How many amps can I bang into my leisure batteries without cooking them? (1 Viewer)

[jongood]

Following my shakedown trip I'm considering update/upgrades to the charging of the leisure batteries on my 2003 Clouliner so it lasts longer off grid.

It's unusual in that it has 2 alternators, a 24 volt one that charges the vehicle batteries and a 12 volt one that charges the leisure batteries which are 2 x 220 ah gels. It has 220w solar which was factory fitted 17 years ago with a CBE PWM (i'm assuming) regulator .

So my plan is to renew and upgrade the solar to around 500 watts 30 amps max?
Fit a battery monitor so I can see whats going on
maybe fit a battery to battery charger 30 amps.

So Ive got potentially 60 amps ( If i'm in Spain etc) and I don't know how much the 12 volt alternator would put in.

My concern is that if I've got half empty batteries and I start driving I could be putting a pretty big charge in and potentially fry something.

Any thoughts/suggestions

Jon

 

[cmcardle75]

Following my shakedown trip I'm considering update/upgrades to the charging of the leisure batteries on my 2003 Clouliner so it lasts longer off grid.

It's unusual in that it has 2 alternators, a 24 volt one that charges the vehicle batteries and a 12 volt one that charges the leisure batteries which are 2 x 220 ah gels. It has 220w solar which was factory fitted 17 years ago with a CBE PWM (i'm assuming) regulator .

So my plan is to renew and upgrade the solar to around 500 watts 30 amps max?
Fit a battery monitor so I can see whats going on
maybe fit a battery to battery charger 30 amps.

So Ive got potentially 60 amps ( If i'm in Spain etc) and I don't know how much the 12 volt alternator would put in.

My concern is that if I've got half empty batteries and I start driving I could be putting a pretty big charge in and potentially fry something.

Any thoughts/suggestions

Jon

The main concern is what else is on that 12V alternator and whether it is designed to work effectively without a directly connected battery. Your battery array can easily take 60A charge current. Generally, maximum charge rate for AGM is 0.3C (i.e. 132A), although reducing to 0.2C increases battery life. 60A is 0.14C.

 

[andy63]

Any thoughts/suggestions

Hi jon...I think you need lithium..
You won't need to worry about what you can give them..
Hope all is well..
Andy

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[jongood]

The main concern is what else is on that 12V alternator and whether it is designed to work effectively without a directly connected battery. Your battery array can easily take 60A charge current. Generally, maximum charge rate for AGM is 0.3C (i.e. 132A), although reducing to 0.2C increases battery life. 60A is 0.14C.

The only certainty is the fridge which is set up to run off the batteries with the engine off which I don't think is correct.

 

[jongood]

Hi jon...I think you need lithium..
You won't need to worry about what you can give them..
Hope all is well..
Andy

Thanks Andy, I agree it would take the problems away, apart from the one about convincing Sue.

Cheers
Jon

 

[andy63]

Thanks Andy, I agree it would take the problems away, apart from the one about convincing Sue.

Cheers
Jon

Lol...you should give that a go..
More peace of mind off grid..you could reduce the capacity of your current battery bank.. think of the weight saving or the extra wine you could carry...charged up in a fraction of the time...and proper maintenance free..
Fit and forget..
All for a few pounds..
well thats the theory
Andy..

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[jongood]

Lol...you should give that a go..
More peace of mind off grid..you could reduce the capacity of your current battery bank.. think of the weight saving or the extra wine you could carry...charged up in a fraction of the time...and proper maintenance free..
Fit and forget..
All for a few pounds..
well thats the theory
Andy..

Weight or space isnt a problem so what would you go for and from who?

would I have to change my mains chargers? 2 x CBE with only Gel or PB settings

 

[tonyidle]

You cannot charge at more than the battery will accept unless using a 'boost' device like a B2B charger. Your solar regulator will output a maximum voltage of 14.whatever volts much the same as the vehicle alternator so how much solar you install is not relevant to over-charging.

 

[Pausim]

I am not sure a B2B will help much with a dedicated alternator. Presumably the leisure batteries get all it is capable of producing and there is no 12V battery to power it from. I think you can get 24V to 12V B2Bs but that sounds like a heap of complications with joining the output to a circuit with it’s own direct alternator.

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[andy63]

Weight or space isnt a problem so what would you go for and from who?

I've already done it jon..
I dont have your constraints...ie a wife
And I took advantage of the offer that battery megastore had running on here for a while..but prices are getting a bit better as time passes
I have also fitted a sterling battery to battery..an mppt solar charge controller with a lithium charging profile..
On the mains side ive bought a dedicated lifepo4 mains charger..its only 20 amps max but thats the rate it does charge at and it does switch off when the charge is complete.. I did retain the cbe mains charger and use that for the start battery when it needs a charge
Only issue is that the lithium charger isn't designed as a power pack ..I only use it from time to time to bring them up to a full charge occasionally..relying on the 60amp battery to battery...and the solar..


So yes there are other things to consider..for me its no bother..I enjoy messing around with these things anyway..
Andy..

 

[funflair]

The only certainty is the fridge which is set up to run off the batteries with the engine off which I don't think is correct.

