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Post Info TOPIC: Solar for fridge


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Solar for fridge


Hi Everyone

           Need some advise if possible ,we have just purchased 2  200 watt solar panels for the roof of our coaster as we want to power our fridge.The plan is 2 solar panels, battery charger regulater then 1   125 amp deep cycle battery.The fridge uses 5amps.We wish to also run off this unit about 12 watts of LED lighting.Will it work and remain operatioal,also will be secondly wired from our bank of house batteries with an isolated circuit

Thanks



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Hi Ian

I would suggest you require a MINIMUM of 200amphr battery capacity to get you through a couple of bad days of solar input

 

You do have excess solar to battery storage capacity& should use that solar capacity for power storage

 Even 300amphrs would not be over doing it & would give you a bigger POWER bank for bad days of solar input

Also remembering the less a battery is dicharged the longer it's life

Your solar panels will AT THE BEST put in about 140amphrs per day

Depending on ambient temp, fridge thermo setting, opening of fridge door, & warm loading ,your fridge COULD  use between  30amphrs [actually running 25% of the time] & 120 amp hrs [running continuous]per day[24hrs]

But probably more like 40 < 90amp hrs per 24hrs

For long life it is advised that a lead acid battery not be taken below 50% of it's capacity

 A 200amp hr battery = 100amphrs safe discharge for long life 

Also remember any power taken from the battery requires about 25<30% more to replace

This applies to that power taken out when no solar input is available[from say 4pm to 9am]

From the above you could work out just what you believe YOUR situation may be

 

Peter

 



-- Edited by oldtrack123 on Thursday 1st of December 2011 10:46:19 PM

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I agree that 200 ah battery capacity would probably be a minimum. You can stay with the 125 ah and see how it works out at this stage if you have already purchased one but given that it is bad practice to parallel connect dissimilar batteries, old and new batteries of the same type would be dissimilar, you should consider this when deciding on your purchase. If you've recently purchased the 125 ah and it's had not much use it should be ok to use with another identical unit.

I would strongly recommend against connecting any more than two batteries in parallel as it risks shortening the lifespan of the batteries, some on this forum would argue it's ok but it's not their money they're risking. Also discuss any warranty issues with your battery supplier. My preferred option would be to use two large 6volt batteries connected in series if this is feasible. Note that you would need two 200ah 6volts to achieve a capacity of 200ah at 12 volts.

Also consider your charging options other than solar. A 20-25 amp "smart" charger would be a worthwhile investment so you can top up the battery when power is available. If really caught out in cloudy weather for some time a night in a caravan park to charge the battery may be a fall back position. Maybe you also have a generator and if circumstances permit you may be able to use this, either way the charger would be a good investment

If doing a lot of free camping I would strongly recommend that you install the necessary gear to be able to charge the fridge battery from the engine when travelling. A "Ctek M205s Dual" 12v-12v battery charger I would think would be ideal, alternately install a conventional dual battery system. I haven't any personal experience with M205 so you may wish to research this further.

I'm not sure quite what your set up is when you refer to your bank of house batteries, but if this battery we're talking about here is an additional one just to run the fridge I would not interconnect it with the separate house battery bank unless you install a marine type battery changeover switch (available at marine and RV shops) for "emergency" use if you need to power the fridge from the main "house" battery. I would also suggest you use one set of solar panels for the fridge battery and the other for the house battery and again do not interconnect them as doing so will also interconnect the batteries. The same comment applies to other charging sources.

I've tried to cover the main issues here and I hope you can get your head around them, unfortunately multiple battery set-ups such as this, especially if they involve separate house and fridge batteries as well as the vehicles own engine battery, are quite complex and thus deny simple answers.

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Hi all,

I agree that the d250s Dual from ctek (I assume that is what you are talking about jimricho) is a great charger,

However the solar regulator built into this is not large enough to support 400 watts of solar, so could only be used for DC-DC charging.

There are basically two thoughts on power charging aux batteries.

