A silly question.....please be nice (1 Viewer)

[SheikhLala]

I'm thinking that for peace of mind I should ensure that my battery charging is up to scratch, so I dont have the worries of nearly killing my leisure batteries, like I did earlier this year. I have a bog standard setup with 1 vehicle battery, 1 solar panel, mppt controller and 2 leisure batteries.
I would like to fit.....have fitted....a B2B....if thats what you call it? I've had a little read up and to be honest, completely confused myself. I understand that the alternator charges the van battery and the solar panel charges the leisure batteries.
Is it possible to have any excess from either charging system distributed to the other system if required?
We dont really need to have the ability to be off grid for days at a time but would like to have the ability for a night or so. I have medical equipment which I need to use overnight, the power consumption is relatively low but if the weather the following day isnt great, I dont want to be stressing about batteries getting charged fully.
Or, am I over thinking this?
Thank you for your patience.

 

[funflair]

A B2B will give you more charge to your habitation batteries while you are driving so the next time you stop you stand a chance of being fully charged.

Edit, just to add the setup you have should give you a couple of nights I would have thought.

 

[Barriesimpson]

We sometimes find ourselves with low leisure battery power (60%, once even 48%) if we have used the air conditioning during the afternoon. So I start the engine and leave it running for 15 or 20 minutes and this recharges the batteries up to 82% which is enough for the night until the sun comes up again in the morning. This works here in the Canary Islands, obviously because the sun always shines every day. Not sure how this habit will hold when in Europe though.

 

[autorouter]

I would like to fit.....have fitted....a B2B....if thats what you call it? I've had a little read up and to be honest, completely confused myself. I understand that the alternator charges the van battery and the solar panel charges the leisure batteries.
Is it possible to have any excess from either charging system distributed to the other system if required?

In your existing setup, the alternator charges the van battery, as you say. There is also a 'split charge relay' which connects the leisure battery to the alternator when the engine is running, so that the alternator can charge the van and leisure batteries. When the engine stops, the leisure battery is disconnected from the alternator.

If you fit a B2B, that will take power from the alternator to charge the leisure batteries while the engine is running. A B2B is a better more powerful way of charging the leisure batteries, and is considered an upgrade from a split charge relay.

The other thing you mention is charging in the opposite direction. A 'battery maintainer' will take a small trickle charge from the leisure battery and send it to the van battery. This is especially useful if the leisure battery is being charged by solar. There are many brands of battery maintainer. A favourite on here is the VanBitz BatteryMaster, but there are others made by Ablemail, CBE, Votronic, Schaudt etc.

An alternative is to get a solar controller that has two battery outputs, where you can change a setting so that say 10% of the charge goes to the van battery. If you get more solar panels and have to upgrade your solar controller, it's worth considering a dual battery type.

 

[meanders]

No such thing as a silly question. However, here you usually will get some silly answers to sensible questions!

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[DBK]

If you can fit a second leisure battery it would help a lot I think.

A B2B comes into its own when you are only driving a short distance each day as it maximises the charging. Alternatively, it also works when you just start the engine when static although that isn't generally recommended.

 

[Barriesimpson]

Alternatively, it also works when you just start the engine when static although that isn't generally recommended.

Why not?

 

[Silverman]

If you can fit a second leisure battery it would help a lot I think.

A B2B comes into its own when you are only driving a short distance each day as it maximises the charging. Alternatively, it also works when you just start the engine when static although that isn't generally recommended.

He's got two leisure batteries.

 

[Spriddler]

Why not?

Frequent topic. Lots of posts and opinions on here. In short it can prematurely clog up the DPF, plus it isn't good to start a cold diesel engine and leave it ticking over with virtually no load. It's advisable to get the engine up to operating temp without undue delay, preferably by driving off.

 

[eurajohn]

Why not?

From your previous posts I believe you have recent van, modern diesels with DPF and catalytic converters will be likely to have engine management problems if the engine is allowed to idle for long periods.

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[Captain Yoghurtpot]

If you fit a B2B, that will take power from the alternator to charge the leisure batteries while the engine is running

But NOT charge the engine battery, as a split charge would do??
Otherwise , I see no difference in either system as both are charging the leisure battery via the alternator.
I am also now confused ( does not take much ) but am also looking at the same scenario as sheikhLala in the original post.

