size of battery needed for my solar panel

[muckington]

I use one, an 8Kw output, to provide heat to my workshop. Very effective, and efficient it is too. At first, I ran it on a 32amp/hour battery, itself connected to a 4amp/hour charger. I then decided to run it on an adapted PC PSU, risking a power outage, which would wreck the heater. These heaters have to be allowed to go through the proper cool down process, fan running, or the electronics will be wrecked by the heat. Running on just a battery, the power could likewise suddenly fail, and wreck the unit.

Did you manage to start the thing off of a 32amp/hr battery with out charger?

Question; why use it your workshop? why not a waste oil burner instead

 

[muckington]

I started around 1965 looking at caravan electrics. At that time, all the battery did was work the water pump, replacing the rubber dome in the floor that I pressed with my foot, lighting was with gas, so was heating, the latter making the caravan very wet.

But no inprovments on the wind generator in all that time then

 

[muckington]

The OP, is starting from the wrong end, and not bothering to involve an maths....

He should start by working out how many watt/hours he needs, for each item he plans to use, then decide how he can source that daily amount, reliably. Instead, he is suggesting what he has in mind as his source, then asking will it do.

I was hoping someone might of picked that up from the OP
As I allready have the pannel

 

[muckington]

This is the one I got

Victron AGM Deep Cycle Battery 12V 14Ah - BAT212120086

BMS Technologies LTD are leading Victron Energy distributors offering free delivery throughout the UK. Free technical advice on all AGM batteries.

www.bmstechnologies.co.uk

Only 23amp/hr! what do you use it for?

 

[JohnD]

Only 23amp/hr! what do you use it for?

14AH, I think.

Backup battery to turn my hybrid on if the 12v battery runs down. It is supposed to stay charged for 12 months.

 

[ericmark]

I inherited a battery pack, the air pump has failed, and the 12 Ah battery did in the end fail, but replaced the battery as it is so easy to carry around, has a small fluorescent lamps, and a 150 watt inverter, and a handy cig socket, so anything designed for a car will run from it, and a wall charger so easy to recharge, and warning lights to show state of charge.

At first, I tried a lithium jump start pack, so much lighter, but no cig socket, or 150 watt inverter, pity about loss of tyre inflator, but easy enough to plug another one in the cig socket. So fitted a new battery. The Lidi battery charger shown will recharge it faster, but I am not after speed.

With my house, the battery is not large enough to last all night in winter, but it is large enough, so my use of peak electric is very much reduced, from what you say, you may be looking at something similar, the solar panel may mean the heater lasts 18 hours rather than 12 hours.

But the point is, having a power pack that is portable, lithium is lighter than lead acid, but more expensive.

 

[RrogerD]

so best forget about that one then


To be honest Im not that bothered because if there is not enough battery to power it then i will just come back home
It was only for the odd night a week



I was on a caravan forum before, but very little info. I am surprised with the lack of knowlage they had (on terms of group think) they could manage 1 night parked up in the frost. Either that or they payed some kind of rip off Halfords to do it all for them

It's not the caravan or motor home forums but moreso, the self-build forums that have all the knowledge and information. The former as you say, just seem to pay someone else to do it for them with no knowledge (I assume also no interest) in what's what. Which is fine until it isn't.
I guess the same as a DIY forum vs "where can I find a contractor for such and such?"

 

[Harry Bloomfield]

Did you manage to start the thing off of a 32amp/hr battery with out charger?

Yep, it was fine, and I worked out it could run safely run, without damaging the battery, perhaps 15 hours, before it would need charging, but as said, I had it on a charger in use.

Question; why use it your workshop? why not a waste oil burner instead

That is what I originally used, but it was messy, needed constant attention, and took much longer to begin producing any heat. By the time it was producing heat, I had finished what I was doing. The diesel heater, is cleaner in use, and fully automatic. I just dial in the temperature I want, and it maintains that temperature precisely. A couple of minutes from switch on, it is producing blown air heat.

 

[ericmark]

In the late 50's early 60's the caravan holiday was cheap, and people got a caravan to have a cheap holiday, so there was a big DIY part of maintaining the caravan. Today it is no longer a cheap holiday, unless hiring a caravan already sited, either way, very little DIY except those who started back when it was cheap, and also the cars have changed, with MOBUS and stop/start so often one can't DIY even if you wanted to.

I lived in a touring caravan for a time, when on the build of Sizewell 'B' and second seven crossing, and stopped seeing living in a caravan as a holiday. I found I needed a battery as so much designed to run off a battery, but I was using a 7 Ah battery, and it was more like a capacitor absorbing peak demands.