1) you do not stay away from power for extended periods of time.
In this scenario you would usually have battery capacity to last you a day or two. Require charging from your tug, and refill your batteries from main on generator.
The main goal in this scenario is to keep you batteries topped up as much as possible, and then use the battery to see you through the times you don't have power.


2) you plan on spending extended periods away from power
Here you would usually have enough solar to keep your batteries fully charged, i.e. providing more power than you will use.

There is usually no need for extra charging in this scenario as the solar keeps the batteries charged. You may want a 240 volt charger and a generator / access to mains in case of extended periods of bad weather.

here charging from the tug is not usually necessary unless you are doing long periods of driving regularly you will not get much benefit.

If your goal is style 2 as stated I would definitely consider putting more battery capacity in allowing you to see out some bad days.

Having a battery monitor is also a good idea as it will let you know if your battery is getting low and you need to top it up from generator etc.

Cheers,
Nichol




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Thanks Nichol, (and Ian and Shaz too)

You make some good points, one of the problems here is that Ian and Shaz's set up is quite complex involving (I think) a separate fridge battery and House battery, or at least that's how I have interpreted their post and this involves in effect having or at least needing separate charging systems for each battery. I agree that if they wish to recharge one or both of these batteries from the engine while travelling it throws further complications into the mix and if their solar is adequate without this it would simplify things not to have it. However they probably wish to be able to use their fridge while on the move without drawing down on its own battery. Maybe they already have a dual battery system installed and connected to the house battery

I also concur with your comments about a battery monitor. I have a Jaycar panel voltmeter installed in my van (camper-trailer actually but I call it a van) it cost about $20 I think and works as well as any fancy one. I also have an aux battery in the tug for my Bushman fridge and have Baintech Low voltage cut-out installed to protect the battery from over discharge.

They really need to sit down with someone who's really knowledgeable and discuss their needs face to face and think through whether they are going the right way about it. I say that without intending to suggest they aren't. I would also suggest they discuss in detail their battery set-up with the battery supplier, especially in regard to any warranty issues.

I can't help but feel a better system would be to simply have a house system of adequate capacity with a battery monitor as you suggest and connect the fridge to this.

Cheers,

Jim


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Agreed,

It is much simpler to have a single house bank, and if you want to have reserved capacity to use low voltage disconnects with different set points.

I also agree that speaking to somebody who can advice, and if possible supply and install is a great way to go as it removes any issues of what equipment is not working correctly in the set-up, as they can go back to the installer as a single point of contact.

However there may be a reason for running a separate battery bank for the fridge, and reasons for doing it yourself (hobby, price etc)

Hopefully Ian and Shaz get their system sorted out and working well for them.




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Hi Everyone
Our house battery is 4 124a/h batteries which run a 6000 watt combi inverter charger,this runs our 240 volt gear,at present also runs fridge and lights.We run A/C toaster jug E/BBQ ho****er system etc of the inverter, the batteries are recharged either at a c/park or when we are on the move from the bus engine via a sterling A/B charger works great,we have worked out that the most important things to run are the fridge and lights as we can run everything else of the generator if we flatten the bank of house batteries.There for if we can run the fridge and led lights of the solar panels we thought that it would almost give us unlimited free camping possibilities .Wieght is not a prob as our coaster all up GMV is 4720 and it is apresent grossing 3500 so is not an issuse.We like doing things ourselves as it gets done and we built it the only thing we dont touch is the 240 volt side of things
Thanks for the input guys it has been very helpfull

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I see where you're coming from but I can't help but feel you're making life rather complicated. Why not just connect your solar to your existing system. Definitely install a voltage monitor so you can keep an eye on the consumption from the battery and take steps to avoid getting caught. I fail to see why you need an electric toaster and jug when you're dependant on battery power. A kettle and and stove top with a little camp toaster or a griller works fine.

As for powering a hot water system from a battery via an inverter???? why didn't you go for a gas system??? or diesel maybe??? Having sufficient battery capacity just to do that must have cost an arm and a leg! Without doing the arithmetic I guess if you live for a couple of centuries you'll eventually amortise this cost, provided you don't add in the opportunity cost.wink  I can't think of a less efficient way of providing hot water!

