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Post by optimystic on Oct 4, 2014 15:48:04 GMT
I'm interested in learning the voltage ranges for a house bank of three batteries while cruising without shore power. All charging systems are working and charging via the engine is accurate. I only run the fridge, water pressure,and a couple of led lights as needed. My voltage dropped overnight from a starting point of 12.5 to 12.0 which seems to large a drop for the time period and so few circuits running. All batteries are lead acid and full of water. New in 2012. Thanks for the input. The boat is new to us and I don't want to experiment while at sea. So 379
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Post by Don Reaves on Oct 4, 2014 17:41:14 GMT
The standard rule of thumb for flooded lead acid batteries is 12.6V 100%, 12.4V 75%, 12.2V 50%, 12.0V 25%, 11.7V 0%. (From Boat Owners Mechanical and Electrical Manual by Nigel Calder) These are resting open-circuit voltages, meaning that there has been no charging or load for some period of time, like several hours, and with the temperature between 60 & 100F (15.5 & 38C).
In your case, the low voltage (12V) was taken under load, and to know if it was too low, you would want to remove the load for a while and measure the voltage again. Almost certainly, it would recover somewhat.
If you really want to keep track of the power you're using, there are devices available to monitor it for you. They're not cheap, and I dont have any experience with them. However, they are discussed in a number of threads on this forum. Go to the search page and search for the phrase "battery monitor".
If you want to learn more about boat electrical systems, I highly recommend Calder's book.
Don
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Post by MalcolmP on Oct 4, 2014 22:05:16 GMT
Couple of things I have found. The standard Jeanneau "Schreiber" panel that was fitted to my 39i under-reads by around 0.4 v on what my after market Victron battery monitor shows - this is fitted via a shunt direct to the house bank - so it maybe that you panel is under-reading.
Not only will the fridge take a lot of amps, but also so will the backlight of Raymarine chart-plotters, if left on full brightness. Shut down your electronics overnight when possible.
A 100W solar panel will make a lot of difference in extending your "non-plugged in days" particulaly if you sail in sunny climes
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Post by electricmonk on Oct 5, 2014 9:21:52 GMT
From your description it sounds like the batteries or one of the batteries has lost capacity. The best way find out is to isolate each one and measure the voltage of each one, you can do this at anchor. (If I can change my stern gland seal at anchor I am sure you can test a battery). With luck you will find one battery that's way below the others so you just take it out of the bank until you can source a replacement. In my opinion all you need is a good digital voltmeter, forget the battery monitors they make guesses and you could end up a nervous wreck worrying about nothing - as I have said many times before weighing the pig wont make it any fatter, so just stick to an accurate voltage measurement and if you are really enthusiastic buy a hydrometer to check specific gravity.
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Post by optimystic on Oct 6, 2014 2:55:29 GMT
It looks like I need at least a new starter battery. The house batteries all tested very close to equal. Is it possible to mix battery types? I would prefer a sealed agm for the starter and add house batteries that match as needed. Otherwise I will waste good house batteries by switching to sealed agm for all batteries. The charger settings looks the same for both types. Or is there really a reason to go with the agm verses lead acid?
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Post by Don Reaves on Oct 6, 2014 10:16:41 GMT
It seems to me that you could have different types of house and starting batteries, as long as the charging circuits were capable of handling the differences. But I would like one of the electrical experts to confirm this.
However, since the house batteries in Jeanneaus are typically wired in parallel, you should never mix types within the house bank. In fact, I would not mix batteries of different ages within the house bank if they are wired in parallel.
A system designed with batteries in parallel makes the assumption that all the batteries will work the same. If one battery is weaker than the others, the stronger batteries will in effect try to charge it. So my recommendation for increasing the size of the house bank would be to wait until you need to replace all the house batteries and then buy a matched set.
Don
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Post by chuckr on Oct 6, 2014 10:55:51 GMT
I can only tell you what works for us and out thoughts which is as good as the money you paid for it.
