Thanks

[beerbeerbeerbeerbeer]

A big thanks for those who gave me advice back in December on what to buy regards fitting a solar panel. (I can’t find the original thread.) much appreciated  

I finished wiring them up this morning.  There’s clouds overhead but I’m getting a nice little charge and a smiley face above the battery icon. Now to read the MT50 instruction book to see what the box will tell me.

One last basic question: 

Should I have installed a fuse? 

I’ve wired the controller directly to the first leisure battery of three because the terminals were easiest to connect to.  (I thought to the + of the first battery  and - of the last battery would be better but I was advised it won’t matter) But should I install a fuse?

[mrsmelly]

Just now, Goliath said:

A big thanks for those who gave me advice back in December on what to buy regards fitting a solar panel. (I can’t find the original thread.) much appreciated  

I finished wiring them up this morning.  There’s clouds overhead but I’m getting a nice little charge and a smiley face above the battery icon. Now to read the MT50 instruction book to see what the box will tell me.

One last basic question: 

Should I have installed a fuse? 

I’ve wired the controller directly to the first leisure battery of three because the terminals were easiest to connect to.  (I thought to the + of the first battery  and - of the last battery would be better but I was advised it won’t matter) But should I install a fuse?

Yes you should have a fuse. I am not the one to tell you the size but you do need one.

[Jess--]

yes, there should be a fuse between the controller and batteries (as close to the batteries as possible)

it should be rated to carry the full output of the solar system (solar panel wattage divided by 12 should get you close enough)

[beerbeerbeerbeerbeer]

10 minutes ago, Jess-- said:

yes, there should be a fuse between the controller and batteries (as close to the batteries as possible)

it should be rated to carry the full output of the solar system (solar panel wattage divided by 12 should get you close enough)

So 150W will need a 12A fuse? 

[Athy]

26 minutes ago, Jess-- said:

 

it should be rated to carry the full output of the solar system .

Jeez, it had better be a big 'un - all those planets.

[Jess--]

150w / 12v = 12.5A

so in theory you need a minimum of a 12.5A fuse

in reality you would probably fit a 15A fuse

[beerbeerbeerbeerbeer]

Great stuff. Thanks, that was quick. 

[MtB]

I remain to be convinced a fuse is necessary in this specific case. What is it to protect against? The solar is hardly going to deliver more than its rated output ever, is it?

To answer my own question I suppose damage to the cable(s) could conceivably result in the batteries delivering a hefty, fire-creating current. 

[Jess--]

1 minute ago, Mike the Boilerman said:

I remain to be convinced a fuse is necessary in this specific case. What is it to protect against? The solar is hardly going to deliver more than its rated output ever, is it?

To answer my own question I suppose damage to the cable(s) could conceivably result in the batteries delivering a hefty, fire-creating current. 

you got it, it's to protect the wiring in case of damage or a fault in the controller (which is why it should be fitted as close as possible to the batteries)

[MtB]

3 minutes ago, Jess-- said:

you got it, it's to protect the wiring in case of damage or a fault in the controller (which is why it should be fitted as close as possible to the batteries)

 

Thanks. That clarifies my thinking. 

[reg]

I use inline waterproofed blade fuses between battery and controller and likewise between panel and controller, as Jess says the are used to protect the wiring and a sized accordingly. 

If I have to work on the system for any reason I just remove the fuse from between the panel and controller and then the fuse from between the controller and battery. 

When putting the fuses back its should reversed I. E battery to controller fuse first and then controller to panel second. 

[beerbeerbeerbeerbeer]

1 hour ago, Jess-- said:

150w / 12v = 12.5A

so in theory you need a minimum of a 12.5A fuse

in reality you would probably fit a 15A fuse

Right, Thanks Jess  , 15A fuse fitted! And the sun is shining.

now just sit back and enjoy free lecky.

I do like that smiley face icon and the battery icon showing it filling up. 

 

 

[reg]

1 hour ago, Goliath said:

 Now to read the MT50 instruction book to see what the box will tell me

Whilst you are reading the book make sure you read the part about setting up the parameters fro the battery bank Size and type. 

I find that when I set these from the mt50 sometimes they don't store first time even though it says it has saved OK,  so now I always double check after I do a parameter save and reset them if necessary. 

[beerbeerbeerbeerbeer]

5 minutes ago, reg said:

Whilst you are reading the book make sure you read the part about setting up the parameters fro the battery bank Size and type. 

I find that when I set these from the mt50 sometimes they don't store first time even though it says it has saved OK,  so now I always double check after I do a parameter save and reset them if necessary. 

At minute can’t work out how to get off any default settings. 

[Tony Brooks]

And that smiley face might be incorrect unless all your loads are taken from the solar load terminal. I use volts and amps (if the controller  shows amps to battery)..

