tomatoes
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Post by tomatoes on Jan 16, 2018 7:47:46 GMT 10
If you have a small solar set up (like a camping set up) for back up - not everyday use - what is the best way to keep that to ensure the batteries have good life? The set up would be portable solar panels, a couple of good batteries in cases, and an inverter the size you’ve calculated to suit your electricals. (And along with that, a huge camping frig/freezer that can be powered by the batteries).
All of it is enough to run various electrical that would be needed in the case of longer term black out. So I’m not talking about how to have a system ready to go at the flick of a switch during a shorter black out (eg a day or two - where most freezer stuff would be ok). It wouldn’t matter if a day were needed to get it all charged up and happening.
Is it best to not use the system at all so the batteries have never been used? Or to get it all set up every six months or so to recharge the batteries? Or does it really need to be kept continually charged?
What is best for the batteries?
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paranoia
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Post by paranoia on Jan 16, 2018 12:44:13 GMT 10
Really depends on the type of battery but if we're talking lead acid make sure it's stored fully charged and take it down to about 50-70% every few months then charge her back up again to 100%.
Not a battery expert, just what I was taught regarding a standing car battery.
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Morgo
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Post by Morgo on Jan 16, 2018 20:08:59 GMT 10
I find what Para has suggested works best for longer battery life.
If left to go flat and it has fully discharged you may not be able to charge it again and if you do it may have adversely affected the battery. I also find batteries that are left on the charger all the time have a shorter life span.
This is in reference to the more common Ni-MH/SLAB's than Li's.
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tomatoes
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Post by tomatoes on Jan 16, 2018 23:07:04 GMT 10
The batteries I’m looking at are a couple of 130AH 12V AGM Deep Cycle Batteries.
Just not sure how best to look after them if I have no need to use them regularly. Sounds like I should treat them like a car that is not used and charge them up regularly.
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Deleted
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Post by Deleted on Jan 17, 2018 9:43:28 GMT 10
Hi guys, for simplicity I advise friends with camp trailer batteries to buy a cheap small multi stage battery charger and one of those time switches you can plug into a power point, then set it to come on say for 15 minutes on off peak power around 3am each night, and it is all sorted then.... The moment you install solar panels as I have, your maintenance requirements increase in needing to check if it is all working ok regularly etc.... You then start to connect more things to run off the batteries since it is 'free electricity' but then the batteries start working for their keep and you need to start looking after everything much more and worry about depth of discharge etc.
In the industry word is Lithium are good for around 7 years... which I think I posted some time back elsewhere here, but again it was confirmed to me with a friend getting me to check his lithium battery, and yes it was eight years old and not holding hardly any charge for long.
If you are looking at more than one battery and you are considering connecting them in parallel, you can have problems because batteries use chemical reactions, the reactions alter with temperature etc.... That means one battery which might be warmer will discharge into the other or when loads are connected one battery will be drained before the other causing one battery to die before the other! That is why many vehicle duel battery systems, use a battery isolator relay that only joins the batteries together when charging or extra power is required.
On the point of temperature regardless of the type of battery it is advised not to install batteries directly on a concrete floor, the cold concrete causes slower chemical reactions towards the bottom of the battery compared to the top giving rise to all sorts of problems with things like stratification etc.
I use to be in charge of battery maintenance for the hundreds of batteries used for critical controls and emergency power in several large power stations... I also lived for over ten years off grid....so happy to answer any questions.
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tomatoes
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Post by tomatoes on Jan 17, 2018 13:33:26 GMT 10
Thank you everyone who answered so much for the advice. There is much that I do know a lot about but the electrical/batteries/solar stuff is definitely not in my areas of expertise! I appreciate the help. Hi guys, for simplicity I advise friends with camp trailer batteries to buy a cheap small multi stage battery charger and one of those time switches you can plug into a power point, then set it to come on say for 15 minutes on off peak power around 3am each night, and it is all sorted then.... Are you able to tell me where I should look for a multi stage battery charger? Is it just something I walk into jaycar and ask for? Is it something like this www.jaycar.com.au/12v-10a-intelligent-switchmode-5-stage-battery-charger/p/MB3625 ?
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Deleted
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Post by Deleted on Jan 18, 2018 9:20:11 GMT 10
Hi Tomatoes, Yes that Jaycar battery charger would certainly do the job, but if you don't want to folk out $139, I did a quick search on ebay and found a 3 stage 20amp charger new, for $40 including postage and further down the page a 18 amp three stage charger for $38. For maintaining a 130AH battery you really don't need much more than a 3 or 5 amp battery charger so both of them are an over kill. Similarly going beyond three stages to say five stages is a bit of an over kill also, but nice I guess especially if your not planing on using a time switch to ever turn if off.
