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Battery Charger/Tender
Ok I may be showing my ignorance here but I have a simple question. I was looking at ordering a battery charger/tender. Following others I was planning on having a dash socket that I could plug the charger/tender into. I know the charger/tender is for a 12volt battery but I am unclear what amperage is required.
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For a battery maintainer, 1 to 1.25 Amps is fine. I prefer the Deltran battery tender + for lead acid batteries. For AGM, look for an AGM specialized maintainer.
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I have also had good luck with Pro Mariner, use them on my boat batteries and they have always held a good charge over the winter.
https://www.amazon.com/ProMariner-Pr...s%2C119&sr=8-3

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Originally Posted by
Papa
For a battery maintainer, 1 to 1.25 Amps is fine. I prefer the Deltran battery tender + for lead acid batteries. For AGM, look for an AGM specialized maintainer.
Thanks Papa! Just what I was looking for.
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You should not overheat a battery with a high charge rate (110F). There is a risk of plate warping and shorting. (Arizona?) 10% of the battery amps is safe, not hard with car batteries, bike batteries should not get more than 2amps.
I have multi-battery type selections on my chargers and desulfating mode for storage. Northern Tool has a good selection, but not cheap:
https://www.northerntool.com/shop/to...ry-maintainers
You would need to buy the cigarette lighter socket adaptor, but that will not work if that port is wired to IGN not BATT.
jim
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Originally Posted by
J R Jones
You should not overheat a battery with a high charge rate (110F). There is a risk of plate warping and shorting. (Arizona?) 10% of the battery amps is safe, not hard with car batteries, bike batteries should not get more than 2amps.
I have multi-battery type selections on my chargers and desulfating mode for storage. Northern Tool has a good selection, but not cheap:
https://www.northerntool.com/shop/to...ry-maintainers
You would need to buy the cigarette lighter socket adaptor, but that will not work if that port is wired to IGN not BATT.
jim
Thanks Jim. Wiring as always hot noted.
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I've been very happy with my CTEK 7002 charger. https://smartercharger.com/products/ctek-multi-us-7002. Consistently gets high ratings and has worked well for me. Handles regular plus AGM batteries. I hit my cars with it about once a month during winter storage. Keeps them topped off plus gives a maintenance check. A CTEK 56-263 pigtail, sold as an accessory, connects directly to the 7002 charger wires and plugs into the aux (cigarette) outlet. Works great.
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Originally Posted by
edwardb
I've been very happy with my CTEK 7002 charger.
https://smartercharger.com/products/ctek-multi-us-7002. Consistently gets high ratings and has worked well for me. Handles regular plus AGM batteries. I hit my cars with it about once a month during winter storage. Keeps them topped off plus gives a maintenance check. A CTEK 56-263 pigtail, sold as an accessory, connects directly to the 7002 charger wires and plugs into the aux (cigarette) outlet. Works great.
Having followed your thread extensively I was cruising the CTEK web site which I found to be somewhat confusing. That's the reason for asking about required amperage. I ended up with the same part numbers as you just posted so thank you for confirming that for me.
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Just another tidbit of info.
Batteries have a self discharge characteristic with lead acid being one of the worse. Left unattended for long periods of time they will go dead which, even if they can be revived, takes significant life out of the battery. So the purpose of the maintainer is to "trickle charge" the battery to offset the self discharge. As such, the trickle charge is on the order of milliamps (well under an amp). That said, many buy a battery charger not only capable of trickle charging but also regular charging as highlighted by many above....
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Deltran Battery Tender 800 mA for a float charger.
For charging, I prefer a charger with both manual & automatic features. A battery that is low on voltage will often not be detected and charged by a straight up automatic charger. In that case, put the charger on manual and push the amps into the battery. Don't forget the charger on the battery because it'll blow up the battery. Get the battery up to ~12 volts and switch over to automatic charging.
My favorite and most used charger (I have several Ive accumulated over the years for RV/Boat batteries, power sports & automotive), is made by Century Tool & Equipment. They used to be made in USA. That may have changed.
https://www.centurytool.net/K3153_1_..._p/k3153-1.htm
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I have had an auto battery so discharged that it lost polarity and would not take a charge. The remedy was to slam a high amp charge into it to re-establish polarity. Then charging could be done normally.
I prefer trickle charge but it can require 24 hours or more. If left discharged too long sulfating ruins the ability to hold a charge. IMO the microprocessor based chargers maintain better and prolong battery life.
BTW if the case sides are bulged, sulfating has ruined the battery, trade it in.
jim
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Originally Posted by
Papa
For a battery maintainer, 1 to 1.25 Amps is fine. I prefer the Deltran battery tender + for lead acid batteries. For AGM, look for an AGM specialized maintainer.
Just so there is no confusion. The Battery Tender Plus from Deltrans is suitable for most types of automotive style batteries, including AGM. Specs are here.
https://www.batterytender.com/plus
I have a number of these on all different vehicles and they work great. You can pay more for a battery maintainer/charger. I choose not to. These are in the middle of the price range and do go on sale from time to time. All my stored vehicles get stored with a Battery Tender attached.
Last edited by frankeeski; 03-02-2022 at 07:21 PM.
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Originally Posted by
frankeeski
Just so there is no confusion. The Battery Tender Plus from Deltrans is suitable for most types of automotive style batteries, including AGM. Specs are here.
https://www.batterytender.com/plus
I have a number of these on all different vehicles and they work great. You can pay more for a battery maintainer/charger. I choose not to. These are in the middle of the price range and do go on sale from time to time. All my stored vehicles get stored with a Battery Tender attached.
Ditto. Good product, reliable. I charge my cobra, motorcycle and seadoo batteries with the same device.
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Originally Posted by
frankeeski
Just so there is no confusion. The Battery Tender Plus from Deltrans is suitable for most types of automotive style batteries, including AGM. Specs are here.
https://www.batterytender.com/plus
I have a number of these on all different vehicles and they work great. You can pay more for a battery maintainer/charger. I choose not to. These are in the middle of the price range and do go on sale from time to time. All my stored vehicles get stored with a Battery Tender attached.

