Charging batteries

[prginocx]

I have a 16ft smokercraft alaskan aluminum. I used to have a 25hp Mercury 2 stroke, and it would charge the batteries.
Now that is sold 'cause my grampa gave me his old (1988 Yammie hardly used) 2 stroke 40 hp.

BUT it doesn't have electric start and thus doesn't have an alternator.
I've looked at the option of getting a 8hp 4 stroke for trolling and battery charging. I like the 2 cyl and low noise smooth running. I don't like the extra weight. What other options do I have for charging batteries while trolling or running w/the 40 ?

 

[tashasdaddy]

Re: Charging batteries

check yammy, it could be as simple as adding a rectifier, or regulator. google, yamaha outboard parts there's a complete parts diagram for you engine.

 

[steelespike]

Re: Charging batteries

As far as charging for normal use I don't think the 8 will put enough out at trolling speed.
If your 25 was maintaining the battery you can most likely just charge at the end of each day.Just run a good deepcycle.A depth finder doesn't use too much nor a regular radio even running lights aren't that much.

 

[tashasdaddy]

Re: Charging batteries

spike you missed it, he sold the 25 electric start, and using manual start 40 yammy, no charge.

 

[steelespike]

Re: Charging batteries

Maybe I wrote it in a confused manner.I understand the 25 is gone ,he wanted to use the 8 to charge while trolling the 40 doesn't charge but in my opinion (because the 25 was able to maintain the battery, apparently light battery use)he could consider forgoing a charging system and simply charge at the end of each days use.With a manual start 40 the battery would have even less use. Maybe save a few bucks.

 

[prginocx]

Re: Charging batteries

Actually for daily use where I return home the battery charge deal isn't an issue. Where I need the charging is on week or longer fishing trips for Bronzebacks on remote lakes. No charging available, so although I use the foot control motor, I do have to run for 15 min or so to get to the location. ( Why is the campsite always far from the good smallie fishing ?)
I have oversized Trojan batteries, and with the 25 and running up and down the reservoir, I could bass fish for like 4 days, and run down two batteries.
My 25 would only supply about 3 amps for charging the battery, but it really helped me avoid running the battery all the way out w/the foot control.

(We are not counting windy days or other variables...)

I'm even looking at towable chargers and such for sailboats....This 40 I'm getting for free is truly pristine, plus my grampa is anal about maintenance.

 

[prginocx]

Re: Charging batteries

I'm taking gramps fishing a bunch of times...and not just to make up for the motor. I catch bigger fish w/him in the boat.
I think he's getting old enough so taking the boat out on his own is a little hairy...

 

[Silvertip]

Re: Charging batteries

How about a small Honda generator, or charging the batteries off the vehicle charging system.

 

[chrismarion]

Re: Charging batteries

Charging your batteries off of your vehicle's charging system is a bad idea. If you were to run your batteries pretty low and one at a time hooked em up to the car ; A) you would have to drive to get a good charge going , B) you would be purchasing a new alternator too.

A car/trucks alternator is not a battery charger, thus trying to make it charge a very low battery will make it strain to supply amperage to it and it will burn out. This I deal with on a daily basis, kind of like going to the bathroom. Its sole purpose is to run your vehicles electrical parts/accessories and while driving it supplies amperage to recharge the battery back up from the starting and whatever else you may have tied directly into the battery. Most alternators charge above 2k rpms.

 

[Silvertip]

Re: Charging batteries

Auto alternators are not a battery charger? Nonsense! Funny how after jump starting a car with a dead battery the alternator does a fine job of charging the battery. There is absolutely no problem charging another battery off an auto alternator. If you are old enough to remember the GM diesels of the late 70's to mid 80's, those alternators charged two paralleled batteries just fine. I owned a bunch of them and they were never a problem. Most newer vehicles have high output alternators (80-100 amps or higher) and they are regulated better than most outboard electrical systems so they will not overcharge the battery. You will also not need to drive many miles to charge the battery. In the absence of no other way -- use the vehicle. Better than nothing.

 

[prginocx]

Re: Charging batteries

I have used the vehicle to charge the batteries, it seemed to work fine, no matter how low they got....BUT...

(And I don't want to hear it from the younger studs on the forum...) These Trojan batteries are large and heavy, I think about 60-80 lbs each...So late in the year when the water level is down, the hike to carry them from the boat up to the truck seems like a long way...I've actually considered a small dolly or hand truck or such...

Of course then we are getting into the Clampett style camping rig, so much **** thrown in it just looks like we are moving !!!


Its funny how batteries work, though. If I use a battery pretty hard during the day (Say 4 hours straight of bass fishing with a little wind), then run the 25 and its 3 amps or so of charge current for an hour so, THEN LET THE BATTERY SIT OVERNIGHT, next day it seems to be almost back to full charge. If you subtract the tiny bit of charging it gets after hard use, next day it is only at about half power or so...You can tell 'cause you have to use a higher setting on the Minnkota speed switch.

Other Deep cycle batteries I've tried (Sears, Interstate, Exide, etc...) didn't even have the moxie for this....Couple years of use and they are done...

 

[steelespike]

Re: Charging batteries

Sounds like under the cercumstances it's a good idea to try to get the 40 set up to charge.A Trojan 30XHS weighs about 64 lbs.I'm a little surprised that one hr. at 3 amps helps much.It takes about 8 hrs to recharge after 4 hrs of use.I supose you could charge with the 8 hp at the dock.But it would be more sensible to charge as you move with the 40.

