Tubular Plate (Wet) or Sealed Spiral Cell (VRLA) for House Batteries, . . . or ?

[Pelagic]

For the last 2 weeks, while Typhoons have been battering the Philippines I have been hunkered down here in Subic studying the details for a balanced Electrical upgrade of my 64ft Dutch built (84) motor sailor (StarGazer), starting with replacing the Batteries that are pretty much shot!

To be honest, after reading up on everything from von Wentzel and the Victron Energy Book by Reinout Valder to then following the entire Forum’s Electrics topics (16 pages) with some very expert contributions, my brain is a bit fried!

I don’t get much technical support here so would like to air my thoughts with a few questions, where things get fuzzy…Thanks!

Boats Purchased configuration: (in 2005)
7 x 12v batteries about 3 years old (Flat Plate heavy duty truck starter type) unknown (Thai?) brand YUSA 200N each about 20”L x 11”W x 9”H. Inventory said they were 200AH each

House = 400AH @ 24V (4)
Start = 200AH @ 24V (2)- coupled to House with Mastervolt Battery Mate 100/2
Radio/Gen start 200AH @ 12V (1) connected to Victron Orion DC/DC 24/12-20 Converter

Northern Lights 12KW Gen
Victron Skyla 24/50 battery charger (Old model)
Prosine 1800 Watt inverter

Main Eng. Perkins 150 hp T6.354 with Balmour 621-24-70-SR and Max Charge MC-624 regulator
(Quickly upgraded from 24v- 40 amp automotive standard-type alternator after delivery trip)

My experience with the present 400AH shows that even with conservative use we discharge past 50% after 12 hours and with the 50 amp battery charger the Gen is running +8 hours (in 24) to keep up. (even when the batteries were fairly new)

Our Usage is as a live aboard couple in the tropics, mostly anchored rather than at marinas. My goal is to find the right balance between charging equipment and Battery Bank, so that the Genset only needs to run for 2 hours twice a day (4hrs total) to recharge an anticipated larger house bank of 600AH from the 50% level. We are not rich!

Purchase list:

1 I need to identify the best value in Deep Cycle battery types that can take fast charging without damage and has a low height profile of 15”

Q1 Reading comments about lead batteries going up in price are the Tubular Plate (wet) or sealed (VRLA) spiral cell Optima Batteries what I should be considering? Any other suggestions?

2 I need to size a Battery Charger so as to only run the Genset for 2 hours twice a day(4hrs total) to recharge an anticipated larger house bank of 600AH from the 50% level

3 I need to size a larger Inverter to be able to handle the HRO System 9/500 watermaker’s 1hp single phase pump motor that shows power consumption at 9/2.1 (Amps/kw)

Q2 /Q3 Is the Victron PhoenixMultiplus 24/3000/70 a good choice to bring the 600AH up from 50% in 2 hrs using the 70amp charger and when motoring will the 3000 Inverter handle the 1hp 9/2.1 (Amps/kw) R.O.?

*If necessary can I couple the existing 50amp Skyla Charger and Prosine 1800watt into the system without doing damage?

4 I need to size a large Case main engine PTO driven Alternator so that it handle the increased DC demands of the Watermaker/Invertor on top of existing running demands

Sailing 24V Ah DC Load Analysis: Observations on the 2000nm delivery from Phuket to Philipppines:

Auto pilot 12 amp on rudder action = 30% of 24hrs = 86 Ah
4 x Isotherm Fridges 12 amps when cycled on = 30% = 86 Ah
Nav Lights 6 amps when on = 30% = 48 Ah
Nav Electronics 2 amps =100% = 48 Ah
E.R. Lights 5 amps when on
Lights/Fans 8 amp allowance = 20 Ah
Other Consumers Stereo / domestic pumps = 16 Ah

Inverter 1800 Watt 20 amp for kettle microwave (40) = 50 Ah
Miscellaneous = 10 Ah
Consumption per 24-hr period underway = 364 Ah

My understanding and calculations are a bit shaky on this but can I infer a scenario of approx 50-amp demand, (Plus the watermaker running through the Inverter) while trying to charge the batteries ?

