Charging your Leisure Batteries on the move.

[wildebus]

Thank you for the advice, could I just add the Cyrix to the existing wiring or would I need to make some changes in the Electrobloc?

I don't know what wiring you have in place so can't really answer that.
The Standard Cyrix is a 120A unit and for that I would ideally install a minimum 16mm cable end to end - you are unlikely to have that as standard. You could try with the existing cable you have and probably will be ok. but just a reminder that you always fuse to the cable capability, not the device, so even if it is a device capable of higher current, you don't increase the fuse size unless you upgrade the cable itself.

Adding another cable is not necessarily that tricky though - today I am in the middle of upgrading my own Split-charge cable from 16mm to 35mm (to support a Cyrix 230A and possible Alternator upgrade). It is involving lying under the van and getting grubby, but all a pretty logical process (just follow the existing cable conduit)

 

[ScoTTyBEEE]

So in conclusion, if you have a big battery bank, circa >200ah then use a VSR combined with solar as this will give you full range to charge the batteries and make use of all the amps your alternator can give....and save you a few quid. You're looking at almost 2 hours of charging over 40A, and if you want a more powerful b2b you're starting to get into loadsa money territory, for what is very little benefit.

 

[wildebus]

So in conclusion, if you have a big battery bank, circa >200ah then use a VSR combined with solar as this will give you full range to charge the batteries and make use of all the amps your alternator can give....and save you a few quid. You're looking at almost 2 hours of charging over 40A, and if you want a more powerful b2b you're starting to get into loadsa money territory.

I would say that is a reasonable conclusion. but a B2B of comparable Current output will still be superior (but a touch pricey!)

I've ended up taking a slightly different route that I didn't test - I'm actually taking out my standalone B2B but I do intend to instead fit an uprated VSR plus a Digital Regulator on the Alternator which will actually convert the Alternator into a full-power B2B at its full capability (the VSR is still needed as it is the automatic switch to combine/separate the Leisure and Starter Batteries).
Ran the new 35mm cable, Starter Battery sense cable and External Temp Sensor wiring today from the Leisure Battery Bank area to the Engine bay in readiness for the new components

 

[nabsim]

So in conclusion, if you have a big battery bank, circa >200ah then use a VSR combined with solar as this will give you full range to charge the batteries and make use of all the amps your alternator can give....and save you a few quid. You're looking at almost 2 hours of charging over 40A, and if you want a more powerful b2b you're starting to get into loadsa money territory, for what is very little benefit.

It can also depend on your van. It took me a good while to decide on the B2B over a VSR. On my setup I could splice a a votronic in before the EBL using existing cables only needing to add some short lengths.
If I had gone VSR I would have needed to buy and run big cables so the end costs were very similar but VSR meant much more work fitting.
Check out cable sizes you have now and length of runs then price it up properly.
On my factory fitted split charge system I don’t think I ever saw 13.6v, I now get proper charging voltages for my batterys

Edited to correct typos

 

[RogerO]

Hi

What is to be done if the van is 'new' with a smart regulator? We have just returned form Australia where we rented a modern Sprinter based camper. The alternator would keep the electric fridge running but would not increase the charge on the smallish leisure battery. Only by plugging in to external power could we charge the leisure battery which would then only last 24-36 hours. We ended up buying ice in order to wild camp!
Thank goodness my old VW Florida doesn't have this problem.

 

[wildebus]

Hi

What is to be done if the van is 'new' with a smart regulator? We have just returned form Australia where we rented a modern Sprinter based camper. The alternator would keep the electric fridge running but would not increase the charge on the smallish leisure battery. Only by plugging in to external power could we charge the leisure battery which would then only last 24-36 hours. We ended up buying ice in order to wild camp!
Thank goodness my old VW Florida doesn't have this problem.

You get a B2B that is compatible with a smart Alternator
Trouble is a lot of converters fit what they are calling and selling as a "Split Charger" but is not a charger at all, but just a relay. And while it does a reasonable job on the older vehicles (reasonable, not the best), it just doesn't work with newer vehicles with 'intelligent' charging systems.
They do that as it saves a couple of hundred pounds

 

[mark61]

If you have a Sprinter (or any recent van I suppose) with a smart alternator but with no B2B, turning on the headlights appears to override the "smart" bit.