Check the reefer and see where the setting is and if you can cut it a bit. We find the reefer is a huge power consumer. Our biggest power consumer at anchor with no nav insturments on is the reefer and the inverter that runs our computers. If we stayed off the computer we would have more power. (right now we are in a marina in brindisi getting our alternator fixed so on shore power)
We have a house bank of 6 6v batteries and 3 solar panels for about 400w. If it is sunny and southern climes it is generally sufficient to meet our needs and that includes a watermakers that pulls 8 amps (i think)
We have been out 7 years now and find that our house bank is sufficient. Would we like more? Of course but we have plenty with the solar panels.
So if you are planning on some longer term cruising think about more batteries and solar panels.
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svmobert
Junior Member
Posts: 18
Country: USA
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Post by svmobert on Oct 7, 2014 2:59:49 GMT
I actually spent time today measuring the current draw of different systems on my SO45.. We also have a 3 battery house bank, it is 3 x Optima BlueTop AGM 31s which are rated for 75AH each. The start/windlass battery is an Optima Yellow Top. We've only had the boat since June and realized during our August 9-day cruise that the battery bank is insufficient. I actually had one morning where the house bank was down to 10V, this after charging the batteries from the Genset before going to bed. The only system that draws any significant amount of power at anchor is refrigeration..
Today I measured that the freezer draws about 3Amps when the compressor is running, and the separate fridge compressor draws about 5Amps. I don't yet know how much of the time these compressors actually run, but I have a Victron BMV-702 on order and will use that to measure my AH consumption over time. I think I have several issues..
1.) The battery bank is undersized.. 225AH (75ahx3) just isn't enough considering the two compressors, electric primary winch, lights, inverter, full electronics, radar, autopilot, etc. 2.) The undersized battery bank is probably shot from being deeply discharged too many times 3.) The primary winch draws something like 120Amps when it's in use and that drops the battery voltage well below 11V during that time. The electronics actually alarm due to low voltage when I use the winch after we've been out sailing (engineless) for a few hours. Actually when you consider that 100Amp draw is 2 hour discharge rate for a 200AH bank, running the winch is taking alot of capacity out of the batteries, even though it's only being used for a short time. 4.) Raymarine E80s (I have two) draw about 4Amps by themselves, not including the radar. The rest of the instruments consume only about 1Amp. 5.) The boat has 23 x 10W Interior lights.. That's a TON of lighting, and my boat is old enough that these did not come as LEDs. Replacing the bulbs with LEDs (while expensive) will cut consumption by 5-10X from lighting.
Right now I'm in the process of optimizing the refrigeration through a few changes.. 1.) It turns out the freezer is keel cooled while the fridge is air cooled. Keel cooling is about 30% more efficient than air cooling. So I'm converting the fridge to keel cooling during our upcoming haulout. 2.) I have no idea what temperature the fridge and freezer actually are, they are probably too cold. Plus the mechanical thermostats are not my favorite thing in the world. So I'm converting to digital thermostats that maintain a a specific box temperature instead of managing the temperature of the plates. 3.) I'm adding smart speed control units (Frigoboat Merlin) to both units which will try and run the compressors slower and longer. Slower compressor RPMs are also more efficient over the long haul compared with higher RPMs. Plus the added side benefit of lower current draw puts less stress on the battery bank so the batteries will have more charge capacity available.
I am also not a fan of the Optima batteries for boats, for essentially one reason. Physical space is tight on boats, especially sailboats, and Optima batteries, being spiral wound, have far less AH Capacity when compared with pretty much every other battery of the same size. The Optima 31's have 75AH while the Trojan 31's have 110AH. The Trojan 12-AGM's (which are only about 1 inch taller than the 31's) have 140AH per battery. So at this point I plan to eventually replace the 3 x Optimas with 3 or 4 Trojan 12-AGMs. That will pretty much double my house bank capacity if I do just 3 new batteries.
We will add solar some day also, but that's farther out.
