Hi All, We have a 2001 winnebago leisure seeker on a mazda t4600 and find our house batteries ( 2 )are not retaining charge for long ( hours ) .Will charge up to 14 volts from alternator and 240v but run down rather quicker than when we first bought the unit ( bout 15 months ago).
Have found previous owner installed sealed heavy duty batteries ( lead - acid ) from RAC in WA ?? they seemed to be fine for occasional free camp of two days but appear now to be cactus.... Also installed is a Mastervolt charger ( IVO SMART )(standard winnie ) which in the manual says it is suitable to charge both lead acid and is switchable for gel/wet battery ?? and can also be switched to " forced to float ".
As relative newbies to this wonderful world of travel we are a bit confused as to what batteries to replace them with and really don't trust your average sales guru at the local battery emporium.Believe Deep Cell and / or AGM are the way to go,any advice would be welcome!! Would like something that will give us more free camping ability so are considering a solar panel to assist with charging.Not really keen on the idea of lugging around a gennie either. Also installed is a 300w inverter ( standard winnie )which has worked fine for powering LCD + DVD & laptop for few hours at night.
PHEW! Also if you know a trusted auto sparky in Adelaide for same also much appreciated as some of the caravan places here think your'e a millionaire if you have any type of rv.lol and thanks for reading !!
Do you have the two batteries connected in parallel. If so, this is the most likely cause of the problem of the short battery life. I would suggest that you replace the batteries with 6 volt types and connect them in series. If the batteries are (say) 100 ah each making up a total of 200 ah, you would replace them with two 200 ah 6v batteries to make up a total of 200 ah at 12v. (200ah 6v batteries would be a similar physical size to 100ah 12v)
Series connection means that the positive wire is connected to the positive terminal of one battery and the negative wire is connected to the negative terminal of the other battery. The two batteries are then connected to each other by connecting the unused positive terminal on one battery to the unused negative terminal on the other battery. (Not sure of your electrical knowledge so forgive me if you're already au-fait with this).
AGMs would be the way to go but if your budget doesn't extend to these, marine batteries may be an option as they are usually dual purpose starting and deep cycling and will usually recharge quicker. Alternately normal deep cycles would be fine and availability may be a deciding factor.
Regardless of the type of battery avoid totally discharging them and keep them recharged when in storage. AGMs generally are more tolerant to deep discharges but this practice should still apply. AGMs also "hold their charge" longer in storage. Anyone who insists on paralleling batteries should disconnect them from each other when in storage or alternately budget for more frequent battery replacements.
Re Auto sparkies, it's been my observation that some are not all that familiar with dual battery systems, you'll need to "sus" this out.
-- Edited by jimricho on Friday 3rd of June 2011 06:12:41 AM
Hi Jim, Thanks for your reply,is most helpful if not confusing as electrical stuff to me is like chinese! Believe batts are in parallel, if I change it to series will this require rewiring of the charging and metering circuits ? Will I have to buy another charger for 6v batts.? Not as simple as just replacing a car battery.Will shop around for a knowledgable sparky as don't want to fiddle with stuff I don't understand, from bitter experience better off paying someone who knows what they're doing! Marine batteries sound like a good thing and your advice regarging storage is welcome as van sits for couple of weeks ( no power at storage ).Have been starting up engine and idling at 1000rpm to charge batts.Is this enough or does it need to be driven for a reasonable distance to charge .( Think charger is 25A/H ).Would A solar panel help with maintaining charge in storage ( in open yard )?Cheers.
I had always been told to get a Deep Cycle battery but while up north I was told by a number of travellers to get a Supercharge All Rounder for the house battery. They all said they are cheaper than a Deep Cycle, can go down lower in charge and are much quicker at charging back up again. One chap also told me a good small truck battery is better than a lot of them. Hope that helps some.
