Generator + deep cycles. Charger or converter?

[IdaSHO]

Working out some of the logistics for my camper build.
Ive got a EU2000 honda and two 232ah deep cycles (6v).


What would be the best and/or fastest way to utilize the generator to re-charge this battery bank?


Looking at basic high amp "portable" chargers, it seems like you can get more bang for your buck when compared to a similar amperage power converter.


Ultimately this rig will have a few hundred watts of solar as well. But for now I will just have the vehicle and generator.


Any thoughts would be appreciated.

 

[wrcsixeight]

Fastest on a Honda 2000?

http://www.bestconverter.com/PowerM...tage-ConverterCharger_p_472.html#.Uyp5HKhdXcw.

Powermax PM4 series, 75 amps and up are power factor corrected and run off a standard 15 amp receptacle. Other converters need 20 amp receptacles above 70 amps.

If you plan on loading the battery while charging, you pretty much need a converter. "portable" chargers will most likely get confused when the load changes and shut off.

Do note that you have One large 232 amp hour battery, in two pieces.

Utilize all available charging sources to keep the batteries at as high a state of charge as possible.

 

[wirenut]

A power converter is designed to be not only a battery charger but also a power supply. A normal battery charger would probably not due well trying to supply 20 or 30 amps or so of load for hours on end while also charging a battery. IOTA has some nice units that I've seen used in RV's that you could check into.
If you're ever planning on adding an inverter you might look into getting an inverter/charger. Magnum and Outback both make excellent products. These units normally have a built in transfer switch so they will automatically switch between the AC input and the inverter when the input disappears. They can also be integrated with battery meters from their respective manufacturers along with remote displays and controls.
Certainly this is a more expensive option but you'll get it all: a high quality battery charger, inverter, transfer switch, etc. The really nice thing about these units is you can program them to only draw so many amps from your gen. If your gen. maxes out at 16 amps you can program the inverter/charger to not allow more than 16 amps of draw. If you plug in a load while it's charging your batteries it will back off on the charging to not overload the gen.

 

[DiploStrat]

What I Did

Working out some of the logistics for my camper build.
Ive got a EU2000 honda and two 232ah deep cycles (6v).


What would be the best and/or fastest way to utilize the generator to re-charge this battery bank?


Looking at basic high amp "portable" chargers, it seems like you can get more bang for your buck when compared to a similar amperage power converter.


Ultimately this rig will have a few hundred watts of solar as well. But for now I will just have the vehicle and generator.


Any thoughts would be appreciated.

If it were up to me:

-- I would delete the genset and add two more batteries.

-- I would not use a "converter" but rather a modern inverter/charger. I have a 2800w Magnum unit on my truck - produces 125A charge rate on shore power. Would do about the same if connected to your genset. And, most important of all, it is a modern, three stage charger that can be adapted to match your choice of battery.

I have lost track of your build thread, so this may not fit your needs, but it is what I did with my truck and it works very well.

N.B. You may want to speed up the install of your solar kit as it can be a vital part of assuring a full charge as, unless you have shore power, it is generally too expensive or too noisy to run a genset (or your truck engine) long enough to assure a full charge.

 

[IdaSHO]

Thanks for the thoughts guys. Here is a little more info about our needs/setup.

The generator is a must-have for us. Less just for "dry" camping, but more for cold weather backup for the big diesel block heater and battery assist.
We do a TON of off-season camping/traveling, when solar is worthless, and batteries are struggling. In the past the generator has saved us numerous times.

Also, this camper will never see "shore" charging. We never have used hookups, and have no intention of ever using them. The only time it will be plugged into the grid will be at home on a trickle charger when the camper is off the truck.

While I like the idea of more battery, weight really plays a part here. Each one of the 6v batteries Im running weight nearly 70lbs. My EU2000 honda generator weighs just 55lbs, and doing the math (roughly) I can recharge the battery banks nearly 4 times on just one tank (1-gallon) Eventually I would like to convert it to propane, so fuel requirements will be simplified, as the camper furnace and stove use propane.

My maximum wattage draw when camped is looking to be less than 10 amps. I dont think an off the shelf "garage" charger is going to have a problem, and for now I think Ill try it out. Many have a 30 amp fast charge, putting my recharge time in the 3-4 hour range, assuming the battery bank is down to 50%. Not the fastest, so after a few trips I may jump on a decent power converter. Though solar will happen, and I may need to fast-track it.

Also, this camper is 100% 12v dc if that makes any difference.

 

[DiploStrat]

Can we Talk?

