Off grid problem..

[murphyproject]

It is not simple or cheap going from your panels to AC for an off grid setup. It is also not possible to use a charger that draws 1600w off panels that produce less than 1600w. The charger will not compensate. And Yes any power conversion is going to lose in the process (efficiency). It takes power to make power.

Going from solar panels to a battery (thus is why I mentioned the 12v in my earlier reply) to power an 12v inverter to create AC so that you can charge the 72v battery bank is one method. Another method is solar panels to a 72v battery and than to a 72v inverter for AC. A final method is a 72v to 12v conversion so that your 72v system can charge the 12v system with needing a AC based charger.

The method of trying to convince a grid tie micro-inverter to work so that you can output AC from PV panels to run a charger to charge your batteries is not a viable plan. It is not more efficient because it will not work as you intend it to.

i think you miss the point.... the problem is between the solar panel and the 72 battery the rest it's not a problem and it' already done

 

[SamDeleted]

I try to search a serius mppt charger for 72 V

Makeskyblue 72v mppt

72V 50A MPPT Solar Charge Controller for 3600W PV Solar Panels

72V 50A MPPT Solar Charge Controller 100% MPPT controller Intelligent Maximum Power Point Tracking technology Built-in DSP controller with high performance Three-stage charging optimizes battery performance Multi-function LCD displays Output limited current protection Overcharge protection...

makeskyblue.com

 

[Hedges]

how is that possible...? the inverter must always put out the maximun it recive from pv, every off grid system or also a mppt must always give the maximum and how can know the inverter know that the charger needs more...?

Inverter just delivers 120VAC. Charger draws current from it. Unless inverter (or generator or grid circuit breaker) can't supply that much.

If you have an AC powered battery charger trying to put say 100A into a 50v battery, it needs 5kW.
If you have 3kW coming from PV to a battery less inverter, it will support AC loads up to 3kW. Loaded with 5kW, output collapses.

This can work if you way over-panel, e.g. have 5kW STC of panels and 1kW (20A, 50V) battery charger.
It can work if you have a PV + battery system, feeding battery charger. With a 5kW battery inverter, it will keep feeding that 100A 50V battery charger until its own battery is drained.

But what you really want is MPPT connected to PV, with output delivering variable current to battery, whatever is available. That is an SCC.

OK, Make Blue Sky can do it for $155, or Midnight Classic can do it for $800. Your choice.

 

[Mattb4]

i think you miss the point.... the problem is between the solar panel and the 72 battery the rest it's not a problem and it' already done

As both Hedges and SamG340 have shown there is MPPT controllers to do that. I also mentioned that there was.

 

[SamDeleted]

OK, Make Blue Sky can do it for $155, or Midnight Classic can do it for $800. Your choice

And obviously you get what you pay for , I'd imagine the midnight is a better quality item

 

[Hardergamer1]

Many of us with ebikes or electric outboard boat motors that have batteries from 24v up to 85v use the Elejoy MPPT charge controller (model EL-MU400SP for boost. And EL-MD400SP or EL-DU400s for step down ) as they have adjustable outputs and are potted so semi waterproof, and cost around 30euros. I have one that I charge my 74v (84v full) electric bike with, but they were intended for boats.

And I agree with what others have said in that if you do not supply the charger or any similar electrical device the needed power it will shut down/turn off, as the electrical field will collapse, and also, this is required for basic safety, or to stop the device getting damaged.

Have a look at PVGIS which I have linked, and you see how much power your panels will make with the angles on a yacht etc, as they will be unlikely to achieve the rated power often, if ever at all. https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html