hi barme1,need more info,how old is your existing battery? if its got a bit of age to it,better to replace it and start with 2 new batteries of same a.hr....as for the inverter,quality will vary with brand, a lot of the cheap ones off ebay are of acceptable quality but have a higher standby current use,size will depend on what you need to power and in turn will dictate if you have enough solar to maintain everything,main thing to remember is don't discharge your batteries below 50% as it shortens battery life. cheers ray

-- Edited by warhorse on Tuesday 7th of March 2017 08:43:23 AM

BARME1 wrote:

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Good day all have 1 deep cycle battery 110 amp wont to fit second and inverter have been told second battery should be same power output as first ?? and whats a good inverter for using when camping out weve got 350 amps off solar and 3.5 kva genie tow tub 2014 bt 50

van 2015supreme exc

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 Hi BARME1

Lots of doom and gloom about the old battery If the old one is going OK and not so old then just pair it up with another of the same type and see how it goes You can easily buy another new one anytime if you need it !

More to the point, regarding the inverter is what you will be running on it. If a big user of power then it is important to get the cables and connections short, generous size and well done. Often the budget inverters are OK but the cables etc are obviously under size. As said the load sets the size and how much time of use sets the battery capacity required to run it, basicly !

If you only want to charge things or use the telly or something like that then a smaller one will be better as the efficiency is better. I assume you are talking about a full sine wave type as you should get that type. Do not get a big one and only use a small amount of current. Bigger just means more wasted power. What ever you get, it should not plug into a socket but be properly wired to the batteries. 

Jaahn 

PS do you mean 350W of solar. That sounds OK for 2x 110Ahr batteries.

 

The second battery should be the same chemistry/style as the first, but it can be any size/capacity that you can fit.

Cheers,
Peter

Aus-Kiwi wrote:

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Think about 12V appliances too ? TV, fridge etc.. I find since fitting 12v the elect system worked way better.. Charging phones etc off 12V is fine also.. Just requires a double or triple plug..

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 Huh...???   I find since fitting 12v the elect system worked way better..

Power points to existing 12 v...???

 

vik...

If you need to buy 2 new 110Ah battery it would make more $$ sense to buy a 100Ah lithium ferrous battery. It will handle the inverter loads better, recharge faster and last longer for around the same $$ outlay as AGM batteries of an equal quality. The other advantage with lithium ferrous batteries is you can increase the capacity later on without having the throw away the original cells, new and old will work together just fine. As an example, one well know and highly respected A van owner powered his microwave and other 240vac electrical appliances from a single 100Ah lithium ferrous battery and it was still going strong when he sold the vehicle to upgrade to a more off road vehicle.
There is no value in buying old out-dated technology when the new technology will do what you want for around the same price  

As far as inverter size/brand/price, depends just what you want to do with it but make sure it is a pure sine wave type, modified sine wave is just not suitable for electronic controlled equipment and will damage it. If you buy a cheapie ebay inverter the capacity required must be greater than the biggest load by around 10%, for example to run a 2,000w kettle you need an inverter with a rated output of at least 2200w, so one advertised as 2,000w - 4,000w won't do the job, the second number is as good as meaningless for practical use and the first number often refers to the input power required at max load, not the mx it can put out continuously. To power a 2,000w kettle you need a 2,500w inverter and this will be big enough to power a microwave or coffee machine or hair dryer..... one at a time and only for as long as the battery capacity lasts of course.

If you want to power a CPAP machine or recharge phones or power the electric blanket, a 300w to 400w inverter will be sufficient.

Hope that helped 

 

T1 Terry

T1 Terry wrote:

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There is no value in buying old out-dated technology when the new technology will do what you want for around the same price  

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I don't think the same price claim stands up:

Let's compare a 60Ah LiFePO4 battery with a 100Ah AGM battery - there is an argument you'll get a similar amount of energy out of each because of the different recommended maximum depth of discharge:

LiFePO4 = $999

AGM = $280

http://www.ebay.com.au/itm/12V-SSB-FUSION-LITHIUM-ION-POWER-SOLAR-BATTERY-60AH-DEEP-CYCLE-N70ZZ-LFP-12-90-/281703921850?hash=item4196dcb8ba

http://www.ebay.com.au/itm/PDC121000-100AH-750CCA-12-VOLT-BATTERY-DEEP-CYCLE-SOLAR-CARAVAN-AGM-SLA-12V-/221342680201?hash=item33890d4489

 

Mike Harding wrote:

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T1 Terry wrote:

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There is no value in buying old out-dated technology when the new technology will do what you want for around the same price  

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I don't think the same price claim stands up:

Let's compare a 60Ah LiFePO4 battery with a 100Ah AGM battery - there is an argument you'll get a similar amount of energy out of each because of the different recommended maximum depth of discharge:

