Battery

[Infoformacgregor]

I’m Planning on buying two new deep cycle marine batteries for my 26M. Any advice on battery size (not a lot of add-ons) or if one needs to be a hybrid? Thank you. Gene

[Inquisitor]

Did you catch this thread going on now? Lot's of good advice on batteries.
viewtopic.php?f=7&t=28031

If you know...

1. what devices you need to power
2. what devices you want to power
3. how much charging sources you'll use... solar panels on the boat or plug-in chargers at home
4. how long between charging's

... its fairly strait forward to calculate what you'll need. If you give details there (or here) there are plenty of people that can get you in the target area for sizes you'll need. Not knowing anything about your equipment/trip length and it'd be impossible to advice you. With what you've given so far... the only qualitative answer you can get... is what fits through the hatch below the steps. When I got rid of mine, I think I had (2) type 24's will fit.

[Inquisitor]

... or here is a quick and dirty cheat-sheet

1. Get the Amp-hour rating of your proposed battery. In this example (ITE) My deep-cycle battery type 24 when new was 80 Ah. You can only use half that if you want to last more than a season or two. I used two... but only used one for the house electricity and the other was only to start the motor. I think that is the most common setup you'll find here.
2. Multiply that by the 12 volts to get watt-hours... ITE = 480 watt-hours
3. Start subtracting the device wattages multiplied by the amount of time (in hours) that you want to use it. ITE... lets do a weekend trip (2 nights) and you have no charging... no solar panels, don't charge with the motor, don't plug in.
   1. Let's say spending the night with the steamer light on for 8 hours. I think its 10 watts unless I'm guessing wrong or you've switched to LED lights... 480 - (10 watts) (8 hours) (2 nights) = 320 watt-hours left.
   2. Let's say you use all the interior lights before going to bed for 3 hours... 320 - (4 lights) (5 watts) (3 hours)(2 nights) = 200 watt-hours left.
   3. Say its the summer and you want to use a cheap oscillating 12V fan... Off, Amazon, I found one that used 3 amps... 3 * 12 = 36 watts. With what you have left over so far, you can run the fan: 200 watt-hours / 36 watts = 5.5 hours... One night you're cool, the other not so much.

... if you use any more, you're dipping your battery below 50% capacity and you're compromising its longevity.

[Chinook]

If you're planning on using two batteries for house battery use, you might want to consider going with a pair of 6 volt golf cart batteries, connected in series. That will give you excellent capacity for house battery use.

[Be Free]

+1 on the 6V. You will get a lot more usable amp hours out of a pair of 6v deep cycle (like used in golf carts) than you will out of the hybrid. You did not mention your engine but I have no problem cranking my BF40 with them.

[Inquisitor]

For 6 volt "Golf Cart" batteries, can you provide a link of ones you're suggesting?

I think I've seen the Trojan brand in "big" battery banks on larger boats and am under the impression that Trojan is a common, top quality make.
http://www.trojanbattery.com/pdf/Signat ... eSheet.pdf Reading their literature, a pair of T-105 might fit under the 's steps. Height might be an issue.

As good as these are, I am real curious why (at least) the DIY'rs here on the forum aren't more motivated to try lithium batteries????


* Dimensions and weight are before putting them inside some case.

The Lithium are a little more expensive, but compared to the other advantages (in the chart) its no contest. And that doesn't even count the zero maintenance. With the nearly double the capacity, I've been re-thinking much of my Mac's mods. I'll be looking at punting the arguably dangerous propane stove and using a Microwave oven instead.

[ris]

When we set up our boat we bought four 6volt Trojan 105’s. 450 amp hour which means you can use 225 with no harm to the battery. They weigh 62 lbs apiece which is a total of 248 lbs and cost $600 ($120 apiece when we purchased). Two 100 amp lithium batteries weigh 60 lbs for the same useable power but cost about $1900. We have only one battery bank in our boat which starts the motor and runs all the electric. In 4 years never had to jump the outboard. There are even people with trawlers that use diesel motors that use six or more 105 batteries and only have one bank. I think cruising like we do if I was just starting I might invest in the lithium iron phosphate batteries. When you are using more than one battery make sure and buy them at the same time. Induction stoves take a lot of power. Propane is safe, it is used in millions of homes and boats. We have a 2 gal tank that lasts us about a month or 6 weeks. We also have a magma grill for burgers and steaks. As far as maintenance on the lead acid batteries, with 4 batteries takes about 10 min every 30 to 40 days if you are cruising and charging the batteries every couple of days.
Richard

[Inquisitor]

I really enjoy this forum and the diversity is incredible. Sometimes I need to pause and remember that. The OP might just want to replace a simple battery so he can go day sailing. The Mac's are incredible boats that fit so many styles. Long term members on the forum can probably "read the tea leaves" of a person's battery and tell you how they use their boat.

