Is a B2B charger necessary?

wildebus

Full Member

Messages
2,531
Oh, I have a different opinion.
A fixed solar panel on the roof is a fit and forget fix. You can ignore it year after year. Yes, you can align a portable panel to face the sun and get more output, but it's far easier, and just as cheap, to fit twice as big a panel flat on the roof instead
You see people setting up their portable panels, then a few hours later the sun has moved and the panels are in shade. Or they blew over in the wind
And even if you don't mind the faff of setting up and packing away, they are always at risk of theft or damage.
For me, one of the best things about having a motorhome is that when you arrive, you just put the handbrake on and the ignition off. No setting up needed.
A lot of people like the Portable panels, and having tilting systems, but I have to say that for myself, I have to agree with everything above 🙃
 

in h

Full Member

Messages
296
I'm not sure if "Far worse" is quite right? Compared to a Truma, there is a bigger start-up current and there is also an increased shutdown current, where I think the glowplug comes on and the fan accelerates to clean the combustion chamber, but apart from those times, the running current is fairly acceptable IMO.

2 to 3 hours to replenish a 33Ah discharge? It does depend on the battery bank capacity, but I would say if your heater had taken the kind of energy out of the battery where you were concerned (so maybe down to 60% say?), then you would get the great majority back quite a bit quicker than 2 hours from either a VSR or B2B.
Whether a load is "acceptable" or not depends on the capacity of the power system. You are happy spending many hundreds of pounds on charging, batteries and monitoring. Not everyone feels that way. The power resources may be more limited

Truma reckon 1.4A on average. Not my figure. They say 0.4 when the heating fan is not running. But of course, that's for a full 6Kw combi system. Not the equivalent of a simple diesel blown air heater.

Their 2400 blown air heater would be the nearest equivalent. I'll need to look that up to see how much power it draws. Although my van also has one fitted, it's rarely used.

[Later]I just looked it up. 0.6A when the fan is running on low, 1.1A on high. 0.01A on standby. But of course, they do cost more than a cheap Chinese diesel heater.

Do you really not know the consumption of the fan and pump? I'd have expected you to measure that when fitting it.
Pretty graphs are no replacement for an actual measurement.

Yes, it will take two or three hours driving to put 33Ah back into a 100Ah battery with just a split charge system.
It may start with a high charge current, but after a while you'll be lucky to get more than 8A.
 
Last edited:

Full Member

Full Member

Messages
3,552
Oh, I have a different opinion.
A fixed solar panel on the roof is a fit and forget fix. You can ignore it year after year. Yes, you can align a portable panel to face the sun and get more output, but it's far easier, and just as cheap, to fit twice as big a panel flat on the roof instead
You see people setting up their portable panels, then a few hours later the sun has moved and the panels are in shade. Or they blew over in the wind
And even if you don't mind the faff of setting up and packing away, they are always at risk of theft or damage.
For me, one of the best things about having a motorhome is that when you arrive, you just put the handbrake on and the ignition off. No setting up needed.
A lot of people like the Portable panels, and having tilting systems, but I have to say that for myself, I have to agree with everything above 🙃
I also have a fixed solar panel on the roof of the Moho which satisfies all my power needs.
But let's not forget that some folks don't have a leisure vehicle with a sufficiently large roof to have a solar panel arrangement that can achieve that.
For those people a portable solar panel can be a very practical accessory indeed.

Colin 🙂🙂🙂
 

wildebus

Full Member

Messages
2,531
Whether a load is "acceptable" or not depends on the capacity of the power system. You are happy spending many hundreds of pounds on charging, batteries and monitoring. Not everyone feels that way. The power resources may be more limited

Truma reckon 1.4A on average. Not my figure. They say 0.4 when the heating fan is not running. But of course, that's for a full 6Kw combi system. Not the equivalent of a simple diesel blown air heater.

Their 2400 blown air heater would be the nearest equivalent. I'll need to look that up to see how much power it draws. Although my van also has one fitted, it's rarely used.

