Al wrote: "I have a 250 watt UPS that I put Binding Posts on the back so I can add more battery capacity when needed. It uses 12 volts." A warning might be needed here. I agree with your advice on taking out the batteries and using a fan and so forth. But the line above suggests paralleling the internal with external batteries. It isn't advise that wet cells (car batteries for instance) in parallel with gel cells (UPS supply internal batteries) because they don't equalize well due to slightly different cell voltages. Even if the cell chemistry were to give equal voltages, a large change can also be easily caused by different thermal environments, with the hotter battery's terminal voltage dropping, and getting hotter as it adsorbs more charging current. I.e., batteries in parallel should be similar in size, location, charging/ usage history and chemistry, and even then you can have problems without careful attention. Regards, Chas. __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>