Buying a new gennie

[Boristhemoggy]

kevina - 2015-08-15 10:11 AM

 

There is some magic here!

 

1. Please explain how a Varta silver dynamic charging from a 15A charger is going to accept twice the charging current as any other wet/agm/gel battery. Where is this extra magical extra 15A coming from? Or are you suggesting that the others will only accept 7.5A or even only a 5A charging rate?

The very last 10% might be quicker but the vast majority of owners who need to charge depleted batteries are only really interested in the bulk charging rate.

 

2. Then you say don't fit a varta silver dynamic in conjunction with a b2b charger because it WON'T accept the higher charging rate!?

Well my gel batteries are specified to accept a C5 charging rate even without temperature compensation, thats 44A (from b2b) into 2 110Ah batteries.

 

Which is it?

 

Kev

 

ps. to save anyone else looking there is NO documentation by either Varta or Bosch that actually gives silver dynamic charging rates, deep discharge cycles (not even medium discharge cycles come to that) nor any other hint that it can be used as a leisure battery. It is not even a stop/start battery, it is just a very good quality starter battery.

 

 

From http://www.autostuc.be/Documents/Varta%20automotive.pdf

 

Note 'quick charge'

 

The charging time

falls proportionately with the rise in the current the

battery can supply (e.g. when the current is doubled

to 8.8 A, the charging time is reduced by half to 1.35

hours).

Overcharging is to be avoided at all costs, however,

as it leads to permanent battery damage.

 

Varta, silver dynamic charging rates:

 

 

2.3 Recharging recommendations

Should the terminal voltage drop below 12.5 V, the

battery must be recharged. The recommended

charge current equates to one tenth of the battery’s

nominal capacity (e.g. 8 A for a battery with a

nominal capacity of 80 Ah). How long the battery

needs to be recharged depends on how it’s going to

be used afterwards. If the battery is going to be

installed immediately in a vehicle, a short recharg-

ing period is generally suf?cient to prepare it for use

(i.e. a terminal voltage of between approx. 12.2 and

12.5 V, measured approx. one hour after the re-

charging period is complete). If the battery is going

to be stored for a further period, then a maximum

possible state of charge should be reached (see

page 21). A 44 Ah battery with a terminal voltage of

12.45 V can be charged to approximately 100 % in 2.7

hours with a recommended charge current of 4.4 A

– equal to one tenth of the battery’s nominal capac-

ity (Uo terminal voltage = 12.8 V).

 

 

[keninpalamos]

aandncaravan - 2015-08-14 10:15 PM

 

There are a couple of comments here about either generators taking a long time to charge the batteries or the fitment of additional 'Fast Chargers'.

One thing often not taken into account is the battery technology which is an important consideration with a Generator, as it can affect the running cost by a big margin?

Gel and AGM batteries take more than twice as long to charge as a quality high technology Wet Acid battery. That is twice the generator running time.

 

A Varta Silver Dynamic Powerframe battery will charge more quickly again and take less energy to do so especially compared to a battery around 3 years old. They can charge nearly 3 times as quickly as a similarly age three year old Gel, more than halving your fuel bill.

 

Likewise when charging on Alternator they will charge in half the drive time.

 

However, a Varta SD must never be used with a B2B like a Sterling as these units charge at a rate much higher than most Battery manufacturers recommend, which a quality battery will not like.

 

Im sure I mentioned what type of batteries I use, let me just check..........yes Trojan traction 2x6v 250amp hr open wet cell, now 5 yrs old and still going strong. On the B2B unit there are 4 charge rates to select from, open lead acid, gel. (Exide spec) sealed lead acid & AGM, and lastly gel & AGM (USA spec) the charge rate ranges from 14.1v @ 20c to 14.8v @ 20c. The shore line mains charger has an even more comprehensive range to select from including Lithium LiFePO4, (what ever that is) Calcium and a de- sulphation/Equalization program. Again once set up you can forget it and just water the batteries while doing your pot plants. Horses for courses and freedom of choice etc

[aandncaravan]

KevinA, No magic at all, however you have misread our text?

 

We don't say it charges twice as fast as other Wet batteries. Just Gel and AGM.

We write, "Gel and AGM batteries take more than twice as long to charge as a quality high technology Wet Acid battery".

 

It is all covered on the website Battery Technology pages and AGM pages : http://www.aandncaravanservices.co.uk/battery-technology.php.

 

But to answer your specifics:

Banner batteries recommend on their website that when an AGM battery is used in a Motorhome without an AGM optimised charger, the Gel program should be selected. No Motorhomes currently in production have an AGM optimised charger.

 

The charging program for Gel batteries tends to be half that of Wet batteries because the Acid Gel is less mobile.

 

So whereas a normal Wet battery will get the full 20amps from a charger a Gel battery will quickly get the current dropped to around half that of a typical wet battery. The voltage is also dropped back slightly, assuming a modern multi stage charger in a typical Motorhome.

Because an AGM battery likes to be charged at a higher 14.7v, not the 14.2v it will receive from most Motorhome chargers it will take even longer again to charge. Some 3 times longer than a Varta SD.

