adding an onboard battery charger

[joho5]

I have a bass boat with an 89 Evinrude 70hp motor...I want to add an onboard charger.

Is this an easy thing to do? To install?

Where does it hook up to your motor, or ignition system?

thanks

 

[wiretwister]

Re: adding an onboard battery charger

Onboard charger is just a battery charger that stays on the boat....
You hook it direct to the battery.....and AC outlet.....if you have two or more batteries and want a onboard for all, buy one with that amount of "banks" and charge them all at the same time,thats pretty much it.


Wire

 

[joho5]

Re: adding an onboard battery charger

ohh, so it doesnt charge the battery when running the engine?

its just basically a charger thats convenient on the boat you plug in at home?

I thought they charged your batteries while the engine was running.

 

[Silvertip]

Re: adding an onboard battery charger

Your engine already charges the starting battery when it is running. why add an on-board charger? If you have a trolling motor and separate trolling motor battery, then you add a one or two bank charger. One bank charges the troller battery and other keeps the starting battery topped off. Most small and mid size engines don't have enough charging capacity to charge deeply discharged batteries. Hence the need to plug in at the dock. Perpetual motion hasn't been invented yet so you can't get 20, 30, 40 or more amps of power out of a charging system that tops out at 6 - 16 amps.

 

[traderdavel]

Re: adding an onboard battery charger

6-16 amps? Assuming on the low end - if a battery is slightly undercharged, (say 12.5), does 6 amps bring it to full charge? Or if the battery is at 12.5 is there no benefit because the 12.5 is greater than the 6. Sorry - just not sure how this is supposed to work. I actually thought it should push out 13.5 amps constant in order to keep the battery t that level.

 

[flargin]

Re: adding an onboard battery charger

two different terms.
Volts or Voltage. The level of a battery's capacity. Boat batteries are typically 12 V. you use the 13-14V to charge the battery.

Amps or Amperage. the amount of actual power in a battery.

You consume the power in the battery... i.e. trolling motor will take 50Amps. if you use it for 1 hour, you have used 50 Amp Hours (1/2 hour = 25 AH's)

What silvertip is indicating is if you used 50 Amp Hours out of your battery, and your outboard's charging system is supplying 6 to 16 Amps (lets use 10) it will take you 5 hours to replace the 50 amps you used (10 Amps x 5 Hours = 50AH). Actually it would take 6 hours, since you need to replace 120% of what you took out...

You have to have over 12v to actually return the power back into the battery...

Remember in Apollo 13, the one guy says "battery 2.. 0 volts, 2 amps" it still had power but not much in the way capacity left. Most batteries, without a load will show approximately 12v, regardless of how dead they are... when you apply a load, that is when the voltage drops to show you how charged they are.

So your current setup will charge at 10Amps (lets say), and if you use your trolling motor, unless you have a long trip home, you likely will not fully recharge your batteries in time... thus the idea of a battery charger onboard, used with your house power, to recharge it is a great idea. If it is only 5 Amps, that is OK, because you will leave it over night, and it will have plenty of hours to re-charge the batteries.