Do I really need dc-dc as well as 320w solar and 30Ah EHU for 260Ah lithium battery bank?

[Deaks]

I will have 2x 130Ah lithium batteries connected in parallel, giving me a 260Ah bank of power.
I am putting a 320 watt solar panel on the roof using a Victron 75/15 smart solar controller and a smart sense module for battery temp and voltage.
For when connected to mains EHU, I have a 30Ah Victron Mains charger.
Should I also put in a dc dc charger?
The van is also my daily driver, and I read somewhere that lots of short journeys (which sometimes I do) could harm the lithium leisure battery bank....... if this is true, I guess I could put an isolator in-line.
Power usage in the van will be a fridge, diesel heater, mobile WiFi router, usb charging of phones, Bose mini speaker, echo dot and a fair bit of led lighting but also the ability to recharge a electric mountain bike battery (around 700 wh 36v) using a 240 volt 6 amp charger with a 2000 watt pure sine wave inverter.

I suppose it’s not always sunny, but as I have not used the batteries ‘in anger’ yet, so I have no idea how long they will last.

Thanks in advance

Deaks

 

[Dellmassive]

100% yes for a dc-dc imho.

 

[Dellmassive]

Fyi short charges for lifepo4 is better that deep discharges..

You will get more cyclea and they will last longer that full discharge cycles.

 

[Deaks]

Thanks for confirming what I thought. Looks like a Victron dc-dc charger is now on the shopping list!!

Btw, I abandoned the plan to fit the batteries under each seat as it was just too tight and a lot of wires running between the seats.

The batteries will now be right next to each other in the kitchen furniture, so now I can link them with some super thick cable (95 mm2 or maybe 120 mm2) and also use this for the inverter which will housed above the batteries.
Will I still need to fuse the positive to the inverter, and if so what size fuse. The inverter will be a 2000 watt PSW type.

Am I right in thinking that if I use the BV-712 and temp sensor, this can send a signal to both the MPTT controller and dc-dc charger to not charge if the temp is too low. If this is the case, then I would not need the smart sense module for the MPTT controller would I?

This just leaves LBD/LVD to cover, which I plan on using a 100 amp Victron battery protect.

I think I also read about using a raspberry pi, connected to the vans 4g mifi system to run the Victron software over the internet, or did dream that?

My brain is melting after working in a portacabin all day today .

TIA

Deaks

 

[Dellmassive]

Am I right in thinking that if I use the BV-712 and temp sensor, this can send a signal to both the MPTT controller and dc-dc charger to not charge if the temp is too low. If this is the case, then I would not need the smart sense module for the MPTT controller would I?

- yes and no. currently the victron orion will not receive the temp data from the 712 via VE-Direct. but the MPPT will RX this data.

but you can use the relay terminal output on the 712 set as a low temp alarm to disable the Orion DC-DC afaik.

.

This just leaves LBD/LVD to cover, which I plan on using a 100 amp Victron battery protect.

- that will work.


.

I think I also read about using a raspberry pi, connected to the vans 4g mifi system to run the Victron software over the internet, or did dream that?

- yes correct, more here>

Solar Sheds & Other Non-t6 Solar Projects - How We Done It -

Solar Sheds & Other Non-T6 Solar Projects - How We Done It - @Pete C requested it, so here it is . . . . . Dell, What do the batteries in your shed power ? I too have a solar powered shed - perhaps we should have a separate thread for sheds :) Pete Lets Post here any NON - T6 related ECO...

www.t6forum.com

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[Lowlec]

Thanks for confirming what I thought. Looks like a Victron dc-dc charger is now on the shopping list!!

Btw, I abandoned the plan to fit the batteries under each seat as it was just too tight and a lot of wires running between the seats.

The batteries will now be right next to each other in the kitchen furniture, so now I can link them with some super thick cable (95 mm2 or maybe 120 mm2) and also use this for the inverter which will housed above the batteries.
Will I still need to fuse the positive to the inverter, and if so what size fuse. The inverter will be a 2000 watt PSW type.

Am I right in thinking that if I use the BV-712 and temp sensor, this can send a signal to both the MPTT controller and dc-dc charger to not charge if the temp is too low. If this is the case, then I would not need the smart sense module for the MPTT controller would I?

This just leaves LBD/LVD to cover, which I plan on using a 100 amp Victron battery protect.

I think I also read about using a raspberry pi, connected to the vans 4g mifi system to run the Victron software over the internet, or did dream that?

My brain is melting after working in a portacabin all day today .

TIA

Deaks

I’ve got a victron Venus in my van linking up all my victron kit(apart from the dc/dc charger, as it operates on a different platform!).great for remote control of various bits of kit in the van,I’ve linked my diesel heater to it so I can switch it on/off remotely with feedback to your phone