LiFePO4 = $999

AGM = $280

http://www.ebay.com.au/itm/12V-SSB-FUSION-LITHIUM-ION-POWER-SOLAR-BATTERY-60AH-DEEP-CYCLE-N70ZZ-LFP-12-90-/281703921850?hash=item4196dcb8ba

http://www.ebay.com.au/itm/PDC121000-100AH-750CCA-12-VOLT-BATTERY-DEEP-CYCLE-SOLAR-CARAVAN-AGM-SLA-12V-/221342680201?hash=item33890d4489

 

 

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 I guess I could find links that indicate your AGM batteries are either over priced or under priced, but quality for quality using say Winston LYP cells and Fullriver or Century or Ritar for example, 100Ah of LYP will deliver 100Ah and retain better than 12vdc at even a 100 amp discharge rate (see attached chart) where any of the mentioned brands would be struggling to deliver 100Ah while retaining the 12v at much better than 10 amps from 200Ah capacity.

As far as the recommended discharge limit, you seem keen to extend the lead acid limit below 40% SOC yet ignore the need to retain 12v under load as part of the comparison. I'm quite happy to withdraw my criticism and accept you are correct if you can display that the lead acid battery you mentioned will deliver 60Ah at a rate higher than 5 amps and retain the 12v under load requirement, but keep in mind the 60Ah lithium battery... well an Winston LYP version at any rate, will deliver a lot more than 60Ah if only loaded to 5 amps throughout the test before the loaded voltage drops below 12vdc. Again, refer to the chart, that 100Ah is rated with a 100 amp load, with a 50 amp load it delivers more than the advertised 100Ah so just how much you could get at only a 5 amp load is really an unknown.

Need to compare apples with apples to really see the comparison, any of the lead acid batteries listed above are simply batteries, no BMS or charge control etc, a 100Ah Winston LYP battery strapped with cell links is around the $800 mark if we are going to compare batteries with batteries.

 

For clarification, the 0.5c means 50% of the advertised capacity as a load in amps (50 amp load from a 100Ah battery) 1C is 100% load etc

 

T1 Terry   

Mike Harding wrote:

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T1-Terry:

I agree with most of what you write - it's just that the two technologies are not compatible price wise with the lithium being about 4 x the cost of a lead acid.

If one requires the specific advantages of lithium then it may be worth paying the extra but for most it will not.

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 This is the part I can't follow, if the requirement is 100Ah @ 12v min then 200Ah of lead acid min is required, even more if the current draw is greater than 5 amps per 100Ah capacity once the SOC drops below around 60%. With a 100Ah Winston LYP 100Ah battery at around the $800 mark that would mean you were buying deep cycle 100Ah lead acid batteries for under $200 each...... then the quality wouldn't be a fair match and over a 1500cycle use period the lithium would still be like new yet the AGM would be in need of yet another replacement.

Many people confuse cycle use and calendar days, the calendar day life of a lithium battery is as yet unknown, the Mars Rover is still going so we know it must be longer than 10 yrs in a very hostile environment yet used every day if it had a chance to recharge.

Cycle life for a lithium battery is discharged to 2.8v in each cell and recharged to a rested voltage of 3.4v in each cell, lead acid is 700 cycles at a 50% discharge and recharged to 100%, less if you discharge it deeper and more if discharged less. The cut off point for lead acid is 60% of advertised capacity, this actually means less than 10% available before the voltage drops below 12v under load. There are a lot of passed on lead acid batteries out on the road just waiting for the owner to discover just how little capacity is really left in their batteries. A few poor solar days and it's all over as the weak cell gets very deeply discharged and never recovers. A string of 12v batteries only requires one battery to have one of 6 cells fail and that will destroy the other batteries in the series chain if the user doesn't catch it very quickly and remove the connections from the now dead battery. The other batteries will keep trying to recharge it till they are all pulled down to the point where a cell will fail. Brand new batteries can sort of take that sort of punishment, batteries with a bit of capacity loss already can't take it and the weakest cell fails making the battery useless for the purpose intended.

Lithium battery packs properly build and monitored do not suffer this problem, a cell never suddenly drop dead, the death spiral is long and clearly evident for mths if not yrs so the appropriate action can be taken at the owners convenience, not when the battery suddenly didn't do what was asked.

 

T1 Terry

-- Edited by T1 Terry on Friday 10th of March 2017 07:04:50 PM

Jaahn wrote:

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Hi

I also think the comparison of the two technologies does not stack up price wise. Terry is a bit one eyed about it as he is an industry expert. That's OK but some balance is necessary for the sake of people not as knowledgeable about the subject.

With Lithium batteries Terry himself has said that you need a 'system' not just a battery, so there is more to buy there. Where as with the old technology LA batteries they are available commonly for a good price, not only premium ones for a premium price, and the associated gear required is also commonly available for a good price.

