Designing My Electrical System

[akio.kanemoto]

Greetings all,

Among interior fairing (aaargh!) and other fun jobs, I'm trying to work out exactly how much space I need for batteries and associated bits and pieces - so I can build the right sized enclosures and plan cabling/plumbing around them.. as I'm sure you're all aware, everything is related and I'm space/weight/cable path constrained - so when one thing changes, a bunch of other things change. For example - if I go for one brand of charger (wider) or another (long and thin) with a particular set of dimensions - the grey water sump dimensions will have to change!

Anyway - here's my whole setup - and could be timely, based on the AGM lifespan argument^H^H^H^Hdiscussion on another thread..

Following a pile of research and looking at the idea of multiple alternators etc and additional brackets on my little Yanmar 3gm30, I have more or less come down to using a Honda EU20i for the daily charging regime, supplemented by a single 125W panel (if it fits.. eventually!).

This is all assuming that the few posts I've seen on CF are correct in that there are full time cruisers out there who are using 100A+ chargers with the Honda.

As a side-benefit for me, by using the Honda, I also deal with my hot water problem as I plan on using one of those 240v electric tap mounted heaters, remotely mounted for use with a shower - although obviously not simultaneously with charging, as the Honda probably won't cope. (As for non-electric heating - my Yanmar Engine is raw-water cooled, no space/desire for an electric/diesel heater/tank/etc and lpg storage is limited to cooking only...)

The Honda itself will be mounted on deck in a ventilated locker with a hatch, so that when opened, the Honda will be sitting on a shelf inside, mounted on stainless captive ball bearing full-extension drawer runners - so that the entire generator can be slid out fully with minimal effort (even by my wife) started and there won't be any heat/fumes/vibration etc problems as it will effectively be outside when being run .. when done, just push back in, lock in place, and close the hatch, voila. This way, it will be more or less permanently mounted, so no plugging/unplugging/fuel lines etc.. not a bad compromise in my mind. Of course, only possible to run at anchor.

Comparisons - 3gm30 will drink 3-4L/hour, Honda will drink 1L - and hey, I can take a hot shower just after charge time and then maybe even hook up a 240v water maker to make a bunch of water for another hour afterwards and I'm still ahead fuel consumption-wise (and apart from the generator enclosure, won't have to fabricate anything myself or pay somebody a million dollars here in Sydney to weld up something simple like an additional alternator bracket).. and since I have limited space for diesel or petrol, I can extend my time away from having to refuel..

Now all this is great and subject to debate on whether it is the right thing to do and should I instead be using engine heat and solar/wind etc (no space beyond a single panel, sorry) - but assuming this decision - the problem is that it is all theoretical.. and based on IF I can complete the charge cycle that quickly. I've read a bunch of threads on this and many state that the Honda will take 5-6 hours etc, but then there's always the variable of charge acceptance, charger size etc - so maybe it is possible in my particular case?

OK, so on to batteries then - with all of this in mind, I'm leaning towards 6 x 6V 225A Fullriver AGMs wired in series/parallel to give 675AH (@ 12V) total. So charge acceptance of 100A should be a non-issue.

I don't know what my daily consumption will be, but am looking at a Frigoboat keel-cooled compressor with evaporator plates (in a well insulated box - already built) and a middle-of-the-road general consumption pattern with high efficiency LED lighting etc - but I am erring on the side of caution and am using the space constraint to drive the equation for max AH - so this is the max I can fit into that space (and also the reason behind the 6V batts as they will fit better than 255A 12V batts for example).. My consumption guesstimate is 150AH day.

