Solar Power Monitor - CTEK250SA

[RikParr73]

1- yes thats fine going to the busbar (you should remove the fuse from the starter battery feed to shut down the dc-dc and also disconnect the PV POS from the MPPT side - that will switch off all power going to the LB and make there disconnected terminals safe (its always good practice to fully insulate any disconnected terminals anyway))

2- the MPPT is putting out power on the BATTERY terminals. when the sun is out (Disconnect the PV POS to shut it down) - that power is connected to the POS Busbar so feeding power into the leisure side of the system. - thats why the sockets are powered up.

The LOAD terminals on the MPPT can be used as a lov voltage cut off - if the 12v for the lights and sockets etc were taken from that terminal.

but are subject to the max throughput of the mppt (thats 15A for a 75/15 mppt)

but you haven't got them connected that way so not relevent in your setup.


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there is also the possibility that the CTEK and Vic MPPT are detecting each others 12v output and assuming its the 12v from the LB 9which has been removed)

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so if future if you need to remove the LB from under the seat . .

remove the main fused feeding the DC-DC at the starter battery and disconnect the PV POS from the MPPT - that will shut down all charging power going to the LB


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Thanks for coming back to me Dell... Ok, that makes sense now you've explained it - thanks, was just doubting things. Main concern was the CTEK output going to the bar, but you've cleared that up for me. Now that I have more time I'm labelling everything up, so not a wasted task - thanks again!

 

[RikParr73]

All wired back in and working. During this I found a positive cable that runs from the current under seat LB location to the rear of the van that is the right gauge with a 30amp inline fuse. My question is, if I were to install a second LB in the rear of the van using this pos cable to connect in parallel to the LB under the seat, could I just ground the neg terminal on the rear LB to the van floor or would I have to run a cable from the neg terminal of the 2nd LB direct to the original LB neg terminal to complete the parallel wiring? TIA, Rik.

 

[Dellmassive]

That's a tricky one due to the shunt.

Normally the 2nd LB would be ground ed via shortest route to chassis... So in rear.

But doing that bypass es the shunt so the shunt reading s will be off.

Running the POS and neg back to the 1st battery will fix that issue, but it have have a large cable resistance and losses over the cable length.

So that needs careful thinking....

It best to have multiple LB battery banks situated together to solve the above issues..... IE.. both at the rear.. or both at the front.

 

[Dellmassive]

Or just replace with one Lifepo4, which is effectively 2x AGM SlA of the same size. ( Due to the 50% DOD on SLA batteries)

 

[RikParr73]

Or just replace with one Lifepo4, which is effectively 2x AGM SlA of the same size. ( Due to the 50% DOD on SLA batteries)

Thanks for the quick reply. All noted, so the rear is out of the question really. So, LifePO4, do you mean remove existing LB under seat and replace with lithium? The 110ah lithium are coming in at £600 each - eeeeek! Not sure I wanna spend £1200.......