 

The Varta SD has revolutionary Patented Powerframe Plate technology, exclusive to Bosch/Varta, that also allows the use a high Silver content, which everyone knows is not only an outstanding conductor but combats corrosion. This makes the battery more efficient so it charges even more quickly than a conventional battery. It is very efficient at converting every amp of input power into real world stored current, very little is lost in heat, or leakage. A conventional battery of three years of age will waste some of that input current, in conversion losses overcoming Internal corrosion, etc.

 

So the end result is a Varta SD that charges very quickly, with almost zero self discharge. Twice as fast as a Gel and AGM battery in the typical Motorhome.

 

This obviously does not apply to B2B chargers with an AGM optimised charge program. But then we warn against the use of B2B's se anyway, for a number of issues. Again see the website.

 

You also misquote us on a high charge rate. We do not write, "Then you say don't fit a varta silver dynamic in conjunction with a b2b charger because it WON'T accept the higher charging rate!?".

 

What we say is quite different. We wrote, "... be used with a B2B like a Sterling as these units charge at a rate much higher than most Battery manufacturers recommend, which a quality battery will not like".

 

No where do we say it won't take a high charge rate.

The Varta will tolerate a higher charge rate than most, we have seen it take 35amps without visible gassing, more than most conventional batteries will accept without fluid loss.

However, all manufacturers warn against fast charging any battery as it shortens it's life. Just as Boristhe moggy warns against in his post.

 

Your quoted 44amp into 2 x 110Ah batteries, is only 22amp er battery so is unlikely to bother a Varta SD as only just outside tolerance. The B2B charge rate is likely to settle at less than 40amp across the two batteries after a short time anyway resuling in a more typical 19amps per battery.

 

The reason we don't recommend B2B's and the use of a Varta is because a B2B does to a battery what every manufacturer suggests should not be done.

If you look on the Sterling website it says how the B2B fools the Alternator in working to the MAX.

One of the options is a Alternator temperature sensor. We think people should ask themselves why an Alternator temperature sensor should be necessary?.

Surely the B2B is not going to work the Alternator so close to the MAX it might overheat and burn out?

 

Where a B2B is fitted, they are at the centre of many of the issues we see.

 

I am glad you agree it is a very good quality Starter battery, exactly as we say on the web pages.

 

[Boristhemoggy]

I've used a B2B for 10 years without problem. Perhaps it depends on the alternator? Mine is 150amps so perhaps it can never be worked to it's max as the B2B would not be able to handle that input?

[kevina]

I'll start again as the forum just lost my reply! It may not be so comprehensive.

 

Gel and agm batteries charge just as fast as flooded, I don't understand why you think otherwise. The link below is an exide document giving maximum charging rates for all of their battery types, for all battery types it gives a rate of 50A into a 100Ah battery, this is obviously way above any motorhome charging capacity. A cursory internet search will find multiple corroborations.

http://www.exide.com/Media/files/Downloads/TransAmer/Battery%20Care%20and%20Maintenance/Battery%20Charging%20&%20Storage%20Guidelines%20%205_9_13.pdf

I'm still not sure if you really think that when you switch to the gel setting that you only get half the output from the charger. I've never experienced, seen, heard or read of any charger that does that.

 

I agree that motorhome chargers are not (voltage) optimised for agm batteries unless a b2b or high spec solar controller is fitted, and/or the mains charger is replaced.

 

B2B chargers are sophisticated 3 stage battery chargers with battery voltage and temperature sensing and are undoubtedly the best way of charging a leisure battery when on the move. They charge at the optimum rate for a fast charge and are kind on the battery because they better avoid the batteries being left in a state of partial discharge. They will place and additional load of up to 30A on the alternator but will not max-out a 140A alternator on a modern van. I have a Votronic b2b, not a sterling.

 

Gel and agm batteries have much lower self discharge rates than flooded batteries, varta sd may be in the same league.

 

Gel and agm batteries are more efficient when charging than flooded batteries. A flooded battery will lose 15-20% of input energy as heat, gels 10% and agms as low as 4%.

 

Kev

 

 

 

[Duncan MMM]

Thread has been moderated. Keep it civil please.

[aandncaravan]

The typical motorhome mains charger will not give an AGM battery the 14.7 volts it likes to both get fully charged or charge quickly. At best it will get 14.4v at worst just 13.8v. Typically 14.1v.

That has a huge impact on an AGM charge rate.

Note also that the majority of Motorhomes have an Alternator that will typically provide 14.2v, but more normally around 13.9v from what we see at the Habitation battery, depending on age and chassis.

So again slow to charge. But worse still the majority of Motorhome Alternators are not AGM optimised so the trickle charge voltage will be way above that recommended for an AGM.

 

Hence the Banner AGM web page saying that their batteries should not be fitted to a Motorhome unless an expert has assessed if the charging systems are suitable.

See our AGM page : http://www.aandncaravanservices.co.uk/agm-batteries.php for more information on charging AGM batteries in Motorhomes and their resultant short life. See also comments from real world users and their experience with AGM.

