Battery consumption of a fridge?

[MapisM]

Scary it is, but only if not done in the appropriate context.
If that's what 60V can do, I'm beginning to think that on new years' eve I could put a few shot batteries which I have onboard on the harbour wall and throw 230V into them, with a remote switch,
With some luck, I could manage a decent explosion just around midnight...!

On a more serious note, I'd be interested to hear more about the thing posted by Trundlebug.
The website indeed gives a sort of "snake oil sale" impression, but if it does work as Trundlebug says it's well worth a try.
Any ideas about the logic behind it, anybody?

 

[jfm]

Any ideas about the logic behind it, anybody?

Total guesswork and Annageek's info will be much better, but I guess it has some capacitors or something that charge up from the battery and -using electronic control/switching transistors- are used to make a pulse of high DC voltage across the battery terminals. (An alternative guess is that it has switching transistors that create a short across the batt terminals for a fraction of a second, hopefully long enough to fuse the thinnest dendrites, but somehow I doubt that). It feels a bit snakeoily so I'll be interested in Annaexpert's verdict. At £80/90 the thing is 50% of the price of a 220Ah LA battery, which feels too high to me; might as well put the money towards the battery purchase

 

[MapisM]

Yep, the price wouldn't be justified if it would be necessary to fit one box per battery, but as I understood it's supposed to work also when connected to a whole battery bank.
If that's true (and if it does work, obviously), it wouldn't take a sensational life lengthening to repay itself over time....

 

[rafiki_]

Good luck with the Raydome MM! Was this on IT E Bay?

 

[MapisM]

Good luck with the Raydome MM! Was this on IT E Bay?

Pardon?

 

[vas]

Pardon?

seems that rafiki, mixed us up MM.
he probably refers to my #10 post mentioning an garmin 24hd radome I won on uk ebay.
I'll report over xmass when I'll have some time to test it, fingers crossed it works!

back to batteries

cheers

V.

 

[rafiki_]

Sorry Vas and MM. End of a very long day here in Brazil.
My interest in IT E Bay is due to my Azi being 2 long glasses short of a full set. I have tried Azi direct, and unfortunately the glasses have been superseded, so I was wondering if these things came up on E Bay?
Apologies again for th Fred Rift!

 

[annageek]

I know we have had a few of these desulphaters in the past for evaluation. We have never really tried them out in anger though. Instead of using them, we just design the battery system correctly. With a correctly sized battery system and decent batteries they are unnecessary.

It is right though, or certainly the versions I've seen. They have a charge pump circuit in them that gives out highish voltage spikes. The problem is it depends on how sulphated the battery is as this affects its charge acceptance. If you catch the battery at the right moment, then such a gizmo might work, but if the charge acceptance is too high or too low then its not going to help. Then again there is a positive testimonial on this thread, and the highlighted unit may be a bit smarter in terms of being able to impedance match the battery. I haven't had a good look at the data sheet yet... I'll browse through it in more detail tomorrow. It'll give me something to do at work tomorrow... and I can call it research!

In my opinion though, these things are just like bolting a jet engine to the roof of your car to make it go faster. It may sort of work, but isn't really a reliable or sensible way to do things. And if you're imminently changing the batteries anyway, then...

 

[MapisM]

Sorry Vas and MM. End of a very long day here in Brazil.
My interest in IT E Bay is due to my Azi being 2 long glasses short of a full set. I have tried Azi direct, and unfortunately the glasses have been superseded, so I was wondering if these things came up on E Bay?
Apologies again for th Fred Rift!

Haha, no worries.
I'm sure you are more than capable of checking IT eBay directly, but if you think I can help with the search, either on eBay or elsewhere, if nothing else for language reasons, just send me a pic of those glasses and I'll see if I can find something.
Possibly some dealers could also have a few of them around, you never know...

 

[MapisM]

I'll browse through it in more detail tomorrow. It'll give me something to do at work tomorrow... and I can call it research!

It probably wouldn't be a big additional justification, but I for one would also appreciate the results of such research, thanks in advance!

