BATTERY FAILURE

Hi Ian....can you explain the low versus the high recombination batteries ??

I have had 2 KK campers and have had no problems with the small Exide 35a/h batts.....either by charging via the 3 stage charger in it or by the 4x4 alternator..

Although I would agree that the size of cabling between batts could be bigger (as well as the feed from the plug ) , to be honest I haven't checked charge voltages because it gets fully charged via the 4x4 when travelling ( although time could be shorter if the cabling size was bigger )....from approx 12.1V to 12.8V over approx 5hrs of driving..

Why are 6 x 35a/h batts versus 2 x 100a/h batts inefficient ??

And a good charging regime is a must.....I always put it on charge as soon as I come home....and for the rare times that I don't go away....every 3 to 4 weeks thereafter.....and been away over 70 times with both KK's and never had a problem with batteries..

Gronk

I tried earlier to post a response but took too long and was timed out and lost what I had done.

The more batteries in that are paralleled the more chance of problems and inefficiencies.

Larger batteries and smaller quantities are better.

Batteries in series are the most efficient so two 6Volts are more efficient than two twelve volt as they work together to reach a terminal voltage where two supposedly equal batteries fight each other for charge and one will win with the other suffering a charge deficiency which continues to compound eventually causing premature failure.

Most Asian sourced AGM batteries are low recombination batteries where Good AGM batteries that are high recombination are of USA origin.

This is reflected in the price as high recombination is expensive.

A high recombination battery is low resistance and although voltage limited can accept high amperage and charge faster to a higher voltage than low recombination batteries.

Low recombination batteries have a higher resistance and are limited in the recharge capacity that takes longer to charge and running time is money.

The sooner a battery is charged the sooner the alternator cuts load and the economy of the vehicle improves.

A high recombination battery with correctly sized cables is efficient to the point that the use of units like the Ranox and other wide ranging acceptance voltage smart chargers strangle the alternator where a battery is discharge to 50% due to their limited output amps and a smart charger should be able to use whatever the alternator has in reserve capacity.

The marine industry is one that the efficiency is critical and its one that we specialise in and our work is gleaned from referrals as we do not advertise.

People talk and everywhere a yacht docks fitted with Sterling or ProMariner equipment it usually means we get a request for information and in the last week we have had calls from Vanuatu,Noumea,Cairns, Townsville and Port Nelson New Zealand.

It is now starting to happen in the land RV industry so it must mean something is working efficiently.

Ian

Further to my post above.
Mikes advice is good and if followed should show your inefficiency.

I have developed a cable chart that goes from 10GGE to 2GGE from 5Ft to 20Ft and from 20A to 50A.

For example if you have a 20A supply at 20Ft with 10GGE you will have a voltage drop of 0.822V.
With 8GGe cable you would have 0.517V drop.
With 6GGe cable you would have 0.325V drop.
With 4GGE cable you would have 0.204V drop
With 2GGe cable you would have 0.129V drop.

0.36Volt drop is an acceptable industry standard but if you have an alternator only putting out 13.6V deduct any of the above voltage drops and see how you are going which should mean not real good at charging.

Ian

"A high recombination battery with correctly sized cables is efficient to the point that the use of units like the Ranox and other wide ranging acceptance voltage smart chargers strangle the alternator where a battery is discharge to 50% due to their limited output amps and a smart charger should be able to use whatever the alternator has in reserve capacity. "


Sorry. I don't understand what you're saying here. Can you explain please.

If an alternator has for example a spare capacity of 50A and the battery is of low resistance and high recombination can accept 50A and the voltage produced is above what the battery requires to improve SOC why would you fit a unit that has an output limited to say 25A and strangle the potential of gaining the other 25A.

The advantage of smart charging is gleaned where the voltage produced by the alternator and voltage drop can be exceeded and the spare amps fully utilised.

Ian

Top stuff Derek, you make some very valid points worth noting.

Derek,

Re: "The one other problem they will have is the fridge on the camper is possibly running off the camper batteries while traveling. This prevents the batteries from fully charging too"

My thoughts are, when using a 12v compressor fridge running on a duty cycle of 35% "running" and therefore a 65% "off" time period, the Camper battery can then be (fully) recharged in this 65% 'off' time period.

Maîneÿ . . .

Hi All
Family members presently in Katherine. I sent them an SMS also suggesting they log onto this site and check this thread. Great work people. I'll know where to seek advise given similar circumstances.
Many thanks
Doug and Jane Hinton

After talking to a KK dealer....it seems most of the battery problems stem from lack of understanding about battery maintenance...After being charged....AGM's will stay that way for weeks or months ( IF they haven't got anything connected to drain them )...but it's when the camper sits for longer than this ( shame on them for not using it !!! ) that problems start...

But for the normal lazy, don't care or ignorant( about batteries ) person, yep...leaving it permanately on charge is the best way...

Gronk
A KK dealer is to be beleieved .

Some time back on a return tripo from Brisbane I called at the KK factory and was shown the KK setup.

I told them I could improve it and it turned out they were not prepared to pay the cost for efficiency that I offered .

One statement that came from the owner who I was led to believe as being an Electrical Engineer said he was worried about sulfation of batteries when travelling.

I was over my head with such a qualified person making that statement so I left rather confused at my ability to be so dumb.

Ian

As I understand it, a major advantage of quality AGM's is they don't suffer from sulphation, as wetcell batteries do

Maîneÿ . . .

Mainey
All lead acid batteries can eventually suffer sulphation whether they are open flooded sealed flooded AGM or Gel but the longer the declared shelf life the higher the ability to withstand it.
Ian

Ian,
yes, I should have 'edited' my post for clarification, as AGM (Absorbed Glass Mat) technology is a process where the electrolyte is held in glass mat separators between lead plates, as compared to a flooded cell battery, where the electrolyte is a fluid sloshing around and only contained by the case.

AGM are known as starved electrolyte batteries or dry cell batteries, I understand they will not leak if the case is split (there is no fluid in the battery)

This is NOT the case in cheap budget priced, elcrappo AGM's.

Maîneÿ . . .