[Later]I just looked it up. 0.6A when the fan is running on low, 1.1A on high. 0.01A on standby. But of course, they do cost more than a cheap Chinese diesel heater.

Do you really not know the consumption of the fan and pump? I'd have expected you to measure that when fitting it.
Pretty graphs are no replacement for an actual measurement.

Yes, it will take two or three hours driving to put 33Ah back into a 100Ah battery with just a split charge system.
It may start with a high charge current, but after a while you'll be lucky to get more than 8A.
I do have the exact measurements of the power consumption from the heater on a minute by minute basis - but a graph of the data is prettier to look at ;).

I could paste the excel file I guess? Here are a few lines from the 45,000 line file for October 2018 as an example ....
1588766739055.png
could be useful for insomniacs?

Now hundreds of pounds charging batteries and monitoring .... I have the monitoring as I LIKE the monitoring, not because it is needed to run the heater.
Say if you did need extra battery capacity for running the heater compared to a Truma? (a definate "if" I think). The extra battery capacity on top of the cost of £100 to buy a cheap diesel heater still adds up to A LOT LESS than the cost of a Truma if you want to talk about cost effectiveness. It all depends where you decide to put the money into the overall solution. And when the heater is not needed in the summer, that extra battery capacity can be used for other things.

We will have to agree to disagree about the charging speed of a battery from the alternator. My pretty graphs tell me something different ;)
 

mistericeman

Full Member

Messages
205
I have to say in my experience of running a eberspacher d2 for the last 4 or 5 years...
The only time I ever see anything like 8 amps is when it runs through its initial start up boost run....
Once up to working temp it ticks over at less than 2 amps... And continues to do so for the time it's on (regularly continual useage in winter)
Ive had it running none stop for 2 weeks at times.
Temperature setting is obviously critical, common mistake is to set the temp too high which causes see sawing of the heater with repeated boost runs obviously using far more power than is necessary.
 

cronkle

Full Member

Messages
209
Ok you lot, I've just been out in the garden and come back in to discover I sparked something. Got to say I was only saying what I do to add another alternative to the argyment. Wasn't looking for an opinion ;). For interest I only use the panel a couple of times a year; we manage at all other times (hook-up etc). I like the old KISS idea. Keep It Simple Stupid, being a simple person and often feeling stupid gets me part way to that :):). (Got to work on the Keep and It bit).
 

wildebus

Full Member

Messages
2,531
I have to say in my experience of running a eberspacher d2 for the last 4 or 5 years...
The only time I ever see anything like 8 amps is when it runs through its initial start up boost run....
Once up to working temp it ticks over at less than 2 amps... And continues to do so for the time it's on (regularly continual useage in winter)
Ive had it running none stop for 2 weeks at times.
Temperature setting is obviously critical, common mistake is to set the temp too high which causes see sawing of the heater with repeated boost runs obviously using far more power than is necessary.
This last point is a good one when discussing different Diesel Heaters. The Eberspacher have a proper temperature controlled function. The cheap Chinese Heaters do not! The most common controller for these may have a setting where you set a temperature in Celcius, but it is NOT a temp you are actually setting, it is just the fuel pump pulse frequency. The more pulses, the more fuel, the hotter the output. But it is fixed at whatever you select regardless of external influence like actual room temp for example.
 

in h

Full Member

Messages
296
I do have the exact measurements of the power consumption from the heater on a minute by minute basis - but a graph of the data is prettier to look at ;).
Sorry, too small to read. My question is quite simple: "How much current does the heater draw when running?" This is a simple number. No need for a graph or a spreadsheet.
Now hundreds of pounds charging batteries and monitoring .... I have the monitoring as I LIKE the monitoring, not because it is needed to run the heater.
Exactly. That's the point I was making.
Say if you did need extra battery capacity for running the heater compared to a Truma? (a definate "if" I think). The extra battery capacity on top of the cost of £100 to buy a cheap diesel heater still adds up to A LOT LESS than the cost of a Truma if you want to talk about cost effectiveness. It all depends where you decide to put the money into the overall solution. And when the heater is not needed in the summer, that extra battery capacity can be used for other things.
I'm not talking about what I need. My van was built with two Truma heating systems from the outset, and a power system easily able to supply them. We are talking about someone (cronkle) who has a Truma heater fitted that is draining his battery in a day or so and is looking for a solution to that. No "if": that is what he described.
We will have to agree to disagree about the charging speed of a battery from the alternator. My pretty graphs tell me something different ;)
Your pretty graphs are not showing the charge rate you get with a standard alternator running through a split charge relay into a 100Ah leisure battery, probably whilst also powering 12v at 10A into a three-way fridge. They are showing a very different setup that will charge much faster. That's why you installed it.

