Battery charger amp decision

I have on board chargers in all my boats but often I need one for a battery not in the boat. For years I have used an old school charger that must be monitored If I want higher amps. I also have a 1.2 amp smart charger that I mostly use. I’m ready to buy a smart charger for home use with more power and have a brand picked out but there are numerous output choices and I don’t want to just pick out the 10 amp output model just because it’s the biggest. They also have 3,4 and 6. What would be the most versatile around home?
They are generally used on large 24 and 27 size batteries but could also be used on atv batts. Thanks

A lot of the smart Chargers will vary the amperage output based on a brief test of the battery at the start of the charge cycle. Mine starts at 12 amps and will quickly ramp down the charge amperage based on charge level and battery size- down to 1 amp for my lawn mower battery when I top it off after the winter. It will also float charge if I leave it connected after the charge cycle is complete.

I’ve read a lot on this and what seems to recur in most thoughts anything under 3 amps don’t bother for charging, just to top off. And anything over 13.5 amps is to much for deep batts and will overheat. Need one to start at 11-12 then slowly make it’s way down. Hope someone can clear this up BC I’m confused as well.

I have a Schumaker that has reg and deep, with 2 amp and 15 amp auto modes. The 2 amp takes forever on my old group 24, just bought a 31 and took several hours on the 15amp to fully charge. Kept checking every hour or so and things were warm, but nothing out of the normal from last batteries. You can watch the amps getting discharged less as the batteries gets more full. Don’t want to overheat anything going with 15amps

I ended up going half way with a 6 amp. I’m partial to Guest chargers which now go under the name of Marineco. Found a Wisconsin company that sells them. Del City. Nice sealed unit designed for marine use so it will be very robust.
I currently have 3 other Guest chargers in my other boats.

You pulled the trigger quickly!

I’ve got a Schumacher that will do 12A, 6A, or 3A, depending upon the battery. It has served me well.

I have 3 smart chargers and use them to charge my 4 boat batteries (2 Parallel, 2 series).

10,6,2 amps.
I usually run on Auto. If they’re drained it’ll ramp up to 9-10amps and slowly reduce amps as it tops the battery off. WHen it’s nearing 14 volts the chargers are usually reading .1-.3 amps.

I spend between $30-40 for the smart chargers that i use.
Also have a manual charger for those times when i accidently drain a battery completely dead and need to manually revive it before putting on a smart charger.

I use my smart chargers for my 7-9ah ice fishing batteries too.

Ralph Wiggum wrote:

You pulled the trigger quickly!

I’ve got a Schumacher that will do 12A, 6A, or 3A, depending upon the battery. It has served me well.

You’re right. Those Schumacher’s look like a better choice.

FishBlood&RiverMud wrote:

Also have a manual charger for those times when i accidently drain a battery completely dead and need to manually revive it before putting on a smart charger.

Its easier using a manual charger to jump start a drained battery but in a pinch connecting a second charged battery in parallel will trick the smart charger into charging the drained battery.
You probably all ready new that but its something new I learned this year.

hl&sinker wrote:

Its easier using a manual charger to jump start a drained battery but in a pinch connecting a second charged battery in parallel will trick the smart charger into charging the drained battery.
You probably all ready new that but its something new I learned this year.

I know, on my Schumacher, at least, that there is a way to bypass auto mode to force it to manually charge a completely drained battery. It wasn’t in the manual, but I found it on their website, I believe.

hl&sinker wrote:

<div class=”d4p-bbt-quote-title”>FishBlood&RiverMud wrote:</div>
Also have a manual charger for those times when i accidently drain a battery completely dead and need to manually revive it before putting on a smart charger.

Its easier using a manual charger to jump start a drained battery but in a pinch connecting a second charged battery in parallel will trick the smart charger into charging the drained battery.
You probably all ready new that but its something new I learned this year.

I imagine that’d work perfectly. Good tip that may come in handy some day when that manual charger is not close by!