SailNet Community

SailNet Community (
-   Learning to Sail (
-   -   battery question... (

marinesniper 08-15-2006 11:19 PM

battery question...
I just bought a 1980 30ft Lippincott and do not know anything about the battery setup ...? I know there are 2...but that is it...

I know this is not alot of info and I might be flamed but if anyone knows I would be grateful...

I want to know how many amps I have to look forward to...I want to run an Garmin 3210 (just bought) GPS, 36 inch plasma tv, XM satellite radio with weather and a small microwave...

Anyone have any ideas or guesses to how long my battery will last before I have to run the engine...?

Should I buy a solar panel or wind (thing for gathering energy)... flames please., I am a newbie...and the microwave is the wifes orders...I am 30 she is 22, so I have to please her...!



sailingdog 08-15-2006 11:44 PM would help if you knew what size the batteries were...that would at least give us an estimate of what the amp-hour rating for them is.... saying you have two batteries means very little... you could have two 60 amp hour, Group 24 batteries.... or you could have two 200 amp hour, 8D batteries... or two nearly dead car batteries.

What you need to do is figure out what your electrical budget for the boat is by calculating what the amperage of each piece of equipment is and how long you're going to run it for per day, on average. Once you've gotten that estimate, you can figure out how much electrical power you'll need on average...

Your battery bank should be based on your daily some multiplier...If you want to recharge every day...then make the battery bank twice the average use...if you want to charge every third day, then make it 5-6 times the average daily use... Generally, you should never run a battery bank down below 50% before recharging it...if you do so, you will drastically shorten the life of the battery bank.

Then you need to figure out how to replace all the amp-hours you'll be using up. Will you be at a dock/marina or on a mooring, or out cruising?

For a mooring or out cruising—solar, wind and water generators are some good choices of ways to go.

Solar panels are a good option, but need to be backed up by another option, as there can be long stretches of cloudy or rainy days.

Wind generators are a pretty good option, while at the dock...not so useful when sailing IMHO.

Water generators are good when sailing, but useless at the dock...

A genset or generator can be useful, but has a lot of downsides to it... as fuel is both heavy and expensive.

If will you be docked at a marina with available shore power. If so, see about getting an AC-battery charger—get a good one, with three or four stage charging circuitry, no cheap ones...they'll kill your battery and burn down your boat.

If you don't have a shore power system might be worth installing one.

Running the engine just to charge the batteries is generally not such a good idea, and should be avoided if possible. Running a diesel under a light load is a good way to give it lots of problems in the long run... they don't like being run under a light load...and doing so too often will result in maintenance nightmares. :D

If you need more specific advice...drop me a PM.

camaraderie 08-16-2006 12:44 AM

Farzam... Without getting technical:
Do you have a battery switch on the boat that says 1-2-Both-Off???
If have one "House" battery for things like lights and GPS and one Starting battery. With the can combine them or isolate them and my advice would be to isolate them so you never run the risk of not being able to start the boat! Any additional batteries you buy should be added to the "house" side to add more capacity to run different things.

The first thing you need to do is determine what type of batteries you have and whether or not they are any good. I assume you have a battery charge on just put your battery switch on both and turn the charger on while you are plugged in at the dock overnight. In the morning...shut off EVERYTHING on the boat and wait an hour...then test the batteries with a volt meter. You should see 12.6-12.8V. If not...chances are you need new batteries...but there are a couple of other tests to make...but we'll save those till you do the above. Also..clean off the labels and tell us what kind you have...Group27, 8D etc. or failing that...the measurements of the batteries. Also do the batteries have water caps? If so...check the water level in each cell and if the plates are exposed...add DISTILLED water and hope for the best!

Finally...your hope of runing a microwave off the batteries will require a LARGE marine inverter AND a large bank of batteries. A 600 watt little microwave uses about 50 DC amps + conversion loss so let's say about 75 amps... or more than a lot of batteries capacity in one hour. A 36" flat screen will use about 15-20 amps as well. This kind of use is way to much for charging by wind and solar. Suggest you look into small generators.

