First foray into Solar. Advice needed

[zoidberg]

Out of interest, here's a pair of pics taken at Douarnenez of the PV panel mountings used by a couple of Mini650s. That's a sailboard flexible mast mounting under there; the aspect, or 'angle of dangle', is managed by adjustable control lines.

 

[GrahamM376]

Once the battery voltage has hit 14.82v, the bulk phase is over and the absorption phase begins. In this phase the voltage no longer rises. The controller attempts to keep the battery voltage at 14.82v. This will mean not using some power from the solar panels. The voltage is kept at 14.82v for the absorption time, which is typically a couple of hours. Only the time at 14.82v is counted. If the voltage drops below 14.82v (because of high load or cloud) the timer is paused.

Once the batteries have been kept at 14.82v for the total absorption time, the float phase begins. During the float phase the voltage is kept at 13.5v.

Thanks, very useful explanation. It seems that as the bulk and absorption stages are identical max voltages then there doesn't seem to any difference between them in a practical sense. My controller is actually set for max absorption time of 6h 59min but always drops into float before this. I'll be leaving the boat for a couple of months and hope that on return the controller hasn't cooked the batteries in my absence

 

[noelex]

The Victron controllers use a system where the absorption time is adjusted depending on various factors so you will find the absorption time will vary. This is better than the the fixed absorption time that is commonly used.

If you are leaving the boat for an extended period of time with little load I would consider temporarily reducing the voltages (especially the absorption voltage) while you are away. It is easy with the Victron system to make this adjustment

 

[Chris_Robb]

Thanks, very useful explanation. It seems that as the bulk and absorption stages are identical max voltages then there doesn't seem to any difference between them in a practical sense. My controller is actually set for max absorption time of 6h 59min but always drops into float before this. I'll be leaving the boat for a couple of months and hope that on return the controller hasn't cooked the batteries in my absence

Perhaps on leaving the boat, it would be worth making some downward adjustments to the voltages- taking them down to 14.4V so that gasing is avoided, and perhaps a lower float voltage? Any ideas noelex on whether you need a winter regime?

edit: posted before I saw yours!)

Currently with my old Steca I had problems with new batteries (Boche110 sealed LA - all I could get) appearing to have failed (full voltage, but unable to turn over the fridge (running amps of 3 - startup of ??) This was in May after 7 months on dry land with just PVs connected. I was also unable to get the voltages to rise on my STerling 80 amp shore charger, so I just repeatedly put it through its equalization routine - about 20 times, and the volts finally rose back to where they should have been - 16V under equalisation. I then had no problems. At this point the supplier turned up to test the batteries as I had put in a claim under warranty, and tested the batteries (along with my own expert). The drop tests performed perfectly (I know that they are only a rough guide).

They gave me a leaflet on over winter solar panel charging. This said that you should install an array of LEDs to come on at dusk and go off at dawn to allow some discharge (10amps or so) overnight, to prevent the STeca a PWM controller from going into full blast every morning into a fully charged battery.

The next year I had no repeat performance of the problem and I await to see results for this year - I have to leave the boat in early July for medical reasons - and wont be back till mid May. I usually do 2 months in early summer and 1 month in September, so there is no way I want to spend a fortune of AGM Lifelines for my main house banks (440 a/h) as I wont be able to look after them properly. (Note - the bow thruster/anchor winch battery is an AGM Lifeline from 2004 and is (or was still perfect when I left last year!)

 

[GrahamM376]

If you are leaving the boat for an extended period of time with little load I would consider temporarily reducing the voltages (especially the absorption voltage) while you are away. It is easy with the Victron system to make this adjustment

Good idea, I'll do that. As batteries will be full when we've motored back to mooring will drop abs to 14.4 and maybe float a bit as well. Will leave monthly equalise as it is. Only loads while away are gas detector, radio memory and nightly led anchor light. Thanks for the help, pity Victron don't do a "guide for dummies".

 

[ghostlymoron]

How often do they adjust the elevation?

Out of interest, here's a pair of pics taken at Douarnenez of the PV panel mountings used by a couple of Mini650s. That's a sailboard flexible mast mounting under there; the aspect, or 'angle of dangle', is managed by adjustable control lines.