This forum is great, thanks to all for your input. Big question. 1981 H-30. When I purchased this boat I reviewed all paper work, (all invoices, sales slip, kept by the two previous owners. I noticed that in the last few years the batteries were replaced almost yearly. After I purchased the boat, which had new AGM (2) batteries, I noticed I could not keep them charged. After about 2 weeks, the batteries would continue to lose voltage. I could stop the lost voltage by disconnecting the ground to the engine. Today, we found that there is a 50 MA drain from the alternator outlet lead to ground! The boat has a Zap-Stop attachment on the alternator and it also has a battery isolator. When the alternator lead is disconnected at the isolator, the voltage leak stops. Any Ideas?