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Post by myarrow1 on Apr 22, 2019 16:24:41 GMT 10
Hi all.
What’s everybody out there using in their caravans re battery and solar panels ?
Needing some advice (bit of a novice with the whole solar thing)
Currently running 1 x 130ah deep cycle with 160w panel. No inverter at all
I run a few lights inside my Franklin Arrow (LED globes fitted throughout), and an 80L 12v/240v camping fridge
I run the fridge at minus 3
System seems to cope,,,, but only just. Charges up fine during the day, in full sun, but is dropping back quite abit over night
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Post by snoops on Apr 22, 2019 19:29:40 GMT 10
If you’re running a 12 volt fridge I would almost double what you have - around 200Ah of batteries and around 300 watts of solar. This would keep up and give you some leeway for cloudy days and Winter etc. My setup runs 500 watts of solar and 400Ah of batteries but I could ditch about half the batteries - I run a 90 litre Engel 24/7/365 off my 12 volt system and never have an issue with it. You can’t ‘over solar’ a system, so if you have room, bung up more panels, they are cheap these days.
Other option for batteries is Lithium - you can use a 100Ah lithium to replace 2 x 100Ah AGM’s as the lithium has more (almost double) actual usable capacity without damaging it. Given that a good quality AGM 100Ah is around $400 and a good quality lithium 100Ah is about $1000 it’s almost apples for apples now and a lithium is so much lighter. Will be going this way soon myself. Charging methods do differ however so it’s not a straight swap to lithium tech and a bit of care need to be taken.
Easiest way for you is to add another battery and a couple of solar panels, a 30 amp charge controller would be needed - just a PWM unit is fine however if funds permit go an MMPT unit.
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Post by myarrow1 on Apr 22, 2019 20:01:50 GMT 10
Hey Snoops good to hear from you.....
Mate I’m a little unsure what it’s doing, as the system has never really dropped below 3/4 charge (I have a small bar metre/gauge, in-line).
The last 2 trips it has been dropping down to almost 1/4 overnight, but I haven’t changed fridge settings or anything else
Battery (ZAP brand) is prob 2-3 Yr old and really hasn’t done much work...
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Post by myarrow1 on Apr 23, 2019 16:31:47 GMT 10
Hey Snoops. As I set the fridge to neg 4, if I put the temp up to +4 or so overnight only, would this make much difference ?
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Post by snoops on Apr 23, 2019 19:18:20 GMT 10
When you say 1/4 or 3/4 charge - do you have any voltage readings? No load voltage (nothing running) of the battery is the best way to tell the state of charge (SOC).
Turning the fridge up will help over night but when you turn it down again, it will work for a lot longer then, so overall losses are about the same and will still require the same amount of charge the next day to recover once you turn the fridge down. Better to bung an extra solar panel on it IMO, but if the battery is getting to 1/4, you may need extra capacity.
Not heard of zap batteries so couldn’t comment if it - do you know what it weighs by any chance? The cheaper batteries are quite light compared to a quality AGM. A good 130Ah AGM should tip the scales at 35 plus Kg. My 100Ah Fullrivers weigh in at 32Kg each and are 7 years old still going strong.
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Post by myarrow1 on Apr 23, 2019 19:36:05 GMT 10
Hi Snoops.
Apparently it weighs 33.4kgs 130ah. I’ve got the battery mounted in front of the wheel arch under the lounge seat. I reckon I’ll mount the 2nd behind the wheel arch (van has the same layout as your old Franklin) ??
Something isn’t right as the gauge would hardly move from full overnight. Last 2 trips it is only show 1/4 charge over night. Hoping that the battery isn’t buggered. Is showing full charge during the day (not sure how accurate the gauge is)
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Post by snoops on Apr 27, 2019 20:23:21 GMT 10
Sorry mate, been offline for a few days. What sort of meter is it? A cheap multimeter will be able to check if it’s right or not? You can get one from fleabay for under $10 or from Jaycar for $15. This would be the best way of checking what the battery is up to while charging during the day and what it is getting down to overnight.
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Post by myarrow1 on Apr 28, 2019 13:16:35 GMT 10
Hi mate. I ended up putting a 240v charger on and it took nearly a full day to fully charge it. I’ve now ordered a folding 300w panel, so I’ll see how that goes as it appears that my 140w panel can’t keep up.
From here I’ll work our if I’m gonna need to add another battery
It tested at approx 12.75v with a multimeter (no load)
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Post by Warrenk on Apr 28, 2019 15:42:37 GMT 10
Hi mate. I ended up putting a 240v charger on and it took nearly a full day to fully charge it. I’ve now ordered a folding 300w panel, so I’ll see how that goes as it appears that my 140w panel can’t keep up. From here I’ll work our if I’m gonna need to add another battery It tested at approx 12.75v with a multimeter (no load) After charging it for a full day and the battery only reads 12.75v with no load I would say the battery is past it's use by date. You should have had a full charge voltage of around 14.2 volts. If are going to buy another battery the way to determine a good battery over a average battery is the weight. You should be looking at .3kg per amp hr, so a 130 amp hr battery should weigh around 39kg. Warren
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Post by snoops on Apr 28, 2019 19:13:52 GMT 10
With no load and the surface charge gone - ie left overnight with no load on it after charging, then 12.7 volts is 100% state of charge so I would say the battery is ok, but voltage alone is not a guarantee of the battery being ok, but a good start. It will only read higher than that while actually being on charge or just after coming off charge while the surface charge is disappating. Agree with the 0.3kg per Ah as a guide though - my 100Ah batteries are 32Kg each. www.lowenergydevelopments.com.au/Battery-State-of-Charge
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Post by myarrow1 on Apr 28, 2019 21:50:05 GMT 10
Yes I did some googling and it did indicate that my battery was at full charge at that reading of 12.75.. I retested it late this arvo and got the same reading 👍
I remember when I first set the solar up in the van, the gauge would only move 1bar off full charge overnight with fridge etc. I haven’t been using a 240v charger to top it up before camping. I’ve just been relying on the panel a day before , so I reckon the new panel should make a difference, and I will probably 240v charge it before we head away camping and see how it goes
(I must get my head around Flickr for adding photos again, too)
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