Quick question about solar panels.

[Simi 60]

Originally Posted by PaulinOz

MPPT Screen will tell you all about what is going into your battery from solar and thats all.
Battery monitor will Give you in and out of batteries via a shunt mounted in line and if programed with battery capacity will also give you percentage charged, time to total discharge and history etc etc.

Thanks for that.
I did ring around trying to get answers but no one seems to be working on a Saturday.
Adds another cupla hundred to the tab.

[PaulinOz]

Remember you need a shunt as well sized for your max charge /discharge rate. Can be $50 to $250 depending on size. It just keeps adding up.

[StuM]

Originally Posted by Simi 60

This MPPT I need.
Every quote I have had regardless of brand always has a victron BMV 702 added in.

I was under the impression that the screen on the front of that MPPT should do everything that a dedicated battery monitor would do.

I find it a lot more convenient to look at a battery monitor on the electrical distribution panel, than to get to where my controller is located.

[Simi 60]

Originally Posted by PaulinOz

Remember you need a shunt as well sized for your max charge /discharge rate. Can be $50 to $250 depending on size. It just keeps adding up.

I take it that would be the shunt that comes with it?

What comes in the box:
BMV-702B battery monitor
BMV square bezel
BMV shunt 500A/50mV
10m UTP cable (For connection between shunt and battery monitor)
Positive supply cable with fuse

[PaulinOz]

"I take it that would be the shunt that comes with it?"

If it is specified with a shunt all good. I purchased from OS a number of years ago and it arrived sans shunt did not think to check when purchased, then had to get it locally.

Think about mounting before drilling hole. I mounted in my electrical cupboard which involved sitting on the floor to read my Battery monitor solar controller, inverter remote control and generator starter control.

So I moved them all to the wall in my sleeping cabin at standing height, so to view or cheek as I walk past was easy and a lot more convenient.

One day I will fill the empty holes in the electrical cupboard.

[barnakiel]

I think there are meters that can use two shunts and which use memory to store each data string. Then the solar regulator does not need its own shunt and monitor.

But I bet some bigger regulators may have a monitor built in. Not always a shunt is (externally) present as this can be mounted inline withing the regulator (or monitor) chasis - nothing external to mount remotely, just set tha cables and you are going.

Small off the shelf shunts (up to maybe 150A) are cheap. Ours, rated 60A cont. cost USD20. We were lucky because our monitor (a Bogart) will happily take any aftermarket shunt. Big shunts, especially bought from monitor manufacturers (e.g. Victron) can be super dear - easily 4x and more over the wholesale price of the same element unbranded.

b.

[Simi 60]

Another question: Can I have to many panels?

The solar mob I got a quote from said I needed 6 x 260w panels to run pretty much genset free and if I wanted more juice at a later stage I needed another victron 60amp MPPT and more panel.

Because I am looking at a MidNite MPPT that can handle 95 amps (I can get it for less than the original quote for a 60amp victron) the supplier of the MidNite says it can run 9 x 250w panels on 3 x 3 strings. (I can get 9 almost new Jinkos for half the price of 6 new others)

Is that going a bit silly considering I have a 600ah x 24v bank or will it just mean that terribly inefficient hot water system can possibly stay for now as there is an abundance of power?

[senormechanico]

Simi,

I have a Midnite Solar 150 on my home.
I also have 18 250 watt panels with 18 Enphase inverters and a grid tie.
When the grid goes down such as during a storm, the raw DC is fed via one big common + and 18 separate - leads through 18 Schottky diodes to the Midnite Solar 150 which feeds a 700 aH LiFePo4 bank.
The Schottly diodes are there to preserve the individual electronic data for the MPPT / Enphase inverters, i.e each system doesn't know the existence of the other. It's a little bit more detailed than that to prevent error messages during switching, but you get the idea.
The 150 is programmed to not go over 94 amps by me.
So the answer to your question is "no" as long as you make sure to program the maximum current feature.

[barnakiel]

Originally Posted by Simi 60

Another question: Can I have to many panels?

Yes.

In some modes, boats will have no solar panels at all, just gensets and big spec alts / +multistage regulators.

I think users fall into those who prefer to make and those that prefer to save, there is very little middle ground.

Not sure I have seen many solar panels on navy ships, fishing trawlers or cargo carriers. I have seen some on a cruise ship, probably a cheap publicity gig.

If you run fridges and freezers, AirCon, watermakers, APs and plasma TVs, you may be wasting your time going the solar way.

If by 'too many' you only understand the scenario when solar is the right way but you are considering the optimum maximum number of panels then you are too probably wasting your time: on most solar installations, the limiting factor is nearly always the storing capacity, not the production capacity. To put it another way: a well sized solar bank will consist of 'too many' panels, unless you have unlimited battery bank that can accept unlimited Amps at any time. This, we agree, is hardly ever (never?) the case on leisure boats.

Cheers,
b.

[44'cruisingcat]

Originally Posted by Simi 60

I am looking at getting several panels and I have a choice of two brands.
Both are tier 1 companies.

The ones on the left (Jinko) I can get for 2nd hand with 9.5 years of the 10 year warranty still in play.

Make sure the warranty is transferrable. They aren't always.

[Simi 60]

Originally Posted by 44'cruisingcat

Make sure the warranty is transferrable. They aren't always.

Hi, he says they are and has given me details to contact Jinko Brisbane for confirmation

[Simi 60]

Originally Posted by senormechanico

Simi,

I have a Midnite Solar 150 on my home.
I also have 18 250 watt panels <snip>
The 150 is programmed to not go over 94 amps by me.
So the answer to your question is "no" as long as you make sure to program the maximum current feature.

Thanks for that.

[Simi 60]

Originally Posted by PaulinOz

Think about mounting before drilling hole. I mounted in my electrical cupboard which involved sitting on the floor to read my Battery monitor solar controller, inverter remote control and generator starter control.

All that gear on this thing is at standing chest height and there is a vacant spot for the 702
Thanks

[Simi 60]

Originally Posted by PaulinOz

Remember you need a shunt as well sized for your max charge /discharge rate. Can be $50 to $250 depending on size. It just keeps adding up.

Shiny new toy for a boat I dont even "officially" own yet just arrived.
Fast postage

[GILow]

Seriously, if that Rheem is the vitreous enamel sort, then you'd be wise to consider it dead. If it is not leaking already, it will start doing so very soon. I certainly would not spend a CENT on anything to support it. I understand it is built in, but once it starts leaking (and it will if it is the V.E. sort) you'll be plugging it off and putting a new hot water system, probably diesel powered. And since you could put in a brand new diesel heater for a fraction of the cost of building an electrical system to support the Rheem, I'd consider it junk now anyway.


Matt