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Battery Tender VS Battery Charger

I never trust or use any of them. Heard and seen too many horror stories with these burning down garages, shops and houses. I always just disconnect my batteries for the winters and walk away. I may occasionally go out and throw a charger on for a few minutes one time while I am out in the garage or fire the car up to charge the battery and circulate the fluids. I don't leave my cordless drills etc charging over night while I am not out in the garage either. Maybe it's just me being paranoid?
 
My hippy van sits outside, has no electronics on it, but yet will kill the battery after sitting over a month. So obvisoly there's a drain somewhere in the system, I just can't figure out where? I just disconnect the + terminal and life is good for months!
My 300 sits in the garage and will drain the battery in a month due to the clock running 24/7/365, again I just disconnect the battery. I do throw on a 4 amp charger for a couple hours before fire-up just to insure I have a hot battery. The needle still shows a charging condition for a few minute afterwards on both vehicles.
 
I use battery maintainers on pretty much everything I don't drive frequently (01 Viper, 70 Challenger, 10 Challenger, 05 Durango, 73 Cuda, 52 B3B, quad, 2 Harleys) as well as spare batteries that I want to use . I have a variety of brands and models to include Battery Tender, Battery Saver, Schumacher, CTek, and Optima. I have to say up front that Ctek and Optima are the best for AGM batteries. I met the guy from Battery Saver at SEMA a few years back and he had all of the scientific data that said his product was "the best", so I bought like 4 of them. Well, perhaps in testing they were the best but not in my shop; if you start with a well charged healthy battery they will probably do ok, but if you have a discharged battery they don't do squat. The Ctek is probably one of the best all around maintainers, however I have to say that the optima will resurrect a discharged Optima battery when others will not. Battery Tender (the brand and product) do pretty well overall so long as the battery starts off good and use them on my Viper and Harleys. The nice thing with Battery Tender products is that they are everywhere and easy to obtain and relatively inexpensive.
 
Most people do not understand that it takes a long time to actually charge a battery via the alternator and allowing a battery to discharge too much will kill them over time especially with AGM batteries. I have red and yellow top batteries but I will not buy another red top, the yellow tops (IMO) last far longer, but having said that I have one red top that is at least 10 years old and is still going strong, I have others that are 3-7 years old and work well (both colors). For me however, the yellow top seem to take longer to drain and bounce back better when recharged. On a couple of my cars I have a battery disconnect which will automatically disconnect and isolates the battery when it reaches 11.8V so it doesn't fully discharge. You can also manually (though a FOB or on the switch itself) disconnect the battery kind of like a security feature. Lastly, on my older 01 Ram I used to use a cheap solar charger because it say a lot which puts out about 4V and tends to combat the computer/clock drain pretty well. Got it from HF for like $15 and made a quick disconnect harness for it. When I am not using the vehicle I just have it laying on the dash connected.
 
The only tender I used was on a jell battery on my Harley. My thoughts are they might shorten the life of a battery. Constant voltage being applied might be harder on it.

I've only put a regular battery charger on the battery in my '62 during a compression test. It's been over two years now and it has always started. During the winter months I might start it once a month. The coldest it gets in the garage might be in the high thirties, never freezing. I do use a disconnect on the positive post and always have it off when not in use.
 
Everyone has to figure out what works for them. I talked to Optima at SEMA and they were pretty adamant about not letting a AGM battery run down and I can attest to the fact that if you let them get down below 6v they are a pain to get back, below 3v and you might not get them back. Like I said, I have probably 5-7 AGM batteries and spent a lot of time figuring out the best way to maintain them (for me).
 
I have 10 or 20 amp Schumacher that is both a charger and a maintainer.

I LOVE it.
 
Different kind of rig but.....I have a Sprinter chassis RV. Thisnis na Mercedes 2018 model. The battery is under the floor on the riverside and is a pat to access. So Mercedes installs a "rail" with a push type cover to expose said rod. There is a ground point very nearby. This is for jumping if you need it. It will NOT work with a trickle charger??? Is there not enough power in the charger when just trickling to transit the distance to the battery...not more than 3'away from this connection. Battery maintains fine if I hook directly to it with same charger.
 
Why.. I can hear them batteries slowly bubbling dry from here. Hope your fire insurance is paid up.......
 
Never had a tender but how many amps does a tender put out? My charger has a 2a and a 15a setting in both auto and manual mode plus a 100a start position (which isn't enough) and so far so good. Recently I swapped out the battery in my garden tractor (automotive battery) and was surprise at the date on it. Got to thinking that it's been awhile since I put a new battery in it and then saw it had 06 date code. The batteries in my diesel are getting old too but not sure how old....thinking about 7 or 8.
 
The way I understand the short story (pun) on battery tenders is.....
They keep a voltage above 12 on the cells so the plates don't sulfate.
Which would happen if the battery became discharged.
That's all.
Very little if any current.
If you put a meter on them you can watch them do that with the voltage.
 
onlyone said:
The way I understand the short story (pun) on battery tenders is.....
They keep a voltage above 12 on the cells so the plates don't sulfate.
Which would happen if the battery became discharged.
That's all.
Very little if any current.
If you put a meter on them you can watch them do that with the voltage.
Click to expand...

Yep, keep telling yourself that ! Hydrogen gas is a wonderful thing..
batteryblown.jpg
 
I really get frustrated with new battery’s . 1978 Plymouth Fury Sport battery lasted 13 years. 1992 Toyota 4 Runner 12 years. 1981 Dodge 150, cheap dealer 5 years. 1985 360 Dodge Vanguard camper van. Bought battery in 2009, calved this year. Never disconnected the battery, sat out through the winters , but finally quit. 10 years, can’t blame it . Maybe my neglect. I have other batteries that faithfully give near the warranty end or just after.
 
Well everyone needs to do what they think is right; I have 10 maintainers going as I type this, have been using them for well over 5 years, no issues, also the vehicles start right up every time.. However, have inadvertently left a maintainer off for an extended period and had a AGM battery die and no matter what I did never came back. Every battery company I have talked with highly recommended a maintainer if the vehicle isnt used frequently. I am not saying a fire couldn't start, but then a meteor could slam into my shop as well so there is that...
 
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