We should start a dialog as we both share a common goal - no shore power, albeit for different reasons.

Our camper, Ndeke Luka, was designed never to need shore power for extended back country camping and for use outside of the U.S., specifically to avoid having to carry a large transformer. You can see pictures here: http://www.pbase.com/diplostrat/ndeke_luka

This translates to:

-- 600Ah of battery (approx. 400 lb.)
-- 500w of solar
-- 2800w of inverter (induction stove top, convection microwave, air conditioner, diesel furnace), there is also a smaller inverter for computers, cameras, etc.
-- 40 USG of water
-- 60 USG of diesel
-- Diesel furnace/hot water
-- Bidirectional charging through 1/0 cables connected to 2x125A alternators

The design goal was to be able to go at least three days with no sun and no engine start and no real economization of cooking, heating, or bathing. Obviously, there are several things you can do to stretch this out, for example, simply pressing the remote starter when cooking and reducing showers to every other day. (My wife and I did cross the middle of the Sahara on 15 USG of water! And yes, we took two showers, each, when we finally made it to a hotel! :Wow1:)

So far, it works very well, with a typical overnight consumption of electricity of 125 - 155 Ah. (I keep a log.) Between normal "tourist" driving from camp to attractions and sunlight, the batteries are typically fully charged every evening, the worst case being one day when they were only back to 97%.

The eastern seaboard is not famous for sun, but I was even getting a (small) charge with the truck encased in ice. (I do have to brush off the snow.)

While we have not been living in the Tiger constantly, it has not been plugged into shore power since before 9 February (the last time I looked) and during much of this time it has not been winterized; that is, it has had water in the tank and lines, refrigerator is running, etc.

As you will note from my myriad posts in this forum, I spent a lot of time researching these issues and I think I am pretty close to a good, dependable solution. Two things that I consider very important:

-- Long term charge - a battery bank requires at least two hours of acceptance charging after the bulk stage. It is almost impossible to achieve this without shore power or solar. The good news is that the solar kit does not have to put out very much current during this stage, so it is easily accomplished during the late afternoon when the angles are much worse.

-- Bidirectional charging to keep the starter batteries happy. Especially important if your truck spends weeks sitting in the cold waiting for your next trip.

We are gearing up for a long trip to Overland EXPO so the next step will be to see how the beast handles warmer weather.

All the best!

 

[fisher205]

The 7.3 diesel likes a little heat at below zero. An Espar or like engine heater would be a nice feature to prewarm it, but a lot of money for a vehicle you are using only a couple of times a winter. Especially if you already have a generator sitting in your garage.

I think solar is a great way to go, and I will some day have my rig set up with a Espar heater and solar, but for now I'll throw the generator in and feel better about the Ford (or any diesel) starting in the extreme cold and being able to charge the battery if needed.

 

[IdaSHO]

DiploStrat, thank you for posting. We do seem to have very similar needs/goals. Though mine are considerably simplified (through design)

Throughout this project I have always tried to lean more towards saving battery vs having more. I feel the 140lbs and 232 AH of battery will do it if work the numbers correctly.

Obviously solar is a must have. So is energy conservation. Primary hog is the fridge, an AC/DC CR-1065 Waeco, with a supposed average draw of just 3.3Amps.


Beyond that is LED lighting, simple LP/CO monitor, and a small marine DC radio that will be used occasionally.

So the only things running all the time are the fridge and the LP/CO monitor.



In total, Im still coming in under the 100AH per day rate. Well within the 50% threshold for these batteries. Though I have read a lot about taking them all the way to 80%??
They are 6V deep cycle golf cart batteries.


Assuming 100AH usage, with the small generator and a 20A charger, that gives me a recharge time of 5 hours or so. Punching the numbers much closer after finding some real world data on the EU2000 fuel usage based upon load, and Im looking at a full 10 hours of run time per gallon, using the eco-throttle and the 20amp charger. So I can do a (nearly) complete charge twice per gallon. Still, one gallon of gas weighs less than 10 lbs. Ive always carried a 2.5g can with me.

That also shows me that 200watts of solar (16.6 amps in a perfect world), provided I have good sunlight for 6 hours a day, would give me the same amount of charge. Roughly 100amps.



Please tell me Im understanding all of this.......

Thanks again.

 

[IdaSHO]

Darn...

Just found the actual data sheet for that fridge.

Darn in a GOOD way. :ylsmoke:

http://www.waeco.com.au/products5.asp?id=339&catId=57&subCatId=61&subCatId2=72


The fridge draws an average of just 1.6 amps at 77 degrees. And 1.9 at 90 degrees.