Hi Jim, Thanks for your reply,is most helpful if not confusing as electrical stuff to me is like chinese! Believe batts are in parallel, if I change it to series will this require rewiring of the charging and metering circuits ? Will I have to buy another charger for 6v batts.? Not as simple as just replacing a car battery.Will shop around for a knowledgable sparky as don't want to fiddle with stuff I don't understand, from bitter experience better off paying someone who knows what they're doing! Marine batteries sound like a good thing and your advice regarging storage is welcome as van sits for couple of weeks ( no power at storage ).Have been starting up engine and idling at 1000rpm to charge batts.Is this enough or does it need to be driven for a reasonable distance to charge .( Think charger is 25A/H ).Would A solar panel help with maintaining charge in storage ( in open yard )?Cheers.
Hi John,
There are two ways that batteries can be connected, they are known as "series" and "parallel"... Lets call the batteries "A" and "B"....it may even help to make a little sketch of how I describe the connections.
As you're aware a battery has two terminals (the posts where the wires connect). One is the positive, the other negative. It is important that the correct wire be connected to the correct terminal, usually the positive wire is red and the negative black but note that other colours may be used. The terminals are marked usually with a + and - signs.
Firstly, Parallel connection.... The two positive terminals are connected to each other and also to the positive wire going to the rest of the system. The two negative terminals are likewise connected to each other and to the rest of the system. By connecting this way the voltage of the combination is the same as the voltage of the individual batteries but the capacity (amp hours) is the total of the two batteries. eg.. two 12volt 100 amphour batteries so connected will give 12 volts at 200 amp hours.
Secondly, Series connection.... The positive wire going to the electrical system is connected to the positive terminal of battery "A" and the negative wire to the system is connected to the negative terminal of battery "B". The negative terminal of battery "A" is connected to the positive terminal of battery "B" When connected this way the voltage of the combination is the total of the voltages of the individual batteries. That is if two 6 volt batteries are connectied this way, the voltage of the combination going to the electrical system is then 12 volts. Note that if two 12 volt batteries are connected in series that the total will be 24 volts. Also note that if two 200 amphour batteries are connected this way the total capacity is still 200 amphours as it's the voltage not the amperage that's doubled.
To my surprise it appears that wiring batteries together in parallel is not uncommon in caravans and RVs but this is almost never done elsewhere, especially in critical applications such as communications facilities or where required as part of a back up power system, as it is considered not good practice to do so. Some battery manufacturers are giving the ok to parallel connecting AGM and Gel batteries subject to both batteries being identical in every respect. I personally don't favour this configuration as if one battery fails prematurely or even starts to deteriorate ahead of the other one it will damage the good battery (catastrohically in a worst case scenario) and one will not be aware of this until it is too late. When replacing parallel connected batteries both batteries must be replaced at the same time.
As "wet" (aka "flooded") batteries (any battery that's not a gel or AGM) do tend to deteriorate unevenly this will considerably reduce the life of the batteries and in practice this is almost always found to be so.
A 12 volt battery consists of six 2volt cells all connected in series (that's why wet batteries have six filler caps) to give 12volts. A 6 volt battery consists of three 2 volt cells connected in series so connecting two 6 volt batteries in series is just emulating a larger capacity 12 volt battery.
It is not highly critical to replace both batteries in a series connected battery bank at the same time but it is good practice to do so unless one of the batteries has suffered a failure early in its expected life. It is also good practice to use similar batteries.
Sorry if this post is a bit verbose but I feel I needed to cover it fully. I hope this helps, don't hesitate to ask more questions if you need to,
Jim
PS: I'll cover a couple of other points in your post in a separate reply as there's a bit here to absorb. Likewise your question Marj. (It's time for me to go a get a beer, that's why )
I had always been told to get a Deep Cycle battery but while up north I was told by a number of travellers to get a Supercharge All Rounder for the house battery. They all said they are cheaper than a Deep Cycle, can go down lower in charge and are much quicker at charging back up again. One chap also told me a good small truck battery is better than a lot of them. Hope that helps some.
I'm not familiar with the Supercharge All Rounder in a "hands on" sense but on checking their website it looks fine for the job. The truck battery recommendation is generally quite valid too, but may depend on the particular brand/model of battery. I think in general there's probably little between them and the All Rounder would be a safe choice.
Whichever battery you choose it is very important to avoid fully or near fully discharging any battery including deep cycle types.
Jim
PS: I'm not sure about the "can go down lower in charge" comment but the quicker recharge time is valid provided that the main and auxilary batteries are located not too far from each other so that the cable runs between the two (including the dual battery isolator) are kept short and are a reasonably large diameter ("gauge" in techie talk)
-- Edited by jimricho on Saturday 4th of June 2011 06:56:44 AM
Hi Jim, Thanks for your reply,is most helpful if not confusing as electrical stuff to me is like chinese! Believe batts are in parallel, if I change it to series will this require rewiring of the charging and metering circuits ? Will I have to buy another charger for 6v batts.? Not as simple as just replacing a car battery.Will shop around for a knowledgable sparky as don't want to fiddle with stuff I don't understand, from bitter experience better off paying someone who knows what they're doing! Marine batteries sound like a good thing and your advice regarging storage is welcome as van sits for couple of weeks ( no power at storage ).Have been starting up engine and idling at 1000rpm to charge batts.Is this enough or does it need to be driven for a reasonable distance to charge .( Think charger is 25A/H ).Would A solar panel help with maintaining charge in storage ( in open yard )?Cheers.
I'm back!
ok to answer a some questions...
1. Apart from the battery connections as described earlier there is no need to do any other wiring modifications to incorporate the series connected batteries. That said I think it's a good idea to have a "Master" switch that will isolate all the loads ("loads" is techie talk for all the stuff that is powered from the battery) when the rig is in storage. This is to ensure there is not some sneaky device(s) still drawing power and this suggestion applies regardless of the battery types or configuration.
2. Your existing charger will be fine for the job as the two batteries connected this way are just emulating a larger single 12v battery, in fact one of the biggest advantages of this configuration is that you're just creating a larger battery out of two without any of the complications of paralleled batteries.
3. The solar option... I have a mate who has a caravan that he uses mainly for bush camping and he has two 6v 200 ah batteries (series connected) and leaves his solar panel connected when when he's not using it. His batteries are ten years old and still ok. They are ordinary "wet" batteries, probably truck types. Note that in your case a regular run of the engine would still be a good idea to keep the starting battery alive and for other mechanical reasons.
Jim
PS: By the way if for budget or availability reasons you find you need to stay with the two 12v batteries let me know as there is an option available to overcome the disadvantages but it does involve switching from one battery to the other and is not as "neat" as the series 6v option.
-- Edited by jimricho on Saturday 4th of June 2011 06:25:18 AM
Hi all, thanks for all good advice have replaced batteries with 2 deep cycle wet batteries.Can recommend Dominic at Modbury Battery Service who is very rv knowledgeable could have sold me expensive gel/agm batteries assured me deep cell wets were the way to go to keep it simple can be charged once a month in storage by any basic charger. See how we go ......
If the rig is kept in storage (I think you said it was but I haven't gone back over the previous posts) my suggestion is to remove them and take them home, mainly for convenience. Most "boaties" do this with their boat batteries when (if) they lay up in the off season. This also ensures there are no "sneaky" loads drawing current from the batteries.
As your battery man said, a basic charger is fine on wet batteries but don't leave it connected indefinitely unless it is the automatic type that switches to "float" charge in which case check the liquid (electrolyte) level regularly. In any case check the level before recharging.
You didn't say whether they are 6 volt series connected or 12 volt parallel connected. if the latter don't leave them interconnected when not in use as this can reduce the lifespan of wet batteries. I've had personal experience of this happening. Fine to leave 6v series interconnected when not in use, in fact you'll need to leave the 6v series batteries interconnected to charge them from a 12v charger.
cheers,
Jim
PS: Your battery man has probably briefed you on this stuff but I mention it just in case and for the benefit of others reading this thread.
-- Edited by jimricho on Friday 17th of June 2011 06:11:19 PM
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