Typical caravan battery size was 60 Ah to 120 Ah with 90 Ah likely the most common size, often 120 Ah would not fit in the battery box, and 90 Ah was about the largest that would fit, so not selected as that was the best size, but selected to fit the space.

I have two ex-vehicle batteries, both 90 Ah AGM (VRLA) the problem with the sealed battery, is it needs a special charger, I use a Lidi one about the cheapest one can buy, think Aldi also do one, rated 5 amps (early ones were 3.8 amps) and in the main it will only charge at 5 amps for first ½ hour, by that point the charge rate has stepped down, the days of the 30 amp charger have gone, they are only any good with a flooded lead acid battery, that one can top up, so the solar panel output of 1 or 2 amp is not really a problem being so low, but it means the controller is often expensive.

These likely can do a good job, but as one moves to cheaper versions, some simply don't look after the battery, but just try to extract the maxium from the solar, be it MPPT (Maximum Power Point Tracking) or older PWM (Pulse Width Modulation) one crosses one fingers and hopes it's a good one, as not enough are used by the trade user to be able to compare how well they look after the battery, so who can say how this

will work? In the main 6 termials two to panel, two to battery and two to the load.

so in some versions, even if the solar panel is only 10 watt, if you want to use something taking 500 watt, then the controller needs to be rated 500 watt, and the controller uses power, so there is a minium size which is worthwhile. I have looked at kits

and I will admit tempting, 220 watt/hour when looking at 12 volts, = 18 amp/hour, and you have 230 volts (300 watt) USB and Cig socket for 12 volts, plus the solar 100 watt, all sold as a complete kit, not a clue how good it is, but it has everything and more to what my jump start kit has, except for the jump start bit, and is portable so easy enough to take home to recharge if solar is not enough. I have also looked at these

as yet not permitted in this country, but used a lot in Germany, it seems there are more and more options, and the price of solar is coming down.

 

[muckington]

14AH, I think.

Backup battery to turn my hybrid on if the 12v battery runs down. It is supposed to stay charged for 12 months.

I dont know what a hybrid is, back i take it the battery is all way on change and never gets used

 

[muckington]

It's not the caravan or motor home forums but moreso, the self-build forums that have all the knowledge and information. The former as you say, just seem to pay someone else to do it for them with no knowledge (I assume also no interest) in what's what. Which is fine until it isn't.
I guess the same as a DIY forum vs "where can I find a contractor for such and such?"

The forum I was refering to is the caravan forum
moreso?

 

[muckington]

Yep, it was fine, and I worked out it could run safely run, without damaging the battery, perhaps 15 hours, before it would need charging, but as said, I had it on a charger in use.

I was told that you would need a minimum between a 90 to 110amp/hr battery just to heat the glow plug! unless yours dose not have a glow plug

That is what I originally used, but it was messy, needed constant attention, and took much longer to begin producing any heat. By the time it was producing heat, I had finished what I was doing. The diesel heater, is cleaner in use, and fully automatic. I just dial in the temperature I want, and it maintains that temperature precisely. A couple of minutes from switch on, it is producing blown air heat.

How big is your work shop?

 

[Harry Bloomfield]

I was told that you would need a minimum between a 90 to 110amp/hr battery just to heat the glow plug! unless yours dose not have a glow plug

Nonsense. If it's the usual 5 to 8kw job, they draw upto 20amps to start for a few minutes, then 1amp. Even a 7amp/hour battery will start one, and run it a while.

How big is your work shop?

.
Around 16x10 feet. I have the heat blowing out from a leaky duct/pipe, along the length of the workbench.

 

[ericmark]

I dont know what a hybrid is

That does seem to vary with vehicles, my hybrid is so called as it can go on a road or in the field, all e-bikes require one to pedal, but is seems one does not need to have a direct link of pedals to wheels, but with other vehicles it means twin engined one electric and the other carbon based fuel. But the same method has been used to power railway engines and simply called diesel-electric, hybrid transport has been around for a long time, even a film made, called Two Mules for Sister Sara the mule is a hybrid between a horse and donkey, there have been many off-road vehicles called mules

so suppose they must be hybrids! But a hybrid is basic a mixture where you have the worst of both systems.

 

[muckington]

Nonsense. If it's the usual 5 to 8kw job, they draw upto 20amps to start for a few minutes, then 1amp. Even a 7amp/hour battery will start one, and run it a while.

I have one of those China type off of ebay. they have a red casing. When the 100 year patancy run out with Webasco. the ones from china came on the seen, as it is just a copy cat desinge but with cheep componants. If that is the type that you have?

.
Around 16x10 feet. I have the heat blowing out from a leaky duct/pipe, along the length of the workbench.

that is quite a small work shop! did your find your old waste oil burner to big/ to hot for it when you had it?