 

[chrismarion]

Re: Charging batteries

Silvertip,
those older alternators are far better than todays. Which is why stereo competitors in the db class use the older alternators off of the diesels and ambulance because of the load they can handle.
Jumpstarting a car, alternator slowly charging the battery is normal. But if you battery keeps running dead and you repeat process it will ultimately kill your alternator. Putting a big load on your alternator all the time will burn it out and could also cause the cables to heat up and burn.

I am not saying you cant do it in an emergency situation. I am saying you cannot do it repeatedly like it is a battery charger. That is not the function of an alternator.

 

[chrismarion]

Re: Charging batteries

Not starting an argument, but I googled this scenario and found an article to better explain what I am trying to say. I am simply trying to inform people why alternators will fail when connected to very low batteries and what we are discussing :

"A common statistic used to rate an alternator is its maximum output amperage at a set standard RPM. In most cases, the unit profile sheet will show a higher output rating. This is one of those extra benefits derived by using components that are capable of higher output while maintaining a guaranteed continuous 100 amp output rating. However, this is only half the story.

Relying solely on advertised full amperage output of an alternator is a common mistake as manufacturers fail to tell you the true RPM at which this maximum output occurs. Most people would be disappointed to hear that at idle many alternators fail to output enough amperage to handle the vehicle's current demands. Think about this the next time you are cruising at low RPM or parked idling with the A/C, radio, lights and electric fan on. You may be draining power from the battery because the alternator output at idle and low RPM is another important stastic included on the unit's profile sheet. With the engine idling and no load on the charging system (lights and all accessories off, battery fully charged), the amperage output should be relatively low (typically less than 10 amps). Also, test and recharge the battery before the alternator is installed. The alternator is designed to maintain battery charge, not to recharge a dead battery. Forcing it to revive a dead battery can overload it and cause it to fail"

 

[Frank Acampora]

Re: Charging batteries

Just something to think about: How much of a load do you think the a/c unit on high or medium fan causes? You have the a/c clutch unit, the blower, the electric radiator fan, the radio and cd player, running lights, etc. That won't kill the alternator under the warranty period. The factory must know something. And if you do fry the alternator by charging batteries buy the police or taxi option--Generally quite a bit higher output.

Anyway, Yammy must have made an electric start option. See if you can find a used alternator and charging system and retrofit. Shouldn't be too difficult.

My intertech manual shows Yammy 30, 40, 50 with an electronic ignition and a "lighting" coil."

 

[chrismarion]

Re: Charging batteries

Your jumping ahead of yourself, you arent doing all those with a dead battery. That load you gave is about 65 amps. And not every vehicle has an 85+ amp alternator. And yes they do fail under the warranty period. Work at a dealer service department? I put my 8 years in already. Newer parts are being made cheaper and are junk.
The diesel scenario, every one has dual batteries. They also have either A) a massive alternator or B) dual alternators. They have to have this due to the amperage the glow plugs draw, injectors and injector pump. Otherwise it will not run. Initial startup alone with only glow plugs and starter operating will almost drain about 80% of one battery if there are not two inline.

If you are out where there is no electricity to use for a few days, why not by a small generator? Would be worth it to charge the batteries and have a power source available. Pretty reasonable ones are around $250-$300 and may come in handy later! Especially if you lived in FL!

 

[Silvertip]

Re: Charging batteries

This thread is getting way out of hand. Chris -- the alternator profile data you posted is correct and applies to any generator/alternator but means absolutely nothing in this discussion. It deals with "maximum alternator output" and "rated alternator output". Look at any portable generator at your local farm/hardware store and it too has two ratings: One "surge" rating for starting heavy loads like electric motors. It also has a "continuous" meaning that generator is capable of running at that capacity full-time. Using your logic, you should never use that generator at even its "rated" output as it will fail. Will it fail sooner running at its "rated" output vs "half" its load? Certainly it will. Will your engine fail sooner running wide open than it will at half throttle -- certainly it will. That's the way things are. Vehicle alternators are rated the same way. Current vehicle alternators are being taxed by the every increasing demands being placed on them, and the ever increasing pressure on auto manufacturers to increase fuel economy. Engine driven accessories take power and the alternator is obviously a big load so every attempt is made to reduce its weight yet maintain high output. Because the 12V system has reached its limit, auto makers are looking at 24, 36 and even higher voltage electrical systems. The fact is, you will not damage an alternator by periodically charging a deeply discharged battery at idle speed. If the alternator can't handle a 10 - 20 or 30A load (whatever its idle output is) it certainly won't last long supplying the vehicle electrical load either.

 

[chrismarion]

Re: Charging batteries

I agree, I stated it couldnt be done repeatedly. If 'prginocx' is out in the woods for 4-5 days at times and he runs his batteries down like he says he might everyday; then this would constitute repeatedly. Periodically or in emergency cases would suffice.

The generator suggestion was for him to run it with a battery charger on it. Maybe even power a tv at the same time. That is a good suggestion to me for this problem.

 

[crb478]

Re: Charging batteries

I have a 16ft smokercraft alaskan aluminum. I used to have a 25hp Mercury 2 stroke, and it would charge the batteries.
Now that is sold 'cause my grampa gave me his old (1988 Yammie hardly used) 2 stroke 40 hp.

BUT it doesn't have electric start and thus doesn't have an alternator.
I've looked at the option of getting a 8hp 4 stroke for trolling and battery charging. I like the 2 cyl and low noise smooth running. I don't like the extra weight. What other options do I have for charging batteries while trolling or running w/the 40 ?

 

[crb478]

Re: Charging batteries

It might be chaeper and easier to use a solar power battery charger. There are some that are water proof and you can usually get one for under 40.00