I will be tracking AH consumption of the fridge and freezer before and after upgrades with the Victron and will be blogging about the results in case anyone is interested.
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Post by MalcolmP on Oct 7, 2014 6:37:34 GMT
......... but I have a Victron BMV-702 on order and will use that to measure my AH consumption over time. .............. Sounds like you are on the right track and I for one would like to hear more on how you get on. One thing to watch for when you fit the Victron is that you don't have more than one negative attached to different ends of the battery bank as my 39i did from when originally fitted at the factory - see thread: jeanneau.proboards.com/thread/3358/odd-wiring-main-battery-bank
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Post by electricmonk on Oct 7, 2014 18:57:02 GMT
"We've only had the boat since June and realized during our August 9-day cruise that the battery bank is insufficient."
If only it were that simple, the problems you face are many but not insurmountable. Sorry but I don't have time to write a book on this but here are some pointers.
1. Your main problem is not battery bank capacity as such but you are running very close to using it all every night, its an inability to replace what is used in a day - the thing you need to understand is "Absorption Rate" how quickly lead acid cells can be recharged, sadly its longer than 12 hours more like 48, so what ever you do its not possible to fully charge a battery in a day. but its not all bad news, you should be able to get them to 85% in 6 - 12 hours. (on shore power you will get the other 15% in 2 or 3 days)
2. So you must ensure you do have the ability to get your batteries to 80-85% full charge in a day from a low point of 50% (take them lower and you reduce their life) so for your system you have a usable AH capacity of around 80ah (roughly 33% of stated capacity), and daily you will have to find 100AH or so to replace this. (assuming you are using all of it and you have normal losses from recharging) the good news for you is you have AGMs and they can accept a high charge rate - but not for a very long time check the battery manual.
3. Reduce your demand, LED lights, keel coolers etc.
4. IF you decide to increase your battery capacity then you will have a usable capacity 33% of the new stated capacity (at anchor) and if you use it all you will have to find more AH every day to replenish it.
5. Battery monitors are unnecessary all you need is a good voltmeter. If your monitor does not require a peukert number to be programmed in - bin it!
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Post by optimystic on Oct 8, 2014 2:14:12 GMT
Today the starter battery measured 12.5 but failed to start the engine.i replaced it with a similar battery so I don't have to worry about different battery formats. Tomorrow I'll fire her up and hopefully all will be good.
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Post by electricmonk on Oct 8, 2014 15:12:26 GMT
This next comment is not aimed at you Opimystic, Its just a technique I have used over the years to determine if a starter battery that says its OK is - OK or if its about to fail.
You need two people, one at the helm to start the engine and the other at the panel to look at the voltmeter, as the one on helm cranks the engine the one at the panel records the lowest voltage shown on the voltmeter. If the voltage drops passed 11 volts then the battery has probably gone home - can no longer supply the voltage required at high discharge (you have just performed a "basic" quick and dirty high discharge test but its a good test) . BEWARE if the voltage did drop below 11 and the engine did start and you say - "that was close" and continue on. The problem is the amps supplied by the "dead" battery have compensated for the loss of volts and the temperature in the starter motor has skyrocketed - it wont put up that for long! change the battery - its cheaper than a starter motor.
enough said.
