Battery to Battery chargers (B2B) and Solar Power?

[aandncaravan]

Hello The Varta LFD's are dual purpose Deep Cycle Habitation and Starter battery. You can extend their life dramatically if you swap them around every couple of years, if that is practical on your vehicle?

The Starter battery on a modern MH gets a really easy life the habitation battery can have it tough, so swapping them spreads the load.

 

 

 

[Guest pelmetman]

aandncaravan - 2016-06-23 3:15 PM

 

Hello The Varta LFD's are dual purpose Deep Cycle Habitation and Starter battery. You can extend their life dramatically if you swap them around every couple of years, if that is practical on your vehicle?

The Starter battery on a modern MH gets a really easy life the habitation battery can have it tough, so swapping them spreads the load.

 

 

 

Excellent B-) .........

[Steve928]

aandncaravan - 2016-06-23 10:56 AM

 

I was just stating that 15.1v was what we saw as that was questioned.

 

However, don't forget it is also the current that the B2B pumps up, not just the voltage.

It is the higher current that will raise the temperatures at the Plates with a risk of increased corrosion and battery degradation.

The gassing from a higher voltage, where selected, is another factor altogether.

 

 

 

A battery charger cannot 'pump current'; current flows purely as a result of voltage difference.

I do have to question your whole understanding of this subject.

[aandncaravan]

A Sterling B2B is designed to load up an Alternator so that the Alternator thinks a massive load has just been connected to it. This causes the Alternator to output a lot of current.

 

The B2B then routes these amps to the battery, boosting the voltage as required. This 'Force charges' the battery at a higher current rate than it would naturally draw.

 

In the first versions of the Sterling B2B the load placed on the Alternator was so great and the Alternator output so high that Alternator burnout occurred.

So an Alternator temperature probe became an option. When the B2B detected higher than normal temperatures at the Alternator, it reduced it's load to allow the Alternator to cool down.

 

 

But then again, you are probably right, my knowledge on the subject of charging batteries is rubbish. Maybe you could explain how a Sterling B2B works?

 

 

 

 

[Steve928]

aandncaravan - 2016-06-24 8:30 PM

 

A Sterling B2B is not like a battery charger in the conventional sense.

 

It is designed to load up an Alternator so that the Alternator thinks a massive load has just been connected to it. The B2B then routes these amps to the battery. This 'Force charges' the battery at a higher rate than it would naturally draw, at least that is what the Sterling web site says?

 

But then again what do I know?

 

 

"A Sterling B2B is not like a battery charger in the conventional sense."

 

Wow, you might need to clarify that statement.

 

A B2B charger (Sterling or otherwise) is a fully functional iUoU battery charger that uses another battery as its source. As that source becomes depleted then the alternator automatically recharges that source, exactly as it would when that source became depleted by other means.

 

You cannot 'route' or 'push' amps. Ohm's Law - basic schoolboy physics. Current (Amps) flows from source to destination because of the voltage difference between the two. There are neither 'massives' nor 'pumping' involved.

 

"But then again what do I know?"

 

I am beginning to wonder...

 

 

EDIT: I see that you have substantially edited (completely re-written) your post since I replied to it - my reply above is to your original post as in quotes.

 

 

[aandncaravan]

The Sterling website http://sterling-power.com/collections/battery-to-battery-chargers/products/battery-to-battery-chargers states,

“Current is NOT taken from the input battery and given to the output battery (as Steve928 states) The B2B uses alternator power to charge the output battery.The B2B charges batteries between 5-20 times faster than a stand alone alternator”.

 

 

How does it charge a battery up to 20 times faster than a normally Alternator connected battery without ‘pumping’ any charge in?

 

 

The installation manual for the 50amp version also states, “it will fool the alternator into working at its maximum ability in order to ensure all its surplus power is utilised to charge the auxiliary battery bank to its maximum".

Never hurts an Alternator to run it flat out at it's maximum, so that's o.k.

 

Ah, yes, but then a Temperature sensor does have to be mounted on the Alternator, not to ensure the Alternator won’t overheat from the load being placed on it, but because it looks the business. You can never have too many temperature sensors, that is probably why they also insist on one being attached to the battery. Not because it might overheat from being charged abnormally or anything, just looks pretty.