 

[Trundlebug]

Total guesswork and Annageek's info will be much better, but I guess it has some capacitors or something that charge up from the battery and -using electronic control/switching transistors- are used to make a pulse of high DC voltage across the battery terminals. (An alternative guess is that it has switching transistors that create a short across the batt terminals for a fraction of a second, hopefully long enough to fuse the thinnest dendrites, but somehow I doubt that). It feels a bit snakeoily so I'll be interested in Annaexpert's verdict. At £80/90 the thing is 50% of the price of a 220Ah LA battery, which feels too high to me; might as well put the money towards the battery purchase

Yep that's right from what I can tell. A red light flashes every second for about 30 times, then green + red stay on for about a second. I'm presuming from that that it charges up a capacitor then discharges it as a spike to reverse pulse the batteries. I haven't put a multimeter across it to test though.

You're missing one thing in your cost assessment above, one Megapulse unit can be used on a whole bank of batteries, you don't need one per battery. This makes it more cost effective.
That's how we have it set up on our cherry picker at work, one unit per bank of about 8 batteries.

There must be something in the technology, Sterling make a similar product I understand and there may be others on the market, also getting round the patent somehow (unless it's run out).
I don't have any experience of anything other than the Megapulse, and I must admit before I bought I was sceptical, but the economics of 2 units @£45 ea (as they were then) vs new batteries for £3k or more made the decision rather easier. I knew the batteries were just sulphated up, they had been left standing without being used or charged for a considerable time and a full charge wouldn't last longer than about an hour's use. Now we get nearly a full day out of it.

 

[annageek]

Right... so I have had a slightly closer look at the Megapulse device, and realised there is pretty much no technical information whatsoever on it. In fact, after reading the whole sales brochure, I couldn't help but think of the news story of the fake bomb detectors (http://www.bbc.co.uk/news/uk-29477894)

I too was aware of the Sterling Power desulfatey-pulsey-things. These seem to have a bit more hope - the fact that they are available not as a one-size fits all solution, but in various models for different size battery banks, is promising. Going from their datasheets, it appears my hunch was correct and they do apply a pulse from a charge pump circuit that's charged from the battery. In principle, I can't see why this wouldn't work, and I am certain that in very tightly controlled conditions, it'd most likely work a treat. The varying size / type / storage conditions / charge regeimes / usage of the 'average' boat battery bank though, is not exactly the 'tight control' I was talking of.

My experience with lead-acid batteries is that no matter what exact type of technology is used, variation can be massive in pretty much every respect. With some of the cheaper batteries, you can see massive variations even in the same batch of batteries! My point is, what works for one battery may not be as successful for another battery of similar design/size/purpose. I can't and I won't disagree with trundlebug's experience with the Megapulse device, and there is a chance that the same device would work on many different types of batteries. However, there is also a chance that it'll have no effect at all, or possibly even a detrimental net effect (increase in parasitic drain leads to a lower cell voltage and higher propensity for sulphation). If the options are a £3k new battery bank or a £90 little box, then the 3% extra 'potential new system' cost seems virtually negligible and thus, worth a try.

I do wonder though, Trundlebug; you say the batteries in question hadn't been used for some time, and now they are used relatively frequently? There may be a chance that resuming use of the batteries, and continuing to use them frequently revived them, and the little Megapulse unit took the credit? Just a thought.

Granted, if your batteries aren't performing, buying a whole new battery system and all the associated ancillaries is overkill. If you are starting from fresh though, I'd invest the £80-ish towards decent batteries, a decent charging solution, and possibly a solar charge combiner/maintainer to supplement regular charging to overcome parasitic drain / self-discharge of the batteries, keeping them at total top of charge. I suspect this would work out cost-neutral in the long run, and you can sleep happy knowing that keeping one set of expensive batteries for twice as long as two sets of cheaper batteries is more eco-friendly... that's something to ponder while you hurl around with two massive diesels cranking out full revs!

And don't forget... simply using / recharging the batteries regularly will help reverse mild sulphation. Another reason to spend more time on the boat.

