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General questions (retrofit, parts, etc.)

PostPosted: Sun Aug 30, 2009 2:46 pm
by JDC
I am 61, retired (well, rejected actually) and still learning about off-grid stuff despite having lived on a remote island up the BC coast for the last 5 years. I cobbled together an off-grid system and, even tho it is not ideal, it is now the one I am working with. I'd like to improve it and I'd like to do it as inexpensively as possible. As a rule, hermits are not wealthy and I rigorously subscribe to that rule.

But I need a new charger. Two old 20 amp chargers blew on me. I currently have 3 gensets and the big ol' reliable one is 15 kw and underutilized by my Outback 2500 watt inverter with its pathetic 18 amp charger. I have been thinking of adding a 60 amp charger - preferably a used forklift charger or something. I have a 600 ah battery bank to charge. The other is a Honda eu 2000 and only puts out 13 amps (great as a portable, tho) and the third is a cobbled together old 5 hp air-cooled diesel that has trouble holding rpms steady. Close enough though to turn an alternator. Could it turn the alternator you carry? More to the point, can I just buy the alternator (100 amps) and use my own diesel?

Is the Genie more than just a diesel and a 48 volt alternator? It seems to have a regulator as well...........

If not, can you recommend a good source for 48volt alternators (and regulators) or is there a reason I shouldn't do it this way?

Outback inverter, MX60, 80 watts of PV panel wired for 48 volts, SW Windpower 400 watt wind turbine (48v).

Re: General questions (retrofit, parts, etc.)

PostPosted: Mon Aug 31, 2009 10:46 am
by Coulomb
Expect short life, (2-3 years) on batteries that are not charged with
multi-step and temperature compensated regimen. We bought an electric
forklift cheap because the "batteries were no good". The original
charger was tossed into the recyle bin and replaced with one of ours.
After a few cycles the batteries started acting normal and it's been a
few years now.

You're using a 15 kW generator to deliver 18 Amps. At 56 Volts that's a
whopping 1 kW. Our ,48V, 200A diesel battery charger uses a smaller
engine, the Kubota D1105, or somewhat bigger, Lister-Petter LPW3.

Even if you buy several of the biggest chargers available, you won't be
able to match the fuel economy of a direct DC machine. But maybe you
aren't concerned about the cost of diesel - our customers in Saudi
Arabia aren't.

The Genie series comes with a Smart Alternator Regulator, made in 12 and
24V. At this time there is no 48V standalone regulator.

The DBC series comes with the EnerMatic Controller, available in 12, 24,
32, 36 and 48V.

Presently, the 48V alternator is only sold with the EnerMatic
Controller, which has a regulator for 48V.

Re: General questions (retrofit, parts, etc.)

PostPosted: Mon Aug 31, 2009 11:09 am
by JDC
I am concerned about fuel. That's why I wrote. And that is also why I live off-the-grid. I also know that the big genset is underutilized, that is why I am thinking of marrying a 48 volt alternator to my small diesel. But it makes little sense to buy a new Kubota when I have something of similar size. That, too, would be making a larger footprint.

So, short of springing for yet another engine and a new one at that, is there a way to get an alternator and regulator separately? Or, alternatively, could I bring my own small diesel in and have you marry it up? You see, space is not an issue. I am living in the forest, not on a boat.

As lovely as the Genie is (and it is), buying a new one is out of the question. So, how can we solve this problem?

Thanks for the info on the forklift charger. I didn't know that.


Re: General questions (retrofit, parts, etc.)

PostPosted: Tue Sep 01, 2009 4:38 pm
by Coulomb
The engineering cost to design and fabricate alternator mounting framework and sheaves for a different engine would be more than the price of a new Genie.

Re: General questions (retrofit, parts, etc.)

PostPosted: Wed Sep 02, 2009 10:25 am
by JDC
Then what about just getting the right chargers and regulators to plug into the big genset? I have a 48 volt system and need around 60 amps. Can that be done with two 24 volt chargers?


Re: General questions (retrofit, parts, etc.)