 

[wildebus]

It can also depend on your van. It took me a good while to decide on the B2B over a VSR. On my setup I could splice a a votronic in before the EBL using existing cables only needing to add some short lengths.
If I had gone VSR I would have needed to buy and run big cables so the end costs were very similar but VSR meant much more work fitting.
Check out cable sizes you have now and length of runs then price it up properly.
On my factory fitted split charge system I don’t think I ever saw 13.6v, I now get proper charging voltages for my batterys

Edited to correct typos

I finished my upgraded Split-charge rewiring today (so runnng 35mm end to end). Checked by just starting the engine and going to 2000RPM (around my usual cruising engine speed) the starter battery (fully charged) was reported at 14.1V and the leisure battery (90% charged) voltage coming through the VSR was 13.97V, so pretty decent output in fact.
Cable does make a big difference when it comes high-current charging over distance. A B2B can make up for the voltage drop as part of its function, but a VSR cannot of course.

 

[nabsim]

I finished my upgraded Split-charge rewiring today (so runnng 35mm end to end). Checked by just starting the engine and going to 2000RPM (around my usual cruising engine speed) the starter battery (fully charged) was reported at 14.1V and the leisure battery (90% charged) voltage coming through the VSR was 13.97V, so pretty decent output in fact.
Cable does make a big difference when it comes high-current charging over distance. A B2B can make up for the voltage drop as part of its function, but a VSR cannot of course.

Yes it took a lot of thinking before I made my mind up, for me the fact it was almost plug and play was a big factor. If I start trying to do much outside I painfully seize up for a few days. Less than an hour inside had it sorted instead but thats for my van and others could find a lot more work needed.

I never saw much above the low 13's on the 'split charge' system that was originally fitted to mine, from what I have found it is a relay inside the EBL rather than a separate VSR or split charge relay. Even if it had a proper relay fitted the cable was not big enough to carry the needed current as it looks to me 10mm. It may have been plenty big enough when the van was built with 3 way fridge and gas heating but as it is now with compressor fridge and Eberspachers it wasnt up to the task.

 

[wildebus]

I doubt if you would ever rind a VSR inside a custom-bodied Motorhome from the factory. They (the MH makers) tend to use an alternator signal to determine if the vehicle is static or not to drive things like the EBL, or the Sargent EC PDUs as well as the Fridge power control - and if they have that signal available, they can use a standard relay that costs approximately £1.50, rather than a VSR than costs £30 (and TBH, the two do the same job anyway, just controlled differently)

 

[wildebus]

I would say that is a reasonable conclusion. but a B2B of comparable Current output will still be superior (but a touch pricey!)

I've ended up taking a slightly different route that I didn't test - I'm actually taking out my standalone B2B but I do intend to instead fit an uprated VSR plus a Digital Regulator on the Alternator which will actually convert the Alternator into a full-power B2B at its full capability (the VSR is still needed as it is the automatic switch to combine/separate the Leisure and Starter Batteries).
Ran the new 35mm cable, Starter Battery sense cable and External Temp Sensor wiring today from the Leisure Battery Bank area to the Engine bay in readiness for the new components

Nipped to my local garage to check about getting the alternator out to fit the Digital Regulator... While removal of the alternator is easy enough, it looks like it could be trickier then I thought to fir the Reg as not clear what kind of Alternator is fitted, so some further investigation required here.
Also took the opportunity to check some outputs as this is the first time out in the van since doing all the tests in this thread and upgrading my cable to 35mm.
I put the water heater on on the short drive home - that pulls around 190A @12V when running (the exact current depends on the battery voltage. It translates to 2300W +/- 20W once the Inverter overhead is factored in)
The current draw while driving was 95A. When the engine was off, the draw went up to around 194A - so the alternator was actually providing 100A of charge to help offset the load.
I am - very pleasantly - surprised at this. I expected a much smaller contribution from the Alternator to be honest so I am not sure how much benefit I will actually get in reality from the fitting of the Digital Regulator in my particular vehicle compared to the cost of installing.
I'm also wondering what Alternator I have fitted. The standard one is 90A and I am getting more than that, so I either have the uprated 120A (I don't see why as the van had no aux battery fitted when built) or the Alternator is just over-delivering, which is not that unsual for a decent branded unit.
I don't think it is worth an upgrade to the 120A unit so will probably leave that aspect until/if the alternator fails and then consider an upgrade.

 

[chas142]

Good article, lots of useful info. Spoken about the different alternator regulator on here before with someone, then decided to hold on with that, but didn't know there was a 4 stage unit. I will look into that after other jobs have been done. I originally only wanted one that gave a boost for 30/60 mins or so. My alternator regulates at 14.4, so may not be that much benefit unless it goes up to say 14.7 - 14.8, my Gels will accept 14.7 but will lose a bit in the cable and relay.

