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warren-marsh avatar image
warren-marsh asked

ADVICE ON CHARGING 48V LIFEP04 SYSTEM using a generator AC or DC??

Hi group,

1st time newbie post...I have recently renovated a chalet in the French Alps that is totally off grid. I have a PV array of 9.6kw and 21kwh of battery storage LifePo4. This all runs through Victron equipment with a 10,000VA 48V Quattro Inverter feeding into our consumer unit. As the winter is drawing in we are losing sunlight, and getting the early frost and snow on the panels so some days very little gain if any moving forward. The chalet is very low consumption with all mod cons but none the less still drains the batteries which need charging on a regular basis. Charging at the moment is with a 7.5kw petrol AC generator with an input charge of around 3kw. This takes a considerable time (hours and hours) to bring the batteries up to a decent percentage. I have seen a DC 48v specific petrol generator which claims to fit the bill? It has ATS and protection but charges direct into the batteries...my question is, 1. do you think this is a good idea 2. do you think it will reduce charging times? 3. Is it safe to do or am I putting the batteries and associated equipment at risk? This is the make and model of the generator https://koenner-soehnen.com/en/48v-dc-generators. Would greatly receive any feedback. Warren

battery charging
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65nw avatar image 65nw commented ·

Charging at the moment is with a 7.5kw petrol AC generator with an input charge of around 3kw.

why only 3kw? the Q10k should do like 6kw with a low battery.

1701057634738.png

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65nw avatar image 65nw commented ·

from the generator site: "the generator has an EXTERNAL mode (or the so-called “dry contact”) for seasoned users, enabling the generator start to be controlled via an additional relay."

your victron system can trigger the generator start/stop and prevent overcharge.

but, its only a 70A charge so, (3000w/48v= 62A) its only a little bit faster than your current quattro setup, which again, should be able to do double the power.

also, its air cooled so may be louder than your current one if its is liquid cooled.

crank case 0.6L is pretty small, you will have to do oil changes more frequently than a larger engine which may have an external filter.

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warren-marsh avatar image
warren-marsh answered ·

Thanks for all your replies...I think the upshot is the DC generator is not really suitable and the Chinese Generator that I have is not generating anywhere near what it claims!! Time for an upgrade before the weather sets in.

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klim8skeptic avatar image klim8skeptic ♦ commented ·
@Warren Marsh one thing to note. Should you have any AC loads, the inverter will draw from the battery, reducing your effective charge rate.
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Michelle Konzack avatar image Michelle Konzack commented ·
Hello @Warren Marsh ,

dou you have this so callef "range extender" which has the 27pol coil attached to the engine and spinning the rotor with the magnets outside?


For 24V there are two models with 3kW and 5kW available but have never seen one in real and do nit know anyone which has one.


If you have such, can you share some technical details?


Both versions using a 19mm taper crankshaft, which let me believe, the chineses are definitively fooling.


Because onky engines 168F to 172F have a 19mm or 20mm crankshaft, because the continious power is between 3,4kW and 4,4kW, hence a 5kW Range Extender would need a 188F or 192F with 8,2-9,6kW wich has in return a 25mm crankshaft.


So ANYONE who consider buying a chinese Range Extender must be very carefull.


Oh, models for 48V, 60V and 72V with up to 8kW exist too.


Since this Range Extender have 27poles, the 8kW 60V version should work in theorie with a SmartSolar MPPT 250/100 and a 48V batterie (Lead-Acid or LiFePO4) since the output power is limited to 5,6kW


I would like to make a test with a 60V 5kW and my 24V SOPzS battery but I have currently not so much spare money laying around.


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warren-marsh avatar image warren-marsh Michelle Konzack commented ·
Hi Michelle,

I’m pretty sure it’s just a standard generator purchased about 2 yrs ago now!!

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Michelle Konzack avatar image
Michelle Konzack answered ·

If the DC Generator is not explicit made to charge LiFePO4 batteries, let the fingers from it.


I made an endless search on this topic abd ur seens, ONLY Lead-Acid, AGM and Gel Batteries can be charged DC.


Fortunately, i use 24V SOPzS batteries and can use a standard engine (Diesel, Benzin or LPG) with a truck alternator (just ordered two 120A models which cost 15% of a 280A model) attached. More robustness is not possible.

