size of battery needed for my solar panel

[muckington]

Too many pointless questions.... However...

As already said.The Webasto, in the car, runs from the car battery. I charge nothing from solar. The workshop heater, now runs on an adapted PC PSU, no battery involved. Yes, that ran absolutely fine from the 32amp, why would it not, but you cannot simply discharge a battery, charge needs to be returned to it.

The charge, must at least match the discharge, when averaged over a day or so, or things grind to a halt.

Because I was told that it would need 110amp battery to power the glow plug

 

[JohnW2]

Because I was told that it would need 110amp battery to power the glow plug

I'm rather surprised by some of the things I'm reading. Does anyone know roughly how much current this glow plug is likely to need, and for how long at a time?

 

[Harry Bloomfield]

But is that 100% discharge of the battery?

Were you not taught any simple sums, at school, or did you take that day off?

0.42 x 76 = 31.92amp hour. In theory, 100%, after which discharge, a new battery would be needed, because that one would be wrecked.

 

[Harry Bloomfield]

I'm rather surprised by some of the things I'm reading. Does anyone know roughly how much current this glow plug is likely to need, and for how long at a time?

10 to 20 amps, but the time is variable. It depends upon how quickly the stable burn takes to properly establish itself. The start is closely monitored, by the control system. The tip of the glow plug, glows red-hot, to ignite the fuel, while-ever it is powered.

Once a proper burn is established, only the control pcb, the combined combustion fan/blower fan, plus the solenoid pump need to be powered. Call it around 1amp.

A motor, operates two fans, on either end of it's shaft, one end in the combustion chamber, the other outside, drawing air past the outside, and into the space of the room.

The solenoid pump, injects a squirt of fuel, into the combustion chamber, every time it is pulsed. In the combustion chamber is a wire mesh, which is kept hot enough to maintain the combustion, once established.

Motor/fan speed, and pump impulse, are varied, depending upon the demand for heat.

Mine, can be set to maintain either a room temperature, or you can have a continuous, manually pre-set level of output. That's the Chinese diesel heater.

The one fitted on my car, works similarly, except instead of heating blown air, it heats the engine coolant, and uses a little electric water pump to circulate the coolant. It is enabled, automatically, if the ambient is less than 10C, when the ignition is switched on, but I can remotely turn it on, ignoring the <10C. It then runs, until the coolant hits 76C, and ramps down, cycling back on at 73C.

The can be run on white/red diesel, heating oil, parafin, even Jet A1. Mine, in my workshop runs on the latter.

 

[JohnW2]

10 to 20 amps, but the time is variable.

Thanks, so it presumably does not need a "100A battery" to power the glow-plug as start up?

It depends upon how quickly the stable burn takes to properly establish itself. The start is closely monitored, by the control system. The tip of the glow plug, glows red-hot, to ignite the fuel, while-ever it is powered. ... Once a proper burn is established, only the control pcb, the combined combustion fan/blower fan, plus the solenoid pump need to be powered. Call it around 1amp.

Fair enough. Does the thing run continuously once started, such that the glow plug is only needed at initial start-up, or does it actually cycle on/off (under thermostatic control) hence needing multiple 'glow plug re-starts'?

 

[Harry Bloomfield]

Thanks, so it presumably does not need a "100A battery" to power the glow-plug as start up?

Why not? A brief discharge of 20amps, is well within the capability of a low capacity lead-acid battery. Where the 100/120ah came from, I have no idea.

Fair enough. Does the thing run continuously once started, such that the glow plug is only needed at initial start-up, or does it actually cycle on/off (under thermostatic control) hence needing multiple 'glow plug re-starts'?

Both of mine ramp the burn down, to a minimum, once temperature is achieved, until shut down. The shut-down, is a controlled process, to ensure all of the fuel is burned off, and the unit cooled, otherwise the pcb, close to the combustion chamber can be damaged. As said, I have mine running from a repurposed PC PSU, so if we suffer a power cut, I it would likely wreck the unit - luckily, power cuts here are rare.

 

[JohnW2]

Why not? A brief discharge of 20amps, is well within the capability of a low capacity lead-acid battery. Where the 100/120ah came from, I have no idea.

I don't understand your "Why not?", since the rest of what you write is what I was suggesting, and therefore agree with. Did you perhaps mean something like "Why would you?" ?