Rather than making an overly complex situation even more so, I feel that your existing house battery combined with the solar panels would be more than enough provided you don't use it up like there's no tomorrow.



-- Edited by jimricho on Friday 2nd of December 2011 08:25:50 PM

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I can see the benefit of having a separate battery here, it does mean that all the solar energy stored will go into storage to be used for the fridge, rather than being used for anything else.



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Nichol wrote:

I can see the benefit of having a separate battery here, it does mean that all the solar energy stored will go into storage to be used for the fridge, rather than being used for anything else.


 Provided the two systems cannot be inadvertantly interconnected in the event of needing to fall back to the main house battery for the fridge.

This can be achieved by installing a marine type battery changeover switch and not using it selected in the "both" position.  These are available at any marine shop and I've seen them in caravan shops too.

With this fall-back position available maybe the 125ah would be enough.  Worth trying it out before committing to the expense of another battery.

PS: Would also suggest changing (with the switch) to the main house battery when travelling as there is no provision to recharge the fridge battery from engine, especially in conditions that are less than ideal for the solar panels.

Would also sugggest installing a separate battery charger to top up the fridge battery and power the fridge when mains power is available.  Your existing combo would not be suitable as it is already "spoken for" for recharging the main house battery.



-- Edited by jimricho on Friday 2nd of December 2011 09:05:41 PM

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Hi Ian

Re :" 6000 watt combi inverter charger,this runs our 240 volt gear,at present also runs fridge and lights.We run A/C toaster jug E/BBQ ---"'

I hope the Combi was installed by someone who knew the requirements of the standards & just how the Combi needs to be installed

Have you had ALL your power points tested for correct operation of the RCD[safety switch] ???

I DO NOT MEAN BY PRESSING THE TEST BUTTON

I am aware that some have not been installed correctly

 

Peter



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Another thought on the combo and house batteries is that the combo would draw some really serious current from the batteries when loaded up and the wiring between the batteries should such that the load is shared equally by all batteries. Heavy "starter motor" type cables would need to used and each cable should be of equal length and run to a common point. This applies to both the positive and negative cables. If your existing wiring doesn't follow this configuration you may need to think about this.

Just interconnecting the individual batteries terminals to each other and connecting the supply cables to one of the terminals will not achieve balancing the load between the batteries. In case the village pedants want to challenge me on this I point out that I recently had this discussion with a battery supplier who pointed out that they may be reticent to honour a warranty claim on parallel connected batteries unless steps were taken to ensure this balanced loading of the individual batteries. He went to the trouble of sketching diagrams to illustrate his point.

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Hi

Jim's points above are extremely important with high currents such as you have with THAT inverter [possibly in excess of 500amps}

 

It is not so important with an all series battery set up

BUT should be standards practise with ANY parallel battery set up to ensure equal load sharing & recharging

Best explained as the curent path using the same sized cable should be always the same length no matter from which battery the current is coming from or going to

Also with such high currents I would also suggest that all the interconnected batteries be the same amp hr rating & type

While Jim & I may have differing views on the pros & cons of series & parallel batteries, this is one type of service where parallel batteries do need great care

The more in parallel then the greater the care needed with the interconnections

That includes cleaness & tightness  of ALL joints

Peter



-- Edited by oldtrack123 on Friday 2nd of December 2011 11:42:07 PM

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Another thing we agree on Peter is your comments on deeply discharging batteries that you make in your previous post...more on this below.

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Hi Ian and Shaz,

Your head's probably "swimming" by now so I'll see if I can keep this simple.....

The more I think about your set-up the more I believe that you should give up on the idea of separate battery/solar for the fridge.

If you are going to routinely discharge the house battery to the point where this backup is warranted you are going to seriously shorten the life of those batteries. A much better option is to monitor the voltage of the battery and to take action to conserve battery power before this becomes critical.


By forgoing the separate battery you can use all your solar capacity to recharge the house battery and I think this is a much better use for those expensive solar panels.

