Yet another battery question

[Guest Peter James]

hallii - 2014-12-07 6:58 PM

 

I would do it by connecting the two batteries and leaving them for a few minutes. The good battery will put enough charge into the flat one to allow a start.

 

H

 

As I understand it, lead acid batteries are only about 50% efficient. So if you try to charge it from your only good battery, you would be losing half your power at the time when you need all you have got

[aandncaravan]

rupert123 - 2014-12-24 10:33 AM

 

Fair enough, although I still reckon a pair of Varta's will work just as well given the way the charging system works on a lot of modern motorhomes.

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Rupert, I think you have nailed it exactly.

 

What a difference 4 years make!!

 

The Banner batteries 'best in the world' hype has been shown to be anything but.

The Varta Powerframes have built a good reputation.

Lenny's AGM batteries did expire, sooner than was expected.

 

While cycle life is important there are so many other factors that affect how a seemingly lower cyclic rated battery can outperform a Gel battery in the real world.

For example if a Gel battery takes twice as long to charge, there is a greater risk that it won't get fully charged before the next use. That may lead to premature sulphation and deterioration.

But worse still, if the owner thinks it has had time to fully recharge and uses a correspondingly high draw, it may end up more deeply discharged than the owner realises.

Again with shortened life.

 

If the Motorhome usage tends more to high current draw, that will again disadvantage a Gel battery.

If the temperature operation is in warmer climes, again a 'High Cyclic' Gel could end up with less cycles than a battery half the price.

And lets not forget that a Gel battery can cost more then double, so should have double the life. I think it is more cost effective to run 2 cheaper batteries, one after the other, that not only reach the cyclic figures but better them.

 

Just as a Gel takes longer to charge and may spend more time 'part charged' and not reach it's cyclic potential, so a Varta Powerframe is more likely to work the opposite way. It will full charge more quickly than a conventional wet battery, therefore not discharge so deeply when it is used from Alternator or Solar. Those shallow cycles will result in more cycles.

 

The Varta technology will reach it's potential even in the temperatures of Morocco and the higher current draws that are a modern motorhome, with a trillion more 12v gizmos than were around 10 years ago.

 

 

I am not flag waving here for Varta, just saying that people get so hung up cyclic capability that they don't even consider the cost let alone other relevant factors.

One recent emailer was adamant that a 350 cycle battery at double the cost of a Varta was a better option and berated me for our web pages.

It is likely that in real world use, 2 x Vartas installed one after the other would have delivered 450+ cycles for the same money as a single 350 cycle conventional, high corrosion, water consuming battery.

The 350 cycler wasn't a bad battery and while it might reach 350 cycles in a laboratory, it's construction was such that corrosion, etc would have resulted in fewer real world cycles.

 

 

There are new EFB, wet acid, technology Leisure batteries that are about to enter the market that are so good they are even ousting short life AGM batteries in cars.

The Yuasa L36-EFB being an example, not evaluated it yet but the technology should mean it outperforms it's paper spec by quite a margin. It's paper spec looks very good.

 

Banner have a new battery coming out that performs well in the lab, lets hope it is better in the real world and doesn't use old fashioned, high Antimony technology like the old batteries.

 

 

Fingers crossed, the EFB technology should usher in the new era of reliability and usability in batteries that AGM promised but never delivered.

With EFB being Wet Acid technology it should be very price competitive without the need for the special chargers and Alternators that AGM needed.

 

 

 

 

 

 

 

 

 

 

 

 

[Guest pelmetman]

As a Varta battery owner x 3 ;-) ........

 

I have yet to run it flat and all our gadgets charged up (in turn) by our inverter whilst taking 10 days heading to Spain without hookup B-) ......

 

The interesting test will be in October when I collect our caravan from storage in Spain :D .......and I'll find out how well its held it's charge after 7 months when I use the motormover to get "Cynthia the Carlight" on our pitch 8-) .....

 

If it's flat at least I'll have 2 spares B-) ..............