Batteries, Batteries, Batteries, Hmmmm.....

Hello all, I am new to this, not to sailing, but sail boats with batteries, engines etc. So..... I have a 25+. The PO did nothing as far as up keep, maintainance. I want to be as self sufficient as possible. Solar power etc. Right now there is a sears marine batterie. Doing some research I'm going to go with Trojan batteries. Heres the question, two 6v batteries for house batteries and the 12v for starting. I've been told they can be grouped together since the 6v are in series to equal 12v, and I've been told they can't be. The two 6v will be on one bank and the 12v on the other. Will I have charging problems. I am open to suggestions!!

Ted

As long as the 6V batteries are tied together to form a 12V house bank there is no reason they cannot be then paralleled to the starting battery for charging purposes. This is actually pretty common. A good shore power battery charger will have two outputs so it will see each bank as separate and take care of them accordingly. A good high output alternator/regulator package will have no problem keeping them all topped off.

The question is what kind of configuration would/should you go with regarding the wiring of the new batteries, selector switch, etc. There are many opinions on this and many posts so do a search. I also recommend Nigel Calders Mechanical and Electrical "bible" to anyone who wants to understand the ins-n-outs of a marine electrical system.

Have fun! RT

It Depends, it depends

It depends on how you use your batteries.

Two 6 volts in series and a 12 v starting battery where all are of the same type (wet cell not mixed with gel or agm) should work fine since the charging voltages for all three batteries would be the same.

That set-up is fairly common with cruising sailors and works well. In fact, If I recall Practical Sailor had a study some years ago and determined that golf cart batteries (6V type) worked out to be the cheapest over the life of the batteries and they considered all types.

I'm not sure Trojan 6v work out to be the cheapest although they have a good reputation for longevity. Last time I looked you could get 6v golf cart batteries at Sam's Club for about $42 each which makes them really cheap.

The issue from a cruiser's point of view, is that wet cells of either 6v or 12v varieties require attention to maintenance, i.e. watching electrolyte levels and charging cycles. If you fail to maintain them properly, you won't get the life out of them.

It really shouldn't matter whether you use 12v batteries or 6v batteries. The only difference between them is the number of cells. 6v batteries have 3 cells (about 2.12v each) in series. 12v batteries have 6 cells (also about 2.12v per cell) in series. Two batteries in series (6v) or two batteries in parallel (12v) get you the same total amp hours and take up the same amount of space (approximately).

The maintenance amounts to making sure the fluid levels are correct and that the charge - discharge cycles are appropriate for wet cells.

One major maintenance issue with wet cells is that the outgassing, caused by charging, depletes electrolyte and it also causes a caustic gas that tends to corrode terminals. Not to mention that the gas (hydrogen) is pretty explosive stuff although lighter than air.

Never let the fluid level get below the top of the plates, keep the terminals clean and never discharge below 50% before recharging and the batteries will last for 5 or 6 years or maybe longer with the Trojans.

On the other hand, if you occasionally abuse your batteries, like I do ... i.e. discharge below 50%, tend to forget to check the fluid, never clean the terminals, require fast recharge, depend on solar cells, use minimal recharge cycles, etc ... you'd be better off with AGM or Gel batteries.

Just my HO.

Batteries

The advice given by Ron is right on the money.....I attended a lecture...or seminar if you will, given by Nigel Calder......I have followed his advice to a "T"......2 No 27 AGM Batteries, 92 Amp Hours Each in Parrallel for the house bank and another of the same battery for a starting Battery. I installed a new Blue Sea Switch...ON/OFF/Combine, and a Blue Sea ACR (Automatic Charging Relay)....so far it works just great.....and as Ron says.....virtually maintenance free!

Ted

All good advice by very knowledgable sailors.

One question that I think needs to be answered, "What are you going to use your boat for?" Daysailing, weekends or cruising?

John

Thanks!! Another question though

Took Ron's advice and checked at SAm's Club. 6v 210ah batterie 55.00, going that route. Have a 12v for a starter batterie now.

Batterie is brand new. Registers 12.6+ volts. I start the motor, goes down to about 12.5. Should i get a voltage reading closer to 14v if my alternator is working, while the engine is running?