While the batteries are quoted as having a capacity of 125ah (or whatever) the real world capacity of any battery is significantly less at the "mega" currents that your system would be drawing at times. The battery manufacturers aren't telling porkies, it's a function of the chemistry of the battery and the way they are rated. (usually based on a 20 hour discharge, 6 amps in the case of your batteries.)

If your hot water set-up contributes to the shortening of the life of the batteries it could make the cost of gas for a gas unit or a gas/electric type, common in caravans, look cheap.

hope this helps,

Jim

PS: If you wish to have some emergency lighting why not just purchase a couple of self contained LED camp lights, available at any camping shop.



-- Edited by jimricho on Saturday 3rd of December 2011 07:35:25 AM

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 HI Jim

 

Totally agree with the above

Very well put

I do wonder just what the true remaing capacity of that battery bank may be!

 Another agreement, Gee what's happening???

 

Peter

 



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HI Everyone
Just to set everyones mind at ease the combi inverter was installed by Gordon Nickleson who has about 20 years experience in the UPS field.Batteries are correctly wired up in series that is 2 banks of 24V.All wireing is 25mm2 all wires are the same lenght.All of this complies with AS3000/AS3001 rules for motor homes.Gordon has wired this bus as a true island system.The switch box that allows us to use park power or inverter or generater has a 100 amp one way resister built into it so that there is no possibility of backfeed,as for RCD yes have a full bank of them one for every circuit in the bus but as you are all aware RCDs dont work when on inverter power so we have fitted a VRCD which does.When we went away on our first trip we had the fridge on running 24/7 we only ran out of power once because we didnt drive long enough in that day,we dont want to have to drive all the time just to keep our battteries charged up,the toaster jug etc is our little thing.The only gas we have on the bus is 2 butane fired stoves if the main bank flattens out i can still use the generater.We have fitted a volt meter in the pack also.The bus was designed from the start as an all electric unit as i have personally seen the results from exploding gas cylinders.The hot water system was chosen because of its compact size and dual voltage 12/240.The inverter handles anything we have on the bus including the A/C.The solar panels while not cheap are not over the moon in price $300 each that with a battery charger /controller and battery.The bus even though it is a 1992 model coaster only had 106,000 genuine Ks on the clock when we purchased it and we plan on keeping it for some consisderable time.Before we did things i spoe to an enginneer and his advise on prolonging the life on deep cycle batteries is to keep them constantly cycling,the inverter cuts out before damage is done as is with most inverters.All batteries were purchased at the same time and are all the same.I have a spare 600 amp sterling rotary switch for switching between solar and house batteries.Hope this puts everyones mind at rest.The panels are going to be there so that if we park up for a week we still have fridge and lights

Ian and Shaze

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Hi Ian

Re :'so we have fitted a VRCD which does."

Excellent .I AM impressed , was that something you asked for or did your electrician advice.

Mind you they can be used instead of the primary van RCD,provided they are wired in correcty with the combi  & mains power

Also effective with genny or inverter  simply plugged in via van power inlet socket

I believe when their mutli function use becomes better understood that is all you will see ,as the primary safety cutout, in ALL VANS MOTORHOMES ETC 

No more worries about isolated supplies developing earth faults & becoming potentialy unsafe

Peter



-- Edited by oldtrack123 on Saturday 3rd of December 2011 04:45:49 PM

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It all makes a lot more sense now that you have explained that it's a 24 volt system. I guess that the original query about a separate system for the fridge is to have a separate 12v system and that the fridge is a 12v unit (or 12v/240v), have I got this right? If so it all makes much more sense. I'm not familiar with bus wiring so I had assumed it was 12v. Obviously 24 volts does make a lot more sense but my mind reading skills are very limited so it does help to state these things.

Getting right back to your original question...obviously the solar/battery combination should work fine. Just what you mean by an isolating device is a bit vague but if it's something to specifically connect the 12v fridge to the 24v main battery I guess that should be ok.  You do have the option of running the fridge from your 240v ac supply as a fallback if you need to, assuming it is a 12v/240v unit.  Whether the 125 ah battery is sufficient, only time will tell.