 

That all reads to me like it is doing things that a battery (and Alternator) wouldn't normally want done.

 

It goes on to say, “Avoid Gel, Sealed and AGM batteries”.

What it forgets to say, is that is because it destroys all battery types by 'force charging' the battery at a rate faster than is ideal. It just takes a bit longer to destroy 'Open Top' Lead Acid batteries.

 

 

Never dismantled a Sterling B2B, so don't know how the electronics achieve the above, but that all sounds to me like it drives a LOT more power into a battery than a battery would normally draw from an Alternator.

 

 

[sshortcircuit]

"“Current is NOT taken from the input battery and given to the output battery (as Steve928 states) The B2B uses alternator power to charge the output battery.The B2B charges batteries between 5-20 times faster than a stand alone alternator”.

 

Unless the starter battery can be physically isolated from the alternator, which it is not, then the B2B has no idea where it is getting power from. The B2B only starts charging at a voltage at which the starter battery is charged and that can come from alternator or starter battery.

[aandncaravan]

Well that extract is from the Sterling website so you obviously know a lot than Sterling as well as us.

 

 

[sshortcircuit]

Not really, its just a basic understanding of circuits and able to comprehend what the manufacturers technical information shows.

[aandncaravan]

I think you are aware that Sterling are saying the Alternator supplies the load because as soon as any load is put on a battery being supplied by an Alternator, the Alternator picks up that load, not the battery. Just as a car Alternator does when someone puts on the Headlights.

 

It is, essentially, the Alternator that supplies the load.

 

One of the reasons a car battery lasts so long, despite so many daily electrical demands from Blower motor, ECU, wipers, Lights, etc. is because it doesn't do any work in real terms.

 

 

 

[kevina]

aandncaravan - 2016-06-24 9:33 PM

..............

 

What it forgets to say, is that is because it destroys all battery types by 'force charging' the battery at a rate faster than is ideal. It just takes a bit longer to destroy 'Open Top' Lead Acid batteries.

 

Here we go again, this b2b and gel battery bashing is getting very tedious. On several threads over the last year or two you have been silenced by evidence proving you wrong.... then several months later off you go again.

 

Its not the fault of the charger nor the battery if people incorrectly install them. There are hundreds or thousands of them being used perfectly adequately, if not optimally (like mine - with gel batteries).

 

Kev

[aandncaravan]

You mean people have put forward arguments that were flawed so we stopped responding?

 

The Sterling B2B 50a documents state, "In a nut shell it charges your extra battery system about 5 times faster than it would otherwise charge and put about 50% extra use full power into them...... For best effect use open lead acid batteries. AVOID GEL, sealed and AGM batteries".

 

Then in another section it states, "My advise is where possible use the open lead acid batteries, which are also by far the lowest cost. Due to their SLOW RECHARGE rate, AVOID GEL batteries for fast charging cycles".

 

That is what Sterling state in their literature, not me, but Sterling on their website : http://sterling-power.com/collections/battery-to-battery-chargers/products/battery-to-battery-chargers

 

Yes the units have settings for different battery technologies, but the statements above FROM STERLING are clearly guiding buyers to use a particular battery technology.

 

As it says above, it "puts about 50% extra use full power into them" and charges them 5 times faster".

 

Speak to any Battery manufacturer and they will tell you that, for Battery life, slow charging is the optimum.

Those most susceptible to damaged by fast charging are Gel and AGM.

 

Sterling say don't use Gel and they point out they take longer to charge.

 

So what is the point of fast charging the slowest charging battery??

You might say it works for you, but you have probably spent £600 creating something that still only charges as fast as a standard Varta LFD and sacrificed battery lifetime doing it !!!!

 

 

But you are right, time to end it as it is getting tedious.

 

 

 

.

 

[sshortcircuit]

So my 110 A/h battery using a Sterling B2B will now have a capacity of 165 A/h

[aandncaravan]

Ask Sterling, that quote is from their website.

 

You never know, it might be true, we have heard all sorts of other wonderful claims for a B2B.