 

[Gaston aires]

I would consider when you tour, spring/ summer/autumn/ winter. Winter you probably want a B2B but we never run short of power spring summer autumn without a B2B
Moderate usage, kettle, toaster, hairdryer, and small appliances. We have a Fogstar lithium 230 Amp hour battery and never been below 150 ah.
Phil

 

[Captain Yoghurtpot]

I'm thinking that for peace of mind I should ensure that my battery charging is up to scratch, so I dont have the worries of nearly killing my leisure batteries, like I did earlier this year. I have a bog standard setup with 1 vehicle battery, 1 solar panel, mppt controller and 2 leisure batteries.
I would like to fit.....have fitted....a B2B....if thats what you call it? I've had a little read up and to be honest, completely confused myself. I understand that the alternator charges the van battery and the solar panel charges the leisure batteries.
Is it possible to have any excess from either charging system distributed to the other system if required?
We dont really need to have the ability to be off grid for days at a time but would like to have the ability for a night or so. I have medical equipment which I need to use overnight, the power consumption is relatively low but if the weather the following day isnt great, I dont want to be stressing about batteries getting charged fully.
Or, am I over thinking this?
Thank you for your patience.

Good post.
Informative.

 

[autorouter]

But NOT charge the engine battery, as a split charge would do??
Otherwise , I see no difference in either system as both are charging the leisure battery via the alternator.
I am also now confused ( does not take much ) but am also looking at the same scenario as sheikhLala in the original post.

The starter battery is permanently connected to the alternator, and is always charged by it. All kinds of bad things happen if by chance the starter battery gets disconnected from the alternator while the engine is running. A lot of effort is put into making sure that never happens.

The split charge relay connects the leisure battery to the alternator when the engine is running, and disconnects it when the engine stops. So both batteries, starter and leisure, are charged by the alternator.

The same happens with a B2B. The starter battery is charged by the alternator exactly as before. The B2B charges the leisure batteries when the engine is running, getting the exact voltage and amps required by the leisure battery for optimum charging.

 

[Captain Yoghurtpot]

The starter battery is permanently connected to the alternator, and is always charged by it. All kinds of bad things happen if by chance the starter batter gets disconnected from the alternator while the engine is running. A lot of effort is put into making sure that never happens.

The split charge relay connects the leisure battery to the alternator when the engine is running, and disconnects it when the engine stops. So both batteries are charged by the alternator.

Thank you autorouter .
If I may ask, how does the split charger know when the leisure battery has had enough charge, or does it just keep pumping away whilst you are running, potentially overcharging a simple Lead Acid battery, which only stops when you switch of the engine completely?

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[autorouter]

If I may ask, how does the split charger know when the leisure battery has had enough charge, or does it just keep pumping away whilst you are running, potentially overcharging a simple Lead Acid battery, which only stops when you switch of the engine completely?

In a vehicle with no leisure battery, the alternator puts out a fixed voltage, and the amps gradually reduces to a low level when the starter battery fills up. The leisure battery gets the same treatment when the split charge relay connects it.

If the leisure battery type is not a flooded lead-acid like the starter battery, it won't get the optimised charging profile that a mains charger would give it. But typically the engine is rarely run for more than a few hours at a time anyway, so even a B2B won't be giving it the extended timed absorption stage that gel and AGM batteries require for best battery life. But when combined with solar the batteries are usually kept in pretty good shape.

 

[Captain Yoghurtpot]

In a vehicle with no leisure battery, the alternator puts out a fixed voltage, and the amps gradually reduces to a low level when the starter battery fills up. The leisure battery gets the same treatment when the split charge relay connects it.

If the leisure battery type is not a flooded lead-acid like the starter battery, it won't get the optimised charging profile that a mains charger would give it. But typically the engine is rarely run for more than a few hours at a time anyway, so even a B2B won't be giving it the extended timed absorption stage that gel and AGM batteries require for best battery life. But when combined with solar the batteries are usually kept in pretty good shape.

