another c40 question

[greenkarson]

Installed my c40 controller with digital display this weekend. installed in charge control mode not as a diverson load contoller. c40 can handle up to 125vdc open load so this is more than enough for this time of year when the creek is running slow.  For those of you not fimilliar with my project its a 24v 100watt aquair turbine with c40 charge controller,1500watt inverter charging 2 255amp hour batteries wired for 24v.

  now for my question. creek was running a little faster according to screen on c40 turbine was putting out 1.2 amps then droped down to 1 amp as creek slowed down but as soon as it went below 1 amp c40 displayed 0.00 amps but i know the turbine was putting out about .4 or .5 amps. so i was just wondering if anybody was fimilair with c40s? do they not display below 1 amp? or is .5 amps not enough to charge my batteries?

any info you can provide will be appreciated

[electronbaby]

Save yourself a lot of headache, (and efficiency) and connect the turbine directly to the batteries. Then use the controller in diversion control mode. You will capture more energy this way.

[richhagen]

I have two C-40's used on solar setups as charge controllers, and I would second Roy's assessment. For alternator inputs I would almost be surprised if the impure DC played havoc on the C-40's charging alogrithms.  

Mine don't agree with each other on voltage, and they only have a .4 volt resolution.  The amp resolution must start at 1 amp as I don't ever recall seeing anything between zero and one.  I have specifically observed that the bank was charging even when the C40 meter read zero Amps.  I have a shunt in series with it and an analog amp meter, which I like much better.  Aside from the Amp hour meter function, which is why mine are still connected, but which I doubt is extremely precise, I much prefer my old fashioned analog guages.  

One additional note is that I had used one of my C-40's as a diversion load in the past and found that it was slow to respond when using a larger diversion load with a smaller battery bank,  allowing the bank to discharge more than I intended.  This was a 48V bank with an actual capacity of about 50 Amp hours and a 900 Watt diversion load.  From what I have read of others experiences, this appears to not be a unique result.  I suspect that the diversion load alogrithm behaves more acceptably for larger battery banks relative to the diversion load size.  Rich

[tanner0441]

Hi

I have two solar controlers both of different manufacture (not C40) they don't agree with each other, and the instruction booklet for one of them states the current reading is only arbitary. The voltage readings are correct so I can't see why they cant sample the voltage across the shunt and display it accurately, especialy as it is a digital display.

If I want to acurately know what's hapening I have a couple of anelog ammeters one 5A the other 15A full scale, it's easy enough to lift a wire and drop them into the panel, or battery line.

Brian

[ghurd]

"For alternator inputs I would almost be surprised if the impure DC played havoc on the C-40's charging algorithms."

I expect that is a typo, and intended to read the opposite?

G-

[richhagen]

Hmm, bad Anglish I guess.  What I was trying to say was that since he is charging from a hydro setup, the instability of the rectified DC he is feeding into the C40 might be affecting the function of the unit, I don't know for sure, as I've only fed mine solar generated DC.  Rich

[Yyrkoon]

We have 2 c60's, and a c40. None of them equalize, hit max charge, or do anything for that matter at the same time. We set them all up as per the manual, and turned the voltage pot until output was at the recommended voltage too. Our problem is; We can not use just a single one of these controllers because our solar output is too much, and we have three sets of different panels. SO for now, we're stuck with what we have.