Ted

To answer John's question, I use it on the weekends, and when time permits I'll be out there 5-6 days. I'm not in a slip so I don't have consistant access to shore power. Want to set up to be self suffecient. Use very little electricity, though want to be able to use a laptop.

Ted

Voltage

Batterie is brand new. Registers 12.6+ volts. I start the motor, goes down to about 12.5. Should i get a voltage reading closer to 14v if my alternator is working, while the engine is running?

Ted

The voltage drop is about what you should expect with a normal start. If the alternator is working ok, the voltage should then rise by about 1 volt over the static reading. Maybe 13.4 to 13.7 or so shortly after the alternator starts putting out. Then as the charging cycle continues, voltage will continue to rise to the regulator set point. For normal automotive regulators this is 14.3 volts. Fancier regulators can be set to voltages suitable for a particular battery type. Gel cells for example should not be charged above 14.1 volts.

It may take hours for the battery voltage to climb that high though. Once the voltage reaches say, 14.3 the battery is probably about 80% charged. At that point, voltage regulators usually drop the voltage to around 13.7 to prevent overcharging and boiling away the electrolyte. 13.7 is usually considered the 'float charge' voltage for wet cells. Temperature of the battery also will affect charge rates and voltage readings. Full charge may take hours of 'float charge' ...

After a 12v wet cell battery has rested at least 12 hours (24 hours is better) ... (rested meaning no charge/discarge activity), a fully charged wet cell battery should read 12.72 volts (2.12 volts per cell)

If you start the engine and don't get a voltage rise of near 1 volt, then the alternator is suspect and the discussion then moves to testing the alternator/regulator ...

Ted

I use my boat exactly the way you do, overnights and the occasional week at Catalina Island.

I use my laptop for movies and have an inverter for some decent speakers.

I have a very well insulated icebox with refrigeration system.

When I go for more than an overnight I use one of the new coolers which keep items cold for three+ days. (I think Howard had a neat setup he installed in a lazarette) I don't use the refrigerator-it's a power hog.

All my bulbs are LEDs. Do a search on LEDs for sources of less expensive bulbs.

Nate Hanson is considering solar panel to recharge his batteries. I'm looking at that as well. Seems to be the best way to charge your batteries when out for 5 or 6 days.

I tried a generator once-couldn't stand the stares from other boaters. Having it lashed to the mast resulted in salt spray and a rusty generator-good thing it was twenty years old.

The trick, FWIW, is to keep consumption down, trickle charge the batteries, if possible, and take advantage of the return policy on your batteries.

I trade my batteries in when they are about 20 months old. It's more cost effective then spending at least a thousand to upgrade to a monitoring system that say Captain Ron needs for his very serious cruising. (Make sure you go to his web site-it's a real hoot and loaded with great advice.)

Keep us updated.

John

jkm said:

Nate Hanson is considering solar panel to recharge his batteries. I'm looking at that as well. Seems to be the best way to charge your batteries when out for 5 or 6 days.

Click to expand...

For about $350 shipped, I've received a 50w Kyocera panel, and a charge regulator. Mounting it is on tomorrow's work list.

I'll give an update once I see how it's working.

All in all, it's a fairly cheap upgrade, and looks like it will be quite a simple install. Just a couple clamps on the rail, and two wires to the battery (via the controller).

Nate

Very anxious for the update.

That is a good price on a solar setup! What kind of charge controller? MPPT design? I looked hard at solar last year and ended up getting a Honda 2000 generator that I use at the mooring primarily to pick the batteries back up after a long weekend. A Honda 1000 would do the trick just as well and at 27lbs not 45lbs, thats what I should have done. I have used it at other anchorages and the Honda is VERY quiet, other boaters don't even seem to notice its on. When I was looking at solar the shock of the fuel cost increase had pushed the solar prices out of sight. Thankfully they appear to be returning to earth. I would like to put a pushpit mounted bimini on my E38 with two solar panels on top and be able to dispense with the Honda. Nate, what was your source for the Kyocera's? RT

Which is better??

A quick question. I run two 6V in series for starting and two 12V parallel for house. I was lead to believe that this was the best config for starting my Yanmar 30 hp motor. Right or wrong? Or does it matter?