Q4 If that seems about right then would the choice of something like the Balmar 97-24-140 amp Alternator be a reasonable choice to handle the increased loads without overheating.
Note:
Bow Thruster 50 amp on action
Anchor Windlass 45 amp on action

Q5 To add a possible wrinkle, Star Gazer had been at one time fitted with a Shaft Alternator, which has not been used in years. Running off a strongly built 14” Stainless Pulley has there been any success in using a PMA type Alternator to give low RPM charging while under sail only. Should it be a consideration?


Q6 The boats electrical consumers had all been replaced in 2002 without much thought to economy of battery consumption as the Owner used the new Gen or stayed at marinas most of the time. Eventually I will replace them when they die out, but any other ideas or thoughts I should be considering?

Thanks for your help

Nick

[Pblais]

Nick,

I don't envy your problem but it's great to see you using the time you have to plan a new electrical system. It sounds like you need one for all the right reasons. Having been in a marina all the time made the approach of the last owner not the same goal that you now desire. You have a lot to turn around. It's going to take a big picture approach to solving it.

Your system has a lot of consumption that isn't easily quantified. You appear to be using marginal batteries and so are running the genset more because you just can't get enough out of your batteries and worse yet your charging capacity isn't very good. It seems you need a whole new design to power and maybe a better way to go forward.

For batteries you need deep cycle batteries not truck starting batteries. Deep cycle batteries Will cycle to 50% quite well but starting batteries don't like it at all. It's not just "bigness". From the sound of the current system I would doubt you have much if anything left in the battery bank.

Your number of amp hours used are a critical set of numbers and one that a battery monitor would help you with a lot. I would add one as part of the new system so you can measure actual use and not have to rely on estimates. You may find that actual numbers are a lot different. I know it was true for me when I added a monitor on my last boat. You learn all about amp hours very quickly. You may be able to add one now. Given your problem if you can make a bettor estimate I know it would pay off for you.

Since you have been through a lot of reading already perhaps you have picked up on some of the technical aspects more than you think. The real problem is that it really is technical and you need all the medicine. There isn't a quick and easy fix for you just yet.

One item you may have seen here already is the discussion with Knottyboys about his electrical plan for his trawler. Not that his plan is the one you need but it's one of the few fully laid out plans along with good discussion we have here. Reviewing it would give you insight to the larger picture so you could learn more about the details.

It would be a good idea to design from the ground up and then work the plan over phases to get there in your own time and budget.

1. Don't even think of adding any more batteries without a fully defined charging plan. Not properly charging batteries all the time is money down a rat hole. You appear to have already done this once. It's not just what batteries you use. It's how you use and charge them that matters more. Right now state of the art are AGM batteries since the lower internal Resistance means they can be recharged faster than wet cell batteries. Were you to drop those in place today your currently unadjusted charger would problem trash them in 9 months and you can throw away a lot of money. You could keep using what you have but you already know where you are at already. The charging pattern must be set up before you add new batteries.

2. From just a preliminary run at your numbers. I see no hope what so ever to recharge all your batteries in 2 hours. Your usage is higher than your charging capacity to deliver it all in 2 hours. When you add a lot of batteries it does not help the problem. All the batteries need to be fully recharged at some point. You want enough capacity to get down to 50% and then quickly get back to 100%. That means the battery bank has to be no smaller than required but also no larger. The last 10% you top off takes a lot longer time to reload. As you near the full mark in charging the rate of charge goes down but the engine still runs. A huge bank kills you worse than a small one while you wait to get the last few percent added back!

3. Consumption is the key to making this a simple system. Every amp hour you never used is saving you time with the engine running. Cutting consumption means you reduce the need for the larger bank. Finding reasons to make the bank bigger is not what you need to do.

4 refrigerators is a big item. The Isotherms are pretty efficient but your numbers might be a tad conservative. Consider how you use them. You may not need to operate them all in the same way all the time. Adding a wind vane to reduce the autopilot power could help more than you might think. When looking at consumption it's not the lights - it's everything you run on the inverter. Thinking of a larger inverter might mean adding a larger genset.

5. Wind and solar can help a lot if you reduce consumption. If you add them make sure you set up a regulator so the charging pattern is maintained. Examine how you might attach solar panels as they work hard and make no noise and require minor labor to maintain. Wind power may work best en route since you are out in the open and prone to having more wind. At a secluded anchorage you probably won't have 15 knots of wind (I hope).

6. The size of the alternator won't seriously help you all that much. It would if you were actually using a lot of power at the same time. You clearly don't use power that way. If you are running a bow thruster or a windlass then of course the engine is running so those huge loads won't dent the battery bank much.

7. The shaft alternator may be of benefit provided the transmission can handle spinning freely without engine power. You can run into cooling problems and indirectly trash the transmission by running in neutral. For alternative energy I would consider it as well as the solar and wind options. Both of those are great under sail. I would develop a pattern of use for when under sail. You really want to reduce the need to run the engine under sail. It is the best part of the trip after all. The idea is you don't use power all the time the exact same way. You need multiple energy budgets based on the ability to make new power. Plugged into shore you have plenty and no worries.

[Ex-Calif]

Excellent post by Paul and I agree that you have done excellent homework.

You are in for a big retrofit as Paul states and investing in the battery monitor now and tracking consumption is a good investment for the future.

Also he is spot on - The capacity of the batteries is important but your amp defecit and credit equation needs to balance. This requires understanding what you are consuming and developing a plan to replenish it. The batteries are just there to extend the time between charge cycles if possible.

I am not sold on wind - quiet anchorages and downwind sailing tend to work against wind generators although a ton of folks have them.

I would look at solar - In the tropics we get tons of sun and you should have a plan that takes advantage of that. You have a large boat so it should be well suited to large panels. The good news about panels is they fundamentally work all the time. You'll get the daily amps regardless.

Beyond that it's battery choices and deep cycle batteries make sense for your house. I wouldn't venture to guess about alternator replacments but I am sure that will be part of the plan.

Once you have figured out the generating and storage of the power you can develop a plan to start shedding load. Some things will be expensive and some things you might be able to do sooner.

In the short term it's probably less capital intensive to get the supply side figured out. Good luck.

[Pelagic]

Thanks Paul, I agree completely that I need to look at the big picture and system re-design to balance the electrical consumers with new storage and charging solutions and in all likelihood some major upgrades in wiring to keep it all safe. This is the project I want to do in the next 2-4 months, while I am still in Subic.

It was immediately apparent before I bought the boat that the aging electrics were dependant on the new generator and the DC charging system seemed inadequate, but what can I say…I was in love!

I do have 2 old “Magnetronic DCC2000” digital Battery Monitors (12 & 24V) that I should explain better if only I could read German! They do give me Battery Voltage, actual Amperage draw/charge and a total amps consumed that can be zeroed for 24 hr measurements. (I will add a modern one to the system)

Starting with a dead ship and turning on each unit independently I got accurate readings and then averaged the daily consumption to get a sense of actual use. My consumption seems to jive with other yachts my size who have either 600 or 800Ah @ 24V storage battery capacity (compared to my 400Ah).

What I suggested above was only a starting point for discussion (I have much to learn) but from experience on using the boat the 12kw AC generator can run a much bigger battery charger than what I have now.

It takes a good 15 knot breeze to get StarGazer going, so I usually motorsail most of the time with the Perkins quietly running at 1000 to 1400rpm. Even in light winds with engine assist at low rpm I am making 7 knots. So I will need to size my pulleys to get the most out of the suggested Balmar 97-24-140.

I am assuming the Max Charge MC-624 regulator can be used on this rated 170 amp model?

There are 3 new Seahorse “Diesel Duck” 43ft trawlers beside me at the club all using the Victron Energy Phoenix Multiplus 24 volt/3000 watt invertor/70 amp charger with their 600 Ah battery banks. I went on a 2 week shakedown cruise on one and the system seemed to work well on their smaller (than my 12kw) generator. Consumers seemed about the same as mine.

Is Victron a good brand or would you recommend another Maker?

Paul, it seems to me that choosing the Batteries would be the first step in planning a complete system. In the Victron Energy “Book” they talk about Tubular Plate (wet) Traction batteries used in Forklifts as “being extremely robust and accepts a very high number of charge-discharge cycles. It is an excellent low cost substitute for Sealed gel or AGM batteries”

Does anyone have experience with them or could recommend an AGM model suitable for 600 Ah Bank?

Wind and Solar charging are part of my plan but finances dictate that I get the basic system working and bring them on line later. (But I will plan for them now as I have lots of room on a new hard bimini to install them).

Did not find the Knottyboys electrical plan. Just photos of other installations. Can you remember the title of his post?

Lastly, can anyone recommend a supplier of Electrics who is also a good technical consultant for this project. I am happy to buy through them for drop shipment here in Subic if they can provide the technical expertise

Nick,

[Alan Wheeler]

Hi Nick. Firstly, If you haven't yet, check out the "Study Hall" at the top of this electrical forum and hopefully you will get a little more info and understanding.
Secondly, Yausa are a very good highly respected name of battery. However, start batteries are not the best choice. You need Deepcylce for house duty and start for Starting. :See the study hall:
I am currently refitting my electrical. I am similar in power consumption. I am fitting 600Ah of deepcycle FLA. I have installed a Heart Interface Freedom 25 Invert/charger. This can provide 130A of current back into the bank and is powered by the Genset. The aim was to get the maximum charge back into the bank in the shortest possible time. Although some designs will accpet a higher charge rate than others, there are two points to consider. The higher charge rate is not that much higher. 20% as against 25%. So you do not achieve that much in saving of charge time. The other issue is finding a charger that is capable of delivering that much current anyway. The Heart unit I am using, has beent he largest I have ever found. A large Alternator is the only otherway, but that means powering from the main engine, which I did not want to do. I had toyed with the idea of fitting an Alternator to the Genset to take advantage of not using all the Genny's power all the time. But finding the charger took me on a different path in the end.
I looked at Solar and Wind, but none of these options could effectivly and economicaly charge or even maintain the bank of 600Ah size in the time frame needed.
The battery choice I have taken is FLA. Because of what I have to pay for batteries here in NZ, I decided I wanted the longest lasting battery I could find.
The only advantage I see in the spiral Optima's, is that they can be very deeply discharged with no ill effects. At least, this is what they have published here. I don't understand why they can be any different to any other design in the respect of discharge, but that is what they say.

[jscott]

Lots of words, but

a battery/ battery charger system should be sized to take a battery from fully discharge to fully charged in about 6 hours (maybe 4 if you hit them really hard).

So if you want to push 360 AH in two hours you from 50% discharge, you need about 720 AH battery bank and 180 amp charger.

Go with the more common 800 AH and 200 amp charger.

@24 V that is 4800 kW So the 12 kW genset should do it with a large 24 Volt inverter charger 5000 W min.

[hellosailor]

Nick, I don't know what Victron is referring to but "tubular plate" sounds like a contradiction in terms, I've never heard it used here in the US. There are "flat plate" batteries, which are conventional batteries made with alternating layers of flat plates. And there are "spiral" batteries, in which the plates are "wound up" in one long spiral, such as the Optima AGM batteries. I've never heard of a spiral battery on the market except for AGMs, but AGM's are built both ways--flat and spiral.
AGM's and gel cells are both "sealed valve regulated" or "SLRA" "SLVA" or similar terms. But only AGMs (as far as I've heard) are ever built using the spiral construction. In theory it lowers costs and increases reliability. In practice, you are putting round cells in a square box, so you lose capacity in the box. And the patents seem to ensure that costs are higher--not lower.

AGM versus wet seems to be the main decision. Wet will be cheaper, AGM can charge and discharge at higher rates, never spill acid, and typically cost 30% or more than wet batteries, even when both are flat plates. Deciding between the two is about that simple.

Fork lift batteries usually are commercial batteries, designed for repeated deep discharge and available as single 2.2-volt cells that you gang up. In some locations, in some capacities, the best bargains are in golf cart batteries simply because they are so common and a competitive market. Fork lift batteries will tend to be aimed at much higher capacity and larger size. Some brands like Rolls and Surrette are terribly expensive--but owners routinely report them lasting over ten years, because they are commercial grade and simply built to a different spec, compared to other brands of deep cycle "marine" batteries.

Once you spec the system capacity you need, given the limits on battery height, local suppliers, and how heavy a battery you can lift, the number of choices will shake out pretty quickly.

[bill good]

Palagic,
G'day are you sure you do not have something faulty? The batteries may be faulty but it would be a shame to change them without proof!!. It looks like when motor sailing every thing is OK. If you look at the loads the fridges are the most. you show at bit less than what it is but allow 140amps per day for the boat.This is 6amps per hr or 35amps per 4hrs. Your 50amp AC charger should be good for this but check its full specs as it might only put out 50amps for a limited time. If so what about a second charger & split the batteries during charging. Just be aware the specs on the genset may be 12kw at 60hz & 10kw at 50hz. You are only using about 1.3kw for the battery charging at present.The batteries can be tested to get the current specs & may need changing. I still cannot get to the real answer on just how good the Optima batteries are. The local agent for them here is saying his made in china has less warranty claims and the optima require special charging . I am currently adding 400w solar system with an outback mx60 controller to ensure it will cover all types of batteries. ( this controller can do 60amps @ 24v) . (1) check there is no discharge with not accounted for. (2) if you can try to establish the present capacity of your batteries by fully charging them, let the stand then discharge them to say 10.6v the books you have should tell how manufactures do this. replace them if you are not getting 150amps total in the 5hrs of test.

Just take it step by step & do not change to many things at once. It all must have been good when first set up.

regards Bill Goodward

[GordMay]

Exide has been manufacturing and marketing Tubular Plate Batteries throughout Europe for several decades, and has now transferred this technology to GNB Industrial Power for sale in the U.S., Canada, and Mexico.
I don't know that they are (often) used in a Marine application.
The difference between Tubular and Flat-Plate lead-acid batteries is in the positive plate design.
In the flat-plate design, the positive plate consists of a latticed grid of antimonial lead alloy onto which a wet mixture of positive active material is pasted.
In the tubular design, the positive plate consists of rods of antimonial lead alloy surrounded by sleeves of an inert, porous material such as polyester. The sleeve is filled with the positive active material and tightly packed around the lead spines.

Goto:
http://industrialenergy.exide.com/gn...n&mp_sub_id=10

Call GNB toll-free at (877) 462-4636 for a free copy of "GNB Tubular Batteries" (technical bulletin #GB-3971)

[Pelagic]

Thanks very much for all the sound advice! In each of your posts you managed to light up some of the dark corners on how I should proceed, so the task doesn’t feel so daunting today. Now as they say, “the devil is in the details”

Basic 24V Plan:

At Anchor

• Confirm average consumption for 24 hrs (between 8 to 10 kWh per day) and Size up to either 600 or 800 Ah House Bank
• Confirm wiring sizes for upgrade
• Identify Charging Rate for selected Bank and,
• As Jscott suggests, size large 24 Volt inverter/charger to suit. (Recommendations on manufacturer?)

Motorsailing:

• As my M.E. hardly works when I have any useable breeze (usually 1000 to 1200 rpm) install a Large case 24v Alternator with external regulator to suit batteries, plus running loads, plus 1 hp water maker pump thru Inverter.
• Adjust Pulley Ratio for Idle Charge plus 1200 to 1500 engine RPM for optimum charge (anticipate Alternator size rating from 140 to 220 Amps (Recommendations on manufacturer?)

Pure Sailing
Takes about 15 knots wind to get cranking and the shaft and my large prop is designed to free wheel. If my speed thru water is six knots, my shaft is turning at about 400 RPM. 14” Shaft Pulley available for shaft alternator

• I have been looking at the PMA (permanent magnet Alternator) to install as a shaft alternator.
• See http://www.hydrogenappliances.com/powerpmas.html#anchor337480
• If you look at the power curves for the #SC24 - $329.95 usd ..do I understand this correctly that at only 900 rpm it is putting out 46 amps @ 30V? Might be worth a try

Batteries:
Thanks Wheels, I did read the study hall primer and it is interesting that you are doing a similar electrical refit. Are you 12 or 24 Volt? I tried to find the Heart Interface Freedom 25, to confirm, but it now is Xantrex.
Would like to know what kind of FLA Deep Cycle batteries you are choosing, so that I can do some costing and sizing.

When I read Vonwentzel, he seems to have a different take on battery charging rates:
· Flooded cells are usually bulk-charged at an ampere rate of about 25% of amp-hour capacity. For example, let's say you have to replace 100 Ah every day and chose to install a 400 amp-hour house battery bank. Using the 25% ratio, the maximum charge acceptance (the rate at which the battery can be safely charged) of your flooded battery during bulk charging would be around 100A. Assuming you have no other charge sources on board, after losses and other loads you would want to consider a 120 ampere (hot) rated alternator.
· If you use Gel cells, you can bulk charge with twice the current that flooded cells can sustain. A 400 amp-hour bank composed of gel cells can safely enjoy the benefits of a 200A charge source and bulk charge in less than 1/2 the time of a flooded cell (due to its higher charge conversion efficiency). Here, multiple small frame or a single large frame alternator may be ideal in order to reduce charge time and engine wear.
· The Lifeline AGM, is not current limited at all during bulk charging according to Concorde, the manufacturer. Theoretically, you could make your bulk charge time as short as you would like. In practice, people are charging AGMs with currents of up to 4x the amp-hour capacity. Accounting for conversion efficiency that would be 18x faster than your typical flooded cell but you'd have to install a charge system capable of delivering 1600 amperes to the battery bank (it would take about 5 minutes per day to replenish the 100 Ah with a 20 kW gen-set). In the real world, two large frame alternators may be more appropriate from a weight/cost standpoint
Pretty different from what I have read elsewhere…. Any opinions?

Good summary from hellosailor. Thanks!

My physical space for house batteries is 80” long x 50” wide x 15” high so that will have a big factor in what I can choose (along with budget).

Nick

[Alan Wheeler]

Firstly, let me make everyone very clear, I AM NO BATTERY EXPERT!! The advice in the study hall is a collection of information I have pulled a re-written to avoid copywrite, from some very respected manufacturers of charging devices(such as Heart) and thoroughly checked and edited by two very respected experts in the field of this topic. Both whom are members here. Without kissing Arses, I do consider "Rick" as our major expert, seeing as he has basicly "written the book" as it were, on charging. From what I do know, I would be very hesitant about using time to charge by. Certainly matching the bank size to charging capacity is more accurate IMO. I can not adise on how much more you can charge AGM, but from what I have so far read, it is certainly not double. In fact, what I have read and if memory serves me correctly, I am sure Rick has also mentioned this, is that an FLA can be safely charged at 20% and an AGM at 25%. That is safely charged. I believe you can thump in much more to either type, but seriouse monitoring is required, of which I don't believe there are any automatic chargers available that will do so.
Firstly, my system is 12V. Sometimes I wish it where 24V, but that brought up issues of 24V equipment and the main fact that 24V equipment was far more expensive down here.
The greatest difficulty I faced, was finding a mains powered charger of sufficient size. Being worried about over supply of current, in my case, was not a problem as I really struggled to find a charger any larger than the 130A unit I have finaly tracked down.
A large frame Alternator is still on my mind, but unless you use a charge controller, they still do not thump in the actual current they are rated for. The charge controller brings with it, it's own set of problems. The major one beign that a failure can cause your system to go way over voltage and fry much of your sensitive electronic systems. Which has happened a number of times to some commercial guy's in my Marina. It put me off going that way, till some manufacturer can guarrantee that they have a safety feature that will protect the alternator from doing such.
Yes xantrex is made by Heart. The freedom range is available in 24V. The Heart Freedom units are not Xantrex and are a different beast compleatly. Rick likes the older black model, (which I managed to track down) because the switching relays are the older large frame type relays. The new models use a smaller PCB type relay. If that is the only problem the new one has, then I would suggest it is still a very good and reliable device to own. If a relay does eventually fail, they should not be difficult to replace and even modify with a large frame type relay perhaps. From my intensive searching, I could find no other maufacturer making chargers any larger. At least not in a Marine application. There were some commercial chargers for specific industry uses, but the things are waaaay huge and not suitable for boats.
I finaly get my hands on my new batteries today, so will confirm what the name of them are.

[hellosailor]

Very interesting, Gord, thanks for the link. From what Exide shows the negative plate is flat, and the positive plate is not really tubular--but rather a rack of rods, instead of the traditional honeycomb plate. The only "tubes" appear to be the separator sleeves wrapping the rods.

Doesn't seem like it would do much besides lower production/assembly costs, but if Exide thinks they are better...Exide certainly might be right.[g]

[bill good]

Nick,
Just looking at that system of yours and noted the 24-12 converter. that could be using a bit more than you think. can't see the specs on the net but if it is being used for radio & charging a 12v battery it may not be a switch mode unit. 3ampsx24vx24hr=same as a couple of fridges!!
Bill

[Pelagic]

Thanks for the advice Bill,

Re: the Victron Orion DC/DC 24/12-20 Converter, mines is an older one and I’m not convinced it actually works. No manual with it so I will contact Victron for advice on Testing. Had not thought about that drain separately but as it runs the stereo, Nav/com, equipment, I put that allowance into the 24v package.

I tried to reply to your last post but next day it was gone. (must have screwed up on late night posting)

All my batteries are thin plate truck starting batteries. New Jan 04, normally replaced after about 3 years. After full charge the hydrometer readings are all uniformly “poor” even after temp compensation. They are probably sulphated up and I can treat them to clean them up, but I’m still beating a dead horse after 4 years of use

Good luck with the Solar project. Spent a lot of time in Brisbane (Dockside marina) when I was Captain of the Double Haven. Wish I had that kind of technical support and services here

[hellosailor]

Mike-
I don't know where your message went, but "Running a large diesel when not under sufficient load (such as powering the vessel) will glaze up the bore of the engine. " is the old school advice. Something has changed, at least in pickup truck diesels. There are a couple of diesel pickups out there with auxiliary powr outlets in the rear, diesel engine powered, and the makers say you can let them idle all day while running power tools on the job site. IDLE. DIESEL. And not void the warranty or glaze the engine up.

I don't know what the difference is, but I suspect it means the old marine diesels as we know them are in some way obsoleted now, and the advice about not idling the engine, will depend very much on how new the engine is. And whatever else is going one with this stuff, that no one is really talking about.