FYI The important thing is to have the multi stage charger because to look after a 12v lead acid battery it should be taken up to about 14.4 volts while it absorbs about 70% of its charge and then the voltage should be dropped down to 13.7 volts for the remaining charge..... The old battery charges that use to just try and force charge into batteries were a bit crude relying on the fact lead acid batteries are fairly forgiving. You may hear about the third stage which is called equalizing, it is done at about 15 volts, and so it has to only be used occasionally no more than about once a month just to equalize the charge between cells, stir up the electrolyte a bit and remove any sulfate build ups.
I hope you found this helpful and if you need any clarification on anything I have mentioned I'm more than happy to reply.
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Post by doomsdayprepper4570 on Jan 22, 2018 6:52:53 GMT 10
If you have a regulator, inverter , solar panels and batteries it would be best to set it up where it gets the most amount of sun in your backyard. You have it so why not use it? This will ensure the batteries are charged for when you need them. Also if any faults develop then you will be aware of the problem and can fix it when you do not "need" your camping backup system. Any type of lead acid batteries do not like sitting and intermittent charging. Do not be scared of the talk about number of cycles for your batteries! And honestly when the agm's die get a set of trojan solar batteries. They have plante plate construction and last a lot longer if flooded lead acid is ok for you.
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kelabar
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Post by kelabar on Mar 30, 2020 1:06:22 GMT 10
Bumped because of all the cheap solar gear that will be available after the virus dies down!
I've only ever used the flooded lead-acid batteries. Get the type where you can add water to the cells. If you regularly check the cells (every couple of months or so), don't let the water get below the plates for too long and keep them charged, expect them to last for 5 years. When I have used the low maintenance ones I never got more than 2 years out of them. This is for starter batteries. Not sure on storage batteries yet.
Do not buy the cheapest battery you can find. You will get what you pay for. I think there are still Aussie-made batteries available too.
Motorbike batteries can be bought dry. The battery comes with a container of acid which you add when you want to use it. These can sit on the shelf unmaintained for at least a couple of years. Not sure if bigger batts are available this way.
Don't leave a flooded lead-acid batt to self-discharge and sit there flat for any length of time. Apparently this doesn't do them any good.
When I do accidently completely flatten a batt, I hook it up to a 4 amp charger and leave it to slowly recharge. This takes a couple of days. Use a smaller charger if you've got one. The advantage is the battery can't get hot from charging too quickly. Also you don't get bubbling in the acid which is bad apparently, not sure why.
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bug
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Post by bug on Mar 30, 2020 7:11:59 GMT 10
On the point of temperature regardless of the type of battery it is advised not to install batteries directly on a concrete floor, the cold concrete causes slower chemical reactions towards the bottom of the battery compared to the top giving rise to all sorts of problems with things like stratification etc. Correct. I've installed many commercial battery banks. They are always on a rack or in a cabinet, never on the floor. It's not an obvious point, so well done for pointing it out. Also, anticipate a spill/battery failure. This means the room the batteries are in should not be one that you sleep in or live in. Make sure it is ventilated and has a drain point in the floor or as a last resort out the door. Batteries can handle a fair bit of temperature variation (think of what your car battery suffers). For best life, if you have a lead-acid battery like a car battery make sure to keep it topped up with distilled water, not tap water. There will be a red/green viewport on top to show you if it has enough water. These batteries are better for starting big loads like motors/car engines etc. If you have a different battery type, consider slightly oversizing it as they don't handle the startup current well.
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bug
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Post by bug on Mar 30, 2020 7:14:43 GMT 10
I think there are still Aussie-made batteries available too.
These are Century-Yuasa. The factory is in Brisbane. They have a backup factory in Yokohama (I think) for when they run out of supply here. Far better quality than the slightly cheaper imported ones. They do sell Century-Yuasa under other brands too, so if in doubt ask the retailer.
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Morgo
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Post by Morgo on Mar 30, 2020 15:36:22 GMT 10
I'm not a fan of the old flooded type batteries, IMO they are not the best option for this type of application.
I bought a couple of Gel AGM maintenance free batteries to use in my portable setup.
Reading the specs they have a 5 year warranty and a 12 year build design/shelf life.
Being gel they can be discharged much further than standard AGM batteries with out hurting the battery giving you a lot more usable power. Plus being a "sealed" battery I don't need to worry about gassing or spillages as much if its knocked over while being transported in the car.
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