Budget backup / 12vdc and 240vac power supply

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DustyDog
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Joined: Fri May 23, 2014 7:23 pm
Location: Cumbria

Re: Budget backup / 12vdc and 240vac power supply

Post by DustyDog »

cheers Andy, think i asked a few questions on another thread, about where how etc, what can you run an the inverter, what do you reckon you would need to run say a laptop, a telly and maybe some chargers and lights??? Cheers

P.s is this a similar setup to your wooden crate power system??? :?:
Up in the wet South Lakeland
Yorkshire Andy
Posts: 8733
Joined: Thu Oct 03, 2013 4:06 pm

Re: Budget backup / 12vdc and 240vac power supply

Post by Yorkshire Andy »

what can run an inverter?

as in how to power it..

theres a bit of a debate on this subject since leisure batteries are designed for caravans and boats and are old tech internally originally intended to run a few lights and a water pump every now and then .. Basically a long but low continuous draw... BIG inverters draw lots of power , was reading recently that the more modern bosch s5 range of car batteries are good for big inverters see below

http://www.aandncaravanservices.co.uk/b ... nology.php

ive copied and pasted this in as small text as i can to not take up to much board space but it makes a good read on the subject

IS THE OLD FASHIONED LEISURE BATTERY NOW DEAD?

Updated 14/10/2014
Please note we do not sell batteries, this is as impartial as it gets. Our sole aim here is to prolong the life of Motorhome chargers which most of the time are damaged by Batteries past their best. We will attempt to show that not all Batteries are fit for purpose in a Motorhome and most definitely not the same. Some will give a Motorhome charger an easier life than others and last much longer.

Can we say thank you to everyone, from individuals to Battery manufacturers, who have helped provide information to put this together.
There is a lot of misinformation about Batteries in Motorhomes and Caravans. Things have changed so much in the last 5 years both in terms of Motorhome and Caravan usage and Battery Technology.
For example you will read lots of advice that a Deep Discharge Leisure battery is the optimum in a Motorhome. Yet many Motorhomes have Inverters of up to 3,000watts drawing almost 300amps from the batteries. There is not a single old style Deep Discharge Leisure battery that we know of designed to handle this power draw. Proper Deep Discharge Leisure batteries are designed to deliver just a few amps over a long period of time. Using an Inverter with this type of battery will significantly shorten its life.
Similarly, many Caravans now have Motor Movers, huge Electric Motors on each wheel, that draw similar amounts of current to a Car Starter Motor that will again very quickly degrade an old style Leisure battery. This will in turn strain the charger shortening its life.
Some Motorhomes are fitted with Intelligent Power distribution units which prevent any power being taken from the battery when it drops below 10.5v - 11v. Where these units are fitted, a Deep Discharge battery will not be allowed to Deep Discharge to the very low volts for which they are designed. If you have a German, Italian, French or Dutch built Motorhome with sophisticated Electronic Battery control, an expensive Deep Cycle/Deep Discharge battery is a very poor investment.
The key to protecting your Battery Charger is understanding how a Battery deteriorates after only a very short time. A Battery contains lots of Lead. You will have seen how Lead tarnishes from a Bright silver colour to dull Grey in days. As a Battery ages the tarnishing/corrosion leads to poor conductivity throughout the entire battery, making it both harder to get the stored electricity out and recharge the battery to put that electricity back.


To understand how this internal corrosion affects a batteries capability, imagine it as a water tank with a small hole in the bottom.
When the tank is new the water that leaks out is insignificant but as it gets older the corrosion opens up the hole so more water leaks out. So after 3 years you need to put more water in just to keep the tank topped up. However, as the tank ages the pipe leading out of your tank from the Stop Tap also corrodes and little leaks develop all down the length of the pipe. Whenever you open the tap some Water never makes it into the bucket so you need to have the tap open longer, taking more water from the tank to fill your bucket. Although you are still only filling the same size bucket you did 3 years before, half of it spills onto the floor so the end result is a tank that is much less full than it would have been 3 years previously.
To fill the Tank back up now requires the Water Pump to force in a greater quantity of water. However, imagine that the pipe from the Water Pump feeding the tank is becoming restricted by 'furring' so getting all this extra Water into the tank becomes really, really hard work. Not only do we now have to pump in more Water but it has to be done down a narrower pipe and even as we pump it in, it's leaking out. The resultant strain on the Water Pump (Battery Charger) causes it to fail.
That analogy is the best we can think of to show how a Battery behaves over time, as the battery ages (which might only be months on a budget Battery) it is harder to get the power in and you waste more of it getting the power out. Additionally, but not always, it may run down more quickly. The above is a simplistic explanation of something very complex but shows most of the issues in normal Motorhome battery use where the Plates have suffered no damage.
Because of the way a conventional Plate Corrodes, a Lead Acid Battery (Gel, AGM or Wet) starts its decline from the moment it is manufactured. Hence the importance of buying only freshly manufactured batteries.

Battery Warranty?
We think that a misconception of most Battery Warranties has led to a false expectation on Battery life.
Almost all of the guarantees we have seen for Batteries (AGM, Gel or Wet Acid) are that the battery will be replaced if it fails within the guarantee time, not that it will perform to specification for that time, which is very different.
If you applied the average battery warranty to a new car like a Kia Ceed the only thing that would be covered would be if the Car 'Breaks Altogether'. The 7 year Warranty would not apply if Fuel consumption dropped to 60% of new, that it took 10 seconds longer to accelerate to 60MPH. Brakes only half as good? Not covered. Heater fan blowing half the amount of Air? Not covered, etc.

The reason Battery Warranties work like this is because, 20years ago it was not physically possible to create a battery that performed to specification for its life. It was not possible to prevent the Plates from corroding or preventing slow deterioration in the Plates.
I suspect if there was more awareness that batteries still within a 2 year warranty can be down to 60% efficiency rather than 'as new' there would be a better understanding of the workload being placed on the charger?
There are many reasons why a an old fashioned Leisure battery is no longer an appropriate fitment in most Motorhomes or Caravans, but the latest Technology is the primary reason :

The technology used in car batteries has had to make major leaps forward because of Car Stop Start systems.
In a car with Stop Start technology the engine cuts out every time the car comes to rest for more than 3 seconds, yet the stereo, heated rear window, heater blower, heated seats, Wipers, electric heated mirrors, Headlights, etc may all continue to operate discharging the battery considerably before the engine restarts. The car Alternator then applies a big charge into the battery only for the engine to cut out at the next junction/lights and the cycle begins again.
Hopefully none of us will experience Stop Start in action to any degree, but in the major German Cities Stop Start is regarded as an essential option on today's cars. It's therefore not surprising that Bosch has been at the forefront of the work to make car batteries Deep Discharge and recharge without the degeneration that blighted Car Lead Acid batteries of old. This technology has been applied across much of the Bosch Battery range even to batteries which are not meant for Stop/Start applications.

What Bosch/Varta have done, to return to our analogy above, is build a Water Tank that is made from a special alloy. It suffers no tarnishing, has no leaks. The Inlet/outlet pipes are again specially coated, so no corrosion or leaks. Bosch have found a revolutionary way of making the inlet and outlet pipes bigger, with less friction (Powerframe Technology) so the water flows in and out of the tank much more easily than most tanks made of Lead. The Powerframe technology makes sure they stay this way, they don't fur up nor leak.
So now the Water Pump (Battery Charger) has half the work to do over a 5 year period. A nice side effect is that the Tank now fills twice as fast. The final Bosch technological trick is to seal the tank so no vapour escapes.
The Bosch product that most benefits Motorhome and Caravan owners is the Bosch S5. While it is not a Stop/Start battery it has much of the advanced high technology like Powerframe Plate construction combining the benefits of both Starter 'Thin Plate' and old style Leisure 'Thick Plates'. This Plate construction endows the benefit of being able to Start Motorhome Engines and perform as a semi Deep Cycle Habitation battery. Click HERE to see how this new advanced Plate construction has revolutionised battery performance. The same webpage also documents the technology that contains the gas normally given off ensuring it remains inside the battery, making it 100% maintenance free and Gas tight.
The S5 100Ah with Powerframe, Silver Calcium, Hydrogen/Oxygen containment, 5 year guarantee costs £98 (or £87 for a Varta Silver Dynamic H3 equivalent, see later text). Little more than the cost of inferior budget 'Leisure' batteries. We don't think any other battery in the price range works better in a Motorhome or Caravan Habitation area.
Please note that we do not recommend a conventional Starter Battery for use in the Habitation area. Only the Powerframe/Silver /Calcium/Sealed Battery. A standard Budget Silver battery without Powerframe is no where near the same product.
A typical Bosch S5 battery is lighter than an old school leisure battery. A battery does not have to be heavy to be long lasting, it is now the technology of a batteries Plate construction that is important, not it's thickness or Lead content. In fact a high Lead, heavy battery is bad on so many levels, bad for the environment in terms of lead poison; increased fuel usage pulling the extra weight; danger of back injury carrying it; etc.
A Powerframe Plate constructed battery will outperform any other other type of conventional 'Thin' OR 'Thick' Plate battery in the same Class by a big margin, it is so technologically advanced.

In addition to the above the Bosch S5 has other benefits for Motorhome owners, it discharges only 5% when standing idle over the winter months compared to 50% for a conventional LA battery. They are also truly maintenance free, to the standards of Gel batteries from the 1990's, so do not give off any Hydrogen or Oxygen gas. They are guaranteed maintenance free for 5 years so can be used INSIDE the Motorhome habitation area, such as under the Driver's Seat.
They are extremely efficient due to the unique Plate construction so recharge more quickly than a conventional Wet Acid battery. WikiPedia notes : "a liquid-medium cell tends to rapidly discharge and rapidly charge more efficiently than an otherwise similar Gel/AGM". See : http://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery.
A Varta Silver/Bosch S5 charges up twice as quickly as a Gel battery and between 1.5 - 2.0 times faster than an AGM Battery. They also perform at extremes of temperatures that would damage other batteries.
Steve Kemp has done some research and found that the Varta Silver Dynamic range is identical to the Bosch S5 but can sometimes be found at a £10 saving. What you read for the Bosch S5 also applies to the Varta Silver Dynamic batteries.

SUPPLIERS.
We have done a lot of research into Varta/Bosch suppliers and these are the cheapest/best we have found : Just Car Batteries, 01772 790999 who sell the Varta Silver Dynamic 100Ah H3 battery at £87, almost £55 less than a major High Street retailer, £15 less than Tanya and £10 less than Amazon.
Gordon Brown recently emailed, "Thank you for recommending Just Car Battery, excellent service and a great price".
The battery that seems to fit most Motorhomes, but you do need to be armed with the Battery Bay size before you call, is the Varta Silver Dynamic H3 100Ah at £87 or the Bosch S5013 100Ah at £98. See bottom of page for sample battery sizes.
JCB have keen pricing on Varta Silver Dynamic and Bosch S5 batteries, DELIVERED TO YOUR DOOR FREE. Ring them on 01772 790999 or CLICK HERE to view their products. Although we have had lots of feedback about this page no-one has yet pointed us in the direction of a better/cheaper supplier. All feedback about JCB has been exceptional. JCB seem to specialise in the Bosch S range/Varta Silver Dynamic. Note that they supply all batteries for Cars, Motorcycles, Buggies, Motorhomes, Lorries, etc. One other advantage is a very high turnover of stock, so when you buy a battery it has not been standing/deteriorating for months in a shop.

Bosch S6 AGM Silver Calcium battery has a 6 year guarantee with 4 times the deep cycling capability of normal lead Acid batteries. The S6 has a much higher cost than the S5 range (yet still less than the usual Leisure AGM equivalent!!) possibly worth it if you spend a lot of time running off 12v without Mains plug in, but ONLY if your charger AND Alternator supports AGM batteries, MOST DO NOT. This applies to an AGM battery from any Manufacturer as most Motorhome and Caravan Charging units do not have an AGM charge program.
Many motorhome chargers will destroy an AGM battery in months, which will then fail the charger. See our AGM page for more info on AGM, particularly the comment on the Banner web site that AGM Batteries should ONLY be retro-fitted when experienced personnel have assessed IF your Motorhome is suitable.
In our experience people are being told AGM is a suitable fit without being asked any questions by Dealers and battery wholesalers. We recently did a survey at 2 Dealers, a Halfords Store and a big battery retailer. They all said an AGM battery could be fitted in our 'imaginary' Motorhome without asking any questions about the Motorhome age, the charger technology or the Alternator. When we then said the charger had a fixed 14.8v output and no AGM charge profile, they all still said an AGM battery was fine when it would have been destroyed in weeks.
Again when we asked what were the advantages of spending twice as much money on an AGM battery, all we got was 'they are better'. Not one of them could tell us the advantages or disadvantages of AGM when used in a Motorhome. AGM batteries are amazing bits of technology in their own right and do have lots of advantages, but not when used as a Motorhome Habitation battery. Bear in mind that if the AGM battery is not a high Silver content battery much of the above about Battery corrosion still applies.

A Varta Silver/Bosch S5 charges 1.5 - 2.0 times faster than an AGM battery, which generally is charged at half the current of Wet Acid battery. The Varta Silver/Bosch S5 charges more than twice as fast as a Gel battery.
A very nice characteristic to a Motorhome owner for the following reasons :
1) The batteries are more likely to get back to full charge after an overnight stop.
2) Because the S5/Varta is so much more efficient the strain on both the Alternator and 240v charger is much less. It only takes half the time of a typical Gel battery so the strain is further reduced because the charger is working for half the length of time.
3) It doesn't take a genius to work out that if a battery is more efficient it will require less energy to recharge. When so many people are fitting Solar Panels with only a few amps output, Battery efficiency has a big impact on Solar capability.
4) That Generator your neighbours on the adjoining pitch don't like you to use will charge up the Bosch/Varta batteries in half the time of AGM or Gel, using less fuel.
These illustrations are very simplistic ones, but demonstrate the overall benefits.

The below is the charging program information from the Technical manual of a Votronic Solar Charger :
Wet Acid : 14.4 V / 13.45 V
Gel : 14.3 V / 13.8 V
AGM : 14.7 V / 13.5 V
As can be seen, the charging characteristics of an AGM battery are quite different. At the very best an expensive AGM battery is going to be a compromise, why spend so much more when you can buy a better solution for almost half the price? See our AGM Battery page for more details.
Note also that most of the Motorhome specific Solar Regulators do not have AGM support.
Another point of note is that while AGM batteries have many benefits due to the Absorbent Glass Mat Plate construction they generally only have low levels of Silver, so all the corrosion talked about above still applies.
The characteristics and benefits of an AGM Battery reduce from the moment it is made.

If you require a Habitation battery to discharge as low as 60% (lower than even some AGM batteries) then try the Bosch L4 Traction Wet Acid range.
We advise you avoid Gel batteries as the only real advantage of being 'Gas free' has now been catered for by the Bosch S5/Varta Silver Dynamic range.
However, the primary reason we advise a Wet Acid battery, apart from saving a lot of money and charging more quickly, is because in the majority of Motorhomes the Charger unit supplies both Starter and Habitation Battery.
If you have different technology batteries and the charger is optimised for just ONE, how can it be efficient in charging the other?
We have a lot of people complaining the Starter Battery doesn't charge properly, 9 times out of ten they have a Gel Habitation battery with the charger optimised for the Gel Habitation battery at the expense of the Wet Acid Starter battery.

If your battery is twice the age of the warranty, we strongly suggest you replace it. Be wary of some manufacturers giving budget batteries a longer warranty than they deserve, in our experience they are not honoured.

TESTING
All the time we hear, "well if you think the battery is past it, I will get it tested". You can't easily test a battery from the point of a specialist Leisure battery charger. We have not seen a Battery tester yet that measures how hard a battery is to charge and the load it places on a charger unit.
The Battery test meters currently being deployed check the amount of power left in a battery which is completely different.
If your charger has failed because of a Battery past its best, the battery won't take long to do the same with the replacement/repaired charger unit.

One recent Motorhome owner with 6 year old batteries (which he described as "perfect") came to us for a charger repair after just spending nearly £600 at the Mercedes Dealer having a new Alternator. He could not see the link between the two different charging systems failing and the common element the Habitation Batteries.


BOSCH S5/VARTA SILVER DYNAMIC WARRANTY
Most battery warranties guarantee to replace the battery if it 'fails'.
At 24 months old a 3 year warranty battery might be only half as good as when it was new (taking twice as long to charge and using twice as much electricity) but if it hasn't actually 'failed' its not covered.
The Bosch S5 Warranty is not about guaranteeing it won't fail inside 5 years, but guaranteed to perform at its best for 5 years, this is very different to most other warranties. Bosch/Varta are so confident of the battery capability it is guaranteed to be maintenance free for 5 years.
Think about that for a minute, its got to be one heck of a Wet Acid battery to not lose any fluid in 5 years.
To achieve that, the internals of the battery have to be working to specification right to the end, no internal corrosion, no plate failure. No faults at all that would cause loss of fluid.

Even if you ignore everything else that Bosch claim for their battery, that Warranty is confidence in a product that can only be very special because no other warranty we have seen comes close.
The Warranty really is 'a promise' that the battery will be as good as they say. Bosch are a big company, with a very big, quality reputation.

However, if you expect any battery to last 5 years in a Motorhome environment, which is probably one of the toughest there is for a battery, you might be expecting a bit too much from something that only cost you £87!!

We would be interested to see a battery comparison that evaluates batteries 'over time' as this is very applicable to our community.
We have seen some Marine battery evaluations on different batteries and technologies but they tend to test a battery by repeated Charge and Discharge cycles over a short time to simulate it's life. These evaluations ignore the fact that most Batteries corrode internally.
This corrosion doesn't build up with use, but over time. A battery with a very high number of Charge/discharge cycles might look good on paper, and even perform really well if run down and charged back up every hour of every day for 6 months. But if internal corrosion is high it will never reach anything like it's potential of use over a longer period of time.
Conversely a battery with low internal corrosion, maybe because of it's technology, might easily outperform a supposedly superior battery once past 2 years of age.
The Varta Silver Dynamic/Bosch S5 start brilliantly and just go on performing well to the end.




We don't have any affiliation to Bosch or the suppliers mentioned above, the examples are the best we can find to illustrate a point. We would welcome all feed back, stronger technical content, more information on suppliers and battery manufacturers using advanced technology.
Just a reminder that we do not sell ANY Batteries.

Remember when replacing batteries, we recommend that ALL the batteries in the bank should be the same age, capacity and technology. The battery bank should not exceed the design capabilities of the charger. Please see item 12 on the Solar Hints and Tips page for more info on how big a battery bank can be. Battery Bank Sizing Item 12
DO NOT USE BOSCH S5/VARTA SILVER WITH A BATTERY TO BATTERY CHARGER LIKE THE STERLING B2B or CTEK. See below for more information.

We are getting a lot of feedback from some who insist you can't use a Car Starter Battery as a Habitation Battery because the Battery Plate construction is completely different between the 2 types. One such person was adamant that a Starter Battery cannot be used in the Habitation area. When we asked him what battery he used he said a Numax CXV XV27MF XV.
This battery is listed as a Dual Purpose Leisure and Marine STARTER Battery, according to Numax this battery can be used as a Motorhome Starter AND Habitation battery. Almost all the big Battery manufacturers now have a Dual Purpose Battery based on Starter Battery construction, so people have been using them a while, contrary to the advice on the forums.
Most dual purpose batteries are basically a Starter Battery with higher capability than was possible 5 years ago. However, we would not recommend you fit an ordinary Starter battery as a Habitation battery. The Bosch/Varta range with its unique Powerframe Plates is very special because its plate construction gives the benefits of both a Starter and an old style Leisure battery. Because the technology is Patented, no one else can copy it. Yet this is only one of the Varta Silver/S5 many special features that really do make it unique.



Car and Leisure battery differences
The Leisure Battery was originally designed to cope with a long slow drain over many days.
A starter battery is designed to deliver a large current to start the engine.
Back in the 1970's battery technology was pretty similar between the two types but the construction was quite different to handle the differing demands. This meant that if you used a Leisure battery to start a Car, the leisure battery would be worse for wear afterwards. Likewise if you ran a Starter battery down very low over several days it would also suffer.
These days Leisure batteries are often little different in construction to budget Car batteries, primarily because Car battery construction has advanced so much in the last 10 years.
There are still true Deep Cycle or Traction batteries around but they are very, very expensive and the 'real' ones are usually 6volt and often American in origin. For example the Dynac Leisure battery range can be discharged down to 50% of the batteries rated capacity. But the Traction Battery range can be discharged right down to 20% of Capacity without suffering damage. The cheapest Traction battery in the Dynac range is £380. It's a 6volt so you need two at a wallet busting £760!!
Of the ones available in the UK, the Bosch L5 is probably the best known traction style battery. The advantage of the Bosch L5 is that you can run it down lower (a Deeper 60% Discharge) without battery damage, however the majority of sophisticated Motorhome Charger/Control units will shut off all power when the voltage drops below 11v, so you can't actually use the deep cycle capability.
We keep getting asked questions about this point, which seems to be totally lost on the industry pushing Deep Cycle batteries, so I will try and say it another way.
If your Motorhome has a sophisticated charger controller like a Toptron, Calira, Reich, Arsilicii, Schaudt (installed in more Motorhomes throughout the world than almost all the other charger/controller units added together) it will prevent any more power being taken from the battery once it drops below 11v to prevent battery damage. So if you have spent £700 on a battery that will safely Deep Discharge down to 8v, you will have wasted your money. In real terms, in a sophisticated Motorhome, a Bosch S5/Varta Silver will out perform a Traction/Deep Cycle battery with the amount of usable energy available. It has a greater Ah capacity for the same physical size, but it is so efficient it also has a higher voltage, typically 13.1v after resting.

The Bosch S5/Varta Silver Dynamic cannot match a Traction Battery for Deep cycling, but then it is 8 times cheaper. As a compromise on cost, quality, life and endurance we do not think the S5/Varta Silver can be beaten.

Inverters
A 3,000watt Inverter can draw up to 280amps (including conversion losses) from a 12v battery, as much as a small car draws to start the engine. It doesn't take much to realise that this is going to place an enormous strain on an old fashion Leisure battery that was designed to provide a just few amps over a long period of time. This type of usage will utterly destroy a true Deep Cycle or Traction battery in months.
If you have an Inverter, or any device that draws a lot of current in a short space of time, your Habitation battery should be more like a Starter battery in construction as this will be designed to provide a lot of amps. Once again the Bosch S5 will handle this abuse better than most, but do not expect ANY battery to last, a big invertor is a load few batteries can cope with for long. Even a car Starter Motor only draws its 250amps load for a few seconds until the engine starts.
Consider also the load this places on the Charger/Alternator, they have to put back all that power that was taken out, it is a load they were not designed to take.
Change in behaviour of some Charger/Controllers with Bosch S5 Batteries.
We have found the Bosch S5 has a resting voltage of around 13.1v as opposed to a conventional batteries 12.7v. This can cause a change of behaviour with some charger units, like the Calira chargers. These units monitor the habitation battery voltage and when it rises above 13.5v it assumes that the 240V charger has kicked in and they connect the Starter Battery into the circuit so it also gets a mains charge. The 'two connected batteries' symbol then lights on the panel. The Calira likewise monitors the Starter battery and when this rises above 13.5v it assumes the Alternator has started spinning and connects in the Habitation battery to charge this from the Engine. The Calira then breaks this connection between the two batteries when they drop down below 13.0v, which the Bosch S5 can take several hours to do. The 'two connected batteries' symbol stays lit on the panel until the connection is broken.
This change in behaviour can at first appear to be a fault, which it is not. However, it clearly demonstrates how much more energy there is in a Bosch S5. As an aside, the Calira Controller/charger will cut all power to the MH if the battery voltage drops below 10.5v. Clearly a battery that begins with a voltage of 13.2v is going to have a much more usable power range down to the cutout point of 10.5 v than a fully charged Leisure battery of 12.6v.
Caravan Motor Movers are more akin to a car starter motor in the way they place a load on a Caravan battery, budget Leisure batteries are not designed to handle such a load over several minutes with a resultant very short life. As a comparison the photo below shows a Powrtouch Model 1 Electric motor on the right next to a Audi A3 Starter motor on the left. As you can see the Audi Starter motor is SMALLER and spins for seconds to start the car engine, the 2 bigger Mover electric motors will be spinning for minutes.
A conventional Leisure battery is just not designed to handle the load of these Electric Motors, expiring very quickly. The failing battery then overloads the charger causing that to fail prematurely.


If your Caravan has a Motor Mover then we recommend you fit a large capacity Bosch S5, it is designed to handle such a load. If your Caravan has 4 electric motors the load on the battery will be even greater so we suggest you consider two large habitation batteries to share the load.
Many of the Motor Mover problems we see are Battery related.
STERLING B2B FAST Chargers
Battery to Battery chargers can be used with limited success in many British made Motorhomes that generally have less sophisticated Charger/Power distribution units. However, they are generally not a good idea in Continental built Motorhomes as these have much more sophisticated Electronics with many more features such as inbuilt Battery to Battery charging with Voltage Boost technology.
Products like the Sterling B2B Force charge the batteries at a higher rate than they were designed for.
The Schaudt/Calira/Toptron/Reich equipment already charges the batteries at the maximum recommended by the battery manufacturer and within the limits of the Alternator/wiring.
Control units like the Schaudt Elektroblock EBL 220 are a sophisticated power feed system, not just split charger.
It already contains voltage boost technology to charge the Habitation battery from the Alternator faster than most other units on the market, but it does it at SAFE levels that follow the Battery manufacturer guidelines.
It already charges the Starter Battery from both Mains 240v and Solar so you don't need the Battery Master style product that are sometimes a good idea on the British built Motorhomes.

The Sterling B2B publicity, see : http://www.sterling-power.com/products- ... t-info.htm, says "it will fool the alternator into working at its MAXIMUM ability, this will ensure all its surplus power is used to charge the auxiliary battery bank to its maximum". Ask yourself when it has ever been a good idea to take anything to the maximum?

It then goes on to say, "Other features included in this system include alternator temp sensing, battery temp sensing". Why is there is a need to monitor the Alternator temperature? The reason is there is a risk of it being burnt out by the strain of the B2B. To run an Alternator to the very brink that it can overheat and be damaged IS pushing things to the MAX.
To my mind, too far.
However, at sea where these units are designed to operate, it is the only option. Therefore the compromises of short battery and Alternator life are usually acceptable.
Boats often have two Alternators, one dedicated just to charge the Habitation batteries. As a result it is often a very heavy duty item built for the purpose.


These after market Battery to Battery units often 'Fast Charge' the Batteries at a higher rate (14.8v and high current) than the Battery manufacturer recommends, as a result they will give off dangerous gas and require regular topping up. PLEASE DO NOT USE A STERLING B2B STYLE CHARGER IF YOUR BATTERIES ARE INSIDE THE HABITATION AREA UNVENTED.
DO NOT USE BOSCH S5 or any AGM battery with a B2B, the batteries will be destroyed in months.
The Sterling web page states, "For best effect use Open (with removable filler caps) Lead acid batteries : avoid Gel, Sealed and AGM Batteries".
Gel Batteries
Conventional Gel Leisure batteries (we are not talking here about AGM technology) are basically conventional LA battery construction but the acid is not in a liquid form, it's a Gel that won't leak out. Very useful if you like to tip your battery upside down on a regular basis. The downside is that the gel doesn't allow heat generated in the charge/discharge cycle to dissipate so fast, so they must never be 'fast charged' at high current or the risk of explosion is very real. Some gel batteries have a maximum trickle charge voltage of 14.1, and many require a lower charging current, hence the need to switch your charger to a slower charge rate. However, when charged from the Alternator in a Motorhome, or the towing vehicle in a Caravan, the charge rate is often too high and the charge reduction units that should be fitted for Gel batteries are often omitted.

