Lithium Batteries- Relion in particular

[Nabsim]

Who's Li are you using? Do they have a Amp rating on input? Most 100ah Li have a max 50a input, be worth knowing.
If we don't fit a Multiplus Inverter Charger combi, we normally go with Sterling's PCU range of mains chargers, as they carry specific Li profile and can be custom programmed if necessary.

I need to be able to run whatever I get from my 1Kw genny if necessary Nick so I am thinking about the Victron Blue Smart 30amp. I am rarely on hookup, my B2B is 30 amp as well

 

[QFour]

I need to be able to run whatever I get from my 1Kw genny if necessary Nick so I am thinking about the Victron Blue Smart 30amp. I am rarely on hookup, my B2B is 30 amp as well

The problem is your generator. It will only kick out 4.166A at 240v so it doesn't really matter what 240v charger you use. The only way to put more power in in a shorter time would be a BIGGER generator or one of the 12v 50A versions. A 2KW generator will give you around 8A. Electric hookup on a site is normally 16A 240v. You could use a fuel cell which would give you a constant amperage 24/7 but they are not cheap.

Best thing to do is save energy in the first place. Do away with the POWER HUNGRY inverter and use 12v equipment.

 

[Canalsman]

You're forgetting that it's essentially 14.4v output that's required, so 30 amps output will require around 1.8 amps input from the generator.

Victron's spec sheet quotes 93% efficiency so bump that up to around 2 amps, well within the capability of a 1Kw generator.

 

[trevskoda]

The problem is your generator. It will only kick out 4.166A at 240v so it doesn't really matter what 240v charger you use. The only way to put more power in in a shorter time would be a BIGGER generator or one of the 12v 50A versions. A 2KW generator will give you around 8A. Electric hookup on a site is normally 16A 240v. You could use a fuel cell which would give you a constant amperage 24/7 but they are not cheap.

Best thing to do is save energy in the first place. Do away with the POWER HUNGRY inverter and use 12v equipment.

You would have 75amps if you plugged in a charger,a 40ah charger is as about as big as you get in a small box.

 

[Sharpie]

My 1kW 240V generator can continuously output 900W, which is nominally 75A at 12V. Or 62.5A at 14.4V.

So it is more than capable of putting massive charge into a battery capable of accepting it, such as a bank of Lithiums, with a suitable mains charger.

It does a pretty good job with my lead ones and small 20A charger, just running quietly on a low autothrottle setting, and I am considering adding a second 30A charger as well, to fully exploit its potential. Charge acceptance with lead tails off as they reach capacity, so it isn't really quite like that.

As I understand it Lithiums can take as much current as the charger can supply, up to the limit of their BMS, maybe 50A per battery.

I don't know how well they load-share, i.e. could two in parallel take 100A, and I think that it is really a good idea to push the current in that hard, but in theory you could take one from flat to full with just 2 hours generator running. Or driving, if you have a big alternator.

I see that as a real advantage over lead. But am not yet ready to fit one yet, I don't have a use case, and I think the technology is still developing, relatively unproven, and reducing in price.

 

[Deleted member 80008]

Victron is a good shout, also Sterling PCU1230 to PCU1250 range of mains chargers is worth a look at

 

[SquirrellCook]

I have two Victron chargers one 24volt at 12 amps and another 12volts at 15 amps. Running the pair on full load at Hereford a little while back my poor 1kva 900watt smart generator was on it's limits. You have to remember conversion inefficacies.

 

[Nabsim]

I checked with Onboard Energy and the Victron Blue Smart 30amp charger uses 2.3 amps at 240v.

I could run a 40 amps but they don’t seem common, I know Charlie has a Ring 50 amp Smart charger and a 1kw genny really isn’t enough for that.

I don’t use an inventor, well extremely rarely I may plug in my 300w investor but that’s uncommon. It’s the compressor fridge and diesel heating that use the power, fridge is approx 45 amps alone.

 

[Sharpie]

I have two Victron chargers one 24volt at 12 amps and another 12volts at 15 amps. Running the pair on full load at Hereford a little while back my poor 1kva 900watt smart generator was on it's limits. You have to remember conversion inefficacies.

I'm not surprised. Lets say that's the equivalent of 39 Amps combined, into 12V. If that's going into Lithiums at a steady 14.4 volts thats 562 Watts. But the 900 VA load rating will be at a power factor of unity, which you will only see with resistive loads. Battery chargers will have a lower power factor so the output has to be derated in proportion.