All the above.

howard keiper
seaquest
berkeley

rwthomas1 said:

That is a good price on a solar setup! What kind of charge controller? MPPT design? I looked hard at solar last year and ended up getting a Honda 2000 generator that I use at the mooring primarily to pick the batteries back up after a long weekend. A Honda 1000 would do the trick just as well and at 27lbs not 45lbs, thats what I should have done. I have used it at other anchorages and the Honda is VERY quiet, other boaters don't even seem to notice its on. When I was looking at solar the shock of the fuel cost increase had pushed the solar prices out of sight. Thankfully they appear to be returning to earth. I would like to put a pushpit mounted bimini on my E38 with two solar panels on top and be able to dispense with the Honda. Nate, what was your source for the Kyocera's? RT

Click to expand...

I ordered from "Affordable Solar". The shipping was pretty fast and overall the order was painless.

This weekend I took my shakedown/delivery cruise from Boston to Ellsworth, ME on the (brace yourselves) columbia 26 Mk2 that I've been fixing up. I Launched on Wednesday, and departed on Thursday. Friday morning I got around to wiring the panel which I had mounted on the pushpit before departing. We had a few hours of sun on Friday, about an hour or two of weak charging on Saturday (overcast), and good charging on Sunday. We used a tillerpilot, GPS plotter, depth/knot/log for about 50 hours on the trip, navigation lights for about 20 hours, and a couple cabin lights for 2-3 hours. My 200Ah of golf-cart batteries started out at 12.4 at launch, got down to 12.0 on Saturday night (after 40 hours underway, and only a few hours charging), and on Sunday they got the batteries juiced back up to 12.6 when the sun was out. Basically I showed that for the most aggressive power consumption that I'll ever have on this boat, my largish battery bank, combined with a smallish solar panel will be more than capable of keeping a charged battery bank. It is very cool what a simple system it is, and it's neat to see the voltage reading on the GPS display climb up to 12.6 or 12.7 when a little early morning sun filters down onto the panel.

It's sunny today, and I expect the boat will recover today and tomorrow from the weekend draw-down.

Nate

When do we get to see a picture??

John

Oh, I forgot to answer the controller questions. I decided the MPPT was too expensive to justify for such a small system. Sounds like they can really maximize output from the panels you have, and if you have heavy loads, that could really save money translating into fewer or smaller panels. But for my minimal system, I thought I'd try a basic model. I got the MorningStar SS-6 controller. It was $40, and it can be set for flooded or Gel batteries. (The more basic model is only set for gel).

I didn't bring a camera on the trip, but I'll see if I can remember to get a picture of the setup sometime this week when I'm on the boat.

Nate

Nate,
Sounds very nice. I want to go for a rail-mounted bimini and would like to have a panel or two on top of it to take care of topping off the batteries and keeping up with the AB system when I use it. RT

solar panel

I'd like to get a small solar panel mainly to refresh batteries and in advance of a reefer unit. But the location bothers me. I don't think I'd care for a rail mount (in the way), bimini top mount or deck mount (don't like holes in the deck; have enuff already) or wrapped around the mainsail. In a late night state of foggy vision, I thought , how about over the companionway? Maybe a flexible panel about 2.5'x2.5' (or whatever the entry way cover dimensions are) that lays on/adheres to the sliding cover with a flexible power cord (curley que like head phones) to allow for sliding the cover forward and back. I imagine I'd have to cut the hard cover that the sliding plexigass slides into, to accommodate the panel, but it shouldn't be much; maybe 1/2". The panel would be exposed to sun while in the slip and buttoned up; and with the companionway closed while under way, it would be charging. It would not be in the way, stepped on or kicked. And not be a bother to remove and reattach as when dealing with the sail cover. Down side would be: not adjustable to the angle of the sun. What else?

I've seen that position a number of times. Also on top of the sea hood (that hard cover over the companionway hatch).

The advantages as you say are that it's out of the way. The disadvantages are that flexible panels (thin film silicone) are much less efficient than multicrystaline or single crystal rigid panels. Also, the panel may often be partially shaded when mounted under the boom, and many panels lose most or all of their output when just part of the panel is shaded.

However, if you're just looking for something to help condition your batteries, and keep up with the bilge-pump draw, it would probably work fine. If you want a panel to help keep up with DC refrigeration while you're away from the boat though, you'll probably need a more productive setup.

Personally I don't find the pushpit mount at all in the way. It's behind the back stay. The only way it could be in my way is if I were trying to do a swan dive off the transom.