So... not the world's most conclusive answer, but I am an engineer, so what do you expect! If you ask an engineer any question, they'll never say 'yes' or 'no', they'll only ever say 'it depends'.

 

[gjgm]

With some of the cheaper batteries, you can see massive variations even in the same batch of batteries!
.

Are you saying that you don't see such variation on more expensive batteries, then ? I ask because it is not an infrequent question on here as to what battery to buy. Perhaps you have some preferred brands ?

 

[Trundlebug]

I do wonder though, Trundlebug; you say the batteries in question hadn't been used for some time, and now they are used relatively frequently? There may be a chance that resuming use of the batteries, and continuing to use them frequently revived them, and the little Megapulse unit took the credit? Just a thought.

Ah, but here's the interesting thing.

The cherry picker has 2 battery banks, one each side of the chassis.
We fitted a Megapulse to each bank and as I said, over some weeks the performance steadily improved, exactly as claimed in the instructions.
Things stayed like that for about a year but then we had another issue with duff batteries on another machine (a small scissor lift - don't ask!) so as a short term measure we took one of the Megapulse units off the cherry picker and fitted it to the scissor lift.
Over a period of time, the performance of the cherry picker fell off and the batteries just weren't lasting. I feared the end may have finally come for its batteries but when I checked, it was still missing its second Megapulse.
So we refitted it from the scissor lift and lo and behold, performance steadily came back again.
And that's how it remains now, nearly 4 years on from when they were first fitted.
(Meanwhile the scissor lift, which only takes 2 batteries, had them replaced).

My conclusion has been that once fitted, the Megapulse needs to stay fitted otherwise performance will drop off. Regardless of usage, charging regime or general maintenance (which is on the whole pretty good, barring the occasional day when they forget to put it on charge).

Yes, it does inevitably "use" a bit of power from the battery bank to do what it has to do, but it's pretty negligible in the grand scheme of things.

I first head about the Megapulse from this forum several years ago, and decided to give it a try after reading other positive feedback. So I know I'm not alone although I was a bit sceptical before I tried it. There may be some more info from others if you do a search through the forum archives.

 

[annageek]

Are you saying that you don't see such variation on more expensive batteries, then ? I ask because it is not an infrequent question on here as to what battery to buy. Perhaps you have some preferred brands ?

It's fair to say the higher cost of the battery, the lower the variation in performance, but variation still exists. No surprises there, then. Often, it's simple things like tighter controls on raw material purity and largely automated production lines that provide the improved consistency. Some of the more 'budget batteries' that we bring in for evaluation can be really rather shoddy and vary massively, even among batteries from the same batch. Needless to say, we keep clear of these.

We tend to only deal with Lifeline batteries for our big lead acids (for us, big is > 100Ah). We've dealt with them for years as a company, and as far as I can tell, they're pretty much bomb proof. The only time that I can think we've had problems with them is when customers have sized them incorrectly for their (non-marine) application (super deep discharge followed by slight undercharge on a daily basis). That sort of use will kill any battery quickly. Mind you, even with such abuse, the Lifeline's have lasted many months.

I can't speak for other big lead acids, as I simply haven't any experience with them. Sub 100Ah though, we deal with a multitude of different types / makes of battery, and continually trial batches from various manufacturers to see how quality varies.

The cherry picker has 2 battery banks, one each side of the chassis.

Out of interest, are they open/wet cells, or are they sealed batteries? And what sort of capacity is each bank? Were the scissor lift's batteries the same type / similar size?

Being female, I'm not afraid to admit that I am wrong about things and your cherry picker test certainly does seem to add some systematically gleaned evidence to support the manufacturer's claims! Also, my scepticism may partly be driven by the fact that I work for a company where the sale of lead acid batteries forms a generous portion of our turnover. Cheap little boxes of magic that mean our customers don't have to buy so many batteries are not good for business, and so convincing everyone they don't work is a good thing. OH MY GOD! I'm starting to think like a salesperson and I didn't even realise it! Please tell me there's a cure!!!

