This thread has highlighted once again the difference between my rose-colored glasses and the actual practicalities of generating power. I was focusing on 'max generator output' and didn't even consider 'most efficient' as being that significant. The @DavidPoz vid above was quite dramatic in terms of kwh/gal of fuel.
Just a thought wouldn’t you be more efficient with fewer larger chargers? Seems there are inefficiencies in all chargers and by stacking many small chargers you are just making it worse. Wouldn’t 1, 2 or 3 larger chargers be more efficient?This thread has highlighted once again the difference between my rose-colored glasses and the actual practicalities of generating power. I was focusing on 'max generator output' and didn't even consider 'most efficient' as being that significant. The @DavidPoz vid above was quite dramatic in terms of kwh/gal of fuel.
I'm working on a powerwall charging system. Just ordered the 8,000w Champion - https://www.electricgeneratorsdirect.com/Champion-100297-Portable-Generator/p67310.html - dual fuel + 8 x 15a chargers - https://www.ebay.com/itm/284647244994 - to give me 120a @ 48v charging ability. But I need to tamper my expectations from 7000w charging to maybe 5000w for efficiency because my propane storage situation is limited. Since I have a large powerwall as a buffer and don't need direct powering of home circuits it would be good to get the most kwhs/gal of fuel as a goal. 5000w would be enough as the average consumption is 2,700wh.
The plan is to create a bank of 15a chargers and be able to turn them on/off individually to adjust the load on the generator. With all 8 turned on I'll have 120a @ 56v = 6,720w. On propane this should reach or go over the efficient range of this generator and if needed can add more chargers. This will give the option of max charging but would be good to know the best fuel economy charging numbers. When I get it setup I run some tests and report back
Good thought. I went with 48v @ 15a because it's the largest I could find for $131 and I have 3 x YZPOWER 15a chargers already and they seem to work well. Above 15a there are very few options for 14s lithium-ion and if you find them they are huge $.
I think 90% efficiency from 5 different chargers is still 90% efficiency right? I don't think it's 10% from every charger making it a total of 50% efficiency?
I would read that as 90% per charger which would make sense. Inverter is 96% efficient but that is each. So two would have a 4% loss per inverter. I get what your saying and you may be correct however with a larger charger your efficiency goes up so one large charger might be 95% efficient whereas a single small charger might be 90%.
Looks like a Growatt 5000ES can do 80a at 48v charging for $738 based on this link - https://www.growatt-inverter.com/product/spf-5000-es/ Not a bad idea - and nice setup!
I’m betting the efficiency of the growatt is higher than the small ones.
YZPOWER https://www.ebay.com/itm/284647244994 says.....
| Efficiency | 80% |
Mine is 96% AC to DCThe YZPOWER https://www.ebay.com/itm/284647244994 says.....
● Efficiency: >87%
The GroWatt charger efficiency? The DC ->AC is listed at 93% Peak but not sure AC -> DC is the same.
Found this for AIMS Battery Charger - https://www.aimscorp.net/ac-convert...art-charger-75-amps-listed-to-ul-458-csa.html
Efficiency 80%
Another tidbit I found interesting... the Champion 8000w Generator docs says:
View attachment 126220
My home is ~1500ft above sea level so I'm going to loose 5.25% generator efficiency?!? I'll be lucky to get any charge into the batteries
I see it. But Sol-Ark is top tier and also many $. I don't think 96% is common among the working class priced equipment from what I'm seeing. I am impressed by the 275a charging capability
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I appreciate/identify with you're enthusiasm
However, without specs or tests - I wouldn't make declarations about GroWatt, especially since they don't publish it in their user manual.Documentation you want documentation you get. 90 days in operation 96% lifetime in real time at all charging levels. Not enthusiastic just a realist. Actual testing from a Victron Shunt and not from the inverter. I stand by my statement a single quality charger will be more efficient than multiple small ones.I appreciate/identify with you're enthusiasm
Also, just because SolArk says 96% doesn't mean that it's 96% at all charging levels - there's usually some conditions such as % charging and temperature. It could be true for all common conditions but with actual testing....
I'll give you an example. My AIMS inverters list DC -> AC inverting at >88% peak efficiency. The highest I've gotten is 83% at significant % loads (>30% continuous overall loading) and the lowest is 78% at low load (<10%) levels. That's a 5% variation in efficiency based on % load revealed from several years of consistent metrics.
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Merry Christmas to all - off to see the neighborhood lights
Correct me if I’m wrong but the smart shunt is messing on the DC side in the negative line what goes in and out of the battery. So the eff is the battery efficiency and not of the charger from AC to DC.
Funny because they are advertised at 99%. I wonder if the BMS has to do with the extra losses? Or just inaccuracies of the shunt?
