10 amp vs. 15 amp charger

[pwrfshn]

In the process of replacing my 4 bank charger, can someone tell me what the advantages of a 15 amp per bank vs. a 10 amp per bank charger are? I know the 15 amp will charge faster, but are there any drawbacks outside of the extra weight?

Thanks in advance,

[yarcraft91]

It depends on how big your batteries are and how much time you have. Slow re-charging usually yields the greatest battery lifetime. I like to size battery chargers to deliver no more than 10% of the amp-hour rating of the battery being charged. 10 amps for a 100 amp-hour battery, 15 amp for a 150 amp-hour battery, will fully recharge deep-cycle batteries overnight. If you don't have the time to allow the slow-charge to finish, a faster charge rate will work, but at the expense of some battery lifetime.

[pwrfshn]

I'm running the Interstate SRM 27 with a 160 RC. The 15 amp seems to be the way to go. Don't know how to calculate the amp hours. Thanks!

[yarcraft91]

I run the Interstate SRM 27B, a 180 RC battery and have always been able to recharge it overnight with a 10 amp Guest charger. You can do the amp-hour calculation a couple different ways- just need an estimate anyway.

One way is to use the RC number, which Interstate measures at 25 amps. Multiply 3 hours (180 RC is in minutes of capacity) times 25 amps = 75 amp-hour rating.

Another way is to take some data from the Interstate website:
http://www.interstatebatteries.com/cs_eStore/content/product_info/marine_f.asp
which says my battery will deliver 5 amps for 20.4 hours or 5 x 20.4 = 102 amp-hours. I used this number to size my charger.

I'd use a 10-amp charger on your SRM 27, which computes to 85 amp-hours- close is good enough and a 5-amp may not charge the battery overnight.

[pwrfshn]

Thanks for the education. Do you think the 15 amp will harm the batts? There are times where we fish back to back long days and overnight is not always as long as it may seem. Guess I erred on the side of caution and went with the 15 to be sure I had a full charge, knowing that trade off may be battery life. ;)

[yarcraft91]

You might get one less season out of the batteries with the 15 amp charge rate rather than 10 amp, or it may not make any difference. I know people who charge batteries that size at 20-30 amps because they are in a hurry. If the 10 amp hasn't always charged your batteries fast enough for how you use your boat, the 15 amp is probably a better choice for you. More important, it sounds like you bought a smart charger and those help to extend battery life.

Good luck with it! :)

[T Mac]

The top fishboat companies routinely install 15 amp per bank chargers as standard equipment on their larger boats.
As a dealer I never saw the 15 amp chargers have a down side or cause a problem.
Only pluses, in my book.

[pwrfshn]

Thanks T Mac, your input is always appreciated!

[bob1]

I was told by a dealer that a quicker charge on trolling batteries is better!

Not sure how true it is however.

My Ranger Reata 1850 has a Dual Pro 3 bank 15amp per bank charger from the factory.

My trolling motor batteries are 27's.

Bob

[ShadTaxi]

15 amps for sure. Unless you want to wait for your batteries to charge...

[rvrdrifter]

not sure what brand charger you have, but it shouldn't matter....if you go to the minnkota website, they have graphs or charts from each style amp charger you can reference that will explain how long it will take to recharge depending on the amps you are using.

[AllenW]

Thanks for the education. Do you think the 15 amp will harm the batts? There are times where we fish back to back long days and overnight is not always as long as it may seem. Guess I erred on the side of caution and went with the 15 to be sure I had a full charge, knowing that trade off may be battery life. ;)


I think you anwsered your own question here, recharging times are more critial to you than someone who fishes a shorter day and has more recovery time.

I've charged both slowly and at a quicker rate depending on time allowed and never noticed battery life being any shorter than the three years I expect out of batteries.
80% slowly at 10 or less the rest prob at 15 or higher.

All my chargers have the tapering feature though and I think that makes a difference as it prevents overcharging.

Al