So my original calcs are WELL overestimated.


Even figuring 2 amp average, that gives me a full two days of usage to use up 100ah.

So Im nearly there already if I want a 3-day tour without a charge of any kind.
Add solar and Im there.


yeah?

 

[DiploStrat]

None of this is hard, but it is complex, that is, you start with something simple and keep building from there.

Shoot me an e-mail (see profile) and I will send you a ponderously pedantic and prolific paper that I put together to make sure that I understood the theoretical as well as practical problems of 12v systems in campers. The paper does not propose answers, but I have learned a few things that work and a few that don't. The good news is that some of the best answers are the least expensive, but that doesn't mean that I didn't have to spend the money first.

One of my sources was some folks at Lifeline batteries and, from them, I learned the following:

-- FLA (flooded lead acid) batteries don't like to be discharged - discharge as little as possible and recharge as fast as possible. Think percentages - this argues for the biggest battery bank you can get away with.

-- FLA don't develop a memory like Ni-Cad, but, if not fully recharged often, they will loose the ability to take a full charge. You need to charge MUCH longer than you think.

-- The 50% rule is about the best compromise between long life and stupidly large battery banks.

-- You CAN exceed the 50% rule, IF you recharge quickly. (And fully.)

The kisses of death to an AGM battery are:

-- Too high a charging voltage - causes gassing and, as an AGM is sealed, you cannot replace the water lost. (But remember that charge voltage is temperature related. U.S. AGM's want 14.4v at 70F and over 15v at 20F.)

-- Remaining in a discharged state for an extended period of time, i.e., several days.

-- AGM batteries like a massive charge current. The minimum is 20A per 100Ah of battery bank. The ideal is 100A per 100Ah and you can go up to 500A per 100Ah. :Wow1:

So, the news you can use is this:

-- Solar is great because, unless it is dark or pouring rain or snow, it is always charging to some degree. You want a minimum of 100w per 100Ah of battery - more if you are going to work your batteries hard - as you intend to.

-- Solar persistance (or shore power) is critical to reach full charge. You can get a lot from your truck's alternator(s) but it will drop off as the batteries approach full charge. You need that extra two/four hours of acceptance/absorbance charge if you are ever to reach full charge.

-- Finally, you can safely drop below 50% if you are sure that you will start the engine or the genset the next day, without fail. That is how I can say that I can use 150Ah per day for three days - because on the fourth day I will start the engine. Of course, as a practical matter, merely running the engine while cooking (0.5 USG per hour) can greatly extend battery life and 500w of solar produce some 25A of power in sunshine.

All the the above correct to the best of my knowledge and belief and experience. As always, YMMV.

 

[wrcsixeight]

Lifeline are excellent batteries but I would not apply their voltage and other current parameters to all agms. Many say to not exceed .2c. Or 20 amps for an hundred amp hour battery. Odyssey wants 0.4c until 14.7v is reached and then held there for four hours. Respect manufacturer recommendations as to recharge parameters. It hurts ts more when one kills an agm prematurely

 

[Shocker]

DiploStrat - Thanks for all the great info! I have learned more about 12v in the real world from you than any book!

 

[DiploStrat]

… Respect manufacturer recommendations as to recharge parameters. …

Agree completely. Lifeline tends to want a lower voltage/higher current than some of the others. Lifeline also stressed the need for time noting that more of their batteries came back dead for too short a charge than for too high a voltage. Fortunately, most modern chargers have several programs, e.g. gel, US AGM 1, Euro AGM, FLA, etc. You need to pick the one that is closest to what your battery manufacturer specifies.

Remember, once your battery is about 80-90% charged, its voltage is going to be well over 13v, often as high as 14v. At that point the voltage differential is too low to pass all that much current. In my case, I see charge rates of well over 150A for the first hour or so, then it drops way off and it takes hours to get that last 5% of charge. Again, one reason I am such a fan of solar kits; the afternoon current may be low because of the low sun angle, but the solar kit is very patient and just keeps charging.

 

[DiploStrat]

DiploStrat - Thanks for all the great info! I have learned more about 12v in the real world from you than any book!

Thank you! I have spent about a year, and way too much money, working on this stuff. I am reasonably confident that my truck will perform as planned, but all of my advice has an Oklahoma 50/50 guarantee. You follow it and your truck breaks into two pieces - you own both of them!

 

[joeyabisa]

Thank you guys! Great information in this thread. Taking notes!