Adding a trolling-batt charger to my boat???

[jwhite]

Mike, that is some very good info there.

Too bad the dealer wasn't able to expand on the reason why he can't achieve this.

[1MoreCast]

I checked my specs on the merc 60 -Alternator 18-Amp, honda 40 Alternator 10-Amp. So I guess DC charging is out of the question .
Thanks for the heads up.

More money now for a good AC charger.

[eye-tracker]

I gotta step in here and ask one very important question.. .

What is the potential of this motors charging system??????

Mike has a point, I did not notice it was a 40 HP engine. With a small alternator you may have difficulty charging a deep cycle battery if it could even handle it with out running around all day.

Contact Honda and ask how 40hp off-shore tenders are rigged with multi battery systems. You can also contact the engineers at Blue Sea Systems at 1.360.738.8230 or by email at conductor@bluesea.com

I am sure you will get some answers to your questions.

-sheldon

[Hookup]

Thanks to all for the help and advise... I have a lot of research that I can do from this point... again, thanks a load... I can now go and research and get my self edumackated...

[miker]

I can only speak for the product that I know of, so here it goes:

<i>If the charging system only puts out 20 amps and the trolling motor wants 10amps and the start battery wants 20amps, what is going to melt?????? </i>

the charging system will only charge one battery at a time. and it will always favour charging the starter battery (always keeps it at 100%). Once the starter battery is charged, it will send what ever amps are being kicked out by the alternator to the trolling motor battery. whether that is 1amp, or 40 amps, it will send that to the battery being charged.

To me at least, it does not matter how many amps are being generated..the more amps there are, the quicker the battery will charge. it's like a solar system at a cottage. if all panels are working full bore, then there might be 5 amps being sent to the bank of batteries, while only 3 amps are being drawn out (because there are a few lights on in the cottage lets say). So in this case, there is a net charge going into the bank of batteries, and hence are being charged up.

now if one of those panels fails, or is in the shade or something..and only 2 amps are being generated..then there will be a net loss of power from the batteries.

all that to say, from what I understand at least...the only difference between a larger motor and a smaller motor charging the deep cycle battery will be the amount of time it will take to fully charge.

and again, to me at least...it seems to make sense that the motor is already charging the starter battery, so it should be able to charge the deep cycle once the starter is at 100%.

[mikemicropterus]

OK I didn't want to make this public but here goes.....


How does one PROPERLY charge a deep cycle battery??? and that is the issue not whether his system could do it.......it can't.......keep it charged properly.......

Now lets go back a few posts as this subject has been flogged like a dead horse......

You are not going to charge a deep cycle battery PROPERLY with any amperage that is not regulated to control it's output as the battery reaches it fully charged state....A deep cycle battery charger floats the amperage and decreases it's amperage from 10 amps to 1 amp as the battrey reaches full charge....his charging system does not......what happens to the battrey if it gets more amps than it needs, IT OVERHEATS and can warp
the plates thus shorting out a cell.......and making the battery useless...

Now I don't really care if a neophyte advises him to do this as I sell batteries and if he shorts one out from improper charging .....KAACHING.....

However my reasons are not monetary but safety related.....I don't want to see the customer melt the charging system and get stranded on the lake with no power.....anyone think of that......and who, from the respondants, has done the same in their own boats. Sheldon is not the same scenario....... .

This is physics guys not conjecture......


If you use a deep cycle battery for 3 hrs it will take 3 hrs to fully charge it with a deep cycle battery charger, I've been charging deep cycles for 20 plus years and this still hasn't changed.....

....I have seen this many times with dead starting batteries, the guys boosts it to start it and then drives around the lake to try and charge the battery only to see smoke come out from under the hood.....I have seen motors start on fire from doing this....hope you have insurance...and can swim to shore when the boat catches on fire....there the reason for a fire extinguisher......

This and most charging systems output increases with RPM, the more RPM the more output. His charging system puts out 10 amps at 3500 rpm.......So lets do the math........2 amps idle.....he uses the deep cycle for 3 hrs..... and starts the motors 6 times....the lake is 20 miles long......it takes him 30 minutes to get from one end to then other at WOT or 5000 rpm......So he would have top run around the lake at WOT for 3 hours to replenish the battery,,,, heaven forbide he use the livewell, fish graph, bilge pump, navigation lights or even a radio/tape deck, certainly not the tape deck......or does he have gps on his boat and 2 year old deep cycles that are only 80% good at this stage......NO one asked those questions.....DOESN'T THIS MATTER. Of course it does but no one asked those questions.....

This is not a cottage and these are not solar panels which have a $3000 controller to PROPERLY charge the batteries......because of erractic output from the panels....... and the cottage has about 20 or more batteries hooked in parallel to have enough capacity to handle all the load that is put on the system....

So the answers that say it can do it don't take into account the time it will take to PROPERLY charge the batteries and if the guy wants to go fisihng all day and NOT CHARGE HIS BATTERIES and if he stops and starts the motor constantly during the day his charging system will be busy charging the starting battrey and not the deep cylce.....

This is not a right fight for me but I just don't like to seeing some advise that was not completely thought out.....And Sheldon seems to understand that......... no offense miker but what you have is just a battery isolater with a fancy name,, I have put lots in boats with big alternators and they work fine IF you are runnig long distances to get the batteries fully charged......the advert gives not claims or perfomance specs just hype......and this isolater only works properly with fully charged battreries to start with......Like I said if he is constantly going from spot to spot it will only charge the staring battery...What is it's output as the battery voltage increases in the deep cycle and the charging system is at WOT?????? where does the residual voltage go????? Heatsink,,, I read the reviews and there was 4 for and 1 against.......But my question is this , What is the max output of the motor attached to the module???????and that is what the limiting factors are...If he had a 150hp I wouldn't have an issue with this device nor recommending it but it's not and that is my point.......compare apples to apples not oranges.....

That is all I have to say on this

[miker]

<I> no offense miker but what you have is just a battery isolater with a fancy name</I>

no offense taken at all

as always, that is great explanation. thanks for the info!!

[Rhodes]

Now that sheldons questions is answered I have one of my own, regarding batterys and charging . mikemicropterus you seem to have quite a vast amount of knowledge, so any help you can offer would be greatly appreciated

I have an 20 aluminum boat out fitter with a 200hp etec i am not 100% on the amperage from the motor but....

I have two batterys one cranking one deep cycle , also have the big red battery swtich made by perko i beleive. my plan is to select my cranking battery to start my motor, once running i will switch the selector over to my deep cycle battery and troll , running as many things as - fish finder, live wells, down riggers stereo systems , depth troll vhf .. ect basically anything you would normally run. will i have an issue with running too much off of one battery, and do you think the motor can keep up with the demand ?

anything you offer in means of direction or education is greatly appreciated

Rhodes

[mikemicropterus]

I PM'd you but in this case you can and should use an isolator...

[Hookup]

So, well as much as I do not like the result, I like the honest answer... I'm glad it's not engine specific, or anything along those lines, but simply a factor of the engine is too-small to effectively charge two batteries..

Again, disapointed, but educated... /sigh...

Thanks very much for investing the time for the info everybody... really, this was helpful to me.