BATTERY CHARGING ADVICE ??

[raysbigfish]

I have twin outboard motors. the question is what, onboard charger do I need if any. On over night trips, when the engins are not running, and the bait tank is on , lights, TV,stereo,etc... will my batteries die. please help.

 

[DaleH]

Confused ... if on an 'offshore' overnight, no on-board charger could work unless you have a generator installed.

How are your batteries configured now? Do you have 2 batteries per motor? Each motor with a 1-Both-2-Off switch? Also note that most OBs don't require much Cold Cranking Amps (CCA), whereas the peak amperage on a V6 starter when cranking is ~225 amps. Do note however, that some new technology OBs require greater than 10-11 volts upon starting of the computer brain (ECU) won’t even come to life.

Most starting batteries, even typical dual-purpose starting/deep cycle batteries have specifications similar to:

Group 24 - Cranking 500 CCA – Capacity 70-80 Amp Hours (see Capacity below)
Group 27 - Cranking 600 CCA – Capacity 95-105 Amp Hours (see Capacity below)

I’d first determine your MAXIMUM worst-case amp load, getting the amperage for all things turned on. If anything, like spreader lights, are listed in watts, divide the wattage by 12.6 to get the amp draw. See ‘just how many’ amps you might be pulling overtime.

If I were you with those demands, without a generator aboard, I’d run two G27 dual-purpose brand name (Interstate or Excide [wet] or Optima [gel], etc.) batteries per motor and would run OUT fishing with the battery switch on BOTH, but would IMMEDIATELY flip the switch to battery position #1 or #2 once you are at your destination. I use #1 for odd days of the week and #2 for even days of the week, as this ensures I am 'balancing' the use of the batteries over the season.

This method will also charge and top off both batteries on the way out, but * * * CAUTION * * * if you leave the switch in BOTH with the motors turned off – you run the risk of equalizing both batteries. So if one was ‘hot’ and the other almost ‘dead’ … you will likely now have two pretty much used-up batteries that may or may not start the motor. Only in a case of severe emergency when either battery position #1 or #2 alone will not start the OB, should you flip the switch to BOTH ... IMHO.

Battery Capacity: See this link here
Battery capacity is measured in ampere-hours (amp-hours). In rough terms, a 100 amp-hour battery can give out 1 amp for 100 hours, or 100 amps for one hour, or 20 amps for 5 hours. However, see the first item below -- you would actually never want to use the entire capacity before recharging.

Maximum Battery Life:
Never use more than half your battery capacity without recharging. If you use 75 to 80% of your capacity without recharging, your batteries WILL be damaged, even if they are "deep-cycle" type batteries. If possible, try to not use any more than 20% of your battery bank's capacity. If your capacity is 1000 amp-hours, start your back-up generator when the meter shows (-)200 amp-hours (or 80% of capacity remaining).

Great topic! I’ve only touched on it here. Hope this helps some.

 

[Megabyte]

I have twin outboard motors. the question is what, onboard charger do I need if any. On over night trips, when the engins are not running, and the bait tank is on , lights, TV,stereo,etc... will my batteries die. please help.

Of the items you noted, the livewell and TV will probably be your largest draw items.

There are a couple of things you can do to extend your time on the hook...

You can limit your current draw by powering off selected items that aren't absolutely needed.
You could also reduce your draw by replacing as many of your incandescent lighting as possible with LED's.

Another solution might be to run each of your motors at idle for a paticular time period, say 2 hours at a time, to keep power up in your batteries.

In addition to upgrading your electrical system, minimizing your draw and conserving, along with running one motor will most probably get you through the night without incident.

If you want further peace-of-mind, buy a portable jump-start battery. :wink:

Good luck!

 

[DaleH]

Good tips there Capt Kevin that really help out the 'total' battery use/capacity issue!

LEDs rock! ... and I don't mean LED Zepplin, though clearly they rock too!

 

[cbigma]

If you want further peace-of-mind, buy a portable jump-start battery. :wink:

Kinda like a portable Defibrillator for your OB! :shock: :shock:

Where do you keep the little Bunny with the Drum? :roll: :roll:

 

[Porkchunker]

Being Old Army, we always ran our vehicles at night for 10 minutes out of each hour. Those RT-524 VHF radios really consumed battery juice and would leave you with a dead vehicle if you didn't have some good crew drill. It was a UCMJ offense to kill your vehicle and not be able to "jump" at O-Dark-Thirty...so we learned to do it right. :shock: :shock: :shock:

I do the same with the Diamond when I overnight. Although there it is usually 30 minutes each 3 hour block. That way, I get a bit of sleep. No one ever expected you to sleep in the Army while in the field...but I enjoy my shut-eye now that I'm retired.

 

[andertonm]

Be aware that commercially available jump start boxes will not start your boat, car, etc if the battery is completely dead. The safety nazis have made them put in a device that prevents you from turning the box into an unintentional arc welder. The professional high current boxes don't have this handicap, but they're expensive. The cheaper jump boxes sold at places like West Marine can be modified to bypass the safety rig, but it's a pain. Try to use one as a 12V power supply - nothing comes out!