Best Battery maintainer for our dual battery setups?

TheBac

Why do I keep doing this?
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Apr 19, 2008
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Considering my truck gets used very little anymore, Im looking to put a battery maintainer on her, just in case. I looked thru the old threads concerning using battery maintainers in the winter, but nobody volunteered WHICH ones would be the best to use.
I've had very good luck with the Delran Battery Tender Jr https://www.batterytender.com/junior on the Vette, the zero turn and my winch's deep cycle, but Im not sure that one has enough power to keep up two large CCA's like we have.

Any thoughts?
 
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PureHybrid

Isuzu Shakes IT
Feb 15, 2012
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I've used the 750ma tender Jr on my truck before, but they're not meant to charge larger batteries. If you put the tender on while the battery is up to charge, theoretically any tender that is above any current draw the truck has will work.
 

660catman

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May 18, 2021
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I would think that a battery tender brand with dual setup would be ideal. It puts out 1.25 amps to each battery. And being a maintainer, it will shut off when battery is charged.




2013 Sierra SLE 2500HD Crew Cab
 

2004LB7

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I would think that a battery tender brand with dual setup would be ideal. It puts out 1.25 amps to each battery. And being a maintainer, it will shut off when battery is charged.




2013 Sierra SLE 2500HD Crew Cab
I'm not so sure a two bank is needed or even wanted. our trucks have a single bank of two batteries connected in parallel. do you know if that charger can have it's outputs connected together? because that's what would happen if you put one on each battery
 
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clrussell

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Sep 23, 2013
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Good info to have. Great thread timing as I was thinking about this over the weekend since my truck sits so much anymore
 

JoshH

Daggum farm truck
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Unless you have a major parasitic draw, there's no reason a tender for a single battery won't work. Since they're tied together, they can be viewed as a single large battery.
 
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Ron Nielson

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Oct 11, 2009
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I park my truck for 5 months straight and use a NOCO from Amazon. It works well both on the truck and the ZTR mower - $30 currently. If you start with a charged battery, it will maintain just fine. If your batteries are spanked, buy a 10 amp or larger charger.

NOCO GENIUS1, 1-Amp Automatic Smart Charger, 6V and 12V Portable Automotive Car Battery Charger, Battery Maintainer, Trickle Charger and Battery Desulfator with Temperature Compensation​

 

1FastBrick

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Dec 1, 2016
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I have a 3 amp and a 6 amp charger/ maintainer from Schumacher electric but both sold under the Napa Brand name and are blue. They were on sale when they first came out so I figured why not, it was cheaper than the Schumacher version that way and i prefer the blue over the red color .

The 3 amp takes time to bring them up but it does maintain them. The 6 amp does it much faster Like within an hour or 2 with the 2 batteries inline.


I also wired in the quick connect Terminal so I don't have to mess with the clamps. Power to the red junction block and ground right off the 2nd alternator bracket.

The latest 3 amp charger has an app you can download and see the charging status of what it's hooked to. Of course I can see the battery voltage on my Alarm System app.




I recommend what ever brand you get, Get a higher amp one. Most of them are Automatic to switch back and forth so as not to over charge and ruin the battery.
 
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660catman

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May 18, 2021
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I'm not so sure a two bank is needed or even wanted. our trucks have a single bank of two batteries connected in parallel. do you know if that charger can have it's outputs connected together? because that's what would happen if you put one on each battery

I was thinking that as I have a 2 bank MinnKota onboard charger in my boat for the trolling motor batteries.


2013 Sierra SLE 2500HD Crew Cab
 

660catman

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May 18, 2021
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those have an isolator or switch to separate them, correct?

Now that I don’t know. I talked to a buddy who deals with batteries. He suggested a two bank maintainer with low amperage. He said 1.25 amps is good and if one battery is weaker it will get a full charge and not overcharge the other battery like a single would. I checked mine and one is 12.42 and the other is 12.54.


2013 Sierra SLE 2500HD Crew Cab
 

2004LB7

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Dec 15, 2010
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Now that I don’t know. I talked to a buddy who deals with batteries. He suggested a two bank maintainer with low amperage. He said 1.25 amps is good and if one battery is weaker it will get a full charge and not overcharge the other battery like a single would. I checked mine and one is 12.42 and the other is 12.54.


2013 Sierra SLE 2500HD Crew Cab
ok. yeah it sounds like they are isolated as each battery can have different voltages. in our trucks since they are connected they will have the same voltage. it would work good if Tom was thinking of disconnecting the batteries for storage. but not any advantage if left connected
 

68ss

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Dec 30, 2019
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Here is what I have. Seems to work great.
 

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660catman

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May 18, 2021
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ok. yeah it sounds like they are isolated as each battery can have different voltages. in our trucks since they are connected they will have the same voltage. it would work good if Tom was thinking of disconnecting the batteries for storage. but not any advantage if left connected

Not sure if I threw you off talking about boat batteries but those voltages I posted are my truck batteries in the truck.


2013 Sierra SLE 2500HD Crew Cab
 

Dozerboy

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Jun 23, 2009
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I've used the 750ma tender Jr on my truck before, but they're not meant to charge larger batteries. If you put the tender on while the battery is up to charge, theoretically any tender that is above any current draw the truck has will work.

Same here. You definitely want to put it on while the batteries are fully charged. The Jr doesn't like it other wise. Honestly my batteries didn't last any longer with the battery tender. However here in TX you lucky to get more then 3 years out of a battery, so they might be more valuable other places.
 

TheBac

Why do I keep doing this?
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I have a 2/10amp battery charger for when a battery is dead/down. I want to put a maintainer on my truck bc it gets driven maybe once every couple months anymore, and the batteries do go down in the winter if the truck isnt started once a week or two.
I ended up buying the 800ma water-resistant Jr bc the truck sits outside all the time. https://www.batterytender.com/weather-resistant-800
If it works, great. If it doesnt, its not like I wont use it somewhere else.
 

2004LB7

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what about those solar chargers that sit on your dash and plug into the cigarette lighter?
 

TheBac

Why do I keep doing this?
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I tried one of those that sit in on the dash and plugged into the cig lighter, but the sun doesnt hit the truck all the time. MUCH easier for me to run a 50ft extension cord out to the truck.
 
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