New to site ... Question about adding a second battery

[Csimoni]

Hi,

I have been lurking for awhile as I try to educate myself about sailing and sailboats. We have found a boat we like, a 1980 Ericson30+ that seems to meet our requirements and had planned to make an offer subject to survey and sea trial but have just learned that the boat has only one battery. From what I have gathered that is suboptimal although the current owner has sailed extensively for years on the Great Lakes.

I would appreciate hearing from those of you with experience whether it is feasible to add a second battery with the associated paraphernalia and, if so, what the cost might be to have a boat yard handle the installation. Thanks,

Chris

[maytrix]

Little more info - is the one battery both for house and engine starting? That is the only thing I can see that would make it sub-optimal. You typically want those to be separate to reduce the risk of running the battery down runnings lights..etc and not being able to start the engine.

Not sure on the cost, probably depends on a number of factors.

[jerrymc]

It's not a big deal to add another or a bank of batteries..cmon man!

[mr-canada]

On a 30 its probably just a truck battery, $150. Like said above one battery is fine if you arent starting your motor with it. My 26 has one battery and it runs the radio, stereo, lights, sounder and gps just fine for a couple days without needing shore power and up to four if im being very.careful of power usage. If i had a motor that put out 5+amps of charge id never need shore power.

If you put an extra one in the easist way is to just bring a fully charged one and connect it to the system if you run out of power. Youll probably end up selling it later

[Csimoni]

Thanks for the prompt reply (and apologies for my delay -- we've been traveling). The one battery currently in use is for both starting the engine and running the VHF, 12v lighting, etc. From reading and talking with people it seems that the 2nd battery provides a measure of protection against finding oneself with a dead battery and the need to start the engine. Is that understanding correct?

[maytrix]

That's correct. I'd imagine it shouldn't be that difficult to add another - probably something you could do yourself, just need to determine which wires go to the engine and make the necessary adjustments. Not sure on the charging aspect though and how you'd connect the alternator to both sets.

[noelex 77]

Adding a separate starting battery would be a good improvement.

It is not difficult to do. Companies like blue seas even make kits with all the hardware and instructions.
There is lot to be said for learning how to fix problems yourself when you own a boat and this would be a good opportunity to start with a reasonably simple electrical project.

I would not let it influence buying the boat although if you get a professional to do it the costs do add up so you need to factor this into your offer price.

Here is a link to the blue seas kit
http://www.bluesea.com/products/7650

It is always difficult to estimate boat repair prices, but the above hardware plus wire, battery box, battery and labour to install the lot if done professionally will probably be in the order of $800.
Warning I have been totally wrong about prices before (with errors of more than order of magnitude ) and I offer the above only because you specifically asked.

[Csimoni]

Originally Posted by noelex 77

Adding a separate starting battery would be a good improvement.

It is not difficult to do. Companies like blue seas even make kits with all the hardware and instructions.
There is lot to be said for learning how to fix problems yourself when you own a boat and this would be a good opportunity to start with a reasonably simple electrical project.

I would not let it influence buying the boat although if you get a professional to do it the costs do add up so you need to factor this into your offer price.

Here is a link to the blue seas kit
http://www.bluesea.com/products/7650

It is always difficult to estimate boat repair prices, but the above hardware plus wire, battery box, battery and labour to install the lot if done professionally will probably be in the order of $800.
Warning I have been totally wrong about prices before (with errors of more than order of magnitude ) and I offer the above only because you specifically asked.

This is very helpful and, after reading the instructions, looks like a feasible DIY project.

[Hydra]

I sailed for 7 years with only one 70 Amp*hours battery. It powered the GPS, the VHF, the sounder+log combination, the running lights and the interior lighting. All the lights were LED, so I had more than enough juice left after 24h sailing to start the 14hp Diesel engine.

Last year, I added a second battery and the coupling gear. In fact, I installed 2 identical batteries. The engine-starting battery is charged by the engine alternator and the house battery by the shore-power converter. They are connected through this device (works perfectly): Cyrix-i 120A/ 225A /425A - Victron Energy

It wasn't difficult to do, the biggest problem was finding where to borrow a suitable crimper for the connexions.

Alain

[Csimoni]

Originally Posted by Hydra

I sailed for 7 years with only one 70 Amp*hours battery. It powered the GPS, the VHF, the sounder+log combination, the running lights and the interior lighting. All the lights were LED, so I had more than enough juice left after 24h sailing to start the 14hp Diesel engine.

Last year, I added a second battery and the coupling gear. In fact, I installed 2 identical batteries. The engine-starting battery is charged by the engine alternator and the house battery by the shore-power converter. They are connected through this device (works perfectly): Cyrix-i 120A/ 225A /425A - Victron Energy

It wasn't difficult to do, the biggest problem was finding where to borrow a suitable crimper for the connexions.

Alain

Thanks this is very helpful and convinces me that this is not a matter that needs immediate resolution.

[Hydra]

Csimoni,
Before adding a second battery, I suggest you install a voltmeter near the electrical panel. It instantly gives a good view of the battery condition. Then, you will know when it's time to stop drawing on the battery and when it's time to start the engine while its still possible! I also suggest you procure a pair of jumper cables, just in case...

I chose a voltmeter with an integral 3-position switch: off, engine battery, house battery.

The second addition, to be done later when you are more at ease with electrical DIY, is a shore-power converter: it's pleasant being able to charge the battery without having to start the engine.

The second battery could be added much later, provided you can find a place for it. I had to squeeze it under the stern berth, just aft of the stern gland, for it was the only possible location.

Of course, all this holds if you don't have such current-guzzling equipment as a fridge or air-conditioning and if you take the precaution of replacing all light bulbs with LED.

Alain

[mr-canada]

A voltmeter. What a great idea. Duh why didnt i think of that... Lol

I spent a long time trying to find a battery guage to indicate where the battery was at before i got my smart charger that has an indicator. However that only works on shore power.

Ill look into getting one of those, they probably are less than 20 bucks