Dual battery charger

[cfrashier]

i was wanting to put 2 batteries in my 16' boat that has a 50esl75b 50hp outboard johnson sea-horse and i was first wondering if it was capable and second what is recommended for an on-the-go charger so the motor would charge both batteries and i will not be stuck in the water with a dead battery.

 

[bruceb58]

You can put an ACR between them but I have a feeling your engine may not put out much current to actually charge them much. What is going to discharging your batteries that you need to charge them back up? Do you know the charging spec for your outboard?

 

[glenn property of pam]

your motor will not be able to recharge the batteries so you will have to make plans to charge at home. With a modern onboard multi-bank charger most will come with a built in acr for free.

 

[bruceb58]

Most modern chargers do not have an ACR inside. They are two separate charging circuits so that you can charge batteries that are connected in series. The outputs(both positive and negative) are completely isolated between banks at all times.

 

[glenn property of pam]

my basspro xps 5/5/5 charger has a acr that works from battery one to either battery 2 or battery 3 I thought that its was standard on most multi-bank chargers now. Guess not

 

[Silvertip]

His question pertains to whether or not the engine can charge both batteries. Alternator output on that engine is either 6 or 12 amps at wide open throttle. If either or both batteries are deeply discharged that output is not sufficient to charge even one of the batteries in a short run back to the dock. If one of the batteries saw a 10 amp draw it would take a one hour run at wide open throttle to replace that current and the battery would still not be topped off. A dual battery switch or ACR would be advised if you really feel the need to tackle this. Not knowing what the accessory load is makes it impossible to make meaningful recommendations. Fact is in a two battery system you are limited by the charging capacity of the engine. On board chargers are separate battery chargers powered by 120 volt AC house power when you are at the dock or at your home/cabin/resort.

 

[cfrashier]

I was just curious because I thought of putting a trolling motor on the front. I would then hook up on battery one my outboard motor, my beilge pump, and my lights. Then on the second battery my ttolli g motor, my fish finder, and a stereo with just some small 4 inch speakers. I don't plan on running it overnight just didn't want to be caught with a dead battery if I run my trolling motor or listened to the radio while I was on a sandbar.

 

[bruceb58]

my basspro xps 5/5/5 charger has a acr that works from battery one to either battery 2 or battery 3 I thought that its was standard on most multi-bank chargers now. Guess not

It doesn't have a built in ACR. If it did, you wouldn't be able to charge 3 batteries in series with it.

It is just a 120VAC battery charger. Its not even operating when the engine is running and not plugged into 120V.

 

[bruceb58]

duplicate post

 

[kjsAZ]

I was just curious because I thought of putting a trolling motor on the front. I would then hook up on battery one my outboard motor, my beilge pump, and my lights. Then on the second battery my ttolli g motor, my fish finder, and a stereo with just some small 4 inch speakers. I don't plan on running it overnight just didn't want to be caught with a dead battery if I run my trolling motor or listened to the radio while I was on a sandbar.

I only carry a jump start box for that reason. It will get the engine up and running and once the alternator works the engine doesn't need much battery juice any more. Much lighter and I can charge it up at home. If you get one make sure it has an AGM battery and not just a gel-cell like the cheap HF ones.
You could also get the smallest jump starter, a micro start xp-3 which is surprisingly small yet does a great job in starting an engine.
http://www.amazon.com/Antigravity-Ba...cro+start+xp-3
A real jump starter has a lot more capacity but if you want something extremely small and lightweight they do well.