AnswerID: 479062 Submitted: Thursday, Mar 01, 2012 at 10:15
Can't see too many problems with the circuit, other than:
* The 25A fuse for the inverter is 'on the limit'. If you ran the inverter at full 300W rating, the fuse may blow. You will obviously get away with the 25A fuse for lighter loads (charging phones, laptop etc) but should go one size higher (30A) in case you use full inverter power.
* The 30A Maxi-Fuse may also be on the limit if all circuits are in use. This fuse should only be protecting the cable to the fuse box as all loads have their own fuses. A 50A fuse would be more appropriate. Again, you will get away with the 30A unless you load up the inverter and other loads.
I see no problem with your large cable sizes. If you can afford them, and physically fit them in the installation, larger cables are always better.
I have the Plasmatronics PL20 in my caravan setup with 3 x 64W UniSolar panels. I have the PLS2 shunt, but my setup is independent of the vehicle charging so I don't have the problem you alluded to. Great setup.
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FollowupID: 754548 Submitted:
Thursday, Mar 01, 2012 at 12:02
Your comments on the fuse sizes make good sense, I'll beef them up a bit as suggested.
There was a lot of good discussion on circuits for caravans, initiated by Drew T (thread 57352). I'm hoping this posting will be equally useful.
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FollowupID: 754642 Submitted:
Friday, Mar 02, 2012 at 10:41
What settings do you have set on the PL20??
We have 2x 68w (136w) uni-solar
panels- batterys are 95aH and 82aH inparallel.
What is a PLS2 shunt??
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FollowupID: 754701 Submitted:
Saturday, Mar 03, 2012 at 09:20
I'm not sure what you mean by 'what settings'...
There are a number of settings required in the PL20 if you want to monitor the battery condition, or 'state of charge'. These settings are different for each installation, things like battery capacity (I have 2 x 100Ah, so 200Ah) etc. I don't plan on going through my PL20 and record everything for you as (as I said) my data is meaningless for other installations. If you have a PL20, follow the instructions in the manual - or you can download a copy from the Plasmatronics site.
The PLS2 shunt is a device that is installed in the main +ve feed from the battery BEFORE ANY LOAD (OR CHARGE) CONNECTIONS. It measures 'drain' current(s) and charging current(s), and allows the PL20 to display the 'state of charge' of the battery. It can only provide an accurate state of charge if ALL incoming and outgoing currents pass through it, hence GOM's comment about charging from the vehicle - although I expect even that could be measured if the PLS2 was in the right position.
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