Micro hydro-electric generator help

[BobK]

Given that we know the generator you have linked to will not provide sufficient output to do any harm, I can tell you how to wire it. Wire the + output of the generator to the + battery terminal. Wire the ground or - output of the generator to the - battery terminal. Done. It may put a tiny charge on the battery. It will never get up to full charge because it requires more than 12V to do that, but then it will also never get up to full charge because the power source is insufficient. If you are lucky, maybe 10 hours of charging will give you one hour of run time.

I am serious. This is how you can charge a battery from a source that does not put out enough power to charge the battery in a reasonable time. This is how the solar garden lights that you see everywhere work.

Bob

 

[hevans1944]

It genuinely makes me sad that I won't even have the chance to try. I was a combat engineer in the US Army, and the engineer motto is "Essayons," "Let us try."

Thank you for your service. My family also served, and some of us continue to serve today. I have the utmost respect for our military, who put themselves in harms way to help preserve our freedom and our nation's sovereignty.

A combat engineer, as a trained infantry, is right up there along the side of non-combatant medics in their selfless dedication to getting the job done on the battlefield. But, and this is a huge BUT, no engineer blindly says "Let us try" without at least obtaining some of the education, experience, and training necessary for success.

You did have a chance to try. It is too bad and so sad that your lame attempt was done without the requisite research to see if your approach was even possible, much less practical. That is not engineering.

With regard to my agenda, all I wanted was 2-3 minutes of someone's time to sketch out a wiring diagram. I'd be happy to discuss a wide variety of possible solutions, when I'm not pressed for time. If you can design a wiring diagram for this, then why deliberately withhold the information? How does keeping information from someone seeking knowledge help them to learn?

Early on, in post #15, @Tha fios agaibh posted a schematic. It used a 3-terminal voltage regulator, PB137, designed to charge a 12 V lead-acid battery chemistry (such as a sealed gel-cell or SLA - sealed lead-acid battery). His wiring diagram is essentially the same as the diagram (Figure 3. Application Circuit) shown on the datasheet. His diagram shows your water turbine generator providing input voltage to a PB137 regulator, an ammeter to measure the current delivered to a 12 V battery, and a pair of capacitors to "smooth" the brush noise no-doubt created by the generator. The input capacitor is 0.1 μF rated at 50 VDC. The output capacitor is 10 μF rated at 25 VDC and this would typically be a polarized aluminum electrolytic. I doubt you even bothered to investigate any of this, but it is the minimum circuit you would need to charge a lead-acid battery while manually monitoring the charging rate by observing the ammeter reading.

Unfortunately, the wiring diagrams do not work for you because both depend on the output voltage and current you can obtain by trolling your water turbine behind or beside you in a boat. You will find that both the voltage and current available are woefully inadequate, but go ahead and try. Continue to ignore our advice and that of Master Yoda: "There is no TRY. There is only DO." The try may make you feel better and will not seriously inconvenience any fish.

As for withholding information... it is you that did this from the beginning, not us. You didn't even bother to mention what water turbine generator you were considering using until post #28! What information do you think has been withheld by respondents to your original post? What have you done to learn about the problem and possible solutions to that problem? If you have a deadline to meet, it is your problem that you did not perform the research necessary to meet that deadline.

 

[Tha fios agaibh]

I didn't see and answer to my earlier question:
Did you call the outfitter and ask if they can supply a boat with a marine battery?
(Surely some boats have an electrical system to supply the required running lights at night)

With your time constraints you probably can't fab up something on your own, but you might consider the crank dynamo I linked to.
Perhaps not fun cranking until your arms are about to fall off while your buddies are sitting around the camp fire drinking Labatts.

Or, consider Dave's solar panel option back on dry land and use the fish finder every other day?

 

[BobK]

I think he has "gone fishing."

Bob

 

[GHamblin]

I’m new to the forum, and very inexperienced in the field of electrical engineering (wishing I chose electrical engineering over biology). I am going on a wilderness fishing trip in northern Canada, and would like to take my fish finder/GPS. The problem is it pulls 1.41 amps (maximum brightness, etc.), and due to weight restrictions, I can only take 2 8 amp-hour batteries along. There is no electricity where I’m going, and I need a way to charge them. I have a small solar panel, but at peak efficiency (and no resistance loss) it would still charge too slowly to be of use. I’ve come up with the idea of a small hydro-electric generator that can be towed along/beside the boat instead. The only generators I’ve found that are suitable (and not outrageously expensive or heavy), produce 10 watts of power, but vary between 10v and 80v with the flow of water through the turbine. What parts would I need to assemble to be able to charge an 8 amp-hour 12v lead acid battery using this generator? I can work out the towing/generating assembly, but don’t know where to begin in the electronics department besides including a blocking diode. Also, would a second inline generator increase the charge rate when wired in parallel? or would it provide too much current and damage the battery? Any help will be much appreciated!

With a 10W generator delivering about 3/4 Amp you'll need around 10.5 hours with the boat in motion to charge your 8AH battery. I don't know how practical that will end up being.