Both of mine ramp the burn down, to a minimum, once temperature is achieved, until shut down.

Fair enough - so the glow plug is only needed once, at start-up?

The shut-down, is a controlled process, to ensure all of the fuel is burned off, and the unit cooled, otherwise the pcb, close to the combustion chamber can be damaged.

Fair enough. Wouldn't it have been possible for them to locate the PCB somewhere 'safer' (or, at least, thermally insulate it)?

As said, I have mine running from a repurposed PC PSU, so if we suffer a power cut, I it would likely wreck the unit - luckily, power cuts here are rare.

Again, fair enough - but even a battery supply could fail (go flat, become disconnected etc.) - so again a safer location for the PCB, if possible, presumably would have been desirable?

 

[Harry Bloomfield]

Fair enough - so the glow plug is only needed once, at start-up?

Yes.

Fair enough. Wouldn't it have been possible for them to locate the PCB somewhere 'safer' (or, at least, thermally insulate it)?

It would be a less compact unit then, but the cool down process, at the end, is essential anyway. Even my coolant water cooled unit, runs through a cool down phase.

 

[muckington]

Were you not taught any simple sums, at school, or did you take that day off?

0.42 x 76 = 31.92amp hour. In theory, 100%, after which discharge, a new battery would be needed, because that one would be wrecked.

No one taught me at school that a 110amp/hr battery would give me a 110amps of current for an hour before I had to recharge it and that the battery would superseed its warrantcy in live performance. i don know so as i am so so stupid Sir! what ells did they forget to teach me then?

 

[muckington]

10 to 20 amps, but the time is variable. It depends upon how quickly the stable burn takes to properly establish itself. The start is closely monitored, by the control system. The tip of the glow plug, glows red-hot, to ignite the fuel, while-ever it is powered.

Dose the air and fuel temprature make ay differance when the plug decideds to ignight. Is there a tempraute sensor o the plug to control all of this?

 

[muckington]

Thanks, so it presumably does not need a "100A battery" to power the glow-plug as start up?

But how did you work that one out?

 

[muckington]

Fair enough - so the glow plug is only needed once, at start-up?

But what is start up?

1. cold start -18C
2. When it has not been used for 1/2 hour
3. When it ran 5 minutes ago

 

[muckington]

Yes.



It would be a less compact unit then, but the cool down process, at the end, is essential anyway. Even my coolant water cooled unit, runs through a cool down phase.

I have had a rethink about the whole current idea now; And I think that you or we are looking at this from the wrong angle!
Rather then how much current it needs to start the glow plug. its more likely that it will self shut off if the voltage drops to a certain number

 

[big-all]

start up is simply like a car going from off to running
so a warm engine /heater takes less energy to go from off to working at maximum efficiency
you cannot work out on a forum what you need 'you need real time information with input and consumption information over several days months and even years to work out the the capacity you need to a level where you have 100% certainty you have enough capacity to leave untouched for a full year

you can off course get a better more practical level after a few months where you will need perhaps 40% the capacity but at the cost off many home charges on a weekly or more basis in the winter months

but you cannot work anything out without actual accurate input and output figures in the real world where hundreds off variables change constantly, often quite drastically

 

[JohnW2]

But how did you work that one out?

I didn't really need to 'work it out'.

When you talk of a "100 amp" or "100 amp/hr" battery, I presume you mean 100 amp-hour (100 Ah). A typical car battery is about 50 Ah, and a typical car starter motor draws 100 - 300 amps (sometimes more) - so even a 50 Ah battery (let alone a 100 Ah one) would be more than able to provide 10-20 amps to a glow plug.

The amp-hour figure is a measure of "capacity" (total amount of stored electricity), and current (amps) is a measure of the speed of flow of electricity out of the battery. Think of it in terms of a tank of water with a capacity of, say, 100 litres. If one draws water from it at a rate ('current') of 1 litre per minute, it will take 100 minutes to empty the tank of its full 100 litre capacity. If one draws water at 20 litres per minute, it would take 5 minutes to empty the tank, and with a flow rate ('current') of 100 litres/minute, it would take only 1 minute. However, that capacity figure (100 Litres, equivalent to the amp-hours of a battery) has nothing to do with how much flow (or current) the tank or battery can provide - instead being an indication of how long the tank or battery could provide a particular flow/current.