I have tested a SCR system charging in those conditions. Either you have not, or you have forgotten.
 

in h

Full Member

Messages
296
Once up to working temp it ticks over at less than 2 amps... And continues to do so for the time it's on
Thanks for a number! Is it a bit less than 2A or a lot less, as a matter of interest?
Bearing in mind that the Truma LPG equivalent draws 0.6A when set to low, that is probably what I'd expect: slightly under three times as much current draw as the LPG equivalent. But the fuel is easier to source.
 

Markd

Full Member

Messages
696
@cronkle
Any chance you could confirm the details of your new heater please?
We seem to have assumed that it's a Truma combi of some sort.
 

Markd

Full Member

Messages
696
in h said
Sorry, too small to read. My question is quite simple: "How much current does the heater draw when running?" This is a simple number. No need for a graph or a spreadsheet.

Several posts earlier Wildebus had provided a simple number below a graph
So Startup hits 9A draw, running is around 1.2A (taking the baseline into account) and Shutdown has a rise to around 7.5A.
 

cronkle

Full Member

Messages
209
@cronkle
Any chance you could confirm the details of your new heater please?
We seem to have assumed that it's a Truma combi of some sort.
Whale. Quite happy with it if a bit loud at full blast. Have worked out how I would like to manage the power useage. :)
 

mistericeman

Full Member

Messages
205
Thanks for a number! Is it a bit less than 2A or a lot less, as a matter of interest?
Bearing in mind that the Truma LPG equivalent draws 0.6A when set to low, that is probably what I'd expect: slightly under three times as much current draw as the LPG equivalent. But the fuel is easier to source.
1.6 amps sometimes dropping to 1.2 as it cycles on low fan and the pump shuts down.
 

wildebus

Full Member

Messages
2,531
Sorry, too small to read. My question is quite simple: "How much current does the heater draw when running?" This is a simple number. No need for a graph or a spreadsheet.
Exactly. That's the point I was making.
I'm not talking about what I need. My van was built with two Truma heating systems from the outset, and a power system easily able to supply them. We are talking about someone (cronkle) who has a Truma heater fitted that is draining his battery in a day or so and is looking for a solution to that. No "if": that is what he described.
Your pretty graphs are not showing the charge rate you get with a standard alternator running through a split charge relay into a 100Ah leisure battery, probably whilst also powering 12v at 10A into a three-way fridge. They are showing a very different setup that will charge much faster. That's why you installed it.

I have tested a SCR system charging in those conditions. Either you have not, or you have forgotten.
1) You assume I am replying specifically to YOU. I am not, even though I am quoting you.

2) My pretty graphs I posted are for the Heater usage. I have not posted them for engine charging so your comment saying they do not show this is pointless and irrelevant.

3) if you just use a mobile phone to read a forum, don't expect to be able to see graphs. If something I post is too small, get a bigger screen or just don't read my posts. I won't be accomodating your (and this time does mean specifically YOUR) mobile device
 

Markd

Full Member

Messages
696
On a phone the graphs display ok after linking through.
However as you say spreadsheets really need a bit more room and I wouldn't dream of opening them on a phone or even a small tablet.
As the saying goes a picture is worth a thousand words and I usually find your graphs very informative in illustrating points made in the post itself.
 

in h

Full Member

Messages
296
1) You assume I am replying specifically to YOU. I am not, even though I am quoting you.

