Calling Nick norman, Lithium Question

Wel I'm happy now it's all sorted, battery kicks in at 11pm when the main power usage drops, as we go to bed, lasts around 7-8 hours, so that's around £1.50 per night of free electric, £43/month reduction, coupled with the day time free electric i reckon we have more than halved our electric bill, of course this will vastly reduce in the coming weeks but looking forward to next summer.

One thing the inverter does have is a bi directional port, this can be plugged into a generator for off grid power, or used as an extra output to a load outside of the consumer unit, say a water heater, you set the system to then shave off spare power and send it to this port, so heating water when power is going spare, i have about running a cable down into the garden and having it power the sex pond in the summer months, i shall ponder some more!

Thats good but how big is your bank?

We do use a fair bit though, on tick over the house pulls 300-400 watts and with us all doing our own things at night we can pull 1500watts plus more when cooking as we have all electric kitchen.

Not really got into the swing yet, problems with the set up and playng around means we won't save much now this side of spring.

I do think another battery is the way forward, sell back to EDF at £0.056/unit or save and run the house long at night saving the £0.36/unit cost.

You on Sunsynk too then?

ETA, guess not, slightly different to sunsynk app looking at it.

Gleamed only 1kWh yesterday from the panels, very grey day.

Have set the system to now wait till 5pm then charge the battery to full from the grid if solar hasn't done it.

Sun is better today but still only pulling 360w at present, which isn't enough to fill the battery back up so will more than likely dip into the grid again later.

We have applied to sell energy back to the grid but they only pay £0.056/kWh so its not really going to pay loads back now.

Battery still running the house all night though from 11pm, that was even with the lad cooking a pizza in the oven last night.

We have no price difference on our tariff, 32p i think, maybe 36p no matter what time of the day.

You try moving to a different tariff at the minute, no chance!

You don’t explain what you want all this for? Bear in mind that cold temperatures are only a problem for LiFePO4 during charging, not during storage or discharging (although discharging will be more sluggish when very cold, same as lead acid.

If you need to warm the batteries prior to charging when they are below zero, then yes some gentle heat is needed to get them up to say +5, but 100w seems far too much for one small battery in an insulated box. I think we have about 60w sitting under 600Ah of batteries. If you put in heat fast, you will cook the outside/bottom of the battery before the central/upper/inside part gets warm.

How much power you need depends on how fast you want to heat it (limited in part by the internal thermal conductivity of the battery as mentioned above), how much you need to raise the temperature by (probably no more than 20C) and how well insulated the box is.

Or just arrange to charge the batteries when the are above freezing. If they are inside the van and you are inside the van, they are likely to be above freezing.