Electrical: DC AC Conversions - Efficiency

Hi TWH99,

I would buy the 3500 watt Champion with built in remote electric start. The Yamaha does fine--at twice the price of the Champion, and you have to add the remote kit from Pinellas for another 500 smakers plus a couple of hours of labor.

Thanks pianotuna. Which Yammy Gen do you have and are you happy with it...what are the pros and cons based on your experience with it. It's Tough to decide between Yamaha & Honda. Since I'm getting a relatively small generator where every 100 watts counts, I like what Yamaha has done, breaching the 2000W and 3000W gap with a 2400W generator that is still at a reasonable weight for regular lifting of unit in and out of a truck bed.

Hi TWH99,

Once the bank reaches 85% state of charge the acceptance rate is about 12.5 amps per 100 amp-hours of battery bank.

Charging voltage ought to vary with temperature--so on the Magnum series there is a battery temperature sensor. Ideal voltage is just below the gassing voltage.

Eco mode, at least on my Yamaha, does throttle back as charge rate declines.

TWH99 wrote:
Thanks Mrwizard for answering the questions related to differences in generator output and charger input and the practical application in the field...good stuff! The puzzle is coming together.

Question: When the Charger transitions from the fast charging rate to the next stage, let's say for example it goes to 1/2 the fast charging rate, will the Generator sense that load reduction and throttle down also to Eco Mode as long as that output is able to satisfy what the charger is asking for?

thanks Tim

The following excerpt may assist in designing a recharge protocol...


Gel and AGM batteries do not need watering, are safer (no acid spilling out), can be placed in a variety of positions, have a slower self-discharge characteristic, and are more efficient in charging and discharging than flooded batteries (see table below). Gel batteries are more suitable for deep cycling applications whereas AGM batteries are more for light cycling and engine-starting applications.

Flooded

Gel

AGM
Charge/Discharge Efficiency
89%

98%

99%
Self discharge rate (per month)
13%

1-3%

1-3%
Finish Voltage
15.3-16.0V

14.1-14.4V

14.1-14.7V
Float charge:
13.2-13.7V

13.4-13.8

13.4-13.8V

I love ho they close their eyes and chant "You can't see me" with regard to the AGM for cyclability. "Only one type of AGM exists (thin plate)" They don't want to "see" telecomm batteries and Concorde Lifeline, is John Banner, stuff --- "I see nothing Colonel Hogan"

Great explanation, thanks!

a honda inverter generator, running in Econ mode will use what ever throttle, little or high to match the load

it will do the same thing with out Econ mode
the difference, is that in econ it idles lower and runs at the bare minimum needed to maintain voltage at the load amps/watts being used

with econ OFF it idles faster and the applied run power is slightly higher than the minimum needed, it will ramp up faster when more load is applied, than when in econ mode AKA response time to load increase is faster with econ OFF

Thanks Mrwizard for answering the questions related to differences in generator output and charger input and the practical application in the field...good stuff! The puzzle is coming together.

Question: When the Charger transitions from the fast charging rate to the next stage, let's say for example it goes to 1/2 the fast charging rate, will the Generator sense that load reduction and throttle down also to Eco Mode as long as that output is able to satisfy what the charger is asking for?

thanks Tim

a charger you can dial down, or one smaller than generator output
a charger that trys to draw 18 amps from a 13 amp generator, equals generator shut down or generator overload/power shut off

you can 'tax' a generator running it on the limit of its power until it gets too hot or until something else trys to run, thens its overload time

you can get 125 amps if batteries SOC 'state of charge' is low enough for them to accept it, but you will NOT maintain that rate, it will taper, and keep tapering thru out the whole charge cycle

if you are down 100 ampHrs, you can;t charge at 125 for 45 min and be full

it will take 2-3 hrs to get close to full and 6 hrs or more to reach 100%

thats why most of us charge until the charge rate drops below what the solar can provide, that changes almost daily, so its a matter of usually charge to the 90% mark with generator then switching to solar only

it depends greatly on your power use habits, and where you camp
in the woods under the trees, foggy beach, sunny desert ?

BFL13 – thanks for confirming ADC is Amps DC. I assumed it was but I don’t like assuming anything when it concerns electricity. A google search, prior to asking could not answer this. I am obviously a novice re: electricity but I do have down W=A*V and it’s other two variations and it makes sense to me. The nomenclature, abbreviations, specification data on equipment and how/or where it applies in all the calculations is where I get tripped up or where I don't feel sure I am interpreting everything correctly. Thus all my weird and simplistic questions. I will be investing a lot of money in a complete system so I would like to try if possible to actually understand at the most basic level (I don’t need to understand how VA is different than Watts) what equipment to buy and compatibility between all components in the system based on each item’s input and output capabilities. I understand if you are tired of answering my question but thanks for all you have offered thus far. I’ll keep asking until no one answers anymore but I think I am pretty close to having just about everything answered. Thanks again to you and everyone else on RV.NET.

Next batch of questions: Are any of these statements false?

RE: Charger – 125 Amps DC: = the charger is capable of charging the battery at a rate of 125 Amps DC

RE: Charger – Input current 18 Amps AC: = the charger can accept up to 18 Amps AC (from generator or shore power). In the case of the Honda EU2000i generator that outputs 120V/13.3A/1596W; it is 4.7 Amps short of using the charger’s 18 Amp capacity. If the charger cannot automatically detect the generators output limitations, the user should dial down the Input Current demand to 13.3 Amps or below to insure the generator is not over taxed running continuously for hours near it’s rated capacity. Theoretically, with 13.3 AC amps entering the Charger, it will output approximately 133 Amp DC at 12V to the battery bank. In practice output Voltage may be a little higher, for example 14.2 and Amps 112. The 112 will be further reduced due to the 87% efficiency of the charger and the >.95 Power Factor.

Specifications for Charger:
125 ADC Continuous Output at 25 degrees Centigrade
87% Charger Efficiency
>.95 Power Factor
18 Amps Input current at rated output (AC Amps)

TWH99 wrote:
125 ADC Continuous Output at 25 degrees Centigrade (battery charger spec)

anyone know what ADC stands for?

Amps DC. IMO you are way too far into theory. Go camping with whatever set-up, see how that works, then adjust as required. Might take several trips, fine-tuning after each trip, to get to where you want to be. You get new ideas each trip.

That's how most of us got to where we are.