Increasing solar panel or adding battery? Which would work better?
Submitted: Saturday, Sep 16, 2017 at 12:26
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Member - William B (The Shire)
Hi,
I have just purchased a Jayco outback pop top caravan (17.58-3) with a 150 watt solar panel running through a TPS 1230 regulator into a 100 AH battery.
I also have a folding solar panel of which from memory is 180 watt.
What would be a better option, running the extra solar panels through the TPS 1230 giving roughly 330watts or using the existing 150 watt panel and adding a second 100 AH battery.
Primarily concerned with being able to
bush camp longer and not stressing about taking the generator, we will be running the fridge on gas, lights are LED, TV is 12 v, the only other draw is a VPAP machine which will run through an inverter for the time being. The VPAP runs at 24v at 3.75 amps, we will be running the machine through a 12v to 24v converter later on. (See thread 135519)
I hope this makes sense, increase solar or battery or both?
William
Reply By: The Bantam - Saturday, Sep 16, 2017 at 13:22
Saturday, Sep 16, 2017 at 13:22
from what you have poster neither will get the job done.
If the figures on the VPAP are correct.
It will draw 7.5 amps at 12 volts time 8 hours equals 60 amp hours. there is your 100ah battery too deeply discharged for long life .... that is IF it is heathy and running at full capacity now
now for the charging demand
60 amp hours times 12 volts equals 720 watt hours, divided by 6 hours when the solar panel will be outputting it's rated capacity and you have the output of a 120 watt panel totally consumed ..... the extra hours of sun either side of the 6 peak ours will be connsumed in charging losses.
No allowance for cloud, rain or obstruction.
so JUST to run the VPAP, it would be reasonable to expect 200Ah of battery capacity and 240 watts of solar pannels ... MINIMUM.
cheers
AnswerID:
613808
Follow Up By: RMD - Saturday, Sep 16, 2017 at 15:08
Saturday, Sep 16, 2017 at 15:08
I second that, no TV or lights there either. You have to over cater for the expected load and then allow more still, to make up for the days that don't yield much from the light in the sky.
I agree with the minimum. 240w 200 ah.
If recharging from a generator it can't be from the 12v charge port either and has to be via a battery charger powered from the 240v output of the generator.
The piddly 12v charge would have you running the genny all day, every day, in an attempt to bring the batteries up in charge but it will never make it from that 12v recepticle.
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Reply By: swampy - Saturday, Sep 16, 2017 at 16:58
Saturday, Sep 16, 2017 at 16:58
hi
You can only use what u recharge
160watt = 38 Ah harvest in 24hr
200watt = 48Ah harvest in 24 hr
Consumption is based on 50% discharge limit
[balance between life vs performance ]
100ah batt = 50ah available for consumption
How we arrive at the figures ..
Average available in Aust of summer and winter 5.5hrs [peak sun hours ]
[sun outside these hrs and mppt is inconsistent so this production is a bonus]
Max prod. less wiring loss , controller loss, panel position loss =20%
basically 160--200 watt per 100ah of battery [200watt preferred ]
25amp 240v charger with at least 1 kv gene
AnswerID:
613812
Follow Up By: Sigmund - Sunday, Sep 17, 2017 at 04:52
Sunday, Sep 17, 2017 at 04:52
Av peak sun hours can be misleading. It can be as low as 1.5 - 2 depending on season and location.
Map
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