[beerbeerbeerbeerbeer]

33 minutes ago, Tony Brooks said:

And that smiley face might be incorrect unless all your loads are taken from the solar load terminal. I use volts and amps (if the controller  shows amps to battery)..

No loads from the solar load terminal as yet. 

Amps were going in and battery level rising. I’ve old batteries that’ll never reach full charge again but  they should still have enough life left to keep me going for awhile, if the solar panel keeps them topped up.

Hopefully I’ll suss out the data to work out how healthy the batteries actually are. 

[Grebe]

Great advice from the electrical gurus.

Just a minor point, when we had a discussion about powering bilge-pumps directly from batteries (when the boat isolators are turned off) the gurus warned that the fuse on the line should be outside the battery box to avoid an explosion should a failed fuse ignite hydrogen from the battery.  In view of the exploded battery elsewhere today should the same warning be given regarding the in-line fuse discussed here?

[reg]

1 hour ago, Tony Brooks said:

And that smiley face might be incorrect unless all your loads are taken from the solar load terminal. I use volts and amps (if the controller  shows amps to battery)..

With the MT50, and i suspect many others, the smiley face should really be a Tongue in cheek smiley face as the values shown on the screen are not entirely accurate but they do at least give you an indication that something  is going on.

At night when the sun has gone and the batteries are rested the meter may well show a battery voltage of 12.6 when in fact the true voltage is much lower, I actually measured mine last night and battery voltage was 12.43v when meter was showing 12.6v. Not so much a problem when batteries are relatively full but can be misleading when batteries are low e.g ive had 12.2v showing when actual voltage was nearer 11.9v (batteries since replaced by the way).

In essence the MT50 will show you that something is happening but the figures if gives out may not be accurate, as long as you know this then it isn't a real issue.

Edited April 18, 2018 by reg

[canals are us?]

1 hour ago, Goliath said:

At minute can’t work out how to get off any default settings. 

You need to change the battery type to "user" I couldn't work it out too, then you can adjust the voltage settings to your own values. If no posh inverter occasionally do an equalisation charge using the EQ charge function voltage on the MT50 Meter. 

I wouldn't take it as gospel the battery charge indicator as mine is showing half charged on the MT50 meter and on mains victron charger. Best first thing in the morning when no solar activity is to start the engine and see how many AH is being charged. If under 2% of the battery bank then full. This way you won't kill the batteries.

James  

[Tony Brooks]

1 hour ago, Goliath said:

No loads from the solar load terminal as yet. 

Amps were going in and battery level rising. I’ve old batteries that’ll never reach full charge again but  they should still have enough life left to keep me going for awhile, if the solar panel keeps them topped up.

Hopefully I’ll suss out the data to work out how healthy the batteries actually are. 

For a typical boat use the solar load terminal has limited uses. The only one I can think of could be an extractor fan in the toilet or kitchen.

[reg]

18 minutes ago, Tony Brooks said:

For a typical boat use the solar load terminal has limited uses. The only one I can think of could be an extractor fan in the toilet or kitchen.

Agree with that, limited use I have a low watt led light connected for use just above the controllers as these controllers are sited in a dark corner.  I use the manual red button switch on the tracer bn series controller to switch it on and off and have all of the automatic timing functions switched off. Not all controllers have this manual switch though so, as you say, of limited use. 

[WotEver]

2 hours ago, Grebe said:

should the same warning be given regarding the in-line fuse discussed here?

All fuses, whatever the feed, should be as close as possible to the batteries but outside of the battery box. Always. 

[beerbeerbeerbeerbeer]

4 minutes ago, reg said:

Agree with that, limited use I have a low watt led light connected for use just above the controllers as these controllers are sited in a dark corner.  I use the manual red button switch on the tracer bn series controller to switch it on and off and have all of the automatic timing functions switched off. Not all controllers have this manual switch though so, as you say, of limited use. 

I might add a socket to use to charge a gadget and use as a cigarrete lighter. The controller is in reach of the tiller  

 

[roland elsdon]

I have fuses inside my battery box. They are 40 amp blow glass fuses. The 2 different coc  men have never said anything. I am happy to be corrected but cannot see how a fuse blowing insde a glass cylinder with inert gas inside can be a hazard.

i am very capable of being stupid and need education on this, before i blindly rewire again.

[Jess--]

10 minutes ago, roland elsdon said:

I have fuses inside my battery box. They are 40 amp blow glass fuses. The 2 different coc  men have never said anything. I am happy to be corrected but cannot see how a fuse blowing insde a glass cylinder with inert gas inside can be a hazard.

i am very capable of being stupid and need education on this, before i blindly rewire again.

a lot of inline fuses used on boats are the car blade type which can spark as they blow, hence the advise that they should be outside the battery box