Originally Posted by
David Hodgkins
Ditto. Good product, reliable. I charge my cobra, motorcycle and seadoo batteries with the same device.

Good info, Frank. Is that true for Optima AGMs? My experience when connecting my Deltran Battery Tender (may have been a junior, not a +) was that the unit didn't like the Optima. I ended up getting an Optima charger and it works great.
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Originally Posted by
Papa
Good info, Frank. Is that true for Optima AGMs? My experience when connecting my Deltran Battery Tender (may have been a junior, not a +) was that the unit didn't like the Optima. I ended up getting an Optima charger and it works great.
It depends on the discharge of the battery. If an AGM drops to low, it's a lot harder to bring it back. One trick to bring back a discharged AGM is to charge it in parallel with a known good battery (using jump cables) and a battery charger.
I use a Junior on an Optima Redtop I have stored in the shop. Seems to keep it topped off just fine.
Frank
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I have 4 optima red tops in the shop, out of the cars, each one on Battery Tender Juniors(750ma).
And I rotate the others into the bank of chargers every month or so.
Have been using this system for a couple of years now with no problem
Last edited by Derald Rice; 03-02-2022 at 11:48 PM.
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I have been using the Battery Tender system for 12 years with 2 Costco marine lead-acid batteries. The boat is located in BigBear CA at 6700 ft. elevation. I had to replace 1 battery in spring 2021. I don't use it during the summer season, no power at the marina. I paid $25 cash at a motorcycle dealer tradeshow. Great purchase.
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I've had my car a few years now and haven't had any issues with the battery dying on me. I like the under car setup if I ever needed one though.
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Costco has a good deal right now on a Battery Tender 4.5 amp that does AGM, Lead Acid, and Lithium. That's tough to beat on a multi battery capable charger.
https://www.costco.com/battery-tende...100679769.html
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I use a Deltron Battery Tender Jr. Having it connected when in the garage, I was able to get 10 1/4 years out of my original Duralast Autozone lead acid battery. The employees were amazed it lasted that long.
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