That's not usually specified, surely some are better than others, some may not even have any power factor correction circuitry, as well as inefficiences of course, they get warm. If plugged into the mains you won't be aware of this, but if using a generator it is important when choosing the size.

Do Victron state the power factor at that 2.3 A? Well I'm quite sure it will be lower than 1.

Example: 900 VA generator feeding a load with power factor 0.7. The generator rating is now 630 Watts, not 900 VA.

You can use an inexpensive plug in meter to show you this, as well as things like how many kWh have been produced, the current being drawn etc. Not sure how accurate they are but they are very useful

Neither would I want to run my 900 VA one flat out continuously with a load with lower PF. It can do it happily for hours, when I used it with two 400W halogen worklights (unity power factor) whilst working on a boat in a barn, even some quite big power tools as well (one of the lights turned off). Turned off the autothrottle of course so it hummed away at full revs. Still gets noisy when full load is applied and it opens the throttle wide.

Edit, replaced Watts with VA to be correct.

 

[Nabsim]

@SquirrellCook i told onboard energy that I needed the charger to work with my genny and they said it needs 2.3 amps. They never mentioned power factors nor did I ask.

 

[Deleted member 72907]

I checked with Onboard Energy and the Victron Blue Smart 30amp charger uses 2.3 amps at 240v.

I could run a 40 amps but they don’t seem common, I know Charlie has a Ring 50 amp Smart charger and a 1kw genny really isn’t enough for that.

I don’t use an inventor, well extremely rarely I may plug in my 300w investor but that’s uncommon. It’s the compressor fridge and diesel heating that use the power, fridge is approx 45 amps alone.

I had one of these in my old MH, recommended by Dave after typically exhaustive testing )). I'm getting another when I'm ready to put a fridge into my self-build.

https://www.amazon.co.uk/Inventor-I...ds=inventor+fridge&qid=1578757128&sr=8-2&th=1

 

[SquirrellCook]

Funny I don't seem to be able to find any power factor figures for the Victron blue smart chargers? I'm guessing it's horrible as it's not mentioned. May explain why I'm not seeing the charging efficienies I expected.

 

[Sharpie]

@SquirrellCook i told onboard energy that I needed the charger to work with my genny and they said it needs 2.3 amps. They never mentioned power factors nor did I ask.

It may be that that is the correct figure, already taking into account the power factor of their charger.

E.g. if delivering 30 A into a Lithium battery at 14.2 V, that's 426 W. From their datasheet they are "up to" 93% efficient, that would mean it takes 458W, which is 1.91 A at 240 V.

So stating that it takes 2.3 A suggests that may already take into account a power factor of 0.83, which would be very good.

I'd certainly not expect a cheap Chinese power supply to be that good. According to my plug in meter for example the charger in my Electrobloc is about 0.7, which is not great, but it's what I have.

Edit:, so at best, if the Electrobloc was putting it's rated 18A at 14.4 V into my 180Ah battery bank just as it moves from bulk to absorption, let's say it is 85% efficient (it as an old basic design) that would be pulling 435 VA from my 900 VA generator. I'd like to put in more than 18A which is why I am thinking about adding an additional charger, either in parallel or to replace it. Also why I chose some different batteries recently which should be capable of accepting that current better than the previous leisure AGMs. The harder you charge and discharge them, the lower the lifetime that you might expect.

I'm not ready to consider say a single 100 Ah Lithium yet, that might, on paper be able to replace my big heavy lead bank, cope with regular 100% discharge, and recharge in 2 hours at 50A, for thousands of cycles with little degradation. I am still skeptical about the realities of that, and their ability to cope with low temperatures. OK the best EV makers can "supercharge" their batteries much faster than the 2C rate, but they don't get discharged in 2 hours, far from it, and have cooling, and warming systems whilst they are doing that.

As for running things like massive 1000 W inverter, for some reason, that has to pull at least 90A. If a single Lithium could do that, and even if the BMS allowed it, it would be brutal for it.

If so you would need 552 VA from your generator to power it, leaving up to 348 VA capacity for other things as well for a 900VA job. Thats VA, not necessarily usable watts, depending on what other things you have plugged in as well.

And I would not choose to habitually run my generator that hard, even though it is rated for that.

In summary I think that the one you have chosen would be well sized, matched to a 900VA generator.

Some basic info about PF, VA and watts:

What is Power Factor? | How to Calculate Power Factor Formula

What is power factor and why is it important? Learn how to calculate the power factor formula, each component of the equation, and why it matters.

www.fluke.com