When I first started, I was on a tight budget and wasn't sure if I really could afford to drop so much money into the hole in the water. I had just the one battery to start the motor. We sailed, pulled kids behind the boat. Weekends on the lake are fond memories. Never gave a second thought about the battery... until it couldn't start the motor. We'd done too much sailing and used too much lighting. A quick jump and a second battery entered the M's hold and we continued for years with never a problem or a second thought about the batteries.

OP, If I(we) haven't scared you off and you're like I was starting out, I'd say... go to Walmart, car parts store, etc and get an inexpensive starter battery, and an inexpensive deep-cycle RV/Marine battery. You need two other things - A Perko switch and a "free" Harbor Freight volt meter. Only use starter battery to start the motor, and the deep-cycle for the "house" battery. Learn to charge one or the other or both batteries with the Perko switch when running the motor. Use the volt meter to make sure you don't drain the "house" below 12.2 volts and you'll last years of care-free boating.

As the years rolled by, we started coastal sailing and it pretty much ruined me for lake sailing. The wind was so relatively constant and from one direction. Not adjusting course or sails every minute was a revelation. I now understand the songs of the sea.

In those previous phases, I considered overnights, weekends on the Mac were like car, tent camping. As we were starting to do longer and longer trips, we started running up against issues... lack of electricity, lack of ice, lack of a shower. Fast forward to now - I'm retired and I want to do some "real" trips up and down various coasts like Chinook exemplifies. I'd really like to be able to tie up to a city dock and not smell offensively to others or myself.

OP, If you are in these phases, you need serious power storage. Thus... this is where we "ole-timers" went off about 6 volt batteries and/or Lithium. For either of these, you need to admit (to yourself at least) whether you have trouble programming an egg-timer or are a complete DIY wizard. You should do some serious research and understand what you really need and how much effort you are willing to maintain your sizable investment. Once you get into these, the next thing will how to keep them charged... are you in a powered slip or do you need solar panels or wind turbines. It all snow balls from there.

When we set up our boat we bought four 6volt Trojan 105’s. 450 amp hour which means you can use 225 with no harm to the battery. They weigh 62 lbs apiece which is a total of 248 lbs and cost $600 ($120 apiece when we purchased). Two 100 amp lithium batteries weigh 60 lbs for the same useable power but cost about $1900. We have only one battery bank in our boat which starts the motor and runs all the electric. In 4 years never had to jump the outboard. There are even people with trawlers that use diesel motors that use six or more 105 batteries and only have one bank. I think cruising like we do if I was just starting I might invest in the lithium iron phosphate batteries. When you are using more than one battery make sure and buy them at the same time. Induction stoves take a lot of power. Propane is safe, it is used in millions of homes and boats. We have a 2 gal tank that lasts us about a month or 6 weeks. We also have a magma grill for burgers and steaks. As far as maintenance on the lead acid batteries, with 4 batteries takes about 10 min every 30 to 40 days if you are cruising and charging the batteries every couple of days.
Richard

Richard, A couple of years ago, I think I would have completely agreed with your assessment and gone that direction. But now, I'm retired and have time on my hands because I can't be sailing (I don't live near Frostproof Florida - Green with envy ). I also love DIY projects as much as sailing. When I want to learn something these days, I simply find a forum and start reading and asking questions. I'm learning about off-grid stuff from another forum and finally convinced myself that I'm willing to jump into using Lithium.

Even today, your criteria of two 100 Ah LiFePO4 batteries that are turn key and have zero maintenance or thought required will set you back about $1800 (see https://battlebornbatteries.com/product ... e-battery/) Swap them out and away you go.

This was still too steep for me, but I found the numbers way too compelling and I'm willing to DIY it from what I'm learning on the other forum. Once I get the parts in, I'll be adding a thread here to build the battery for those of a like mind. 1 battery, 55 pounds, 272 Ah (220 Usable Ah with 3500 cycles) for $600 and that includes the battery monitor electronics that can cost nearly $300 for people using lead-acid batteries. It's interesting... I started out looking at just doing 100 Ah, but there was very little difference in the price of 100Ah cells and 280Ah cells. So... why not... do one large battery (it still lighter than 1 6v battery)

With so much power available, I started thinking about how to use it. Propane tends to start flaming wars on this forum. Some are decidedly pro or decidedly con. I was heading toward the pro side with a serious installation with remote valves and cylinders and propane sniffers. But, I realized that with this much electrical power available and the way I'd probably cook "most of the time", things would be far simpler with just plugging in a microwave oven. Reduce heat in the cabin, no propane concerns, quicker cooking, less mess to clean up. Pop popcorn in minutes, open a can of chowder, pore in mug and heat in minutes. I think, I'd still have a propane grill outside for the more ambitious/special cooking times.