I will be supplementing the vehicle 240v charger with a Photonic 12v 10a, it's a 7 stage charger, this version and the 12v 20a units have two separate isolated outputs, for 2 sets of batteries. Will also be fitting dual digital voltmeters to be able to check the battery voltages easily and see what I am losing in the system when out on a run. My solar has a dual battery controller and that seems to be on float mode at 13.8v, it auto senses the battery type. The Photonic has a selling for 3 different types but will be set for Gel/SLA, so 14.4 and 13.8 on float.

 

[wildebus]

What size battery have you? A 10A charger does sound very small TBH. And if that 10A is shared between two outputs it is little more than a trickle charger in some ways?

You mention your alternator puts out a regulated 14.4V . That is good on one hand, but I think has a downside on the other. You will be getting a good charging level but if you are driving for a while, the batteries may want to just have a float voltage applied to them but you are keeping them at 14.4V. It's the same as if you left a dumb mains charger on all the time with a 14.4V output.
The saving grace with the Alternator is driving times are such the impact is probably minimal.

I've had quite lengthy discussions with Ablemail on this topic of voltage and the owner - who used to work at a battery manufacturer in fact - has deliberately set his voltage peak to avoid over-voltage on the battery. His 14.1V is a little lower than ideal but is safe. He goes along the line of better too low than too high (the Ablemail chargers are designed as plug and play for non-technical installers. Many products have so many options that they end up wrongly setup by folk who don't know what is required).

 

[Okta]

I remain a fan of a good B2B, which once set up properly manages the Volts and Amps delivered to the leisure battery. Leaving it to the alternator on its own is always going to be hit and miss. Make sure the B2B is close to the leisure battery and it will iron out any voltage losses and variations from the alternator and wiring.

 

[chas142]

What size battery have you? A 10A charger does sound very small TBH. And if that 10A is shared between two outputs it is little more than a trickle charger in some ways?

You mention your alternator puts out a regulated 14.4V . That is good on one hand, but I think has a downside on the other. You will be getting a good charging level but if you are driving for a while, the batteries may want to just have a float voltage applied to them but you are keeping them at 14.4V. It's the same as if you left a dumb mains charger on all the time with a 14.4V output.
The saving grace with the Alternator is driving times are such the impact is probably minimal.

I've had quite lengthy discussions with Ablemail on this topic of voltage and the owner - who used to work at a battery manufacturer in fact - has deliberately set his voltage peak to avoid over-voltage on the battery. His 14.1V is a little lower than ideal but is safe. He goes along the line of better too low than too high (the Ablemail chargers are designed as plug and play for non-technical installers. Many products have so many options that they end up wrongly setup by folk who don't know what is required).

Yes, the 10a is low in output, (was in a sale 25% off), but as it is fitted to work in conjunction with the original charger it should be fine. The liesure batteries are 2 x Leoch Gel 110 at C100. The standard vehicle charger on my set up should charge both batteries but appears to be a resistance somewhere, I expect in the Elektroblock and or wiring, another job to sort out, but worked around that at the moment.

So far I have only ever connected to mains at home, when driving never drive a huge distances without stopping, be that for a quick cuppa or to explore and overnight on route. So as you say should be minimal issues with this set up.

So after your info, I'm happy that I have the standard split charge system with the dual solar and dual charger, will suit my system and usage better than the other types.

Something else that I did purchase recently was a Silverline Car to Car jump charger, plugs into the cigar lighters, as that is a quick charge system I could use that as my battery bank has one battery in a removable battery box, so I can disconnect from the standard system and charge through the Silverline for the removable battery, that may well charge quicker as I assume the voltage is higher but would need to monitor that to avoid damage to the Gel.

Will also look again at better monitoring systems, I think as I have the dual batteries set ups I may get a couple of the wi-fi unit that are connected at the batteries, or even just one and wire in as removable, with quick fit plug and socket.

I think 14.1v is a little low myself, I would go with a higher voltage and fit an adjustable over voltage cut out if I considered it a problem, but as I said I think this set up suits my needs and habbits. Need more monitoring equipment to prove these points.

Yes, to many people they wouldn't understand or even want to understand the differences between difference set ups and voltages.