 

[gjgm]

Ok if Lifeline are 3-4 times the price of a cheapo battery , I am glad to hear they are better!
Fair enough; for me its a disposal item every few years.

 

[MapisM]

We tend to only deal with Lifeline batteries for our big lead acids (for us, big is > 100Ah)

Do you include also AGM in the lead acid category? I've yet to see any flooded Lifeline batteries around...
Regardless, if in your experience there's any cheaper/flooded stuff which you'd recommend, we are all ears!

That aside, many thanks for your comments, this thread is developing into the most interesting debate on batteries since ages.
I've got a couple of doubts on which you surely can throw some light.

Firstly, is there any solution which in principle could work better, when combining batteries to create a 24V bank for domestic usage onboard?
I mean, at the moment I've got 4 pairs of 100Ah/12V batteries. The 4 pairs are connected in parallel (and obviously the 2 batteries of each pair are in series), hence making it a 400Ah/24V bank overall.
But since most of them are shot (aside from possibly trying the "magic box" ), before buying other rather expensive ballast, I am wondering if it wouldn't make sense to use 6V or even 2V batteries.
In other words, a 400Ah/24V bank could be made of just one couple of 400Ah/12V batteries, or a dozen of 400Ah/2V batteries.
Or by any combination in between, using 2/6/12V batteries in series and in parallel, my current setup being just one of many possible combinations.
Now, aside from the obvious size/weight differences (of course I'd never consider 400Ah/12V monster batteries, which maybe don't even exist), are there any other technical pros/cons to consider for such choice?

Secondly, again on the megapulse thingie (on which probably also Trundlebug can advise): I already understood that it doesn't take one box for each battery, but would one still be sufficient also in a "combined" bank, like for instance the 4 pairs of 12V batteries I've got at the moment?
I suppose it could be connected to any of the 4 pairs, since they are all connected in parallel anyway, but I suspect that there might be a catch...?

PS: Oh, and one thing I forgot in my previous reply to your post: a very warm welcome to the asylum! :encouragement:

 

[jfm]

many thanks for your comments, this thread is developing into the most interesting debate on batteries since ages.
....a very warm welcome to the asylum! :encouragement:

Very much agreed MM. I was going to make another thread but it’s better now to keep this info in one place so I’ll ask my “which new batteries” Q here. I suspect the question will apply to many of us from time to time when batteries need replacing

I need/want to change boat batteries so I have the wet lead acid, AGM or Lithium question. I’m thinking AGM but am interested in other views. Anna, please keep it technical; I and others on here are engineering grads, Mech in my case, so we like technical

Currently I have 8 x 220Ah @12v wet LA batts, 520mm x 300w x240h. All 18 months old from when the boat was new. 2 for port engine start, 2 starboard, 4 (making 440Ah@24v nominal) for house/hotel loads. I think all 8 have to be same technology, because all the chargers charge the engine start batts AND the house batts (I can explain that more if needed) so if I mixed say Lithium for the house and LA for the starters, one set would always see the wrong charge voltage. Feel free to correct me on that though.

I have plenty of charging – 160amps @24v from 230vAC chargers, 2 x 150amps @24v nom alternators. All mastervolt, with 3 stage bulk,abs,float, and with the voltages of those stages user adjustable thru set up menu to 0.1v resolution, on both 230v ac chargers and alternators. Also there is batt temp sensing by wired heat sensors, for both the alternator and 230v charger outputs . I have a mastervolt monitor that tells me % DOD, by coulomb counting charge and discharge

Here are the choices. Prices are inc VAT, rough from internet:
8x middle of road wet LA @£170 = £1360
8x AGM LA cheapies @£270= £2160
8x AGM LA “Rolls Royce” Lifelines @£540 = £4320
4 x lithium LiFePO4 Mastervolt 5Kwh @ £4800 + bits = £20grand (this is equivalent nominal capacity)