PostPosted: Wed Sep 02, 2009 4:56 pm
by Coulomb
Where did the 60 Amps come from? Is that 10% of your capacity and you're using some traction batteries that have a 10% charge rate limit.

Even at 60 Amps and say 56 Volts you're running a 15 kW generator to deliver less than 3500 Watts to the batteries - not a model of efficiency. Can you do it with a stack of 12 or 24V chargers? Yes, provided the earth grounds are isolated from the charger output, AND, you have a way to control all the chargers to deliver exactly the same voltage. If not, the batteries will get out of balance, and life for them after that is short and brutal.

You're in the same situation that 99.9999% of other offgrid residents find themselves. Instead of first studying the power system options and the place of batteries in the system, everyone runs out and buys a generator. After all what else is there, and you need a generator to run the skill saw. Finally, when the sawdust settles a great awakening occurs -- charging batteries efficiently and in a manner to extend their life isn't as easy as turning on the generator. And no, all the solar panels can't keep up with demand, and the wind turbine doesn't help as much as desired.

Most people at this point fuelishly tend to limp along with what they have.

The real solution is a professionally designed system with batteries that accept a high charge rate so that the engine doesn't need to run very long, but when it is running it's at an RPM and load factor that is the most fuel efficient operating point. That's what we do.

Re: General questions (retrofit, parts, etc.)

PostPosted: Wed Sep 02, 2009 5:46 pm
by JDC
Well, I appreciate that. Sounds right. But, of course, you didn't start out so smart. You learned. Just like the rest of us. Some of us do it sooner than others. Some become experts. Most of us don't. I am not one. But I learned fast enough to snatch a little 6 hp diesel when I could. I'd like to employ that if I can. If I can't, it'll go into the little clinker-built I am rescuing so I am OK with that. And no, I did not run out and buy a genset as the foundation of the system. In fact, I rescued an old Isuzu 15kw and, as you suggested, have come to realize it's limited utility. But $13,000 for the right system(Genie) is out of the question right now. Right now, I am looking to mitigate my circumstances by politely asking if any of your products can get me part way there.

Not all of us can do it right, right from the start. Sorry to be so irritating. But I am trying my best. Circumstances and budgets, timing and knowledge, expediency and, in my case, remote location all played a role. Next time around, I'll ask you first. But I am currently in round two and getting my lights punched out.

So - last time - can you help? Can you suggest something remedial? As you point out, 99.9999999% of us erred. There's a huge market there for some solutions.

Re: General questions (retrofit, parts, etc.)

PostPosted: Thu Sep 03, 2009 10:50 am
by Coulomb
You're correct. Back in 1962 I cockily thought I new all there was to know about batteries, until I was asked to rescue a product that was failing because of short battery life.
So I did what I needed to do to design new charging circuits - read a whole lot more and experiment.

Whether you were smart buying a 6 hp diesel remains an unanswered question. If it is one of those slow rev units using 1920s technology then you'll find that it isn't really good for driving an alternator, and fuel consumption versus power generated is VERY poor.

Anyone with a hack saw and a drill can cobble together an engine and alternator. Will it be as efficient as one of our units? Will the control system charge the batteries as well as our EnerMatic? Will it be as reliable? In the end, will it cost less?

As mentioned earlier, at this time we don't have a regulator capable of 48V. The DBC series with the EnerMatic is the only solution we can presently offer.

Like yourself, most people living off the grid spent their money on inefficient technology, and are without funds to upgrade to a proper system. That doesn't translate to a market.

Re: General questions (retrofit, parts, etc.)

PostPosted: Fri Sep 04, 2009 8:52 am
by JDC
OK, Coloumb, I give up. There obviously is no solution to the problem facing so many of us except to buy yet another engine/alternator combo. We are so stupid. And you are not. Good for you. I'll go back to 'cobbling' what I have. Someday, in a perfect world, everyone will have Genies and I may be able to buy one used. Now, to stay going until then.............

Re: General questions (retrofit, parts, etc.)

PostPosted: Fri Sep 04, 2009 10:58 am
by Coulomb
We've been making Genies since 1988, so there's some chance you'll find a used one.

Good luck with your project. Sorry you didn't find us sooner.