At 14:52 -0700 28/4/11, Starlight Solar, Larry Crutcher wrote:
...."Until now"?.....For proper VRLA battery charging, once it is full, you MUST reduce the voltage. It does not matter that you are opportunity charging. What if your turbine is making power 24/7? The voltage will still need to be reduced after a few hours or have a fixed voltage setting. I don't think you are ungrateful but again I encourage you to re-read this thread and the manufacturers instructions. It's all there.
OK thanks for driving that home. My previous message was maybe a bit provocative, trying to get to the key issues. The manufacturers instructions are a bit confusing in places "The charger can maintain the current I1 indefinitely or until the charger is shut off or unplugged. This stage is ideal to maintain battery state of charge...."(Rolls FAQ) The Fullriver instructions offer two methods where the final voltage is either below or above the absorb level. In both methods there are criteria that are unusual for small system charge controllers.
It's not going to be possible to follow these instructions accurately with opportunity charging. For example the initial charge will likely be outwith (below) the specified range of currents. It is unlikely that there will be a shunt to measure current, or a system to monitor dV/dt to determine the transition points between stages in the process. Nothing will be constant (except for a programmable voltage limit, given adequate wind/sun) and there is no assurance that the battery will be fully charged or discharged to any known level.
You state that "Once you have programmed the 2512iX charge controller from the IPN Pro, the controller retains the information and can be installed as a stand-alone unit" However this does not come with a battery shunt that I can see. And it's primarily a MPPT solar controller, with some sort of load control that may or may not be suitable for wind diversion (which can be done with the 'duo' I know). The Tristar offers simple diversion load control suitable for both wind and solar inputs, with a float setting that takes over (by default) after one hour of absorb time. Whist this is not likely to fit the manufacturers curves exactly it does seem likely to do a reasonable job of charging the battery whilst preventing the balloon of gas in your dramatic photo.
I will read the document that you reference (about thermal runaway) carefully. I am sorry if I seem a slow learner. This list is an invaluable resource for the industry. I like to ask naive questions and I get a deeper understanding as a result. Thanks to all.
-- Hugh Piggott Scoraig http://www.scoraigwind.co.uk
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