NAUTICAL SKILLS/ Decisions, Decisions, Decisions
By Hans Nickstadt
There are two fire hydrants standing a distance apart but in plain view of each other. Ignored by passer-byes for centuries. Here comes a dog, he sees the two hydrants and his easy going lifestyle comes to a screeching halt. Now he has to make a decision.
The decisions I am talking about don’t carry such drastic consequences. Many of
you might have already made the decision, so I will talk about your wallet, the contents in it and how much remains in it after you made the decision. The first boater I am talking about is called the deep cycler. When you look into a West Marine catalog you see that flooded acid batteries have a life span of 200 cycles, AGM batteries about 300 cycles. It also describes, that with every cycle, you destroy part of the battery’s ability to store power, so after 100 cycles the battery can only store half the charge. That requires that you have to charge the batteries more often. After 200 cycles the battery is virtually useless. A cycler really doesn’t need a volt meter. When nothing works any more, he knows the batteries need a charge, so he starts his main propulsion engine equipped with a Balmar 190 AMP alternator; he paid 1500 Dollars for it. That puts a fast surface charge into the batteries. He knows, in order not to ruin his engine, he has to put it in gear to put a load on it. How much load, that is the question? I would say 1800 to 2000 RPM would be alright on a dock but at anchor, that would pull your chain lead anchor right out of the mud and bury your steel cable anchor beyond recovery.
During a cruise on Chesapeake Bay, my friend could not start his engine. According to the high starter speed, the mechanic from the marina suspected low compression. After the compression test came the verdict, the engine has to come apart to see whether it can be repaired or has to be replaced. This is a very uncomfortable situation. Your trusted mechanic is not at hand and you might have to deal with a happy bill writing marina owner. On top of it, your first mate with her never exhausting effort for comfort says:” I will go and get you a knife that you can sharpen the pencil to write that 5 figure check. As it turned out he got a phone call that the engine could be repaired, so he only had to pay a 4 figure amount. I did this job hundreds of times and later supervised the mechanics. In automotive we call this a motor job. I still have all the tools, a ridge reamer, a snap gage set and micrometers to measure the worn cylinder walls. If it is under ten thousand of an inch new piston rings will work, otherwise the cylinders have to be rebored or resleeved. I also have all the ball glaze breakers to put grooves in the cylinder walls to carry the lubricating oil.
“I don’t understand why this happened” my friend said “I always put a load on the engine when I charge the batteries.” Obviously the load was not high enough.
There is a way to avoid all this trouble when you become a volt watcher that means you never deep cycle your batteries you discharge them only 50% that would show on the volt meter 12.25 volts. For that reason you need a digital voltmeter and since you are only using half the capacity of the battery bank, you would have to enlarge it. If you have a “smart” charger it probably has 3 outputs. Instead of the starting battery connect another house battery in its place. That increases the battery capacity by 50%. Assuming that you keep the voltage above 12.25 volts you would never need a starting battery. Like a spare tire, it is a good idea to have a little battery with jumper cables on board. If you would like to have the battery permanently installed in the system, it is easy to do. I just replaced my little battery in my boat because of age. I found one on the internet for $ 65.00 all inclusive. It is an AGM battery group U1. Since it doesn’t need a box, it is easy to install with a heavy duty “on-off” switch in line from Harbor Fright. That little battery has 32 amp hours; I started a Jeep engine with my 7 year old battery. An AGM battery has little internal discharge, ideal for this application, but you have to check the voltage occasionally. A battery in storage needs more than 12.4 volts. A chart, copied from a magazine shows 12.66 volts as a 100% charge. Now that is debatable. That is the point where the charging rate rapidity tapers off. It is not feasible to keep on charging at a rate of 2 to 4 AMPs , unless you use solar panels or a wind generator. A fully charged battery can show 13+ volts (it did after motoring to Ocracoke). I charge my 4 batteries with a little Honda generator and a Ferro resonant charger (which has adjustable voltage ) at 40 AMP. If you work in the upper 50% of your battery capacity, that is a range of 0.5 volts. You don’t need that 1,500.00 dollar alternator, your original 40 AMP alternator will do.
This entire decision making can be avoided. Throw out the refrigeration and buy the ice.
I know somebody who did that.
About the author
Hans Nickstadt is a Lifetime Member of the NSA. He lives in Oriental and single-hands his 29.5-foot Seidelmann.