Charger: I plan on using the 12V Kipoint 100A charger (KIPOINT ENTERPRISE CO. LTD. www.kipoint.com.tw) - they're really cheap and appear to use the IuOU charging mechanism as recommended by Fullriver (http://www.fullriver.com/products/ad...ile/charge.pdf) - and the voltages are pretty damn close to the Fullriver "ideals" (I've asked and they'll even build a custom unit if you wait two weeks with different setpoints - but for the Fullrivers there's no need):

Kipoint charger:

1. Bulk voltage : 14.6V +/- 0.2V
2. Float voltage : 13.7V +/- 0.2V
3. Sense transfer current from bulk to float : 6A

Lead Acid Battery Charger (100Amp,12Vdc,230Vac ) - New - eBay, Power Tools Equipment, Garage Equipment Tools, Cars, Parts Vehicles. (end time 09-Apr-09 21:07:13 AEST)

The thing that I am worried about here is that the charger states a max current draw of "13A for 230Vac" - which works out to be 2990W, almost 1000W above the Honda's max output.. but then again, 14.6V @ 100A is 1460W... so even with inefficiencies, could it be OK?

So in summary (wow that was a long post!) - can you provide your thoughts on the following:

• Thoughts on the overall setup
• Is the Honda going to handle the 100A charger? Are any of you using the Honda EU20i with a ~100A charger? If so which one?
• Has anybody heard of Kipoint? Does anybody have one and are using it on a boat?
• Considering that I don't plan on charging for more than an hour or two MAX - what are your thoughts about potentially cycling the AGMs between 60% and 80% almost on a daily basis with no shorepower (ever) for a long/full charge cycle etc? (Will the single solar panel maybe help with this? Is the full charge even required in my setup for long AGM battery life?)
• Bearing in mind the 60-80% parameters and my ~150AH/day usage - can I expect to run the Honda for 1.5 hours to get those amps back in my setup?

Thank you copiously for reading my version of War and Peace!

[Boracay]

From experience with the Honda 20i it is very quiet when there is a low load, but gets very noisy when loaded.

For example:- Imagine us in a beautiful secluded bay, first mate decides to put a 2400W grill on the generator.

Peace and quiet shattered.

We did not overcook the meat!

[bill good]

The thing to match is the load on the Honda. I use the 1000w & if the load is over at all the Honda drops the load by design.If the charger & battery load is capable of taking more than 2000w then the same will occure. Ditto for the instant heater. So you are good for about 140A max (derate to 100A & you have no worry)

[Islander]

Matching the load is the issue, but here is how the numbers work for me.

I have a Prosine 2.0 which also has a 100A charger. Normally, connected to shorepower (30A @ 120V) all is fine, but the 2000i really puts out about 1600 continuous which is around 13A @ 120V. When I leave the dock I dial the charger down to expect only 12A - the generator then can handle the load.

I don't know if you can configure the Kipoint like this, but I see at the end of the specs KIPOINT ENTERPRISE CO. LTD. www.kipoint.com.tw

it says:

"Suit for Lead Acid Battery" - if this is the correct one, you may need a different charger.

Cheers.

[akio.kanemoto]

Originally Posted by Islander

Matching the load is the issue, but here is how the numbers work for me.

I have a Prosine 2.0 which also has a 100A charger. Normally, connected to shorepower (30A @ 120V) all is fine, but the 2000i really puts out about 1600 continuous which is around 13A @ 120V. When I leave the dock I dial the charger down to expect only 12A - the generator then can handle the load.

I don't know if you can configure the Kipoint like this, but I see at the end of the specs KIPOINT ENTERPRISE CO. LTD. www.kipoint.com.tw

it says:

"Suit for Lead Acid Battery" - if this is the correct one, you may need a different charger.

Cheers.

It looks like the Kipoint voltages are correct and AGM is a subvariant of Lead Acid anyway - but having said that - Kipoint cannot be adjusted to reduce load at all.

Looking at your numbers though - if the 2000i puts out 1600W, then that is 1600W/12V = ~130A, so shouldn't it be happily powering your Prosine @ 100A without any current limiting? Or is this the inefficiency part?

[Islander]

There are some inefficiencies in there, but also the Prosine will split the supply as demand requires, i.e. I can use some of the AC and it will reduce the draw for the charger as needed.

The charger will run pull 14.5V or so initially which brings it near the full capacity of the generator. I found that if I left the setting at 30A (shorepower) it would occasionally overload the generator. This way I don't need to worry about it.