Finally...before we into an extended help the articles on batteries & systems here on sailnet
...They'll answer most of your questions....we're here for the rest!

infonote 08-16-2006 03:07 AM

I would recommend, you get an electrician, even just to have a layout of the current electrics setup.

Maine Sail 08-16-2006 08:05 AM

I hope you saved about 5-6k
To wire this system up. Your requirements are high and will require significant cost to get the rated output you require. The satellite radio alone will draw 5-6 amps per hour, a 36 inch plasma (I can't beleive this was not a typo) will draw roughly 30-45 DC amps per hour after being converted to AC from DC. Although you won't be running the microwave for long periods you could burn upwards of 150 amps per hour depending on the size of your microwave. I'm guessing you'll also want to run electronics, running lights, water pressure, refrigeration etc. etc... I would suggest loosing the floating movie theater concept and use a laptop computer to play movies on. An HP 17" screen laptop plugged into the cigarette lighter and a car stereo aux input for sound draws about 7 amps per hour. You also need to take moisture into account when installing a TV. They will only last about 2-3 years in the damp cabin of a boat plus they are not designed to take the pounding when sailing to the weather in 25 knots of wind. At best buy an inexpensive 15" or 17" LCD tv. It wll draw less and when you have to throw it out you won't be out 3k..

For the set up you listed you would probably want at least six six volt golf cart batteries and 2500 watt inverter, a Xantrex battery monitor and at a minimum a 100 amp alternator with three stage regulator. Neither solar nor wind will keep up with these requirements..

sailingdog 08-16-2006 08:09 AM

Anyone with a good dose of common sense and half a brain can generally do most of the electrical work on a boat. It just takes a bit of knowledge and mostly patience. Cam's advice is sound...

marinesniper 08-16-2006 09:23 AM

Yes I have an A and B or both, I will find out what size batteries I have when I return to the US. I think I should lose the microwave and opt for using a smaller 20" LCD screen, this should be more realistic.


Cruisingdad 08-16-2006 10:02 AM

You know, just my thoughts on the matter:

There is really nothing wrong with the microwave, the tv, nothing. If it makes you more comfortable and you have fun, do it. Just be conscious of the implications you will be introducing.

It may sound silly to first time boat owners, but even adding little household items to a boat can cause huge issues (not bad issues... just things to be conscious of).

I am sure there are some cruisers on this forum that do not have a microwave... but I bet most of them do. I do. I have a flat screen TV too. However, I have sized my boat loads accordingly and added a generator, dual, back-up, isolated bateries and banks, etc. Generator: $10,000 (unrealistically low) - $15,000 (maybe a little high, but not that much). Dual, isolated banks: about 1500-2000 dollars. Not to mention, all types of battery monitors, etc. PS, as mentioned earlier, microwaves and hair dryers take a "real" inverter... better budget at least $1000-1500 if you do it yourself. And one last little thing to point out: This has to be marine equipment. You cannot go to home depot and buy copper wire and put it in your boat unless you want serious issues. Marine wire only, amongst many other things.


This is how you learn... ask away. Sailors & boaters in general help others. All we are trying to do is give you the basics of what your decisions will involve.

Good luck... and make sure you get a good copy of Capt Ron for that new TV!!!

Surfesq 08-16-2006 10:10 AM

Farzam: Congrats on the 22 year old wife! I personally am not a fan of Microwaves but I understand the need. Especially with kids and bottles! But the TV is a must. My favorite Sunday afternoon activity: Head out to my favorite little secret spot near Oxford, MD....spin on a hook, fire up the grill and pull the flat screen out into the cockpit for a little barbeque, beer and Redskins!!!!

camaraderie 08-16-2006 10:35 AM


Farzam... Assuming you will spend most of your time at a dock...the microwave is not a bad idea. can run one with a big enough battery bank & inverter for short to heat up a burrito!
I would downsize your TV ambitions however. You can get a nice 17-19" LCD that will only use 6-8 Amps and you can watch all evening for less than 30 AMPS which is nice. Satellite Radio is only a couple of amps unless you are trying to power a big stereo system too. All quite do-able with an adequate battery bank, inverter and charging system. Live the life YOU want afloat!

All times are GMT -4. The time now is 12:21 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome