Battery Monitor - Advice & Recommendations

[psneeld]

Trawler or sailboat, both can be rigged and used in a variety of ways.... AND in exactly the SAME way.

Same ease of power consumption and production.

 

[sunchaser]

I love our magum Battery monitor. Last year upgrade our gen and inventor and add the battery monitor, totally redesigned the batter bank wiring so all the ground go to a super huge bus bar then a shunt and then the house grounds all go on that side. We also have solar. So I can see amps in, amp out, total amps use total amp stored, it is super accurate. I disagree with voltage only, did that and it only give a feel. with a properly designed setup you can see what devices/equipment are pulling what load (ie tun on bait pump and see the draw, turn on the refigerator and see what our inventer draws, put on all the lights, etc.
I also know when on Solar what it is adding gross amps and net. With just a volt meter you will see a high voltage when solar is charging for 5-8 hours a day but have no clue if it is adding 1 amp or 25 amps of something in between.

I guess I am nerd and like the details.
https://www.magnum-dimensions.com/battery-monitor-kit

Our two Magnum BMKs are equally effective. With the BMKs we are able to discern the amp hour savings by shutting the inverter off at night when at anchor. So many subtle things can be tracked which can be very important for long distance cruisers. Much like watching the screen on a Tesla to note differences in range when running at night or driving 85 vs 65.

 

[Codger2]

When it takes a left turn, I know it....but then again, I monitor it as I walk by almost each time.

Same here!

 

[john61ct]

Trawler or sailboat, both can be rigged and used in a variety of ways.... AND in exactly the SAME way.

Same ease of power consumption and production.

The ability to mount kW worth of panels, the effect on the aesthetic sensibilities of the owner and impact on the performance of the vessel will be different.

Trawlers usually have the advantage in all three factors.

Not to mention sailing cruiser-liveaboards are much more likely to go weeks without burning any dino juice.

Regardless, the statement that any one category of boat/owner "cannot avoid PSOC abuse" is simply false, or at least a gross over-generalization.

If you really want to get to 100% Full as per endAmps at least a few times per week, all it usually takes is motivation, knowledge and the right gear.

 

[DDW]

The problems only occur on a liveaboard boat, using flooded batteries with a minimum charging system. In that situation you will be running between 50% and 80% or so, ...

Well, I think I am. Your statement was just too wide ranging to be accurate.

Like many statements a lot of people have made in this thread.

You might have used the words some or many liveaboardsvwith minimal charging.... And I would have skipped over it.

I'll stand firmly behind my original statement. Nearly everyone living aboard with a minimum charging facility is going to try to minimize the run time of that charging system. To fully charge LA batteries from even 70% requires something like 5 hours, because of the long asymptotic tail on the charge acceptance curve. The last 3 hours will be at very low amperage finally decreasing to only a couple. The fat part of the charge acceptance curve is below 80% SOC, this is why these people will run from 50 - 80%. AGMs will fail very early with this treatment, hence the flooded batteries.

There are rare ones who might run the genset or main engine the 5 - 7 hours sitting at anchor to fully charge their batteries. Very rare. Also not smart, as the lifetime costs of doing so will far exceed a proper DC system.

Most of us either plug in periodically, move enough to have long engine runs periodically, or have more sophisticated charging facilities (solar in particular is very good at the long charge tail for LA batteries). Any of those fully charge the bank, and reset the AH counter.

But, tell me what you use for charging and how you manage them and maybe I'll change my mind.

 

[Xsbank]

What an appalling thread! This topic is as weird as anchors and bow thrusters.

Your batteries are good for 5 - 10 years, no matter what. Save your beer-bottle deposits to replace them when they are toast, a tiny but admittedly annoying drop in the boat maintenance bucket. Most of you are wildly overthinking all this and you are exactly why a battery-monitor company can get rich while you worry about nothing. Just use your boat for what it was intended and stop fussing. Go for a swim or a paddle and wait for the sunset...

 

[psneeld]

A couple of people have strong, generally correct personal opinions but no clue of other possibilities...

 

[john61ct]

I'll stand firmly behind my original statement. Nearly everyone living aboard with a minimum charging facility is going to try to minimize the run time of that charging system. To fully charge LA batteries from even 70% requires something like 5 hours, because of the long asymptotic tail on the charge acceptance curve.

Yes, in fact can often be 7hrs if you're really getting to true 100%.

But high-amp dino juice for an hour or two early AM to 80-85% when it's going to be a nice sunny day, then **if you have solar**, does not need to be a lot, you have the whole solar day to complete that long tail.

 

[john61ct]

There are rare ones who might run the genset or main engine the 5 - 7 hours sitting at anchor to fully charge their batteries. Very rare. Also not smart, as the lifetime costs of doing so will far exceed a proper DC system.

I believe no one was talking about that.

But there are owners who are often motoring that long in any case, so with a good alternator + external VR setup, they can get to Full even without any solar.

 

[DDW]

^^ As I said in the same post.

And if you have a solar charge system capable of that, you do not fall into the category of having a minimum charging facility.

 

[john61ct]

What an appalling thread! This topic is as weird as anchors and bow thrusters.

Your batteries are good for 5 - 10 years, no matter what.

Maybe Starter batts, or ignoring SoH specs for EoL, but

for those living aboard deep cycling their bank that cost thousands when new,

it's all too common to murder a bank in 2-3 years, that **could** last over 12 if cared for properly.

Obviously if those conditions are outside usage patterns you're used to, then this thread's topic is of only academic interest if any at all.

 

[john61ct]

if you have a solar charge system capable of that, you do not fall into the category of having a minimum charging facility.

Many owners have all the gear, but not the knowledge to give optimum care, or just lack the motivation, don't mind replacing the bank more frequently.

Which is perfectly valid of course, your rig your choice.

 

[psneeld]

Keep trying both of you....some of us have it figured out without being lab rats.

 

[DDW]

I believe no one was talking about that.

Actually you were talking about that nearly exclusively. The argument for the SOC meter is that it is the only accurate gage, because AH counters tend to drift off. They do not drift far if reset every few days. They get reset every few days by a full charge. The only boats that don't get a full charge every few days are the category I mention.

The SOC gage may be fine. But it is similar to an idiot light on your car. It gives you very little information. That may be all the information you are after, fine. I prefer an oil pressure gage and a coolant temperature gage to idiot lights, however complex the interpretation of them might be. I'll note that some car manufacturers (Ford, at least) have taken your side: the oil pressure gage in my truck is in fact an idiot light. When the oil pressure is above 5 psi it jumps to a fixed position in the green range. When it drops below 5 psi, to goes to the low stop. The reason, as explained by Ford, is that owners did not know how to interpret the gage reading, and complained when it showed low pressure when hot at idle. So they fixed it, no more complaints.

 

[john61ct]

Actually you were talking about that nearly exclusively.

No, the "that" refers to some straw man telling members to burn dino juice for 5+ hours a day just to charge the House bank.

Obviously ridonculous.

 

[john61ct]

The argument for the SOC meter is that it is the only accurate gage, because AH counters tend to drift off.

Most SoC meters are of the coulomb-counting type.

If you mean SmartGauge, I stated only it is most accurate and most user friendly, out of what has been on the market past few years.

SG200, which includes both types integrated together, as well as SoH (residual AH capacity) uniquely, looks promising but likely it will be another year or more before I'd maybe recommend it, unless Bruce @ OceanPlanet or CMS publish thorough vetting reports in the meantime.

> They do not drift far if reset every few days.

Yes, and that should be a manual process, many consider it inconvenient, if not difficult. The CEF, Peukert coefficient, and current SoH values must also be calibrated / adjusted, as CMS details in the link above.

So yes, an AH-counting SoC meter like BMV-712 or LinkPro is fine, great,

nothing wrong with choosing that type if you want the extra AH information **and** are willing to do the extra work and get less accurate SoC.

Or get both,

or neither!

your rig, your choice.

The point is just to help fellow members be informed, to make better choices.

 

[Gordon J]

I would not buy a mustang coupe to haul rock, and I would not buy an SOC gauge to tell me everything about my batteries. I only want to know when I get to 50 percent. I can not always tell this when loads are running. My smart gauge can. I can get the charge rate from my charger interface, and can reasonably learn when I am at 80 or better - typically when the absorption charge amperage gets to about 35 amps, on my 100 charger.

The smart gauge was cheep, and, compared to the link 20, magnitudes easier to install. I am surely wrong, but I am guessing most of us don’t want a science project, but only want to know when to fire up the genny.

My next and last batteries will be carbon foam.

 

[Simi 60]

What an appalling thread! This topic is as weird as anchors and bow thrusters.

Your batteries are good for 5 - 10 years, no matter what. Save your beer-bottle deposits to replace them when they are toast, a tiny but admittedly annoying drop in the boat maintenance bucket. Most of you are wildly overthinking all this and you are exactly why a battery-monitor company can get rich while you worry about nothing. Just use your boat for what it was intended and stop fussing. Go for a swim or a paddle and wait for the sunset...

Tiny drop in the boat maintenance bucket?
For you maybe but $4000 for agm to $8000 for LP4 (and we dont have a huge bank) Vs $200 for a decent battery monitor I don't see the battery monitor companies getting rich.

 

[sunchaser]

I agree with XS, at least in our case. We average about US$400/yr on battery replacement. This is about 2% or less of the vessel's annual cost excluding DDA.

Yes, a drop in the bucket.

 

[Simi 60]

I agree with XS, at least in our case. We average about US$400/yr on battery replacement. This is about 2% or less of the vessel's annual cost excluding DDA.

Yes, a drop in the bucket.

You agree that battery monitor companies are getting rich off of one off $200 monitors while you spend $400/year on replacement batteries?

Care to explain that logic and maths to us?

 

[sunchaser]

You agree that battery monitor companies are getting rich off of one off $200 monitors while you spend $400/year on replacement batteries?

Care to explain that logic and maths to us?

50/50. The battery monitoring companies only got my money once, rich no. Logic, geez it's a boat.

 

[john61ct]

It is 100% true that only a tiny fraction of boat owner and use cases "require" paying much attention to these topic areas.

And even if doing so might save some money, if the owner is happier ignoring it and replacing their bank more often, that's fine too.

Others treat electrickery as a hobby, so want detailed info, custom program rPi and Arduino gear just for fun.

Whatever floats your boat.

 

[psneeld]

I am good with that ....as long as a lot of new boaters realize in the real cruosing world, that only a tiny fraction of the debate may ever be relavent to them.

Their time might be better spent learning the other enormous amount of info concerning cruising.

 

[Xsbank]

AGMs are even more bullet-proof than flooded so you need even LESS useless information provided by complicated devices. I see the battery monitor/sog/whatever as being as useless as a fuel flow gauge; after a week of running and one refill, you have enough information about fuel burn that you'll stop looking at that too. Unless you are doing an Atlantic crossing or similar, detailed fuel burn is useless and I'll bet dipping the tanks is more accurate. Tanks get dipped on airliners despite all the electronics on board.

Lithium batteries in this discussion are a red herring, their care and maintenance is an entirely different topic than our lead-flooded.

If you stare contentedly at a sog for 8 years and then change your batteries or you look at a voltmeter for 8 years and do the same, how have you benefitted?

My insurance is $1400 ANNUALLY and my moorage is $6000 ANNUALLY and my fuel costs last year were $2500, that is about $100,000 over ten years and you think the cost of a half a dozen golf cart batteries (average for the owners on here) is relevant?

 

[john61ct]

FLA are much more robust, long lived stand up to abuse better than AGM. And much cheaper per AH per year.

Plus hydrometers.

So all in all, if you want / need to know SoC, going with AGM makes, the need greater not less.

I agree LFP is another topic, but it is worth noting SmartGauge only works with lead.

 

[DDW]

I'm not saying you NEED to know everything or anything about your batteries. You don't NEED a boat, for that matter. But if you've spent $100K just on basic overhead, do you think the $200 for a good battery monitoring system is relevant?

 

[Xsbank]

No.

 

[Simi 60]

I'm not saying you NEED to know everything or anything about your batteries. You don't NEED a boat, for that matter. But if you've spent $100K just on basic overhead, do you think the $200 for a good battery monitoring system is relevant?

Yes.

Take right now, fairly sunny day but there are clouds coming through.
240v hot water system is running, plus all the other gear and I look at the BM as a bank of cloud rolls through and see the amps in drop from +5 in to -55 out. I wont turn on the electric pressure cooker just yet and also turn the HWS off until next lot of clear sky comes through.

Being able to have some sort of idea what the draw is, what the charge is, whether or not the bank is 100%,80% or 50% at a glance gives a lot of confidence in the "electrickery" system for me and the wife and all available at a glance.

$200 well spent.

 

[john61ct]

And even now I'm thinking, hmm, how to automate that, only heat the water when bank is well on its way to full so only solar or alternator surplus production is being used. . .

Fun stuff

 

[BruceK]

Most solar controllers have a load connection as well as a battery connection, and have systems inbuilt for setting when the load receives power.
Boat owners get to know their boats and from a range of factors usually know how their battery and power systems are running. It`s being made out as more complex here than needs be.