 

 

Can we just point out that this is not "B2B bashing" it is about trying to counter the 'marketing' which doesn't always show the whole picture.

 

We don't sell B2B's or market another option.

There will be people loyal to a product they have spent a lot of money on, and we understand that. However, should that 'loyalty' be allowed to misinform others?

 

My only angle here is from the point of view as a repairer where we see B2B's causing owners big bills. This is about informing and highlighting the downside that some manufacturers 'forget' to reveal.

 

As I have said earlier in the thread, a B2B might be the correct solution for some, on some Motorhomes. But be warned that some installers, even the big names, don't fully inform (or even understand) the ins and outs.

That is not said because we want the B2B business, we won't install B2B's. We won't even work on a Motorhome Electronics system if a B2B is installed.

 

I have no issue with people continuing to install them, it's good business for our industry, but you might want to check how it impacts Warranty?.

 

 

 

.

 

 

[Steve928]

aandncaravan - 2016-06-25 11:27 AM

 

Ask Sterling, that quote is from their website.

 

You never know, it might be true, we have heard all sorts of other wonderful claims for a B2B.

 

 

Can we just point out that this is not "B2B bashing" it is about trying to counter the 'marketing' which doesn't always show the whole picture.

 

We don't sell B2B's or market another option.

There will be people loyal to a product they have spent a lot of money on, and we understand that. However, should that 'loyalty' be allowed to misinform others?

 

My only angle here is from the point of view as a repairer where we see B2B's causing owners big bills. This is about informing and highlighting the downside that some manufacturers 'forget' to reveal.

 

As I have said earlier in the thread, a B2B might be the correct solution for some, on some Motorhomes. But be warned that some installers, even the big names, don't fully inform (or even understand) the ins and outs.

That is not said because we want the B2B business, we won't install B2B's. We won't even work on a Motorhome Electronics system if a B2B is installed.

 

I have no issue with people continuing to install them, it's good business for our industry, but you might want to check how it impacts Warranty?.

 

 

 

.

 

 

You really shouldn't be allowed to have the last word, but I just cannot be ar$ed to refute your supposed points one by one as you have already demonstrated your lack of understanding of the basics. User manuals do not override the laws of physics.

 

Say what you like, but I suspect that most people on here know that they now have to take your posts with a large pinch of salt.

 

Out.

[sshortcircuit]

Thanks Steve, I could not be bothered. My rather silly suggestion that my 110A/h battery would increase to 165 A/h was responded to with "Ask Sterling, that quote is from their website."

 

Enough said

[aandncaravan]

Steve928, Well if we are going to talk about not understanding the basics, you wrote, "A B2B charger (Sterling or otherwise) is a fully functional iUoU battery charger that uses another battery as its source. As that source becomes depleted then the alternator automatically recharges that source, exactly as it would when that source became depleted by other means".

 

That is a complete misunderstanding of electrical flow.

 

Where two power sources are connected to the same point, the one with the higher potential difference supplies the power.

 

So if there is a battery at 12.9v with an Alternator running at 14.4v connected to it's terminal posts and a load is placed on the battery terminals, power flows DIRECTLY from the higher PD source to the load.

 

The 12v battery does NOT supply ANY power to be then replaced by the 14.4v Alternator, as you seem to believe.

 

That is basic school boy physics.

 

My physics teacher got us to visualise it as two water tanks, one at higher pressure than the other. When a tap opened in the joined outlet pipe, the higher pressure is going to flow down the pipework.

No '12v' will flow at all from lower pressure (battery) tank because the higher '14.4v' pressure in the pipework actually pushes the lower pressure '12v' 'back' into the Tank/ battery as opposed to letting any out.

 

So I am not sure you, or shorcircuit who believes the same, are any better than I?

 

 

I have always liked Salt with my Chips.

 

 

.

