2x 100w panels enough to power diesel heating electronics through darkest, cloudiest winter months in the UK?

[QPiepelr65]

These panels x 2.
This lifepo4 battery.

Heating is pretty much the main reason I have setup the electrics. I suddenly realized that when it is required most, to power the heater components is when the solar will be least effective.

So is it hopeless or can you draw enough to power heating through the winter months?

I know there is DC DC stuff. I may have to resort to that but that would involve changing my lifestyle as I only drive once a week to do a food shop.

I was thinking I may start driving more anyway though to "chase the sun". I am just parked at my mums while working on the van but I started to think that harvesting electric could become part of the vanlife experience.

I am just wondering what I should expect from solar though. I have 2x renogy flexibles (I know much hated) and 100ah lifepo4 battery.

I wired things up the other day first time and was able to drawn 2-3 watts according to the mt50 controller for the mppt running for 20 minutes or so mid afternoon in partial shade. I have no idea what that pertains to if it is 2-3 watts per minute, total or what?

How much would I have to gather to power diesel heating electricals for one day to know what I am aiming for?

 

[Dellmassive]

i doubt 200w will be enough.

. . .

i run 400w renogy panels on the solar shed,

now powering a 105A lithium,

and its not enough to keep the battery charged, that just runs garden night time LED lighting.

let alone a Derv heater. ( obv it depends on how many times you start it, and how long you have it running )


the charts below show me adding a DC charger on the 12 Nov 23 to stop that battery running too low.

 

[Dellmassive]

wired things up the other day first time and was able to drawn 2-3 watts according to the mt50 controller for the mppt running for 20 minutes or so mid afternoon in partial shade. I have no idea what that pertains to if it is 2-3 watts per minute, total or what?

that 2-3watts is all your getting . . . . thats it,

as an instantaneous reading.

the best you can expect from solar panels is 50-80% of the plate readings ( as they are lab test outputs )

so the max you can expect may be 100w-160W from those in mid summer. ( or direct sun in winter )

 

[Pete C]

My brother has over 6kW of solar panels on the roof of his house. Yesterday he got 100W max out of them.

Pete

 

[Pete C]

And that's an angled south facing roof. Flat van roof is going to be worse.

Pete

 

[Bigsidavies]

My diesel heater draws 10a at startup for a few minutes then drops to very low draw, so starting it once and keeping it running would be most economical.
You say you don’t drive often, so with a Renogy 50a dc-dc converter you could run the engine for 30 minutes and put 25 amps back in (someone correct me if I’m wrong there). Work out your useage, but that would probably replenish a couple of days useage.

 

[Dellmassive]

Assuming a 50A dc-dc charger.

Efficiency losses not counting for.....

50A charger could charge 50A for an hour, or 50Ah.

So half hour would be 50Ah/2 or 25Ah.

Assuming a 100ah lithium, that would be 25% SoC replenished.

So your bang on the money @Bigsidavies

A more accurate calculation would include a 20% efficiency loss, so 80%.

And running 50A charge rate on a 100Ah lithium is pushing it a bit.... 20/30A would be more suitable.... For long term SoH.


.

 

[Bigsidavies]

Assuming a 50A dc-dc charger.

Efficiency losses not counting for.....

50A charger could charge 50A for an hour, or 50Ah.

So half hour would be 50Ah/2 or 25Ah.

Assuming a 100ah lithium, that would be 25% SoC replenished.

So your bang on the money @Bigsidavies

A more accurate calculation would include a 20% efficiency loss, so 80%.

And running 50A charge rate on a 100Ah lithium is pushing it a bit.... 20/30A would be more suitable.

I knew a grown up would be along shortly to give my idea credibility.

 

[Huba]

I have that battery, I have a diesel heater, I have 200w of solar. Went away couple of weekends ago, was fine for 2/3 days from 100%, but solar wasnt topping it up in any meaningfull way as raining most of time

 

[cgtmiles]

We use our diesel heater, which I believe is connected to the starter battery, when away for weekends in the winter. Parked up all weekend (3 nights usually) and turning the heater on and off I’ve not yet had an issue starting the van. Maybe just lucky so far!