 

AGM batteries do have some outstanding characteristics when used with an optimised charger, but in a typical Motorhome environment they perform well below specification, being outperformed by cheaper Wet Batteries. We have seen failures in AGM batteries of less than 6 months old because they don't get fully charged.

 

The technology inside a Varta Silver Dynamic/Bosch S5 is more efficient than most wet batteries. It requires less power to charge up. Charging performance is not far off AGM when new, but by the time the two batteries reach 3 years old the Varta SD will out perform it. This efficiency is not lost as the battery ages. There is no Self Discharge.

 

The majority of B2B fast chargers 'overcharge' the battery, hence why so may suffer rapid fluid loss.

A quality modern battery in normal use will not loose any fluid, the reason why Maintenance free, sealed batteries are the norm. The Sterling B2B web site advises the use only of Open Wet batteries so the fluid can be replaced. You will read on here the major quantities of topping up that B2B charger owners have to do, if they are not then either the system isn't working or the battery is getting dry. That applies to Gel and AGM. If you have been running a B2B for more than about a year with a sealed battery, check for a bulging battery case. This obviously depends on the size of the battery bank and the B2B as to how the much battery is affected.

 

[kevina]

Our opinion of agm batteries in motorhomes is the same. However I made some mention of them regarding industry recognised advantages of them which is at odds with your previous statements.

 

Regarding b2b chargers, we will have to agree to differ. My opinion is that they are "faster" chargers but optimised for the battery. Below is an extract from my manual stating that, besides gel batteries, it is also suitable for modern silver/calcium batteries which you dispute.

 

„ Lead Acid “: Universal charging program for lead acid/lead-acid batteries:

For charging and trickle charge of supply (board) batteries. Ensures short charging times, high charging factor and acid mixing for open standard batteries and closed, low-maintenance, maintenance-free "non-solid electrolyte", "lead-acid", drive, lighting, solar and heavy duty batteries. Also suitable for recently developed batteries (low-antimonous, batteries with silver-alloy, calcium/calcium or similar) with low and very low water consumption.

Universal Characteristic Line IU1oU2:

U1 Main/Full Charging: 14.40 V (28.80 V) 22 °C 2.5-6 h

U2 Full/Trickle/Storage Charging: 13.40 V (26.80 V) 22 °C Continuous

 

My gel batteries have had approx 150 days of actual recharging by my b2b charger, mostly in deep winter (skiing) so involving a significant charging current. I monitor the charging situation closely and have only seen the b2b drop back the charging voltage by up to 0.1 volt on a couple of occasions due to battery temperature sensing. The battery temperature to hand was not perceptibly different to ambient. I have absolutely no concerns about the system.

 

That's all I'm going to say in this thread as it is way off topic.

 

Kev

[Boristhemoggy]

aandncaravan - 2015-08-19 1:15 PM

 

 

 

The majority of B2B fast chargers 'overcharge' the battery, hence why so may suffer rapid fluid loss.

A quality modern battery in normal use will not loose any fluid, the reason why Maintenance free, sealed batteries are the norm. The Sterling B2B web site advises the use only of Open Wet batteries so the fluid can be replaced. You will read on here the major quantities of topping up that B2B charger owners have to do, if they are not then either the system isn't working or the battery is getting dry. That applies to Gel and AGM. If you have been running a B2B for more than about a year with a sealed battery, check for a bulging battery case. This obviously depends on the size of the battery bank and the B2B as to how the much battery is affected.

 

I find this odd because I've had wet Trojans for 3 years now and I've only had to top mine up twice: once when I drove almost non stop from Venice to Sunderland.

[aandncaravan]

As I said, "This obviously depends on the size of the battery bank and the B2B as to how the much battery is affected".

 

I would guess your Trojans make up a pretty big battery bank so each battery is probably getting not much more than the recommended for each one??

 

 

[RogerC]

Having need of a decent genny to power things like tyre warmers/kettle etc when doing silly things with motorbikes on track I invested in a Kipor lg3000 which admittedly is bigger than your needs.  However I can confirm that even the 3000 is quiet so I would imagine the 2000 which should suit your needs and is a 'suitcase' type will be quieter still.  Mine has done sterling service and while the 'key' ignition is now defunct (knackered battery) it still starts second or third pull after months and months of sitting unused.  

[Boristhemoggy]

RogerC - 2015-08-20 9:01 PM

 

Having need of a decent genny to power things like tyre warmers/kettle etc when doing silly things with motorbikes on track I invested in a Kipor lg3000 which admittedly is bigger than your needs.  However I can confirm that even the 3000 is quiet so I would imagine the 2000 which should suit your needs and is a 'suitcase' type will be quieter still.  Mine has done sterling service and while the 'key' ignition is now defunct (knackered battery) it still starts second or third pull after months and months of sitting unused.  

 

I did eventually buy the Champion and so far it's proved to be a good buy.

 

Time will tell of course, if you wish to read a whole lot about it go here...

http://www.thelastgreatadventure.com/archives/2015/08/new-generation-3/