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svmobert
Junior Member
Posts: 18
Country: USA
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Post by svmobert on Oct 8, 2014 19:35:00 GMT
Understand and agree.. We do have AGM's and onboard charging system capable of over 120Amps at anchor.. We can get from about 50% to float in ~2 hours currently using full AGM programmed charging with temperature compensation.. I know that we are not at 100% charged at that time. I'm convinced at this point that I need to upgrade the battery bank size itself AND reduce consumption. I'm focused on consumption right now but will deal with the batteries sometime this winter I'm sure. Can only do so many things at once... Agree on the battery monitors.. The Victron unit is very powerful and includes temp and peukerts compensations, both of which can be adjusted as needed. With the upgraded batteries (3 x Trojan 12-AGMs is what I'm looking at right now) I'd have 420AH total capacity, so at anchor, about 140AH available. With reduced lighting and refrigeration I think that would be enough.. However I want to get more accurate consumption values, hence the Victron addition.. Very much appreciate the contribution! "We've only had the boat since June and realized during our August 9-day cruise that the battery bank is insufficient." If only it were that simple, the problems you face are many but not insurmountable. Sorry but I don't have time to write a book on this but here are some pointers. 1. Your main problem is not battery bank capacity as such but you are running very close to using it all every night, its an inability to replace what is used in a day - the thing you need to understand is "Absorption Rate" how quickly lead acid cells can be recharged, sadly its longer than 12 hours more like 48, so what ever you do its not possible to fully charge a battery in a day. but its not all bad news, you should be able to get them to 85% in 6 - 12 hours. (on shore power you will get the other 15% in 2 or 3 days) 2. So you must ensure you do have the ability to get your batteries to 80-85% full charge in a day from a low point of 50% (take them lower and you reduce their life) so for your system you have a usable AH capacity of around 80ah (roughly 33% of stated capacity), and daily you will have to find 100AH or so to replace this. (assuming you are using all of it and you have normal losses from recharging) the good news for you is you have AGMs and they can accept a high charge rate - but not for a very long time check the battery manual. 3. Reduce your demand, LED lights, keel coolers etc. 4. IF you decide to increase your battery capacity then you will have a usable capacity 33% of the new stated capacity (at anchor) and if you use it all you will have to find more AH every day to replenish it. 5. Battery monitors are unnecessary all you need is a good voltmeter. If your monitor does not require a peukert number to be programmed in - bin it!
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svmobert
Junior Member
Posts: 18
Country: USA
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Post by svmobert on Oct 8, 2014 19:45:04 GMT
Malcolm, I actually read your other post about the wiring before I originally commented on this one. I was mapping out my own wiring that same day and noticed an issue myself. Specifically it seems that the charger/inverter is completely connected to just one of the 3 batteries in the house bank.. while the rest of the house loads have a normal + on one end of bank and - on the opposite end.. I plan to move the inverter cabling to match the rest of the house loads.. After looking at the Victron install guide I believe I know how to integrate the shunt into my battery bank.. So I drew up 3 diagrams.. here they are, one is how it's wired now, then how I think it should have been wired, followed by how I believe I need to wire it to use the Victron shunt.. Attachment DeletedAttachment DeletedAttachment Deleted ......... but I have a Victron BMV-702 on order and will use that to measure my AH consumption over time. .............. Sounds like you are on the right track and I for one would like to hear more on how you get on. One thing to watch for when you fit the Victron is that you don't have more than one negative attached to different ends of the battery bank as my 39i did from when originally fitted at the factory - see thread: jeanneau.proboards.com/thread/3358/odd-wiring-main-battery-bank
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Post by optimystic on May 29, 2015 0:03:11 GMT
I'm getting ready to change batteries from the stock 3 yr old 12 volt wet cell to Trojan agm or Trojan 6 volt. My batteries require water every 4 months and voltage drops from 12.8 to 11.4 in 24 hours with only the fridge and bulge pump circuits on. Is it worth the move to a 6 volt bank? We have 3 house batteries now so I guess we would need 4 or 6 of the 6 volt and they are expensive.
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Post by so36idavid on May 29, 2015 3:24:20 GMT
Opti,
You need to get on top of the Ah that you're pulling out of the batteries so that you can do an energy budget. Either get a clamp ammeter or install an Ah meter to figure out how much your fridge, lights etc. are drawing. Then double that and you have a lower bound on the capacity of the battery bank you need between charges. If you draw more than that you will destroy your batteries, which is what you might have done to the current lot. A good set of batteries should last a lot longer than 3yrs if properly taken care of.