Aha........now it's becoming clearer.
So for me, with no solar other than perhaps a cheapo portable panel which I can use as and when and connect directly to my leisure battery , using either of the solar charger types (mppt or the other one) when stationary and engine not on, to keep leisure battery topped up, or if on site, hook up to 240v via my charger on board and charge leisure battery that way, a simple split charger system to keep my basic 85amp leisure battery topped up when travelling maybe all I need?
We are rarely off- grid when away but will use the van daily to get out and about in the area we are in and I will also be using our van now as my daily drive.
Thanks for your patience and sorry to hi- jack the thread somewhat, but hope my scenario might be one others are considering and pondering over and can get some inspiration from.
Cheers
Iain
PS we have not got a " smart" alternator, just a bog standard one.
Does this affect things?

 

[autorouter]

PS we have not got a " smart" alternator, just a bog standard one.
Does this affect things?

There are times on the average journey where you take your foot off the gas as you slow down. You also brake to reduce speed when you see an obstruction far ahead. The alternator is a load to the engine when it is charging the starter battery. It might be a good idea to switch off the alternator while the engine is working hard to accelerate, and switch it on to present a load when you are slowing down or braking. With modern electronics, it's easy to detect when the vehicle is slowing down or braking. A smart alternator switches charging on when slowing down and braking, and switches charging off when accelerating or cruising.

It doesn't actually switch on and off, it just changes the voltage. At 14.4V, it charges the battery. At 13V, it doesn't charge the battery, but can still power the lights, wipers, fans etc. It keeps the starter battery at about 70% full, so there is always room for a bit more charge when braking.

That is not what you want for the leisure battery, you want charging all the time until it's 100% full. A split charge system just splits the alternator charging between the starter and leisure batteries, so the leisure battery would never be full. Even worse, if you connect a full leisure battery to a half full starter battery, the leisure battery will charge the starter battery, losing some charge in the process.

A B2B takes charge from the alternator at whatever voltage it happens to be, in the same way that the lights and wipers do. It then gives out the correct voltage for charging the battery. That's why a B2B is considered essential if you have a smart alternator, but is just a good upgrade for a standard alternator.

 

[Lenny HB]

Why not?

With modern diesels they should be started and driven off straight away.
You should never start them and run them on tickover unless you have very deep pockets.
They never get up to operating temperature on tickover which bu**ers the CAT & DPF can cause glazed bores and various other problems.

 

[scotzsue]

I'm thinking that for peace of mind I should ensure that my battery charging is up to scratch, so I dont have the worries of nearly killing my leisure batteries, like I did earlier this year. I have a bog standard setup with 1 vehicle battery, 1 solar panel, mppt controller and 2 leisure batteries.
I would like to fit.....have fitted....a B2B....if thats what you call it? I've had a little read up and to be honest, completely confused myself. I understand that the alternator charges the van battery and the solar panel charges the leisure batteries.
Is it possible to have any excess from either charging system distributed to the other system if required?
We dont really need to have the ability to be off grid for days at a time but would like to have the ability for a night or so. I have medical equipment which I need to use overnight, the power consumption is relatively low but if the weather the following day isnt great, I dont want to be stressing about batteries getting charged fully.
Or, am I over thinking this?
Thank you for your patience.

We have 1 leisure battery, solar and a battery master, use medical equipment overnight, can last 5 days without moving.but we don't watch much tv so it's lights and pumps mostly and charging phones, we do have small back up power packs for those if needed.

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[PlacidoD]

In a vehicle with no leisure battery, the alternator puts out a fixed voltage, and the amps gradually reduces to a low level when the starter battery fills up. The leisure battery gets the same treatment when the split charge relay connects it.

If the leisure battery type is not a flooded lead-acid like the starter battery, it won't get the optimised charging profile that a mains charger would give it. But typically the engine is rarely run for more than a few hours at a time anyway, so even a B2B won't be giving it the extended timed absorption stage that gel and AGM batteries require for best battery life. But when combined with solar the batteries are usually kept in pretty good shape.

So as I read what you say with flooded lead acid leisure battery/ies the benefits of B2B are limited but with Gel, GSM and LiFePo4 there are greater benefits. So in my case a 2nd 95Ah lead acid to go with the first would be the best use of money unless part of a planned upgrade to one of the latter types?

I would like to upgrade to Lithium but that would mean:
(a) a B2B
(b) New mains charger (Current unit is gel and lead acid only)
(c) New solar charge controller
So while the price of lithium is getting competitive it is the cost of the ancillaries that weighs the balance against a change over at this time.