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kevgermany avatar image
kevgermany answered ·

Suggest you check the AC input current limit, this could be set too low, limiting your charge rate.

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phoenix avatar image
phoenix answered ·

@Warren Marsh

As you are in France, buy a diesel generator which you can run off red diesel. It's become expensive, about 1,40/l by me in the south, but you get more kw out of the genny compared to petrol and usually quieter. Several stations by me sell it by the litre. You could also look at lpg/petrol replacement carb. For my 2kva petrol genny it was 15€ off aliexpress.com. 10kg of gas is about equivalent to 20 L of petrol without any spill risk and a bit cheaper.

Not a recommendation, but have a look at hyundai diesel generators. Well priced. I have a friend with 2, a 6 and 9kVA and he is happy!

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Michelle Konzack avatar image Michelle Konzack commented ·

Red Diesel?

You mean MAKED DIESEL FUEL?

If you are NOT a Farmer and have no Tractor, the use of this Diesel is illegal!

I am Farmer and got last year the authorisation to use MAKED DIESEL FUEL, but since I have an electric Tractor and consider installing a RangeExtender (Bensin or LPF), my consumption would be under 100l/y. It is not worth, to bother with the Customs and Fiscal Office. At OLEREX the red diesel cost 1,32€, while the ordinary one 1,52€


Better make a friendship with a farmer who has a truck, because the truck has to use ordinary diesel, but farmers buy it in VERY big quantity and my neighour sell me the liter for currently 1,22€...


I need for my Berlingo 200l a month and for my Hatz Diesel 1,9kW 28V 68A around 40l.


Hence I have not to explain anyone something because everything is legal.


HOWEVER:


DO NOT FORGET, that a Bensin Generator running LPG, has around 10% lesser power.


I pay in Estonia 86€ for a 33kg bottle, but only 312€ for a "Big Boy" 200kg. However, for the Big Boy you need to have a Forklifttruck or Frontloader with 450kg capability availlable, because the delivery trucks (also the ones from Strasbourg where I was living for 19 years) have no cran on it.

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kevgermany avatar image kevgermany ♦♦ commented ·
The diesel Hyundais are very very noisy, even the 'quiet' ones.
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warren-marsh avatar image
warren-marsh answered ·

Hi Phoenix,

I bought a new diesel generator last year Euro V. Being situated in woodland near the bottom of a valley in winter with snow on the ground, when running (only 3hrs) you could really smell the exhaust fumes and when turned off the smell of the heavy oils had settled on the snow! Its hard to imagine as I thought this would have been the perfect solution...I drained the fluids, packaged it up and sent it back, with a full refund (luckily).

Last night I purchased a LPG/ Petrol 8kw max power on a black friday deal 42% off, direct from the manufacturer! My fingers are crossed!!

LPG / Gasoline generator "Könner & Söhnen" KS 10000E G

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Michelle Konzack avatar image Michelle Konzack commented ·
Hello @Warren Marsh ,

if you get it, please can you report back, especially about Voltage and Frequency stability...


I can get this 230V singel phase GenSet for 1100€ in Estonia and before I invest this money I like to know more about.


The KS10000 has 7,5kW continious output power, which mean, I can charge my Batteries with two Victron MultiPlus-II 24/5000 and AC input limit set to 2x 12A.


Together with a 200kg LPG bottle it give a nice price per kW output power.


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phoenix avatar image phoenix commented ·
Try approaching companies like Butagaz and set yourself up as a 'seller'. They deliver a rack and fill it with bottles. IIRC gas is about half price. Not sure if you need to be registered as a pro. A friend looked at it briefly then changed careers.


An auto-changeover valve will save a lot of swearing, and will mean 9kg propane bottles are feasible, rather than lumping around the massive 35kg ones, which weight 70kg.
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alaskannoob answered ·

I currently use a gas AC generator (with two wire start connected to the Victron system) wired into an EG4 Chargeverter which takes the generator output, converts it into 48V DC, and is wired directly into the DC bus to charge the batteries and provide power to the inverter.

It works great, but I want to switch to a diesel DC generator. Unfortunately, the DC generator I am looking at currently doesn't limit its current output like the EG4 Chargeverter does, and since my batteries alone can demand 800A of charge current, it would put too big of a load on this particular generator.

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