Opinions vary as to the suitability of the Honda on a boat, generally those with them love them, those without them think they are dangerous. With sensible precautions they allow a lot of flexibility, hot water in remote anchorages being one of the better features.

Cheers.

[motion30]

I looked on line at the kipoint chargers. The voltages seem a little high for agm batteries

[Beausoleil]

Originally Posted by motion30

I looked on line at the kipoint chargers. The voltages seem a little high for agm batteries

Fullriver recommends higher charging voltages for their AGM batteries than, for example, Lifeline. The voltages cited by akio are spot on. My only concern (and I haven't checked) is whether the Kipoint charger is temperature-compensated (or does it use PWM like Iota's chargers do)?

[akio.kanemoto]

Originally Posted by Beausoleil

Fullriver recommends higher charging voltages for their AGM batteries than, for example, Lifeline. The voltages cited by akio are spot on. My only concern (and I haven't checked) is whether the Kipoint charger is temperature-compensated (or does it use PWM like Iota's chargers do)?

Unfortunately there's no temperature compensation.. but hey, their 100A charger is approx USD350..

[Beausoleil]

Originally Posted by akio.kanemoto

Unfortunately there's no temperature compensation.. but hey, their 100A charger is approx USD350..

Then like btrayfors says, check out the Iota line - pretty good bang for the buck. I've been happy with my DLS-75 so far. They have a 90A charger, but it's not UL certified... And since it uses PWM, they claim there's no need for temperature compensation since the battery temperature doesn't get as high as with a normal DC charger...

You can parallel two DLS-75s, getting 150A, still for under $625. Not as cheap as 100A for $350, but arguably better for the health of your Fullrivers.

[CharlieJ]

IOTA's do not have temperature compensation either. Not advisable for use with AGMs

[Beausoleil]

Originally Posted by CharlieJ

IOTA's do not have temperature compensation either. Not advisable for use with AGMs

Not according to Iota. I just tried looking for it, but can't find the relevant posting. It was either Rick or btrayfors who posted a bit a few months ago about Iota's use of pulse width modulation in their DLS series in order to dispense with the complication of temperature compensation. In a nutshell, by using pulsed DC rather than a steady current, the charger can pump more amps per unit of time with a lower increase in battery temperature.

There's a paper by Morningstar, the solar charge controller guys, that explains PWM fairly well.

[CharlieJ]

Jon-If the temperature of the battery rises; the charging voltage, be it bulk, absorption or float, must be decreased to stay within the manufacturer's charging profile. For many AGMs, this temperature compensation is negative from 25C and is of the order of 4 to 6 mV/cell/C. I understand PWM. I do not understand the black magic that is going to reduce the charger's voltage as the battery temperature varies from the 25C standard. There just isn't a feedback loop. Until IOTA adds temperature compensation I will not recommend them.

[goboatingnow]

(A) at that type of charging current you must have temp compensation

(B) You also need to be able to dial down the charger output so that its draws less from the AC load, 100A chargers trip mains inputs all the time , I know I have one.!

(C) in general cheap chinesse stiff is like all cheap stuff, you pays your money and you takes your chances. I have fried too many chinesee invertors to bother anymore, my current invertors and chargers are mastervolt and I have good experiencs with Victron.

[Strygaldwir]

I'd think bulk charging you have whipped with the Honda. I think the acceptance phase is going to be a bit of an issue. It seems most chargers are three step now. This is a good compromise, but not the most optimal way of taking advantage of large ammounts of current. That being the case, you might reach the acceptance voltage levels and have to maintain it there for longer than the 1-2 hours you want to run your Honda.

This is where a solar panel might be very helpful. Run your Honda between 9 and 10 am or so, then let your panel supply the acceptance voltage. If you get your waterheating and such done in that time and limit your current use durring the acceptance interval, you might be able to get up to %100. I'd get at least a 150 watt pannel, go for a 24 volt unit and get an MPPT controller. Much more effective.

Keith