Leisure battery charging

linkshouse

Full Member
I was looking at battery to battery charger options and was more or less settled on the Sterling B2B unit when I came across an article that made me think. There they suggest a simple relay with suitably size (large) cable offers a better solution that is kinder to the leisure batteries.

It's not so much the cost savings as the wish not to cane my leisure batteries that makes me ask.

I'd be grateful for the views and experiences.

Thanks

Phill
 

Nabsim

Full Member
My factory fit split charge setup was never that good, never saw higher than mid 13’s on volts with engine running. I fitted a Votronic 30amp B2B and immediately saw plus 14v with engine running and same cabling.

I think you first need to decide what battery technology you want to fit, split charge system not good for Lifepo4 for example.

From what I have read older technology battery’s and properly sized cabling should fit the bill for most folks. I did toy with getting a plait charge kit from the likes of 12v planet but as the B2B I was interested in was almost plug and play with what I had there wasn’t much cost difference for me.

If you have a smart alternator I think you may need to go B2B regardless
 

linkshouse

Full Member
My factory fit split charge setup was never that good, never saw higher than mid 13’s on volts with engine running. I fitted a Votronic 30amp B2B and immediately saw plus 14v with engine running and same cabling.

I think you first need to decide what battery technology you want to fit, split charge system not good for Lifepo4 for example.

From what I have read older technology battery’s and properly sized cabling should fit the bill for most folks. I did toy with getting a plait charge kit from the likes of 12v planet but as the B2B I was interested in was almost plug and play with what I had there wasn’t much cost difference for me.

If you have a smart alternator I think you may need to go B2B regardless
My van is a 2013 Citroen Relay so it’s looking like a B2B will be the way to go.
 

wildebus

Full Member
I was looking at battery to battery charger options and was more or less settled on the Sterling B2B unit when I came across an article that made me think. There they suggest a simple relay with suitably size (large) cable offers a better solution that is kinder to the leisure batteries.

It's not so much the cost savings as the wish not to cane my leisure batteries that makes me ask.

I'd be grateful for the views and experiences.

Thanks

Phill
I would say if you want to look after your batteries in the best way then a relay solution is absolutely NOT the optimum solution (for ANY battery technology).
An alternator is NOT a battery charger and does not charge batteries fully (and this is just as true of Vehicle Starter Batteries which would benefit of regular proper charging from a battery charger to give them the best service life.
 

Millie Master

Full Member
Well, as has been written on here and elsewhere so many times over, electricity and anything to do with it is a black art that so many of us get totally fudged with!

Now Dave (@wildebus) is one of those lucky bods who appears to soak up anything and everything to do with this dreaded subject almost like a sponge, and I am sure he knows what he is writing about with his above advice............. but Phill, this is what I did in my installation and so far it has worked perfectly for almost 5 years of quite extensive use.

My VB is connected via a split charge relay (https://www.vehiclewiringproducts.co.uk/c-219-relays-flasher-units/c-232-split-charge-relays) and the requisite fuse to the 2 x LB's which are also connected to the solar panel.
I also have a large and powerful battery charger wired into the system which I only use when stopping on sites with EHU, it is connected to the first of my LB's but in turn it obviously feeds power to the 2nd LB and no doubt also back to the VB if the LB's have both reached full charge.

As I said, this installation has worked for me over the years, it might not be the best, but for me it does!

Phil

ps. currently I have the original and now getting on for 5 year LB disconnected from the system as I am running some tests on it to see how it is holding its' power as I have a sneaking suspicion that it isn't!
 

linkshouse

Full Member
Well, as has been written on here and elsewhere so many times over, electricity and anything to do with it is a black art that so many of us get totally fudged with!

Now Dave (@wildebus) is one of those lucky bods who appears to soak up anything and everything to do with this dreaded subject almost like a sponge, and I am sure he knows what he is writing about with his above advice............. but Phill, this is what I did in my installation and so far it has worked perfectly for almost 5 years of quite extensive use.

My VB is connected via a split charge relay (https://www.vehiclewiringproducts.co.uk/c-219-relays-flasher-units/c-232-split-charge-relays) and the requisite fuse to the 2 x LB's which are also connected to the solar panel.
I also have a large and powerful battery charger wired into the system which I only use when stopping on sites with EHU, it is connected to the first of my LB's but in turn it obviously feeds power to the 2nd LB and no doubt also back to the VB if the LB's have both reached full charge.

As I said, this installation has worked for me over the years, it might not be the best, but for me it does!

Phil

ps. currently I have the original and now getting on for 5 year LB disconnected from the system as I am running some tests on it to see how it is holding its' power as I have a sneaking suspicion that it isn't!
Can I ask what year your vehicle is?

Actually it's the alternator that I'm interested in.

I gather the split charge relays don't work with Euro5 (think it's 5) vehicles
 

wildebus

Full Member
Well Phil, a simple Relay based Split Charge system can be very effective. It is what I am using myself at the moment in fact, but my comment was in reply to the idea that it "offers a better solution that is kinder to the leisure batteries" which is basically balderdash.

Quick summary of my take on this subject ....
You need at least one way to regularly FULLY and PROPERLY charge your Leisure Batteries.
An Alternator just will not do this, so a Relay split charge system will also not do this - but if you have a Multi-stage Mains Charger and/or a Multi-stage Solar Controller that can complete the job, then a Relay split charge is fine to get a decent part-charge into the battery (in fact, the CTEK D250 B2B with SmartPass does precisely this - it uses an relay in the Smart Pass module which operates at lower states of charge and as soon as the main D250S detects the battery has a certain level of charge (based on voltage level) it disengages the relay and uses the B2B Charger electronics to finish the job.

