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Join Date: Apr 2006
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Re: Batteries and charger ideas?
You have two, 12v 75AH batteries, yes? That's a total of 12V 150AH.
And you plan to buy two 6V 230AH batteries, which would give you 12V 230AH, a good 50%more AH than what you have.
What you need to do before you even look at that, is spend some time with a pencil working up your actual energy budget. Every device that you will use has a power rating, in watts or amps. And you can figure out, or guestimate, how many hours you will use each device.
For example, if you're racing at night, you will be using nav lights. You may have one 20-watt combination light, or three 20W lamps. Sunset to sunrise may be 12 hours on race day, so those lights could take 20W for 12 hours (240 watt-hours) or 60W for 12 hours (720 watt-hours). You have to run the numbers. Add anything else you may use, autopilot, radio, stereo, cabin lights. A VHF is usually figured as 90% on receive/squelch only, 10% on transmit, and the manual will give power consumption for both.
Once you figure out all the watts or amps you will burn, compare THAT to your battery capacity, and only then do you worry about having enough power or needing to buy more. Remember that lighter is faster, so the less battery you lug around, the faster you will race. Sometimes all you need to do is replace all your lighting with LED lighting, and good LEDs aren't cheap, but then you may be able to stick with smaller lighter batteries and not need to buy anything else.
If you're using an ice box...also consider shifting to pre-frozen foods so you don't need ice. Or use dry ice, it is lighter than water (block) ice. "More" isn't always better or faster. If you run the batteries down to 80% discharge instead of the more typical 30-50%, that's OK for occasional use like "one big race" too.