Engine Charging Capacity (87 Evinrude 140hp)

[compcrasher86]

Ive been wondering this for a while... I have a Evinrude 140hp V4 from '87. Shes in great shape and is attached to my 22-2. I have a single battery mounted aft on starboard next to my anchor light slightly under the gunwale in a battery case. I was going to move it to the console for preventative maintenance but it doesnt seem like a big issue for now.

Anyways, I am curious how much charging power my ol motor is giving off. I have a bilge pump, gauges, nav and anchor lights, gunwale lights, and an AM/FM stereo and I do not notice any battery depletion issues but I want to know how much more I can draw before I exceed what the engine is charging.

I imagine my stereo uses around 7 or 8 Amps max (its internally fused at 10) and my lights probably use an amp or two combined. (They're all LEDs) The bilge pump is usually never on so I won't consider it. I would like to add an built-in VHF and maybe a halogen spotlight in the front.

[compcrasher86]

Thank you to Captain bob, I now know that it has a charging capacity of 9 amps. I guess I really am never using more than 5 amps continuously at a time. I usually have my stereo on low volume (4'ish amps) and since my lights are LED that equals out to be like 4 or 5 total. Guess I'll forget about those halogen lights, their probably 5 or 10 amps alone. Maybe some more lighting, a vhf, and maybe a gps. Anybody know how many amps an average Garmin GPS uses?

[Capt. Bob]

maybe a gps. Anybody know how many amps an average Garmin GPS uses?

My old 180 Garmin consumes 10 watts so that's less than 1 amp (if I remember Ohm's Law). You could go with a hand held (that would be 0 amps)
On the older outboards, you just need to keep that battery charged when not in use. You could also go to a second battery as a back up.

I thought that there was aftermarket stuff that allowed a higher charging capacity that would fit outboards but....
Maybe someone here knows.

[compcrasher86]

Yea second battery is a must, but If I am getting two batteries, I am going to have to move them to the console which = new battery cable and automatic charging relay = $$ and new connectors and terminal blocks, etc etc. I would rather put that money towards a new gelcoat.

[GoneFission]

Your stereo will draw about 1 amp, unless you have installed a big amp and subwoofer.   :twisted:   Then, as the EPA says, you mileage may vary...     The 10 amp fuse is overkill, and has to also handle higher transient loads - not just the average RMS watt load.  

You should be OK with what you have planned.  The most power would come from the 55 watt (4.5 amp) spot on the front, but you will not run that very much, so it's not a big deal...  

See ya on the water!

[RickK]

You really want those batteries under the console anyway.  Balance the boat out better by shifting that weight forward.

[compcrasher86]

wow I never knew how much leeway I had   My stereo has a removable fuse on the back and it came with a 10 amper already in it so thats what I'll fuse it at. I am not using any amps or subs so I guess I have some extra amperage to take advantage of!

Before I treat myself to any new electronics, I will move the battery to the console. Maybe that will happen over the winter, I hope

[DOCREED]

You can exceed the charging capacity of the OB.  You just cant do it for a long time.

When i am trolling at idle speed with the radar, GPS, autopilot, live well pumps and the stereo on---I am using way more amps than the starboard OB is producing.  However,  That battery bank consists of two 6v high capacity batteries.  If it isnt completely re-charged by the time I get back in,  A short time with the charger at home brings that bank back up.

You can overcome the small charging ability by adding amp capacity, But you will have to run longer to fully charge the batteries or use an external charger to make up the difference.

Here in Florida, sailors cant seem to understand why they cant run an A/C unit all night on an inverter.

The problem is they will pull a huge amp draw at 12v and try to charge the battery bank with a tiny alternator.  It just doesnt work.

You can do it however with what you are using.

You can add a battery switch for not a lot of money that will allow you to parallel the batterys when running and separate when the engine is off---YOU have to remember to use the switch--thats the weak part of this plan.

thats my 2 cents.

[MarshMarlowe196]

Another added benefit that I haven't seen mentioned yet concerning the location of the batteries:

If you put the battery(ies) closer to the starboard side underneath your console, it will help offset the tilt caused by the rotation of the prop as well.  It's all around win-win to have the batteries under the console.  

What's an automatic charging relay?  I run two batteries in my 19-6.  One's a cranking battery that I have everything else hooked up to (GPS, Sonar, Lights, Bilge Pumps, etc) and one's a deep cycle that is STRICTLY for the trolling motor and the 12V plug I use for the spotlight.  I keep a set of cheap jumper cables on board in case I have to double them up, or when I need to charge them, I slowly charge them hooked up together.

A nice little feature that seems to come standard on all SONAR/Depth Finders is a battery alarm that goes off once the battery it's hooked to drops below a voltage you select.  I have mine set to go off @ 11.5 volts, that way I can just crank the motor and let it run for a while, then everything is fine.

I sell industrial supplies (including electrical) so I can get you a VERY good deal on things like wire/connectors/fuses/etc.  I can even ship it to you.  8)

[bdtsr]

Your LED lights will use less than an amp total.
Your stereo cranked up some maybe 5 amps.
GPS with backlight on 1.5 amps or so.
VHF radio while listening about 1 amp, transmitting at 25 watts (only one brand, Icom, have I EVER had come out of the box at 25w) 6-8 amps. Most are 18-22 watts. You'd be surprised what some can be cranked up to!
The 9 amp charging capacity of these motors is a pain. On my 115 Evinrude I ran 3 batteries, 1 for electronics and 2 for start, bilge and running lights. I did run up to 35 miles off shore with the boat in question. 2 starting batteries was a must. I always had a battery tender on them at home to keep them hot this way the motor did not have to charge low batteries. Of course I could rope start my 115 too. Can't do that with my 225!

[No Class]

When I first got my 1968 22-2 Flatback 25 years ago, it had a single battery on the stbd side at the transom. This just didn't make sense since water collected there & it was in the way. The first thing I did was to add a second battery. Both fit neatly under the console. The expense- a battery switch & some heavy duty battery cable. The benefits - always having a second battery to come home on as well as balancing the load forward & amidships.

[compcrasher86]

If I am going for a second battery, I have decided I want the Blue Seas System Add-A-Battery package which includes a switch AND an automatic charging relay that will combine both batteries for charging when the engine is on and isolate them when the engine is off. There will be one deep cycle house battery and a starting battery for the engine. Winter is here and boat is in the yard. Cold weather makes going out and doing electrical a pain so its off until the spring