David
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Post by ianpowolny on May 29, 2015 5:15:47 GMT
Opti, last year on anchor we would get down to 12v overnight but I didn't do anything about this. Our 4 (house) x 110ah Trojans; 1 X Trojan engine start and 2 x Red Tops for the bow thruster. They were all the originals from 2008. This year we couldn't get the bow thruster to work. I change out the two Red Tops and found one was swollen. Having now had time at anchor I find the power at 12.4v overnight. Seems the old swollen Red Top was causing the problem. I had great plans to make changes to the 12v power system when we bought Affinity 3 years ago. I'm glad I didn't. We live aboard 6 months of the year and don't have solar panels, diesel generator, wind generator, upgrade charger or alternator. We may add solar if we every find a reasonable price for an arch. Until then all is fine on board Affinity. Ian
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Post by vasko on May 29, 2015 10:19:33 GMT
It all depends what type of sailor every person is - marina boy or anchor boy
if you are marina boy you do not need any type of solars or wind or big house bank ( 130ah - 150ah will do for you just great)
if you are a anchor boy then a (house bank >= 300ah) + (solars >= 240w) + (wind >= 300w) is a must
if you go on anchor only occasionally and you find yourself in the morning to not be able to take the anchor off without starting the engine - the first thing to consider is increasing the battery bank to about >=250ah and if this still not enough second thing is a petrol silent generator with remote control (HUYNDAY has very good models for about £600-£700)
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Post by Xlnt on May 29, 2015 11:53:23 GMT
For what it's worth. I have had alot of energy problems but mine now seems sorted out. Had a battery in the housbank with a dead cell - Replaced them all. Voltmeter underreading by 0.4 volts - Got mine fixed at Schriber, but still underreads 0.1/0.2 volts Rewired some nav stuff that makes me able to use less instruments/gadgets as radar and a second GPS while sailing. Dead fan on the fridge compressor / replaced fan and fridge runs a lot less hours. Bad thermostat in fridge, was sitting at full speed - managed to wiggle it and suddenly at started to work again at a lower setting. Replaced TV's with low energy 19w oled TV's Replaced all halogen bulps with LED bulbs Had a bad Mosfet battery isolator / replaced with new from Quick Had a bad Mastervolt chargingregulator/alternator - Reinstalled the original Yanmar alternator with builtin regulator
My housebank 7*110amps can now last ha whole weekend without a problem, TV's running, fridge, lamps, heater most of the time, radio, pressurepumps, cellphone chargers etc. Drops from 12.8 to 12.4 over night but sits long time between 12.0 and 12.4 volts
It is worth looking into, tears you up that you constantly have to worry about voltage and not enjoy your weekend.
Rgds
XLNT
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Post by vasko on May 29, 2015 12:15:10 GMT
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Post by Zanshin on May 29, 2015 17:21:15 GMT
Vasko - I tinker with Arduino boards and have been monitoring my energy use for quite a while, and am now working on a "Fridguino" which will perform some interesting logging and sophisticated fridge control (especially on variable speed compressors such as the Danfoss and Cubigel) - details to follow. It has 4-6 pea-sized digital thermometers arranged from bottom to top of fridge (in order to measure the thermocline) and has better algorithms than the smart controllers from Danfoss. But back to the original post - here's a graph of a typical day of my main bank voltage. The voltage spikes downward in the morning are my making coffee with 70Amps, which draws down the 440Ah (@24v) bank. I have a constant drain overall of 5A (fridge and freezer plus incidentals), this pulls the voltage down a bit. 06:30 Espresso 06:30 - 07:50 One can see that the sun is putting a bit of charge in the bank through the panels, but not really charging the bank yet 07:50 I started the generator to make breakfast and charge the bank 09:15 Turned off the genset - put in about 70Ah 17:17 Turned on watermaker
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Post by alex1949 on May 29, 2015 22:43:08 GMT
Hi Optimystic, In order to control your elect. Power first start by implying one of those meters like the Victorn 701 or similar. Only with it you can measure and give yourself any exact figures about power consumption and battery control for both house and engine batteries. Your fridge is drawing 60-70 vats (5-6 Amps) on running. If it is the usual Jeanneau junk box that they call fridge than expect the compressor to work 90% of the time on relatively warm day.This is enough to answer your question about where all those Amps going to. Install a meter, than take care about your fridge isolation and picture will be much clearer thereafter. The old regular volt meters installed on our boats worth nothing and you need being real experienced to run a sound elect. system with it. I did all that on board my 2005 40DS. Alex
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Post by MartyB on May 29, 2015 23:21:23 GMT
I will not rehash what some have said. BUT, going to AGM' bats of either the 12 or 6V version may require you to spend $$$ to upgrade the alternator on the motor. As they can take a charge of 40% of the total drop and will try to get this being charged, vs 25% for a lead vs 20% for a gel cell battery. Going to an AGM while positive in some ways, may be negative in others.