That battery arrangement is a lot better as you are only operating the parallel batteries in pairs. The comments made by both Peter and myself about the need to ensure the load on the parallel connected batteries is balanced between them still applies but this can be achieved more simply without taking the individual batteries back to a common point as previous suggested, just check the positive lead to one of the batteries in the parallel bank is connected to the terminal of one battery and the negative lead to the terminal of the other battery.

I have heard that one about cycling deep cycle batteries to allegedly extend their life and must say I do wonder. Regardless, if you regularly deeply discharge them it will achieve the opposite result and yes this applies to deep cycle batteries too.

I don't have "hands on" with 24volt systems especially in the area of connecting 12v devices but I am aware that it is bad practice to just tap into the bottom 12 volts of a 24 volt bank. You would obviously be familiar with 24v/12v converters that are readily available and suitable for low power devices.   There are technologies for connecting higher power 12v circuits to a 24v battery bank and maintaining a balance between the two halves of the series connected bank but I'm out of my league here.



-- Edited by jimricho on Saturday 3rd of December 2011 06:48:07 PM

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Hi Ian

Re:' spoe to an enginneer and his advise on prolonging the life on deep cycle batteries is to keep them constantly cycling,the inverter cuts out before damage is done as is with most inverters."""

I realy wonder what he meant.

All lead acid battery life is based on number of charge discharge cycles

They do have a limit

The biggest enemies of long battery live are:

[1]overdischarging

What consist of over discharging depends on battery type, but generally it is considered that a LA battery should not be discharged below about 60% capacity for max amphrs per dollar of battery life

The actual voltage for each type @ which that occurs is a little load dependent

With heavy loads it will aroung 11.5, light loads more like 11.8<12v

So your battery life will be very dependent on the actual drop out point of your inverter

[2]how long they lay discharged before being FULLY recharged

[3l the max total power for dollar over the life of such batteries is with frequent SHALLOW discharges ie taking out no more than 30<40% of their capacity, for a useful purpose ,before recharging

It is not advisable to simply discharge them for no useful purpose  

IF that is what cycling referred to .

It is an old wives tale             

THAT will not extend their life

[4] the rate @ which current is drawn. high rate current withdrawal gives reduced capacity[amphrs] & if excessive will do long tem damage to LA batteries

Again  different types have different acceptable discharge rates 

Your battery maker should be able to supply you with such data 

[5]Excessive overcharging will damage the battery particularly AGM types.

[6]correct charger float/ maintenance voltage .too high a float voltage can shorten life

  

So it is essential your charging system is set for the actual battery type

Again battery maker should be able to supply their preferred figues

[7] then of course there are all the normal checks :

;fluid level if flooded wet cell

terminal clean & tight

 heat if AGMs . They do not take kindly to high temps

AS Jim has said it is bad practise to take 12v off a 24v bank unless via an equalizer

Realy now that we understand your reasons for wanting a dual ,set the picture changes significantly

 

 

Perhaps if you can post just what you wish to use on 12v& their current draw.it can be looked @ a little different

For instances it may be simplier to just keep your whole system 24v [using the new panels in series]

 & supply any 12v appliances from 24v to 12v converter

Peter



-- Edited by oldtrack123 on Saturday 3rd of December 2011 09:04:44 PM



-- Edited by oldtrack123 on Saturday 3rd of December 2011 09:07:47 PM

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Another point about overcharging AGMs is they do not like el cheapo chargers due to their high ripple voltage.

By the way Peter, a bit off topic I know, but my Optima Red Top that I use for my Aux battery in the Pajero is nine and a half years old! The Red Top is classed as a starting battery rather than a deep cycle. It still has plenty of amphour capacity and will recharge quickly from the alternator. I've measured a charging current of over 50 amps when charging from an (estimated) 50% discharged condition. The battery is mounted in the engine bay.



