[HWYSTR455]

Makes me wonder if it's the tenders. Batteries should go bad in 1-2 years.

Those Griots Garage chargers say they are for lead-acid batteries, no mention of AGM by the way. And t can surge to 20a, never heard of a 'tender' that does that. Most are 2a-5a range.
This is the only one I use on my cars:

https://no.co/genius5

I have yet to find a better, and they can charge/recover batteries that are fully discharged, a rare feature. They also make single units that can manage up to 2 or 4 batteries at the same time.

https://no.co/genius

Anyway, on the lead acid ones, make sure you have enough acid in them. The AGM ones, once there is a dead short, even momentarily, it will cook one or more cells. No recovering those.


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[HWYSTR455]

They also make a full line of accessories, extension cords, different size eyelets, etc.

https://no.co/collection/accessories/genius-accessories

They come with a wall mount, the unit can be easily removed from the mount if need be.

They are only 4.25" long, easy to pack and take with you on trips.

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[Pershing]

Thanks for the info. I bought a new battery amp tester. Only the older AGMs need replacement.

[HWYSTR455]

My blue top is almost 6 years old, my yellow top is more than 8 years old, both still working well.

The OE Delco AGM in my 2018 truck I just replaced before the winter. It would have probably been fine, but noticed the ALT was cycling the charge more often and didn't trust it to make it thru the winter.

Something is amiss, you should look hard at your setup.


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[Pershing]

Originally Posted by HWYSTR455

My blue top is almost 6 years old, my yellow top is more than 8 years old, both still working well.

The OE Delco AGM in my 2018 truck I just replaced before the winter. It would have probably been fine, but noticed the ALT was cycling the charge more often and didn't trust it to make it thru the winter.

Something is amiss, you should look hard at your setup.


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No real pattern here. I have one AGM still good from 2012, lead acid from 2017 still good, yet newer others are bad.

[HWYSTR455]

Originally Posted by Pershing

No real pattern here. I have one AGM still good from 2012, lead acid from 2017 still good, yet newer others are bad.

Swap a good one from one of the other cars into one of the ones that have a bad and see if it goes bad.

I guess it could just be bad batteries, but that seems way too soon for them to go bad. Like I said, I would be looking hard at the systems on the cars that went bad.


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[Pershing]

Originally Posted by HWYSTR455

Swap a good one from one of the other cars into one of the ones that have a bad and see if it goes bad.

I guess it could just be bad batteries, but that seems way too soon for them to go bad. Like I said, I would be looking hard at the systems on the cars that went bad.


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That's a good idea on the swap. Thanks

[Entropy11]

Originally Posted by HWYSTR455

Makes me wonder if it's the tenders. Batteries…

I’m late to this but I’m totally on the same page. So many battery “tenders” practically do more harm than good. I will only use the NOCO or CTEK chargers. The CTEK is often relabeled/rebranded for certain manufacturers/models (like for Subaru, and is also shipped as the OEM charger for the C7/8 Corvettes). I have more if the CTEK (MUS 5.0) versions now since the price is back under $100.

You can also run your charger(s) through digital repeat cycle timers like the ones offered by BN-Link (under $20) so they only come on every few hours at a time or once every day for an hour or so if you want. These are outdoor rated and capable of 15A unlike those old school ones you used to use indoors for Christmas lights.

[HWYSTR455]

Yes, NOCO and CTEK are the way to go. I know the NOCO actually does go thru certain cycles, on, off, trickle, etc. There are other good ones out there now, but NOCO is working for me, so no need to break the habit.

An interesting note. I bought a new KTM EXC-F 500 in spring of 2022, and used a NOCO for it. By fall, I was having an issue with gas in the oil, and took the bike in for a warranty service. Service department knew exactly what was going on, and told me it was the NOCO smart charger. Those cycles would impact the ECU programming, which also had a type of 'smart' capabilities, specifically to cycle the fuel pump for startups (efi). I switched to a Battery Tender and all is fine. The factory even issued a reprogramming TSB, they applied it on the following service interval, but I had already switched anyway. The service notice had a list of chargers that were known to cause the issue, and a list of suggested ones to use, Battery Tender being one of them.

I can't even count how many battery chargers I've owned over the years, 99% of them were junk, and not inexpensive ones either. I had some issues with some early AMG batteries and learned from those experiences. That's what eventually led me to NOCO.


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