January 20, 20233 yr I have asked on other Powerforums here but no luck. I need to do myself a small load-shed backup system. I DO NOT want a trolly unless I can feed it through the DB. Without DB connectivity load-shed backup is useless. I am not camping. I gather modified sine wave cannot be fed through the DB. In any event I need something that is durable and quality. I need to walk into the house and switch the lights on and then the TV etc So please help: A Victron Phoenix 12v 1200VA inverter - it will far surpass all critical requirements. I do not average more than 300Watts on normal usage and no more than 2000Watts surge. I intend having all this on a single circuit - maybe two. 1. Can I feed it through the DB? If not why not? How do I achieve this seemingly simple thing?? 2. I need an automatic transfer switch - how is that sized/acquired/spec-ed/installed? 3. A 12volt 200Ahr Lifepo battery is fine - cannot imagine how one needs more thus: 4. How to charge it? Assuming I run it down in 4 or 5 hours during a load shed what do I need to charge it again during the next 4 or 5 hours? 5. Then at some point I decide to add panels. How do I size them? How do I size the appropriate regulator? 6. How do I get the charger/regulator/panels/auto transfer switch all to work together? Maybe there is a site where I can find this information? Or a sticky here somewhere? Regards to all.
January 20, 20233 yr 43 minutes ago, Clivevan said: I am not camping. Then why are you looking at an inverter intended to be used for this outing? The inverter you're looking at cannot charge the battery, so, you'd need a battery charger that understands and can handle a LiFePO4 battery as well, the switching should be doable by any competent electrician, you'd basically let commercial power switch a contactor/relay, which connects the load in question to the inverter, when mains is not there, else when commercial power is available, it'll disconnect the inverter and connect the circuits to their normal source. All you want is doable, you'll need an electrician to quote you on all the work and switching, but I see no big problem, other than you wanting to use a *really* small inverter, which isn't really ideal for what you are trying to achieve, since it has no MPPT/charge controller from either mains (which can not be connected to it) or from solar panels (which obviously also can not be connected to it), so you'd need a Victron Phoenix battery charger also wired up appropriately and a Victron Smart Solar MPPT of appropriate sizing, based on the Solar panels to be added, which would probably be not more than 400W to recharge the battery. Personally, I'd look at something with a bit more power, 3 to 5kW, ideally, probably more integrated and certainly 48V on the battery end, but then again, here the house runs mostly off solar with a 5kW inverter...
January 22, 20233 yr Author Thank you - I am starting to see problems everywhere. Most certainly I don't need 3kW to run 4 lights a fridge and a TV. Let me ask if this is feasible: Is it possible to install a VICTRON MULTIPLUS 12/1600/70 INVERTER/CHARGER together with a Lifepo 12v 200ah and then: 1. connect the set-up to 2 x 400W panels each straight to the battery via a 35A PWM regulator. And so, 2. whenever the sun is up the two panels each charge the battery via its own PWM. EVEN IF MAINS ARE SIMULTANEIOUSLY AVAILABLE. 3. Whenever there is no mains the two panels will simply chug along each charging the battery with its own PWM. Or will the PWM fight the charger built into the Multiplus?
January 22, 20233 yr 23 minutes ago, Clivevan said: Is it possible to install a VICTRON MULTIPLUS 12/1600/70 INVERTER/CHARGER together with a Lifepo 12v 200ah Yes, only possible problem I see is that this inverter has fixed values for battery charging etc. which seem not to be user modifiable... 24 minutes ago, Clivevan said: 1. connect the set-up to 2 x 400W panels each straight to the battery via a 35A PWM regulator. I see no problem with this 25 minutes ago, Clivevan said: 2. whenever the sun is up the two panels each charge the battery via its own PWM. EVEN IF MAINS ARE SIMULTANEIOUSLY AVAILABLE. again, should be ok, although, I'd think the battery may already be full, so not much happening, I'd think, if you have solar panels, you should probably run the load off the solar end, once the sun is up and power is produced... 27 minutes ago, Clivevan said: 3. Whenever there is no mains the two panels will simply chug along each charging the battery with its own PWM. yup and like the previous comment, depending on the load etc. you may want to create your own "load shed" to utilise the free power from the sun... but this will have to be a manual affair, although, one can probably with some effort automate this, after all you'd have to keep an eye on the battery's level of charge etc. not that you end up at 6PM with a real load shed and only 40% SOC in the battery...
January 22, 20233 yr Author Thank you so much for this - I was worried the inverter/charger fights with the PWM regulators. The idea is to place the regulators in parallel. Am I right this means each panel is separate and isolated and runs through its "own" PWN into the battery? And then of course the Inverter/charger is also connected to the battery. Is my mental picture correct? I want to install it on a farm where half the time there is no mains anyway and only solar but often times (very cold and cloudy and/or many visitors) I am short of solar and mains happen to be available so the idea is to be able to manually switch onto mains but AT THE SAME TIME retain the solar charging functions. So it is not one or the other but BOTH. And both for extended periods.
January 22, 20233 yr Author Thanks again - I just could not work this out. Is it true for any inverter/charger that you can add solar panels via a regulator without a problem?
January 30, 20233 yr On 2023/01/22 at 4:57 PM, Clivevan said: The idea is to place the regulators in parallel. Am I right this means each panel is separate and isolated and runs through its "own" PWN into the battery? yes, although you normally would have a MPPT or PWM charger that can handle a few panels, thus normally only 1 charger would be used, if you have a lot of panels in different directions, then, maybe you may want more than 1 charger, but even under this scenario, assume 3 panels in series looking east, 3 panels in series looking north and 3 panels in series looking west, assuming the panels in series are within the Voltage specs of the charger, you'd run all three string to your charger and parallel them up there... but if you had 2 or 3 charge controllers you would parallel the output of these up to the battery... On 2023/01/22 at 4:57 PM, Clivevan said: Is my mental picture correct? yes, inverter also paralleled up with the charge controller(s) at the battery end... On 2023/01/22 at 4:57 PM, Clivevan said: And both for extended periods. on a farm here with 8S2P 280Wp panels into a 5kW Infinisolar V2 inverter (so charger / solar MPPT charger and inverter in one), we have an extension lead to the neighbour which can carry 2kW, but mostly live off the solar and off a 8k2Wh LiFePO4 battery (not enough battery) for comfort, but we get by for now... luckily here in the green Kalahari we don't have that much cloud cover, although I use some choice words when they come and cause shade on the solar panels... On 2023/01/22 at 4:59 PM, Clivevan said: Is it true for any inverter/charger that you can add solar panels via a regulator without a problem? if you only have an inverter without solar inputs, then you can do the battery charging thing which also should produce power and let the inverter run off this, as if it was the battery, without a battery to charge though, all bets are off...
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