-- Edited by jimricho on Saturday 3rd of December 2011 09:17:01 PM

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Hi Jim

That is good going

From what I have heard Optima users are happy users & they do accept high charge rates

Perhaps they should be "OPTIMUM"

Of course their construction is totally different to wet cell lead acids

Peter



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Hi Everyone
Thank you Oldtrack re, spoke to an engineer,he is actually an electrical engineer who has many years of mine experience especially off grid solar systems,generators and also UPS power supply systems his words AGM batteries life expecancy 10 years in realality 5 years put them in the outback 3 years its all relative in what yo do with them what he found was that if you keep them discharging them then recharging them they lasted longer and he is dealing with some very big banks of batteries.All we wish to run from our solar panels is our 12v fridge and 12v LED lights,our combi charger is a pure sine wave unit,We have tapped 12v of 24v using a converter no probs.The VRCD was a suggestion Powerstream RV made to us as we have heard that very soon they will be mandatory,Our house batteries are AGMs not L/A.No we don't want to keep the panels for 24v as we only use the inverter when we need it.


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That's interesting your comments about AGMs and regular cycling. I killed an Odyssey AGM many years ago by over-discharging so I still do feel that regular very deep discharges should be avoided even for AGMs. Maybe deep discharges are ok but I've better things to spend my money on if it isn't (booze, long lunches, etc.)

My Optima does get regular discharges but I can't recall it ever having been what one would call "nearly dead flat" in its life and I attribute its longevity to this. At one stage I also had a Yellow Top (deep cycle) and it did get a few deep discharges and did not last nearly as long as the Red Top has. The trip point of my low voltage cut-out is 11.1 volts and this is lower than I would care for with a wet battery but fine for an AGM.

You seem to have your system very well sorted out, much more so than I (and I think the others on this thread too) felt from reading your initial post and much better than many who come to this forum seeking information. Much of the querying of your setup was a result not having some of the info early in the thread, so I guess the original question was mainly about the adequacy of the 125ah capacity. If so my thoughts are... I doubt it, but "suck it and see" before committing to another expensive battery. The test will come after a few cloudy days.

Another thought is that you have the carrying capacity (and dare I say it, the budget) to be able to install such a large system. A system like that would overload the average caravan.

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Hi Everyone
Thank you Jimricho,time will tell,with L/A batteries they need to be used to stop sediment buildup between the plates,i am not saying to completly flatten batteries,my inverter drops out at about 11.8 volts,With our bus we have 1000kg before we reach our GVM.We have had the inverter on dropout once on us in a 2 week trip free camping however on that trip we where covering quite a few Ks per day and the Sterling AB charger kepted our house batteries charged up but we want to do some short w/end stuff we would soon run out of battery power
Thanks
Ian and Shaz

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Ian and Shaz wrote:

Hi Everyone
Thank you Jimricho,time will tell,with L/A batteries they need to be used to stop sediment buildup between the plates,i am not saying to completly flatten batteries,my inverter drops out at about 11.8 volts,
Thanks
Ian and Shaz


 

Hi Ian

The below is relevant to wet cell deep   cycle LA  batteries

If the sediment between the plates up is the reason for regular cycling , then I have serious doubts about your sources knowledge

Normal gassing when charging & vibration when travelling  will dislodge any sediment.

Bear in mind, that sediment is due to plate degradation that occurs during charge & discharge cycles

The more you charge & discharge the greater the degradation & LOSS OF ACTIVE MATERIAL

It is part of the life cycle!

the sediment rarely causes any problem unless it  becomes so deep in the bottom of the battery that it shorts out the plates

Undercharging & sulphation are the major causes of early battery failure

Actual shorting between plates can also occur, due mainly to plates buckling caused by excessively high discharge currents

Longest life wil be achieved by :

 [a] keeping the battery fully charged at the correct float /maintenace voltage [one that hold the battery around 13.2<13.6v] depending on makers reqs

 This is a voltage just below gassing

avoiding excessively deep discharges ,limit to about 50% at the most ,better to only use 30<40%

[c]Fully recharge ASAP after discharging

[d]Do not let stand in a partialy discharged state, even one week can lead to suphation occurring