Not sure what size your current house setup is. But if say 3 size 24 or 27 12V lead cells, You can get two 6V Batteries, do not remember the size, that have more reserve than the named options. Issue with ANY lead 6V is most are around 1-1.5" taller than a typical 12V, and may not in the battery compartment. This was not an issue with an RV trailer I had when moving to the 6V bats I am recalling, that were from a floor space, the same size as a 27. But total amp hours were equal to slighter greater than 3 27's. If you go with the typical golf cart sized 6V, you will probably need at minimum 4, if not 6 to equal these two I had, or the say 3 27's you have. I have not looked up the numbers to be positive.....but worth doing so.
A nice factor about the 6V lead cells, is they can take upwards of 1000 charge/discharges, vs AGM, gell and typical 12V lead in the 200-500 range.
Locally, Fisheries has "Lifeline" 12V batteries, they are a bit heavier than other brands typical lead ones of equal size, they have 5-10 AHR more. I had a size 24 on my boat for a couple of years, it was 5 ahr short of a typical 27, the 27 was equal to a size 31.
My 02 on the subject, as it is not an easy one to figure out and do in reality.
Marty
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Post by vasko on May 30, 2015 12:15:31 GMT
Vasko - I tinker with Arduino boards and have been monitoring my energy use for quite a while, and am now working on a "Fridguino" which will perform some interesting logging and sophisticated fridge control (especially on variable speed compressors such as the Danfoss and Cubigel) - details to follow. It has 4-6 pea-sized digital thermometers arranged from bottom to top of fridge (in order to measure the thermocline) and has better algorithms than the smart controllers from Danfoss. But back to the original post - here's a graph of a typical day of my main bank voltage. The voltage spikes downward in the morning are my making coffee with 70Amps, which draws down the 440Ah (@24v) bank. I have a constant drain overall of 5A (fridge and freezer plus incidentals), this pulls the voltage down a bit. 06:30 Espresso 06:30 - 07:50 One can see that the sun is putting a bit of charge in the bank through the panels, but not really charging the bank yet 07:50 I started the generator to make breakfast and charge the bank 09:15 Turned off the genset - put in about 70Ah 17:17 Turned on watermaker Using Aduino to monitor and control the fridge is actually very good idea... in fact a Arduino can be used to control all electricity on board including the charger ( there s a Arduino MPPT controller available) etc. pity I did not got this idea before starting to improve my electricity system, currently I already have all setup with old school stuff - like NASA battery monitor MPPT controlers etc..
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Post by optimystic on May 30, 2015 16:21:30 GMT
Marty our current setup is 3 group 24 for the house bank. After a day with mixed motor and sail then a night on the hook and the fridge turned off we are at 11.7. The only other drain was the led anchor light. I need more power but duration is critical for summer trips. Your input on the charging system is key. I'll look at fisheries. Maybe look at sealed lead acid. All batteries are under the floor and a pain to access. The 6 volt idea needs more thought. It seems to be much more complex than anticipated. Thank you for your input. It's valuable as are all the comments. Maybe Jeanneau should build better capacity on new boats. 3 years isn't very acceptable.
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