> I believe that a good solar charge controller is needed here, > to properly manage the battery charging and protection.
A great choice would be the Trace C35 Charge Controller. What ever charge controller you have might include low/high voltage disconnects. If not you seriously need to add at least a low voltage disconnect to the system. http://www.newmarpower.com/lowvoltdiscnct/ldv.html Although the Trace C35 is rated to 35 amps typical, I seriously doubt if you would ever get close to its max value ratings. I push them around quite a bit and they take a bit of extra abuse just fine. The difference in the Nemar LVD 12-30 and the 75 amp version is only the internal relay. The LVD 12-30 is just the ticket if you don't have the lvd function built into your charge controller. A bit over-kill... you could even build your own charge controller (with built in lvd). http://www.solorb.com/elect/solarcirc/ccntlvd-orig/index.html People even make & sell pc boards for charge controller projects if you get motivated. > Lose the wind generator, the bridge rectifiers, and the > resistors. I would keep the Wind Generator. If the generator is AC output you need some type of rectification depending on what the output lead connections are. The load resistors are probably not needed with the amount of energy generation you have. Even at or near a full charge you'll never have enough extra energy to go past the charge controller equalization mode. > Connect the 115 watt solar panel directly to the input terminals > of the solar charge controller. Depends on the output voltage of the panel really but the above is a practical location unless you need more panel output and the type of charge controller. Some are only ppt choppers and some have pulse booster circuits. The no free lunch rule applies... > Do not ground either of these wires. Connect the battery > terminals of the solar charge controller directly to the battery. > Do not ground either of these wires. Connect the load terminals > of the solar charge controller directly to the common DC input > terminals of the radios and controller. Ground the negative wire > at the radios- which are already grounded internally and > through the antenna feedline shield. Typical connections for most but not every application. > Batteries intended for solar or wind power applications do > not have CCA (Cold Cranking Amperes) rating; they are always > rated in AH (Ampere Hours). If you are using vehicular wet-cell > batteries, that may be part of the problem, since car batteries > do not do well in deep-cycle applications. Use AGM sealed > lead-acid batteries for solar systems. Large Car/Truck batteries can/do work in some applications and they tend to be a lot cheaper than solar/wind specialized cells. It's also hard to over charge one or more 8D truck batteries as the extra charging energy most always tends to help equailize the system. There are pro's and con's for both choices... > A solar charge controller that is ideal for your system costs > less than what you spent for your large load resistors. You do > not need resistors in a solar power system. Even with additional external sources I/we never seem to have extra charging engergy to divert to a load at any of our solar sites. Batteries seem to love the extra top off when available (regardless of type). My solar site load diverters have never operated except for testing. > A solar charge controller handles voltage regulation > and battery charge control without any external components. If.... they have low/high voltage disconnects built in. Otherwise you had better add one. > Since you have dissimilar solar panels, you first need to > balance their outputs if you want to run them in parallel. > The procedure for doing that is too lengthy to go into here, > but you can use two Schottky diodes in the positive leads only > to safely run two panels in parallel. Schottky diodes have > extremely low forward voltage drop that is almost independent > of current. Check the panel... most of my newer solar panels have the protection diodes built right into the connection point/block. > If the two panels are identical and from the same lot, it is > usually okay to hook them directly in parallel. Depending on location, type and choice... some people op for the higher voltage series or even series-parallel connection (with 4 or more panels typical for the series-parallel connection). It's a combination of the most practical design/operational choices made with good information and the specifics of your resources. > Let me tell you about what I have: > Now when the repeater is turned on, it draws one amp and > in tx it draws about 7 amps. If you don't have the energy capacity to deliver 7 amps for extended tx operation (duty cycle), drop the tx power and you'll learn how little rf it actually takes to make a repeater work well. > For isolation for the panels I have one 85 amp diode on the > plus and negative lines to keep the wind gen from energizing > the panels with up to 41 amps. The panels and the wind system should only deliver energy to the battery bank. The best connection for your wind system depends on it's output and type. We'd need to know more about it to suggest the most practical connection path/method. How many output leads? ... is it a Perm Mag type or do you excite the field(s)? The output is probably "wild ac"? > Now for some reason the panels and the wind gen are not keeping > the two batteries charged. Not sure why. The panels are set for > the winter setting for my location. I was at the site today to > test the batteries, because the repeater was not working. Both > batteries tested at 7.81 volts and the panels tested at 8 volts > at about 4 pm. The sun was almost down. Even though you have mis matched panels it would probably be better to series the connection and use a PPT type charge controller like the trace C35 unit. You don't have much/enough solar energy input and it's not being properly used the best way it could be applied. How you choose to connect the solar panels depends on their no-load voltage and what the most practical average output voltage is based on your location and the time of year. The panel output will drop off pretty fast in anything but bright sunlight. Sometimes the typical chopper charger still wont work well enough with lower single panel or parallel inputs connections. In your case a series panel connection might might be better animal when you are making direct (no charge controller used) connections. > We pulled the one fuse that all the voltage goes thru and I > will go up there tomorrow and check the voltage on the batteries > in sun light. You really need a low voltage disconnect unit... stand alone or built into the charge controller. Until you get your system bugs worked out the lvd would at least keep your batteries from dis- charging down to a bad condition/state. > The current from the batteries can not back feed to the wind > gen due to the bridge rectifiers (the wind gen produces ac). > The wind gen can not back feed to the panels due to the 84 amp > diodes on the positive and negative lines. The two batteries > are not isolated from each other. We would have to see a basic system connection diagram to review the best connection method/path for your application. > On November 18 the batteries tested at 12.79, repeater was > turned on. We took the batteries down to about 11.9 using an > inverter with 110 volt ac test equepment plugged in. On November > 24 the voltage was 11.27. On Novemner 28 the voltage was about > 10 volts. Many lvd units are set to remove system voltage at about 10.5 to 10.8 volts. You really don't want to discharge the battery much below that potential. > I turned the repeater off (tx radio only) remotely. Then you > have all the information I stated above. I will be going up > there today after church. A personal devine recharge... > From what all I have told you, do you see anything why the > two panels a lone should not keep the batteries up? Yeah... off the top of my pointy head I'd say you might be best suited to series connect even the mis matched solar panels, add a ppt type solar charge controller (with lvd). You are not getting nearly as much energy out of the solar panels in the winter sun as you think you are. Since you're running gm300 radios (not the best for solar aps) you might consider removing a lot of the extra controller stuff... or change it out for other options. > The repeater has been turned off since last Tuesday morning. > But yet the batteries are still being drained. In the > turned off mode, I mean the tx radio is turned off, but > everything else is still on. Get out your multi meter and measure how much current is being drawn by all the devices. You might want to replace some of those energy hungry repeater controller/id units. Repeater voice id is also legal. > The last three days have been sunny day here in Yakima, with > no wind for the wind gen. I am at a loss of what is going on; > the batteries are getting weaker. Why? > Rod At night you need to remove the constant current draw when the system voltage goes down below 10.8 volts using a low voltage disconnect. Change the solar panel connections to series (for the moment) and plan/budget for a good charge controller. As configured you probably don't have enough energy input when the solar and wind system is idle. cheers, s.
