Micro CoGen.

I think veggie talks about a ground to air, or ground to water heat pump, where the latter are the most efficient kind, reaching a COP of over 5 easily. A circulation pump to circulate coolant in the ground loop are required, but 1HP sounds excessive; 100-200W would more likely suffice. A ground heat pump are preferred in climates where several months have below freezing temperatures...

I have an air to water heat pump with a COP of 4,6 @ 0deg. C., which are 5 years old now, so why you guys talk about COP of 3 i don't get. That's atleast 30 years old technology....

Most of the wooden boat engines i've worked on (mostly Norwegian 1- and 2-cyl gasoline engines from the 40's and 50's) have a pipe/tube from the crankcase breather to the air-filter...



Wouldn't think diesel engines would be different?

I've just re-read the first posts here; just to re-focus on what you really need, and that would be - More charging amp when you're living on board.
It's a sailboat, which means you're using it often when it's windy...

Have you considered a wind generator to supply your charging?
The wind almost always blows along the coast, and are usually nice and steady over water...  A windgenerator, like the AirBreeze, would give you a steady 5-10A in a good breeze.

My experience with 12V Lithium battery packs (LiFePO4) are, when given charge from a 'standard' 12V charger for FLA, they take whatever they can get, until they reach 95% SOC, then the internal bms ease up... So - maybe your alternator isn't too bad for that purpose...

I guess you wouldn't be able to 'try-before-buy', would you? That would have given you the best idea on what to do first...

You could borrow one from me, but i'm a little bit long away, i guess...

Remind me Jens;
The reason for wanting more power, was to be able to charge an upcoming Lithium bank as fast as possible? If so; i'd get the Lithium bank first; then worry about charging noise... The Lithium batteries wouldn't mind sitting at 40% DOD for a couple of days, but FLA/SLA would start to gag...

I'm waking up this old thread, since i want to update the story of my portable generator...

I've been serious lax in maintaining my 12V, 1060Ah bank of 4x 6V Rolls S-530 batteries the last year; just a peek into the cells to confirm the acid still covers the plates. (It's all Rolls' fault... There's way too large acid reservoir in those batteries; closer to one litre/cell... )

The day to day charge are managed by 800W of solar and a Tristar TS-60 controller; the Tristar seems to do a decent job - bringing the bank up to 14.4V (+/- temp compensation), then keeping it there until the amp-draw are around 1A. (then it goes into float at 13.6V) It also tries to do an equalize every 30 days at 15.3V for 3 hours. I also have a no-name 40A charger that brings the bank up to 14.3V; used in emergencies (more than 4 days without sun).

I could ramble on how i got these batteries for almost free - new, since they're all 'transport damaged' (they leak acid when moved around, since the lids have cracked open some places), but - it's enough to say that two of the batteries has always been a bit 'off'. One, have always had way too high SG; 1.35 fully charged at the worst, and the other one have unbalanced cells. (typical 1.28, 1.23, 1.26), but they've served well so far.

A couple of days ago, i got around to give these batteries some tlc, and disconnected all of them and put them on a standard charge with my 40A charger. (The 'stand-in' battery for my system is a 12V, 55Ah LiFePO⁴ - lovely battery! I want a Big LiFePO⁴ bank! )
After all 4 batteries was fully charged, i dragged the initially mentioned (first post) portable charger out of it's hiding place, to give the batteries a good whopping equalize.
I hooked up the first 2 batteries, and dialled the rheostat up until the voltage was at 16.5V; 30A, and kept it there for 2 hours. (according to Rolls, these batteries really enjoys this!) But... The Noise! And then i ran out of gas... 

Not really enjoying that racket the B&S engine makes for hours, i unscrewed the 4 bolts keeping the engine in place, and put a 3phase, 1.5kW motor in its place...

Oh, joy! The silence!

Since my main usage of this (previous) portable generator has been equalizing, i think the latest incarnation are best suited for me. And since we have a robust grid here in Norway, (and it's close to 100% hydroelectric) it's way cheaper and easier on the ear this way... Besides; it's only 4 bolts - and the B&S are once more in place, if the need arises...

Quote from: Jens on November 05, 2013, 10:07:56 AM

Quote from: Cornelius on November 05, 2013, 01:37:37 AM
I fully support your decision to move to Lithium batteries. I've already swapped my 110Ah LA battery in my caravan with a 55Ah LiFePO⁴ battery, which has integrated bms, so i can charge the battery with whatever i have around

Not to cause thread drift but what is the make of the batteries you use ?