2) My pretty graphs I posted are for the Heater usage. I have not posted them for engine charging so your comment saying they do not show this is pointless and irrelevant.

3) if you just use a mobile phone to read a forum, don't expect to be able to see graphs. If something I post is too small, get a bigger screen or just don't read my posts. I won't be accomodating your (and this time does mean specifically YOUR) mobile device
If you are replying to what I have written, quoting my actual words, you are replying to me. Fact.
Your screen capture of a spreadsheet is too small to read on my 24" monitor. I was not going to bother switching to the 39" monitor because I don't care enough what your spreadsheet says.
 

wildebus

Full Member

Messages
2,531
If you are replying to what I have written, quoting my actual words, you are replying to me. Fact.
Your screen capture of a spreadsheet is too small to read on my 24" monitor. I was not going to bother switching to the 39" monitor because I don't care enough what your spreadsheet says.
:ROFLMAO: I posted the spreadsheet screengrab as a joke! you cannot read a 40 column or whatever spreadsheet on a 24" or even on your (wow! aren't you impressive) 39" monitor.
you must be donald trump with your "facts". any more "facts"?

PS. If you can't read the numbers on the graph on a 24" screen, I really can't help!
 

nabsim

Full Member

Messages
2,207
Everyone getting a bit stir crazy I think lol

Whatever works for you is good. A lot depends what you want in the van, personally my van is like a house, if I would have something in the house I have it in the van, I am in it all the time though not just holidays. I need lots of power compared to most although only a little if compared to Phil (admin) :)
 

Dads Train

Full Member

Messages
6
So the question is, what is the advantage or not of B2B over this VSR setup (see picture) that I found on aandncaravanservices web page? This VSR setup - 2 boxes - can be purchased for £25 plus and all you need to add is cost of cables & fuses

1589215600688.png
 

Users who viewed this discussion (Total:150)

Trotter, wildebus, TeamRienza, mr brown, TJBi, korky, in h, Tribute11, bobemmo29, mistericeman, shortcircuit, DnK, Edina, St3v3, Topmast, trevskoda, Budgie, Full Member, LANDS43, witzend, hayhiker, Molly 3, katv, Bigshug, Jeffcav, Forresbroons, cbdriver, Boots, jasi1710, Lee, Clunegapyears, mark61, jagmanx, Wooie1958, AdriaTwin, Taurian, eurajohn, HurricaneSmith, tripper, Phase3begins, RV2MAX, Kyran, frankii, Dom, bmc, vtwinner, yorkslass, peejay, Mr and Mrs Tupcox, tapfitter, WildThingsKev, menis, Okta, bartman, SquirrellCook, clarkpeacock, Georges, Winks, alwaysared, Carrotts, vanda, xsilvergs, Obanboy666, Markd, debs, rustydog, nabsim, Barge1914, Bigredf, helmit, timatabsa, Spike69, Mark135, Orkneybob, WingNut, rugbyken, jason9876, kevlakes, Shaun944t, The laird, Geeky Philip, Stonesthrow, FULL TIMER, smg, snapster, Northumborman, cronkle, Amudle, Steveandjulie, greyduster, Kraken, Ian1950, andromeda, PeteS, barlicker, loulou, MOJO, Vanterrier, Kennyb, 2cv, Kenno, Chris Evans001, Lord Lucan, roadroamer, Forrory, paulhelenwilko, alun100, old cronies, THE COLLIES, Mickrick, davef, WanderingEllie, Jann, arkwright01, steve strange, bdm, Dads Train, andysm, Chris356, rogerha, familywagen, SimonM, Nitkn, Val54, Andy906, Skiptonian, WillyO, Exwindsurfer, phillhend, coffeenut, big tom, charlie356, Wully, Bouydog, Livotlout, TheLizard, Bugsbunny, Dulvil, Driventemple, CherryPirate, Wrighpm, Alcfire, RogerO, Forcesixwindy, Barry n Jackie, Ronnie B, 47643, AliW, ScoTTyBEEE, jonscase,
Top