Note

These remarks are relevant to wet cells they, do not  necessarily apply to AGMs which are more tolerant in many ways

Peter



-- Edited by oldtrack123 on Sunday 4th of December 2011 11:00:55 AM

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I'm confused..... Isn't the system 24 volts....what does the 11.8 volts represent? Is that the voltage across each battery and the actual "trip" point of the low voltage protection 23.6 ? that certainly will prevent a deep discharge and AGMs would tolerate a lower trip voltage giving more effective capacity.

re the battery cycling... maybe your engineer mate is referring to UPS operation where the batteries sit for yonks in a stationary environment with a float charge connected and only get a discharge on the odd occasion of a mains outage. In some (possibly many) installations the UPS only has to supply power until a backup generator cuts in.

I also wonder whether the battery cycling rationale is relevant to AGMs at all. Either way your usage pattern is obviously one of regular cycling anyway.

As we've drifted into a more general discussion on batteries I'll drift further and throw in couple more..

When I started doing some 4WD Tag Alongs many moons ago our convoy leader at the time told us that he had found from his extensive experience that the best battery for an auxiliary in a dual battery system was Yuasa Overlander, (a 4WD starting battery) and he had better results out of that than a normal deep cycle. One of the advantages was its quicker recharge time from the alternator. This was before the days of widespread use of AGMs.

Another one to throw into a more general discussion....Gel batteries are usually not appropriate for RV use but I wonder whether this application (the solar for the fridge one, not the main system) might be an exception and their principal limitations, ambient temperature, and charge/discharge current limitations, do not apply here ?????

I don't have any "hands on" with gel batteries but perusing manufacturer's data they seem to have much greater longevity as expressed in charge/discharge cycles.



-- Edited by jimricho on Sunday 4th of December 2011 05:50:56 PM

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Hi Everyone
jimricho,our bus is 24v the inverter is 24v between the bus altenater and the inverter batteries is a Sterling 24v 60amp AB charger which can be set to charge L/A, GEL or deep cyle batteries it actually charges the bus batteries up first which are normal crank batteries it then monitors those for charge, then it switchs to the AGMs at the back of the bus and charges those as we are driving along and these are charged as for AGMs,a little black magic box that works. The inverter drops out at 23volts This inverter is a fairly serious unit Coaster conversions at Casino use one to power his house as he lives out of town and has not had any problem with it, it is 6000watt contiinous 18,000 watt peak,on main power it charges at 70amps, talking to various people i think AGM or deep cycle batteries are the only way to go with our bus nobody has recommended using L/A batteries except for cranking.The AGMs are constantly passively cooled.I have also been advised that is i fit a 120 amp altenater i can floated the charge from the Sterling AB charger across the top of the batteries and run our ibis A/C while driving along.Our budget for our bus has come in at less than 1/2 the price of purchasing a ready to go new conversion to our requirments.My partner and myself still work at this stage,friends of ours desided to hit the road so to speak after retirement and their budget was limited, In our desision to build a motorhome was also the commitment that we would no longer rent accommodation for our annual holidays,Australia became our holiday home,also w/end getaways whenever we wish to as we like to go fishing along the north or south coast with our boat or just busing about.This seems to have been a very intesting topic.Interesting point our solar system will cost us approx $1500 this includes replacing AGMs at about five years if we amortise the cost over a ten year period it is costing us 42 cents a day to own has anyone bothered to work out how much it is costing to run their fridge at home.I think that in future i will be a bit more carefull on what questions i will ask
Ian and Shaza

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Please dont be more carefull, its questions like these, and the discussion that follows, that enables newbies like me to learn more
thanks
Merg

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Hi Everyone
All i asked was a simple question i am also a newbie to.We will still be procceding with our plan of 2 solar panels etc,we have since spoken to a friend of ours who has done exactly what we are wanting to do ,he did it a number of years ago with the results that we are looking for he has a rather large motorhome
Thanks
Ian and Shaza

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Body total worn out and stuffed steak sandwich in one hand glass of sctch in the other skidding sideways into the box if thats life what a ride

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