My only real necessary decision is whether to hold off on a 2nd 95Ah lead acid with a view to an upgrade somewhere down the line or assume that I am sticking with lead acid for the next 2+ years (My 1st leisure 95Ah is just one month old).

Chris

 

[autorouter]

So as I read what you say with flooded lead acid leisure battery/ies the benefits of B2B are limited but with Gel, GSM and LiFePo4 there are greater benefits. So in my case a 2nd 95Ah lead acid to go with the first would be the best use of money unless part of a planned upgrade to one of the latter types?

If you get a second 95Ah flooded battery, the maximum charging current (for the pair) will be about 40A rather than 20A for the existing single battery. I don't know what amps you get from the split charge relay, but I would imagine it's about 20A at most. That's fine for a single 95Ah battery, and would also be OK for a pair of them.

But with two batteries you could fit a B2B. If you got a Victron Orion XS, that has settable amps values up to 50A, so you could set it to 20A for one battery, or 40A for two. Then when you get lithium, set it to its maximum of 50A.

I don't think the mains charger on gel setting, or the solar charger, will cause any damage to a lithium battery, they just won't charge it up to 100%. But that's no bad thing, apart from maybe you missing out on that bit of extra charge. The only thing that's advisable for lithium is a B2B.

 

[Barriesimpson]

With modern diesels they should be started and driven off straight away.
You should never start them and run them on tickover unless you have very deep pockets.
They never get up to operating temperature on tickover which bu**ers the CAT & DPF can cause glazed bores and various other problems.

Ok, I've been reading up a lot on this. It seems that a short run of the engine on tick over - 15 minutes, will do no damage whatsoever and the DPF will clean itself up on the next run. The problems start when idling for a couple of hours or even days (yes, in very cold countries they do this). So for now I think I'll be ok all the time it's only 10 or 20 minutes. Feel free to counter my thinking and if anyone has any horror stories on this subject, please share.

 

[1967bowesj]

Ok, I've been reading up a lot on this. It seems that a short run of the engine on tick over - 15 minutes, will do no damage whatsoever and the DPF will clean itself up on the next run. The problems start when idling for a couple of hours or even days (yes, in very cold countries they do this). So for now I think I'll be ok all the time it's only 10 or 20 minutes. Feel free to counter my thinking and if anyone has any horror stories on this subject, please share.

I’m sure you will get some replies

 

[Spriddler]

Ok, I've been reading up a lot on this.................Feel free to counter my thinking and if anyone has any horror stories on this subject, please share.

No need. You've read it up. Your choice. Most of us have already made our decision.

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[Barriesimpson]

No need. You've read it up. Your choice. Most of us have already made our decision.

Helpful comment of the year award goes to...........

 

[OldAgeTravellers]

Helpful comment of the year award goes to...........

I think that is unnecessary sarcasm. Your comment #23 says that you have been reading upon it and think you will be ok.
That is your conclusion others may be different which is all that Spriddler said.
In your case it may be ok, you live in the Sun your engine and oil is relatively warm all the time. Your general wear will be less. Cam belts for example last longer in warm climates because the rubber is not stressed by the cold so much. It is only a few degrees but with flexible compounds a small amount matters. Your bores will not glaze as much because your oil is less viscous all the time. The differences are small.
However living where you do you may not do the extended highish speeds needed for regeneration.
It is all a matter of “Do you feel lucky” you asked a question, you got an answer, you did your research and found an answer that suited you more. The choice is yours. There is no absolute answer other than “It depends”.
I know my usage conditions and make my choice accordingly.

 

[Bessy765]

Why not?

In an ideal situation diesel engines should be run and operated at its design temp. Ticking over for extended periods of time is not recommended, excess water will collect in the exchaust and on modern engines clog up the DPF filter.

 

[Bessy765]

Re the B2B it will certainly help if you are driving, but adding extra solar will help when not moving. Also a lot of converters fit wiring that will not handle charging currents efficiently if you have the B2B fitted the wiring should be heavier allowing more current to flow.

 

[Spriddler]

Helpful comment of the year award goes to...........

I was in the motor trade for 30 years and spent too much of my time giving free advice to worried owners and patiently explaining the options and solutions only for them to say............"Well, on the internet..........." or "A bloke in the pub reckons ........", never to see them again.

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