 

[mk1]

Nipped to my local garage to check about getting the alternator out to fit the Digital Regulator... While removal of the alternator is easy enough, it looks like it could be trickier then I thought to fir the Reg as not clear what kind of Alternator is fitted, so some further investigation required here.
Also took the opportunity to check some outputs as this is the first time out in the van since doing all the tests in this thread and upgrading my cable to 35mm.
I put the water heater on on the short drive home - that pulls around 190A @12V when running (the exact current depends on the battery voltage. It translates to 2300W +/- 20W once the Inverter overhead is factored in)
The current draw while driving was 95A. When the engine was off, the draw went up to around 194A - so the alternator was actually providing 100A of charge to help offset the load.
I am - very pleasantly - surprised at this. I expected a much smaller contribution from the Alternator to be honest so I am not sure how much benefit I will actually get in reality from the fitting of the Digital Regulator in my particular vehicle compared to the cost of installing.
I'm also wondering what Alternator I have fitted. The standard one is 90A and I am getting more than that, so I either have the uprated 120A (I don't see why as the van had no aux battery fitted when built) or the Alternator is just over-delivering, which is not that unsual for a decent branded unit.
I don't think it is worth an upgrade to the 120A unit so will probably leave that aspect until/if the alternator fails and then consider an upgrade.

I'd like to agree & add a little to this in case the bold text raises any eyebrows...

I have a standard-factory-fit 140A alternator & needed to run a microwave to defrost food for hot sales at a market. Measuring the voltage drop across a shunt (old school) I calculated that the alternator was contributing around 100A & the battery bank made up the rest (approx 200A total). Obviously I couldn't go for a drive so this was with the van engine at idle behind my stall. You could hear the engine was under load but no extra revs. Looking at the alternator spec sheet output graph (amps vs. rpm) I couldn't explain it until I realised that alternator RPM is not the same as engine RPM since it is geared-up something like x2 or x3 (I forget) so can produce the bulk of its power all the time. 2005 panel van nothing fancy. I have no idea whether this would knacker the alt/rec eventually but it was pleasing to discover & useful at the time!

 

[wildebus]

I'd like to agree & add a little to this in case the bold text raises any eyebrows...

I have a standard-factory-fit 140A alternator & needed to run a microwave to defrost food for hot sales at a market. Measuring the voltage drop across a shunt (old school) I calculated that the alternator was contributing around 100A & the battery bank made up the rest (approx 200A total). Obviously I couldn't go for a drive so this was with the van engine at idle behind my stall. You could hear the engine was under load but no extra revs. Looking at the alternator spec sheet output graph (amps vs. rpm) I couldn't explain it until I realised that alternator RPM is not the same as engine RPM since it is geared-up something like x2 or x3 (I forget) so can produce the bulk of its power all the time. 2005 panel van nothing fancy. I have no idea whether this would knacker the alt/rec eventually but it was pleasing to discover & useful at the time!

This video from Charles Sterling is quite interesting regarding Aternators and it talks about Engine and Alternator RPMs in some detail which may help translate those output graphs.

 

[chas142]

Yes, interesting video, whilst rebuilding various alternators and bench testing on various alternator test benches there can be a huge difference between outputs at lower RPM, (alternator), but can also be a huge difference between price of the alternators and the applications.

 

[chas142]

I'd like to agree & add a little to this in case the bold text raises any eyebrows...

I have a standard-factory-fit 140A alternator & needed to run a microwave to defrost food for hot sales at a market. Measuring the voltage drop across a shunt (old school) I calculated that the alternator was contributing around 100A & the battery bank made up the rest (approx 200A total). Obviously I couldn't go for a drive so this was with the van engine at idle behind my stall. You could hear the engine was under load but no extra revs. Looking at the alternator spec sheet output graph (amps vs. rpm) I couldn't explain it until I realised that alternator RPM is not the same as engine RPM since it is geared-up something like x2 or x3 (I forget) so can produce the bulk of its power all the time. 2005 panel van nothing fancy. I have no idea whether this would knacker the alt/rec eventually but it was pleasing to discover & useful at the time!

You could consider fitting a slightly smaller alternator pully, that would give you higher alternator speed, possible higher output and the fan a higher speed, cool the alternators internals better.

 

[mk1]

You could consider fitting a slightly smaller alternator pully, that would give you higher alternator speed, possible higher output and the fan a higher speed, cool the alternators internals better.

Yeah with little airflow in the engine bay I did wonder if heat would spell the end of that set-up eventually. Makes me wonder whether letting a powerful B2B charge flat house batteries at a standstill is a good idea too (that's the only reason I'd be interested in one i.e. fast charge without moving vehicle). I guess they have alternator/rectifier temperature monitoring?