Gel (and AGM) batteries are usually more efficient than the average Wet Acid battery so often require less input power to to charge the battery to full capacity. However, while a Gel battery requires less energy because of its greater efficiency it can only be charged at half the current (approx) of a standard battery so still takes longer to charge overall than an average Wet battery.
The Bosch S5/Varta Silver, because of its Improved efficiency, will recharge almost twice as fast as a Gel/AGM battery, particularly as the batteries age. A crucial consideration for many Wild Campers who only have short journeys between stops to replenish the power used the night before.
The biggest advantage of Gel batteries was that they tended to produce less hydrogen gas and required no topping up. However, modern maintenance free batteries like the Bosch S5/Varta Silver Dynamic are now sealed so well they don't vent gas or require topping up. The Bosch S5 has a gas trap that prevents any evaporated fluid from escaping so no fluid is ever lost.
Therefore as Gel batteries are more costly and no longer have any real advantage over a S5 battery we suggest you avoid Gel batteries as the risks are real but without any advantage. If you switch from Gel batteries to Bosch S5 Wet Acid don't forget to change the Battery charger from Gel to a Wet Acid setting WITHOUT the MAINS HOOK-UP connected.
A & N Motorhome and Caravan Services do not profess to being experts in battery technology. This should be borne in mind when reading the above which is designed to stimulate the reader to do their own research.

Example battery types and sizes:
The Bosch S5 010 is 315mm long, 175mm wide, 175mm high. 12V, capacity 85Ah, cold test current 800A (sometimes called cranking amps). Cost as of May 2012 = £87.50. (VARTA equivalent SD F18 @ £82)
The Bosch S5 013 is L - 353mm W-175mm H-190mm, Capacity 100ah, 830A CCA, Cost £98 (VARTA H3 SD 019 @ £87)
The Bosch S5 015 is L - 393mm W-175mm H-190mm, Capacity 110ah, 890A CCA, Cost £110 (VARTA SD 610 200 @ £93) This is a very capable cost effective battery but may be too long for many battery boxes.

Lucy Cranston says, "to fit the Varta Silver i1 or the Bosch S5 110ah - I have used Stainless Steel Bar drip trays 400mm x 200mm ".
That idea appeals to me a lot, Stainless Steel Beer Drip trays for a Battery tray! Great idea.
Try this supplier :
http://www.fridgefreezerdirect.co.uk/dr ... wwodSA8AZw

Note that Exide G80 Gel batteries often fitted in a MH are 353 x 175 x 190 (incl. terminals) so a match for a 100Ah S5013, Varta H3 (information courtesy of David Chambers).


for running chargers or lights go 12v car plug in charger type things far more efficient same with lighting go 12v led

my led lighting project
viewtopic.php?f=38&t=10935

http://www.ebay.co.uk/itm/5M-300-LED-St ... 234085fbae

and charging small appliences off a 12v battery:
Image


as for what can the inverter run ... look on the ratings plate of your appliance and the inverter....

a 300w inverter will run a load of 300w and in my case draw about 35 a from the battery at max loading.. run less off it it will use less power


be aware of moddified sine wave inverters they lead to RF noise issues with tv and radios and can make some motor types and tranformers run hot..

i much prefer pure sine wave
If your roughing it, Your doing it wrong ;)

Lack of planning on your part doesn't make it an emergency on mine
Yorkshire Andy
Posts: 8733
Joined: Thu Oct 03, 2013 4:06 pm

Re: Budget backup / 12vdc and 240vac power supply

Post by Yorkshire Andy »

Added a £10 battery power gauge over the weekend so i can see at a glance how much charge is left

Image

wired between battery live and negative with the switch wire to the load side of the inverter isolator switch
If your roughing it, Your doing it wrong ;)

Lack of planning on your part doesn't make it an emergency on mine
User avatar
DustyDog
Posts: 302
Joined: Fri May 23, 2014 7:23 pm
Location: Cumbria

Re: Budget backup / 12vdc and 240vac power supply

Post by DustyDog »

Thanks for all that Andy, i live in a very rural area and winter is coming, so want to make sure i can keep as many things running as possible.
Up in the wet South Lakeland