Not easy to say, since there's no makers name and it's probably made in China. But i bought it here in Norway... The supplier i bought it from, have mainly cells from Chinese manufacturer "Heter"

(I also have a smaller battery from the same supplier; a 12V, 30Ah, used as an all-round battery, because of it's weight - 4.4kg, and 24pc 3.3V, 10Ah cells in series-parallel to make 36V, 20Ah for my E-bike, also from Heter...)

My meager experience with car/engine alternators are that the charging curve are all wrong. They usually are full(ish) throttle until the batteries hit around 14.2-14.4V, then they cut the voltage abruptly to 13.4-13.6V instead of keeping the voltage and dropping the amp - therefore, the batteries takes ages to top up.
A good 3-stage external controller would do better i think. Also, at 50-60F, the charging voltage should be higher. (14.6-14.7V?)

I fully support your decision to move to Lithium batteries. I've already swapped my 110Ah LA battery in my caravan with a 55Ah LiFePO⁴ battery, which has integrated bms, so i can charge the battery with whatever i have around; a standard LA charger, alternator, or even direct from a solar panel, since the bms cut the charging to the cells when full. And since one can discharge these batteries over 90%, i have no loss in practical capacity. It also support charging at C/1.

Correct me if i'm wrong, but isn't 30A charging close to ideal to your 320Ah bank? (C/10)

I think a good external regulator with an external temperature compensation (since your batteries are around 50-60F) would do your batteries good.

I think it's GREAT that some people are trying to defy the laws of physics. It gives us something to giggle about, and who knows; some day, one of them stumble across something nobody have thought about and - if not break the laws; at least bend them a bit...

This is what google first shows (mostly); http://en.wikipedia.org/wiki/Opposed-piston_engine

But are you thinking of the Stelzer engine? http://en.wikipedia.org/wiki/Stelzer_engine

Or maybe a Free Piston engine? http://en.wikipedia.org/wiki/Free-piston_engine

goldenmotor.com have some motor controllers for Brushless DC motors, though, they're ment for permanent magnet DC motors...

Quote from: BruceM on February 04, 2013, 08:58:02 PM
Thanks Cornelius, alas the shaft drive BLDC motors I could find there are 5KW and up.

Click on 'BLDC Motor' in the menu on the left and scroll about 3/4 down the page, where you'll find the BLT series specially for trikes...

Bruce;
Sorry, no magnetic field meter...

The whole hub motor are encapsulated in aluminium,but i guess that doesn't shield the AC magnetic field much... The motor are from Goldenmotor (.com), and they also have motors with sprocket for trikes, up to 800W i think...

The chemistry used in laptops, cellphones, (and probably) Dreamliners etc., are usually Lithium Cobalt types, which gives the best energy/weight ratio, but they are also the most thermal unstable. Using Manganese or Iron Phosphate adds some weight, but they're safer, and can often give higher continous amps, and longer life.

I had a ramble over at Otherpower about the Lithium-* tech over a year ago...: http://www.fieldlines.com/index.php/topic,146304.msg1000453.html#msg1000453

My only real experience with li-* batteries are with my E-bike with a 36V, 750W BLDC motor (avg. draw: 15-20A@36V). I started with 3pc. 12V, 18Ah SLA batteries, and i got max a 15km trip before the Low Voltage Disconnect kicked in. Needless to say, with a weight of 21kg and the short riding distance, they didn't last long on my bike...
Then i got a 36V, 16Ah LiMn2Co4 with 4p10s 4Ah-cell config, and my mileage increased to 35km; weight: 5.5kg. This battery pack dwindled down to half capacity after 18 months.
My current battery are a 36V, 20Ah LiFePo4 with 2p12s 10Ah-cell config, with an 50km mileage; weight: 9kg. This battery pack are still going strong after 12 months, and there are no loss in cell capacity. (The cells Internal Resistance are still as new (8-12mOhm/cell).)

I use a 10A charger with a cell-balance port to charge the latest pack, since it has no internal BMS (Battery Managment System).

I'd love to swap out my current FLA bank (12V@1060Ah] with LiFePo4, but the price tag are still too high for me... (Edit: If one use only 30% capacity of a FLA bank, one can manage with a Li-* bank with 1/3 of the FLA capacity, since one can safely use 80% capacity of a Li-* bank...)

Edit;
I think the need for a good BMS would appeal to most off-grid users, because they really takes good care of each individual cell, and reduce the risk of abuse of the bank.