The engine start batts have a nice life, except for the two I’ve probably busted. For ¾ of the year, the boat is on shorepower and the house batteries have a nice life but for the other ¼ they get whacked and that will continue – being nice to batteries is low priority. They get big DOD overnight eg down to 30-40%, due to refrigeration load (6 compressors via 2 inverters), then a 160amp charge in the morning when the genset(s) fire up for breakfast, but acceptance tails off and often I stop charging @ 80% because I do not want to run a genset ~5 hours which is what the charge acceptance curve would demand to approach 100% charge. In the afternoon when gensets are on to power lunch+airco+stabs, the batteries might get to full charge if they’re lucky. Then they get run down in the evening say to 60-70% with lighting, u/w lights (120,000 lumens = 40amps@24v unfortunately), refrigeration, then they charge back up to 80% before bed because I only want run a genset for say an hour else it spoils the evening. I fully realise this is a terrible way to treat batteries – it breaks every rule in the book

Because of all that I definitely do not want wet LA. Not enough charge acceptance. It makes no sense running a 3,3 litre diesel genset that can make 100amps @230v just to do the last 3 slow hours of LA battery charging consuming perhaps 4 amps @230v

The lithiums are seriously expensive and involve a lot of faffing around due to odd shape. Sure they save weight and have plenty of advantages, but £20grand, sheesh. I’d rather put the £15k delta on the black at the casino and not have to read a thousand pages of manuals on lithium batteries

So I’m thinking AGM, and having now heard Annageek’s info and read the Lifeline website I’m thinking of the Lifelines and hoping to get a deal if buying 8 of them. They are much 25% of Lithium money, have much faster charge acceptance than wet LA so fit partly with my desire to not run genset just to top off the batteries, and they are standard physical size. They also come in a 260Ah version, slightly bigger than the 220Ah but might fit, 4 of which would increase my nominal house capacity to 520 from 440Ah. I’d stick with the 2x220Ah for each engine start

So, any different thoughts on the Wet LA/AGM/LifelineAGM/Li choice?

 

[vas]

Nice set of Qs MM & JFM

MM have you considered all the fuffing about building new connecting cables with the right endings if you go 2V or 6V?
If you're happy with the weight maybe you should go up to 200Ah and have less pieces about, I think it probably is a bit cheaper to get less larger batteries.

If I may add (since I'm also looking for batteries, but not even considering as a remote chance going lithium):
there are open lead acids and
sealed lead acids.
when you're talking LA J, are you also considering the open version (ie. 6 cups to see and topup electrolyte in them) ?

also J, re your setup, if you indeed go for 260Ah and since Ah means larger physical dimensions (and unfortunately weight!) check if you could reduce the starting batteries to 180Ah (hell, should be more than plenty for a starter motor!) and save some cm to fit the larger domestic ones without messing about battery trays (if they are next to each other that is ofcourse, sorry cannot search through 2K posts for the right pics in the built threads atm!).
Mind, I fcked up my back for a week by lifting out of awkward spot (which was really not that bad) 4X 50odd kg 180Ah sealed LA batteries from MiToS Wouldn't even want to know how heavy the 260Ah ones are!

cheers


V.

 

[MapisM]

also J, re your setup, if you indeed go for 260Ah and since Ah means larger physical dimensions (and unfortunately weight!) check if you could reduce the starting batteries to 180Ah (hell, should be more than plenty for a starter motor!)

LOL, if it weren't that in jfm boat the number/size of cylinders to get moving is a multiple of what we are used to consider...!
Though actually I was also thinking along similar lines, i.e. why have two sets of starting batteries?
I mean, assuming that in an emergency there is a parallelator which allows the temporary use of domestic batteries to start the mains (not sure about the Sq78, but I've seen this on many boats), one pair of starting batteries should be good enough.
AOTBE, that would mean 660Ah instead of 440Ah for domestic, not a trivial difference by all means!

Re. my previous question, yes Vas, I see your point re.cabling, and I don't disagree.
But I was curious to hear about other let's say "electrical" rather than "logistic" pros and cons of the possible combinations, if you see what I mean.