 

 

 

 

 

[arthur49]

Well for what its worth aandncaravan I enjoy and value your posts

 

I say this as a Sterling B2B user. It was professionally installed in a van 3 years ago with basic Sargent charger etc - EC155 - and with careful use of the van I've never seen it put more than 27A into my batteries and then only for a short period. Maybe doesn't do my alternator any good but I'm happy to live with that possibility because I would not expect to deplete my batteries so much that I use the full 45A capability of my B2B

But when I change the van I'll probably opt for the smaller CTEC version which has a 20A capability

 

Lang may yer lum reek aandncaravan :-D :-D :-D

[aandncaravan]

Arthur, at that charging rate neither the batteries nor the Alternator are likely to be stressed. A B2B goes ok with an EC155. You shouldn't see much fluid loss from the batteries either?

 

 

I don't have a Smokey chimney, but the gas Boiler is getting on a bit and emits a few fumes now and then, so now you have wished me that, maybe it will last a few more years yet!!!! (lol)

 

 

Thank you, appreciated a lot.

 

May the moose ne'er lea' yer girnal wi a tear-drap in its ee.

 

 

[arthur49]

aandncaravan - 2016-06-25 10:04 PM

 

Arthur, at that charging rate neither the batteries nor the Alternator are likely to be stressed. A B2B goes ok with an EC155. You shouldn't see much fluid loss from the batteries either?

 

 

I don't have a Smokey chimney, but the gas Boiler is getting on a bit and emits a few fumes now and then, so now you have wished me that, maybe it will last a few more years yet!!!! (lol)

 

 

Thank you, appreciated a lot.

 

May the moose ne'er lea' yer girnal wi a tear-drap in its ee.

 

(lol)

Forgot to say that where I think the B2B is flawed is on open lead acid setting. Here it charges at 14.8v for 1 - 3 hours, then it drops to 13.6v.

The issue is if you stop driving to stretch your legs, have a coffee/pee within the 1 - 3 hour period, which is sensible. When you restart engine the 'clock' resets so off the B2B goes again at 14.8v. Effectively mine never goes to 13.6v.

I retro fitted the remote which shows me what my B2B is doing. The B2B is great at giving my batteries a dose of higher voltage because the EC155 on hook up only produces a straight 13.8v. I switch the B2B off using the remote to protect my batteries.

[aandncaravan]

Arthur, That is a flaw on a lot of chargers that are pure timer based. The good ones interrupt the timer, if they 'sense' the battery is full.

 

Noticed similar on one or two of the budget Solar Chargers, that 'lose' the fact they were on a 13.8v maintenance charge when the Sun disappears. They can 'restart' the next day at 14.4v for several hours when such a high voltage is not appropriate. Not an issue when the vehicle is being used as it needs a good charge, but when in long term storage, the batteries will still be 'boost' charged up at the start of each day.

Trying to get the message across these chargers will degrade the batteries is not easy when the Solar Installers are saying the opposite. As you might tell from some of the threads?

 

But nice to see more Solar Chargers with reduced maintenance voltages, saw one this week with 13.3v which should extend the life of the batteries.

We have gone on record saying that we think 13.8v is too high for long term maintenance charging. Seems like the manufacturers now think so too, like your B2B's 13.6v ?

 

We also had a couple of people recently tell us that they have stopped putting the Motorhome on long term EHU, following our advice. What they do now is put it on a timer of 'just' 8 hours a day and they don't understand how that can be worse!! We advise once every few weeks.

 

.

 

 

 

[arthur49]

aandncaravan - 2016-06-25 10:54 PM

 

Noticed similar on one or two of the budget Solar Chargers, that 'lose' the fact they were on a 13.8v maintenance charge when the Sun disappears. They can 'restart' the next day at 14.4v for several hours when such a high voltage is not appropriate. Not an issue when the vehicle is being used as it needs a good charge, but when in long term storage, the batteries will still be 'boost' charged up at the start of each day.

 

 

Yes I've noticed this on my solar system. When not in use, sitting at side of house, every (bright) morning its at 14.4v then after a while down to 13.4v

 

On EHU, because the EC155 is a constant 13.8v I rarely hook up at side of house, and when I do only for 48 hours or so

[aandncaravan]

A Solar maintenance charge of 13.4v suggests it's a quality, state of the art, regulator? Is it a Victron?

 

However, we would still suggest that if your batteries don't need topping up during the Summer, because it's being 'stored', you consider isolating the Solar Panel from the regulator for a few days at a time to avoid the 'start-up' 14.4v 'overcharge'?

