Hi David, how do you normally charge them or how are you thinking of charging them.
By a battery charger, your vehicle’s alternator or by your boat’s alternator?
They are used to drive a refrigerator, most of the time.
David
Hi David, how do you normally charge them or how are you thinking of charging them.
By a battery charger, your vehicle’s alternator or by your boat’s alternator?
driveon,
Charged by M.V alternator, is the idea.
David
Why would it matter according to yourself 2 unmatched batteries will charge and discharge perfectly and have a full happy life performing to their manufacturer specs???. Sorry except if you have a high current draw?
They will self regulate, not overcharge, not get hot,, not boil, not sulphate, not bulge the cases and be accepted for a warranty claim.
Hi David, your vehicle alternator will give you your best charge when wired direct to the two batteries wired in parallel, via an ordinary isolator and use decent sized cable to connect everything together.
6B&S twin ( 13.5mm2 x 2 ) cable would be the best to use and I take it that with two batteries, they are going to be mounted somewhere other than the engine bay. This size cable will be perfect.
If the batteries are in your vehicle all the time, when ever you set off on a trip, the batteries will already be fully charged and there is no need to do any maintenance, your alternator takes care of that.
In normal use on a trip, if you don’t use all that much auxiliary capacity, you will probably fully charge the auxiliary batteries in a couple of hours driving.
If on the other hand, you use a fair bit of power, you are probably not going to fully charge them unless you do 5 or 6 hours driving ( depending on how low they were when you started driving ) but with an alternator, you will replace more used capacity than you can with any other device, so in the long run, your batteries are going to be in a better state at the end of a drive.
Hope that all helps.
Nothing like a bit of scare mongering when you can’t put up a civil argument.Originally Posted by cormorant
When a vehicle is wired properly, none of this happens.
arguement?
So far you have not answered the Physics, chemistry, manufacturers recomendations, others experience in much higher tech solutions where results have been measured. Instead you have done short replies with no information or backing and avoided the points that have been made.
Yep it will work but it has risk and also will reduce the life of the batteries.
What you are saying is that you have got away with it and you or your clients are satisfied with the life and performance of their batteries - hardly scientific or a real measure.
Now you are saying if it is correctly wired it will overcom eany issues?
So you have never had batteries bulge , cook etc?
I love statements like this, especially when they are made by people who don’t have any hands on experience, just want to make people think they have some.
You have done nothing but make statements based on your own mythical theories because, as posted above, these problems do not occur like you keep trying to make out.
Do they happen, sure do, but not when systems are set up properly in the first place and unlike you, I work in this industry and work with these set ups and have done so for over 20 years, and the only time I see problems like what your trying to make out are common place, only occur when unsuspecting people take notice of self proclaimed experts, who usually have absolutely no idea of what they are talking about, but think they have the right to lecture others on how they PERCEIVE set ups should be.
David's questions have been answered based on tried and proven practices, but you are of the opinion that he is going to have all sorts of problems.
The problem with your theories is that there are thousands of others using exactly the same set up and not having any problems at all, getting long operating lives from both their cranking batteries and their auxiliary batteries, using them as they need them, which proves your theoretical problems are just that, MYTHS.
What in your system prevents any of these issues happening?
How could the idea of having matched batteries make it any worse?
System - so far all I have read is wires and a alternator - what's your system . What's properly installed?
What you are doing is a compromise and depending on batteries used will have various results.
Pretty much wasting time here if you can't put forward anything and answer questions.
EDIT
"" The problem with your theories is that there are thousands of others using exactly the same set up and not having any problems at all, getting long operating lives from both their cranking batteries and their auxiliary batteries, using them as they need them, which proves your theoretical problems are just that, MYTHS."
No you and your clients just don't have the skill, tools or ability to measure them so you ignore them as in your situation you can't see the financial or safety benefit. You will get away with it with some battery combinations and get reasonable Ok performance, others will be poor and others downright dangerous. All your experience has shown you is OK combinations. It is wrong to say across the board to combine batteries of any sort as there will be issues in many combinations.
This one is simple to answer so even you can understand, they are installed properly in the first place, using the correct materials.
Not once have I posted that using matched batteries would make it any worse. This is just something more you've made up.
Again, NO, it's not a compromise, what I’m doing is best practice installations, and if you actually worked in this section of the RV industry, and had some hands on experience, you would know that a system comprising of no more than correctly sized cable and an alternator and a conventional dual battery isolator, is not only the simplest set up but is the most efficient, most reliable and MOST effective way to charge batteries in a vehicle and to keep them properly charged.
You keep making statements like this but have no evidence to back it up, again mythical theories
The original suggestion was that the two batteries be hard wired together without an isolator.
Hi fox and yes there should be more detail in what I posted, in that the isolator is only intended to protect against accidentally draining the cranking battery so low that it could not start the vehicle, but otherwise, the isolator really doesn’t have anything to do with what batteries are use in any set up.
BTW, I am referring to my own brand of isolators.
The isolator will also be handy when one of the batteries fails ;-)
Definitely an additional advantage but this still comes back more to being able to start the vehicle than any form of protection for the batteries, similar or dissimilar.
The argument has been that putting two batteries together in a parallel set up is going to cause problems. I base my argument not just on single vehicle set ups but where batteries are installed in a camper trailer or caravan, where dissimilar batteries can be mounted side by side and connected in parallel.
I’ve heard heaps of THEORIES on different web sites and forums but not once in all the years I’ve been working with these set ups have I seen or heard of an on going problem because anybody has wired any batteries in parallel.
You will obviously get the occasional battery that goes flat and take the other battery with it, but in most cases, the second battery can be recharged and not suffer from any long term problems.
This is not always the case, but it is very rear that both batteries fail. To be honest, I have heard of more batteries being stuffed while charging them with a battery charger and not just by cheap charger either.
Don’t get wrong, I too, after reading some of the hype posted and printed, use to think that paralleling dissimilar batteries would pose some form of problem and instead of looking more into it, would often simply advise my customers not to mix battery types.
AGMs have only been readily available for the RV market for a little over 10 - 15 years.
After a while, I was getting feedback from customers who had been running dissimilar batteries for a good few years and were having no problems, so I started carrying out my own tests and as posted REPEATEDLY, based on first hand experience and loads of feedback from many customers, I have yet to find a problem with paralleling dissimilar batteries.
Cheers.
[quote]
Using a battery charge is a little different but you can not fully charge one battery while any other battery in the set up is low. The lowest charged battery will draw the greatest portion of the battery chargers current ( if not all of it ) until all the batteries are about the same SoC and then the voltage will rise evenly over all the batteries.
Hi All,
Sorry to throw a spanner in the works, but this statement is wrong.
Batteries have what is called "Internal Resistance", and the amount of internal resistance is related to the battery's state of charge.
A FULLY CHARGED battery has LOW internal resistance, and as the battery discharges, it's internal resistance INCREASES.
Therefore, if you try to charge two batteries in PARALLEL, the battery with the higher charge offers a lower resistance to the flow of current from the charger, and therefore will take most of the current (charge).
If you want to charge the flatter battery to bring it up to the more fully charged state of the other battery, you should charge them separately or use a Voltage Sensitive Relay, which in effect does the same thing automatically.
Richard.
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