If you DON'T have a proper charger to finish the job, then the end result is you have a battery that will never get fully charged and loosing out on maybe the top 10% of the battery capacity - and with the typical lead acid battery only recommended to go down to 50% SoC, the end result is only accessing around 40Ah of the normal 50Ah per 100Ah of battery - so in other words, loosing out on 20% of the available capacity (40Ah instead of 50Ah for a 100Ah battery for example)
 

linkshouse

Full Member
Well Phil, a simple Relay based Split Charge system can be very effective. It is what I am using myself at the moment in fact, but my comment was in reply to the idea that it "offers a better solution that is kinder to the leisure batteries" which is basically balderdash.

Quick summary of my take on this subject ....
You need at least one way to regularly FULLY and PROPERLY charge your Leisure Batteries.
An Alternator just will not do this, so a Relay split charge system will also not do this - but if you have a Multi-stage Mains Charger and/or a Multi-stage Solar Controller that can complete the job, then a Relay split charge is fine to get a decent part-charge into the battery (in fact, the CTEK D250 B2B with SmartPass does precisely this - it uses an relay in the Smart Pass module which operates at lower states of charge and as soon as the main D250S detects the battery has a certain level of charge (based on voltage level) it disengages the relay and uses the B2B Charger electronics to finish the job.

If you DON'T have a proper charger to finish the job, then the end result is you have a battery that will never get fully charged and loosing out on maybe the top 10% of the battery capacity - and with the typical lead acid battery only recommended to go down to 50% SoC, the end result is only accessing around 40Ah of the normal 50Ah per 100Ah of battery - so in other words, loosing out on 20% of the available capacity (40Ah instead of 50Ah for a 100Ah battery for example)
Thanks very much for this.

I have a 200W solar panel with a Victron controller so hopefully that should do the finishing off for me.

Just one more area that I’m unclear on is the split charge relay compatibility with modern vehicles. I’m sure I’ve read somewhere that they won’t work with newer alternators.
 

Greggbear67

Full Member
My leisure batteries are charged through a simple homemade split charge setup. A cable goes from my starter battery via a heavy duty rallycar style isolator then through an 80amp midi fuse to the 2 leisure batteries which are then war that to the chassis. I can isolate the batteries so when parked up I only use power from the leisure side & don't flatten my starter battery. When locked in the isolator allows all 3 batteries to charge. A voltage meter fitted to the leisure batteries regularly shows 14.1- 14.4v when the engine is running.
Next job for me is solar & an inverter/domestic fridge.
 

wildebus

Full Member
I think it’s a problem for any vehicle that has a smart alternator fitted. Someone will correct that statement if wrong but that’s how I saw it. Don’t think it is necessarily Euro number of engine
That is a good summary of the situation :)

If in doubt if you have one fitted or not, if you provide the relevant Main Dealer with the VIN or Registration Number, they should be able to confirm one way or the other - or a trip to the Garage and a look under the bonnet by them should reveal the situation.

A 2013 Van really could very easily be either but at a guess I would say probably not a Smart Alternator as a standard fit.
 

linkshouse

Full Member
That is a good summary of the situation :)

If in doubt if you have one fitted or not, if you provide the relevant Main Dealer with the VIN or Registration Number, they should be able to confirm one way or the other - or a trip to the Garage and a look under the bonnet by them should reveal the situation.

A 2013 Van really could very easily be either but at a guess I would say probably not a Smart Alternator as a standard fit.
Thanks

I'll do a bit of investigating

Phill
 

Millie Master

Full Member
Can I ask what year your vehicle is?
Phill, as you might recall, my 'Millie' is an 08 Renault Master, but when itcomes to the SCR does it really matter?

I know you can beat the prices charged by the company I gave you earlier, but I did arrange with the owner some time ago that if you mention the Motorhome Builder name when ordering any parts that they will give you a discount.
The main man there is very knowledgeable and he shuld be able to answer any technical questions with regards to compatability with the alternator and other systems fitted to your wagon.

Phil

ps. As for discounts, it was always part of my commercial background where, when considering suppliers, I always went for the best with regards to service and quality of product and then when all of those boxes had been ticked I always asked what discount off their normal prices they were willing to give and I normally got at the very minimum 10%.
 

linkshouse

Full Member
Thanks

I'll do a bit of investigating

Phill
Looking on t'Internet it looks as though the 2013 Relay has an old-style, non-smart, alternator. Once I get that van in my hands on Thursday I'll chuck a meter on the battery and test the alternator operation to verify. If so then I'll skip the Sterling unit and just go with a split charging relay.

Phill
 

linkshouse

Full Member
Phill, as you might recall, my 'Millie' is an 08 Renault Master, but when itcomes to the SCR does it really matter?
Sorry, yes I should have known about your vehicle from browsing your conversion write up.

As for the SCR, it does matter if the alternator fitted is a smart one controlled through the vehicles ECU as they only deliver a reduced charge when driving to improve fuel economy and then boost the charge when coasting (regenerative breaking).

I know you can beat the prices charged by the company I gave you earlier, but I did arrange with the owner some time ago that if you mention the Motorhome Builder name when ordering any parts that they will give you a discount.
I wasn't trying to save money on the SCR and will probably go with the Durite one you've recommended once I know for sure that I can safely use this simpler option rather than having to go down the B2B route.

Good to know about the discount though as I am sure I will have lots of electrical items to buy along the way. Thanks for arranging that.

The main man there is very knowledgeable and he shuld be able to answer any technical questions with regards to compatability with the alternator and other systems fitted to your wagon.
Also good to know.

Phil

ps. As for discounts, it was always part of my commercial background where, when considering suppliers, I always went for the best with regards to service and quality of product and then when all of those boxes had been ticked I always asked what discount off their normal prices they were willing to give and I normally got at the very minimum 10%.
Thank you for your help and advice.

Regards

Phill
 

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