If you want to spend the money on Lithium that's OK and benefits come with it, but if you just want to "keep the lights on" they do not care what battery the electrons come out of. Your choice but I believe the lithium way will cost considerably more !

Jaahn   

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:lol: @ x $200 for cheap LA that last for how long? Then another $400 or more due to inflation now equals the cost as the same 100Ah useable from the quality lithium battery that would still be doing what it was bought for, storing energy and releasing it when needed. That how long in both cases depends on some form of battery management.

For those who "just want to keep the lights on" won't have them on for long without some form of battery management. Even a start battery will require some sort of battery management if it's going to last more than a few weeks because it will go flat if not charged. Simply connecting a solar panel or the alternator direct to the battery will over charge it and destroy it, they both need a voltage regulator, the alternator has it built in these days but it is still there, the solar requires a solar regulator to act as the voltage regulator. Lithium batteries are no different, they also require a voltage regulator or they will be destroyed by over charging. The difference is the lead acid battery has no method of measuring cell voltages so any cell in the battery can end up getting over charged resulting in a reduced cycle life, just because you can't see the problem doesn't mean it doesn't exist. Lithium again is no different, it will suffer damage if a cell is over charged, the difference is properly built lithium batteries can have their cell voltage monitored and for a the grand total of $30 plus $5 for the plug and leads to install such a monitor..... but that is a step beyond comparing batteries with batteries, we are now talking about monitoring to extend the batteries life. You can do without the cell monitoring if you want, it's your hard earned $$ that bought the battery so it's up to the user to decide if a bit of insurance is worthwhile or not, the battery really doesn't care.

Any additional costs revolves around reducing the time spent looking after the battery pack, if you want it to look after itself yet still get the long life then you have to pay for the control equipment to do that. If you are happy to do it all yourself then even the $35 can be saved and just use a multi-meter, but I'm sure I could find better things to do with my time than watch batteries 24/7  If you don't want the lights to go out without you expecting it then a battery monitor is required, again, an aid for the user and not mandatory equipment so that can not be included in the price of the battery.

If you are going to compare $$ costs then you do need to compare apples with apples

 

T1 Terry 

 

Jaahn, go back to the thread title and give an honest costing and expected cycle life to show your method is better budget wise. By the way, there is no such thing as Good Old delicious apples, they are either fresh and good or tasteless/flowery old, but then anyone who knows their apples already knows that ;)
Lithium is not for the caravan park jumper who never free camps, ever, I can't see why they need a battery at all really.
Lithium is not for the one or two week ends a yr caravan user who doesn't want to use an inverter, lead acid will do that job fine
Lithium is for those who use their RV a lot, they like to camp off grid even in a caravan park because those spots are roomier and further away from the pool and jumping castle. Lithium is for those who do want to use an inverter and who want to move towards 21st century travelling with a few of the comforts from home.
I note it rarely the other half who says they are perfectly happy with roughing it and being restricted in what can be used when, ever thought that might be the reason they are not as keen on travelling as the driver??? Happy wife is a happy life, is parking the van in the yard most of the time a good financial choice when you could be out there enjoying it which was the reason you spent all those $$ in the first place.

T1 Terry

Mike Harding wrote:

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T1 Terry: do you have any kind of commercial interest in lithium batteries?

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Yes, my wife became frustrated by the amount of gear I had around the house so she bought a workshop for me to play in, not many blokes have a wife like that eh :lol: I've mentioned else where that I install custom lithium battery systems using as much of the users original equipment as possible by building an interface to adapt just about anything to work well with lithium batteries. Hundreds of systems fitted and all say a similar thing, couldn't live our present lifestyle without them.

I don't want to promote any business interests here, that is not my intention so I won't name the business set up and run by my wife, my interest is in promoting lithium batteries for what they are and trying to quash the myths set up about cost, safety and use that seems to be so wide spread across the internet.

 

T1 Terry

Something a bit wrong there...

600Ah @ 24V = 10 @ 120Ah/12V, not 10 @ 160Ah.
And 10 @ 120Ah/12V should cost about $3,850, not $5,500.
And if you are happy to use a Dingo for the Li (plus BMS) then you can also use it for the AGMs (minus BMS), so your control comparison is somewhat biased.

Cheers,
Peter

Opps, I'll take that back, my sums were incorrect....  

The control systems will not be the same costs for each system.
50% DOD is a nominal % for AGMs. There is no damage to go much lower to keep things running, so that 80%/50% DOD comparison is also flawed.
The Li excel for big heavy continuous loads, but not everyone needs that feature.
If AGMs are currently providing the service that you require then the only real benefit to Li is the weight saving plus a life increase that is still to be proven.
They are all "just batteries".

Cheers,
Peter