The point being... with this much power, having a fridge/freezer, microwave, and a shower will move the Mac from tent camping to RV camping and hopefully extend the time and enjoyment of my Mac.

Again... long winded.

Happy New Year all.

[Russ]

OP, If I(we) haven't scared you off and you're like I was starting out, I'd say... go to Walmart, car parts store, etc and get an inexpensive starter battery, and an inexpensive deep-cycle RV/Marine battery. You need two other things - A Perko switch and a "free" Harbor Freight volt meter. Only use starter battery to start the motor, and the deep-cycle for the "house" battery. Learn to charge one or the other or both batteries with the Perko switch when running the motor. Use the volt meter to make sure you don't drain the "house" below 12.2 volts and you'll last years of care-free boating.

Since our outboards do not need a lot of cranking amps, I have 2 Walmart deep cycle batteries. Gives me plenty of storage rather than cranking amps.

I also have one of those $50 jumper packs for emergencies. They really are amazing. I used it to start my truck one cold 10-degree day.

[dlandersson]

Ditto, except I have a Genius thingy

OP, If I(we) haven't scared you off and you're like I was starting out, I'd say... go to Walmart, car parts store, etc and get an inexpensive starter battery, and an inexpensive deep-cycle RV/Marine battery. You need two other things - A Perko switch and a "free" Harbor Freight volt meter. Only use starter battery to start the motor, and the deep-cycle for the "house" battery. Learn to charge one or the other or both batteries with the Perko switch when running the motor. Use the volt meter to make sure you don't drain the "house" below 12.2 volts and you'll last years of care-free boating.

Since our outboards do not need a lot of cranking amps, I have 2 Walmart deep cycle batteries. Gives me plenty of storage rather than cranking amps.

I also have one of those $50 jumper packs for emergencies. They really are amazing. I used it to start my truck one cold 10-degree day.

[Neo]

I also have one of those $50 jumper packs for emergencies. They really are amazing. I used it to start my truck one cold 10-degree day.

Is that the Super Capacitor type?

[Inquisitor]

Its worse than I thought. While working MX-4 project, I removed the interior bulbs.
They are CEC1141 and according to the Internet... they use 18.4 watts!

Redoing the calculations above in post #3 for the simulated weekender...

320 watt-hours left / (4 bulbs) / (18.4 watts) / (2 nights) = 2.17 hours.

We can not use the fan at all and we can only use the lights for 2 hours and ten minutes each night.

[Jimmyt]

Yup. LED will knock that way down. One of the first things I did. Low hanging fruit.

[Tomfoolery]

Yup. LED will knock that way down. One of the first things I did. Low hanging fruit.

LEDs are just the bee’s knees for boats. And RVs, for that matter.

The OP should look for parasitic loads, too. Our boats are small and therefore don’t have much by way of electric loads, but anything on standby is a parasitic load. Like an inverter, no matter how small. Phone voltage converters. Radios. Electric coolers, especially if sitting in the sun. Even an indicator light in the DC panel, especially if it’s incandescent, adds to the total load. My Caframo fan, with its fancy speed and timer settings, may also draw a small amount on standby, so I leave the light circuit (that it’s tapped into) off until either lights or fan is needed.

The propane solenoid valve in my van draws about 1A at 12VDC. That’s 24Ah of battery power every 24 hours. If the house batteries were small like my boat batteries, it would draw a Group 24 batt down about all the way, assuming draining to no lower than 1/2 rated Ah capacity, in two days.

There is also a 3000W inverter/charger that draws about 3A on standby (no-load), or .25A even when it’s “off” but connected. And the monitoring system, which I don’t actually need energized unless accessing it via computer. I don’t know what that draws, but it’s a proprietary interface (Xantrex’s “Xanbus” network) plugged into a wifi router for wired or wireless access. That’s a lot of battery power being drawn with zero utility.

I don’t know if my OB allows any current to sneak in when it’s off but connected, and I would hope not, but it might be something to check at least.

[Be Free]

For 6 volt "Golf Cart" batteries, can you provide a link of ones you're suggesting?

I put 4 of these in to replace two abused 12v "marine" deep cycle batteries that came in the boat.
https://www.batteriesplus.com/productdetails/sligc110