 

Probably won't be an issue in the Winter with the shorter days, lower Sun and reduced current?

 

 

I would agree it's not a good idea to leave the EC155 on long term EHU, but when you do plug in, you might want to leave it longer than 48hours if you know the batteries have got low?.

The simple charger inside the Sargent EC155 is a fixed 13.8volts so isn't the best at getting the battery up to full capacity or recharging it quickly, so it might be an idea to leave it on EHU a bit longer than 48 hours?

 

Because of the simplicity of the standard charger, your choice of going for a B2B (although it hurts me to say it (lol) ) is probably a good one.

 

Like I said early in the thread, a B2B can be the right solution for some Motorhomes, just not all.

 

 

 

 

[arthur49]

aandncaravan - 2016-06-26 1:23 PM

 

A Solar maintenance charge of 13.4v suggests it's a quality, state of the art, regulator? Is it a Victron?

 

Because of the simplicity of the standard charger, your choice of going for a B2B (although it hurts me to say it (lol) ) is probably a good one.

 

 

You've made my day Allan! I decided on the B2B precisely because the EC155 is basic .... and with the B2B remote I operate my own 'timer'. Its not a sophisticated algorithm, I just press 'Off' when I think thats enough!

 

The solar regulator is Votronic MPP 160 without temperature sensor

 

[aandncaravan]

You made my day yesterday with your - Lang may yer lum reek

 

That Votronic is amongst the best. It is a shame that more don't understand that a budget Regulator is false economy.

You are probably the exception to the rule that we see, in that you understand the B2B does give the batteries a hard time so you don't leave it to it's own devices, intervening to manage the system yourself. Like switching it off when you think it's done enough.

 

Plus understanding about the 'timer' for the initial 'fast' charge, when the unit should be on a 'maintenance' charge. Few Installers we know would have spotted that 'feature'.

 

 

When we see a particular issue out there which we then 'help address', it is very easy to lose sight of the fact that amongst the 'target' group will be those who really do have it sorted, like you and Veletron.

 

I find it hard to try and inform about the mis-sold solutions we see, without alienating those who may have the exact set-up we are warning against, but understand fully the limitations under which they are using it.

Veletron has everything we advise against from the point of view of creating problems in the Motorhome. But his skill level and understanding is such that he, like you, is operating within those confines and understands the compromises he is making. He has such a high knowledge base he is able to get the best out of it. He is also able to fix it if it does break.

 

Is this starting to sound like an apology, because it is supposed to be!!

 

If you ever read Derek Uzzell's reponses they are written in such a wonderful way, with great detail and effort but never condescending.

When I respond, I am aware that the thread might be read by someone else with a slightly different issue at a later date, so sometimes try and put extra information into the post. This the OP may already understand so maybe thinks I believe them to be stupid?

It's a balance I find hard to get right, as RobinHood has rightly commented on!!

 

Can you tell the 'Pinch of Salt' is getting to me now?

 

This Forum is fantastic and has some amazing talented people that are also held in high regard on the other forums, with information put out on here, being picked up and replicated by the others.

 

An example of that is that some time ago Brambles, Derek and myself had a very protracted, sometimes heated, debate about the merits of the Bosch S5 Starter battery as a Leisure battery.

Although there were lots of disagreements and counter arguments, out of that thread, thanks to Derek and Brambles research, came the realisation that the Varta LFD/Bosch L range are amongst the best for the money by a big margin.

Within months, those batteries, previously regarded as just another battery, were all over the other forums as 'the battery' to have.

 

Almost everyone on here is here to help others, many passing on the knowledge they have freely.

I have never professed to knowing everything, I am not an educated man, my knowledge being acquired from experience, not books. Starting off at 11 years old building radios and going on to repair TV's, etc as a Saturday job at 18. I was able to repair these TV's without always understanding the full complexities of the circuitry. Just as some Musicians can create music without being able to write a Note.

 

My knowledge has huge gaps, but I also have a lot of hands on experience with Motorhomes and their electronic systems. Particularly charging systems.

Please don't castigate me if I get it wrong, educate me

 

I write on here to help others avoid the issues we see becoming problems.

Please bear that in mind?