGM batteries.   If your AGMs are 6V, it can be set to 6V as well as 12V.

https://www.amazon.com/NOCO-GENIUS10-Fully-Automatic-Temperature-Compensation/dp/B07W3QT226

I considered NOCOs before buying my C-Tec, at the time the price was a big consideration. This looks like a great choice, 10 amps for $89 (BF price). Have you ever used yours in Power Supply mode (constant voltage)? Wondering if it works without being connected to a battery, for example to anodize small aluminum parts in an acid bath…? It would save me $100 over buying an eBay variable power supply. Sorry for the topic drift. Thanks.

John Davies

Spokane WA

 

[Rivernerd]

12 minutes ago, John E Davies said:

Have you ever used yours in Power Supply mode (constant voltage)? Wondering if it works without being connected to a battery, for example to anodize small aluminum parts in an acid bath…?

I have not used mine in Power Supply mode.

I once used it in Repair mode (which I believe uses variable low, not constant voltage to desulfate) when an AGM battery I used to power my CPAP machine on wilderness river trips got more fully discharged than I liked.  It restored the battery to full charge on that occasion, although I was never able to verify for sure that the over-discharged condition had not shortened the battery's life a bit.

That was before I switched to 12V LiFePo4 batteries (with internal Battery Management Systems), to power my CPAP.

[Dave Mazone]

11 hours ago, Rivernerd said:

Then, as John Davies suggests, invest in a high-quality (ergo more expensive) lead acid battery charger that has a "repair" or "desulfate" feature.

I have had good luck with NOCO Genius chargers.  They are small but effective.  Below is a link to a 10A version for $79.96 that includes a Repair feature for deeply discharged lead/acid or AGM batteries.   If your AGMs are 6V, it can be set to 6V as well as 12V.

https://www.amazon.com/NOCO-GENIUS10-Fully-Automatic-Temperature-Compensation/dp/B07W3QT226

In your shoes, I would invest the $80 to see if the batteries can be salvaged.  Your 400+Ah battery bank will take several days to recharge with this charger, even if it can be saved.  After the charger has done its job, verify voltage of each battery with a multimeter, at least twice, before concluding that you have "dodged a bullet."

Even if you can't save the batteries, a NOCO Genius charger is handy to have around just for maintaining automotive lead/acid batteries.

Good luck!  And, please report your results.

Thank you! I just ordered it.

[Dave Mazone]

On 11/26/2023 at 9:39 PM, Rivernerd said:

Then, as John Davies suggests, invest in a high-quality (ergo more expensive) lead acid battery charger that has a "repair" or "desulfate" feature.

I have had good luck with NOCO Genius chargers.  They are small but effective.  Below is a link to a 10A version for $79.96 that includes a Repair feature for deeply discharged lead/acid or AGM batteries.   If your AGMs are 6V, it can be set to 6V as well as 12V.

https://www.amazon.com/NOCO-GENIUS10-Fully-Automatic-Temperature-Compensation/dp/B07W3QT226

In your shoes, I would invest the $80 to see if the batteries can be salvaged.  Your 400+Ah battery bank will take several days to recharge with this charger, even if it can be saved.  After the charger has done its job, verify voltage of each battery with a multimeter, at least twice, before concluding that you have "dodged a bullet."

Even if you can't save the batteries, a NOCO Genius charger is handy to have around just for maintaining automotive lead/acid batteries.

Good luck!  And, please report your results.

So, my charger arrived. Now I have another question: Do I need to charge them individually (there are 4), or can I charge them in parallel? I suspect I should not charge them in serial, right?

[Rivernerd]

18 minutes ago, Dave Mazone said:

Do I need to charge them individually (there are 4), or can I charge them in parallel? I suspect I should not charge them in serial, right?

I presume your battery bank consist of four 6V AGM's wired in series?  If so, I must defer to the expertise of others on this forum, who are more experienced with 6V systems, for the "best" answer.

That said, it seems to me that the "safe harbor" is to:  (1) take a photo of the battery bank wiring so you can replicate it later; (2) remove one battery at a time from the battery tray, and then (3) using the Repair mode, with the charger set for 6V batteries, begin the repair/recharge process on the first battery.  I would monitor progress with a multi-meter every 6-8 hours or so.  Then swap out the remaining three batteries one at a time.

One advantage of this approach is that you may be able to isolate any truly dead battery or batteries in the set and just replace it/them, since your batteries are only 1 year old.

Do any of you electrical engineering types out there disagree?  Presuming he has 6V AGMs wired in series to create a 12V battery bank, is it o.k. to just attach the leads from the charger to one of the positive and one of the negative terminals, and recharge/repair the entire bank using the 12V setting?

[ScubaRx]

Four six volt batteries would be wired as two sets of two batteries, each wired in series to create two twelve volt sets, but the amperage would stay the same as one battery. Those two sets would then be wired in parallel to keep the voltage at twelve volts. At that point, the amperage would double to that of twice the amperage of one of the batteries. 
 

Take a picture of the wiring, take each battery and deal with it separately and follow the advice that @Rivernerd outlined above. 

[Dave Mazone]

On 11/27/2023 at 7:40 AM, John E Davies said:

I considered NOCOs before buying my C-Tec, at the time the price was a big consideration. This looks like a great choice, 10 amps for $89 (BF price). Have you ever used yours in Power Supply mode (constant voltage)? Wondering if it works without being connected to a battery, for example to anodize small aluminum parts in an acid bath…? It would save me $100 over buying an eBay variable power supply. Sorry for the topic drift. Thanks.

John Davies

Spokane WA

 

 

[Dave Mazone]

SUCCESS!!!

I purchased the NOCO 10 charger. Three of my 6v AGM batteries read between 1.8 and 2.3 volts. The 4th read .5 volts and the charger wouldn't recognize it. I connected two sets in series and used the 12V option to charge them...and the .5 volt battery was revived.

I discovered that AGMs don't have a "recovery" option (or necessity) so the plain 12V option on the charger was appropriate.

I reinstalled the batteries and everything appears to be working well. Thank you all for your input and helping me dodge a $800 to $1000 expense.

 

[topgun2]

37 minutes ago, Dave Mazone said:

SUCCESS!!!

This is great news for you!

However, keep a very close eye on these batteries - especially the one battery - in that they may now exhibit different behavior than they did prior to being so deeply discharged.  This advice is particularly true if you plan a remote trip and/or a long trip.

Bill