That's normal for N+B in my experience Jon

 

[funflair]

Weight or space isnt a problem so what would you go for and from who?

would I have to change my mains chargers? 2 x CBE with only Gel or PB settings

What about a combi charger/inverter Jon, you could get rid of your poxy little 1kw kettle and runs proper 2.4kw one on a 6 amp site supply.

Re your second alternator at 12v,

78395 basically says, "second alternator in place of charging converter" so 65A instead of 30A as standard, if that's how N+B plumbed it in it should be good for that amperage.
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[Lenny HB]

Exide recommends a max charge rate for their Gels of 25% of the capacity. Using that as a base your 2 x 220a/h Gels could be charged at up to to 110 amps. I doubt if you are going to achieve that and it would require some seriously heavy cables.

 

[Lenny HB]

The only certainty is the fridge which is set up to run off the batteries with the engine off which I don't think is correct.

That's normal for N+B in my experience Jon

Standard on most German vans.

 

[jongood]

Exide recommends a max charge rate for their Gels of 25% of the capacity. Using that as a base your 2 x 220a/h Gels could be charged at up to to 110 amps. I doubt if you are going to achieve that and it would require some seriously heavy cables.

Im not sure how old the gels are, ive got 2 lever arch files of records and gone back to 2011 and not founf a bill for leisure battery yet. I also know the previous owner always took ehu.

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[jongood]

Standard on most German vans.

Every day is school day

 

[funflair]

Every day is school day

Obviously except your old Arto's Jon.
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[jongood]

Obviously except your old Arto's Jon.
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While we re on this subject, the D+ has a wire going to it, is this the one?

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[funflair]

While we re on this subject, the D+ has a wire going to it, is this the one?

Assuming it is AES Jon that just tells the fridge to run off the 12v batteries while the engine is running, you should also be able to manually select 12v if you wanted to if you come out of AES.
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[funflair]

Just for reference, anybody who thinks vans are expensive today should check these out from 2003 and Jon can save the link.

https://magazine.camperonline.it/cataloghi/Clou_650_750_2003.pdf

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[Lenny HB]

Just for reference, anybody who thinks vans are expensive today should check these out from 2003 and Jon can save the link.

https://magazine.camperonline.it/cataloghi/Clou_650_750_2003.pdf

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A sign of the times, it seems strange that in such large vans the majority of the layouts have a transverse rear bed.

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[jongood]

Just for reference, anybody who thinks vans are expensive today should check these out from 2003 and Jon can save the link.

https://magazine.camperonline.it/cataloghi/Clou_650_750_2003.pdf

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Thats right Martin and as today it was only the starting price. I have the invoice showing that the previous owner paid 226,000 euros for it in 2005 at 2 years old.

 

[DBK]

You've got over twice the battery capacity we have and the same amount of solar. If the sun is shining and it is summer we can last more or less indefinitely off grid. The problems come when the sun stays low in the sky, say around October onwards, or when it is cloudy. I've fitted a 60A B2B and it has proved very useful, a drive of less than an hour is usually enough to recharge things after a few days without EHU. I know my alternator can handle this load but if you are concerned with yours you can get temperature sensors which fit on the alternator and matched to a suitable B2B they will prevent overheating.

But I would also look at why you are running out of power. Are all your lights LED and how old are the batteries?

My suggestion, assuming the batteries are good and loads have been minimised would be a battery monitor and B2B first then see how you get on.

 

[autorouter]

The main concern is what else is on that 12V alternator and whether it is designed to work effectively without a directly connected battery.

It's important to make sure there's always a battery connected to the alternator while it's running. If the battery gets isolated, the alternator voltage can surge to over 60 volts, for several seconds at least. It's unlikely to happen with the starter battery as that's permanently connected, but the leisure battery connection can be lost either by a fuse blowing or the switching the isolator off.

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[bigtwin]

With an alternator that is dedicated to the leisure bank, there is no need for a B2B surely?

The raison d'être of the B2B is to overcome the fact that the output from the (single) alternator is throttled back because the vehicle battery requires less charge than the leisure bank. In this case, the output from the second alternator will feed the leisure bank (at its rated output) as long as the leisure bank requires a charge.

Narrowboats have the same arrangement of two alternators; one for the engine battery and one for the leisure bank.

Happy to be educated to the contrary of the above.

Ian

 

[funflair]

With an alternator that is dedicated to the leisure bank, there is no need for a B2B surely?

The raison d'être of the B2B is to overcome the fact that the output from the (single) alternator is throttled back because the vehicle battery requires less charge than the leisure bank. In this case, the output from the second alternator will feed the leisure bank (at its rated output) as long as the leisure bank requires a charge.

Narrowboats have the same arrangement of two alternators; one for the engine battery and one for the leisure bank.

Happy to be educated to the contrary of the above.

Ian

My feeling is that you are right as there is no battery to B2 from, in Jons set-up the habitation batteries would be the starter batteries.
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[cmcardle75]

With an alternator that is dedicated to the leisure bank, there is no need for a B2B surely?

The main purpose of the B2B in this situation is to effect smart charging. A directly connected dumb alternator knows nothing about bulk/absorbtion/float and will reduce battery life by overcharging. It probably just gives 14.4V, so would act like an eternal absorbtion charger. If it is a smart alternator it probably does a better job.

So if you have a dumb 12V alternator, you have a few choices to make. Connect directly and hope the battery doesn't overcharge, connect via a B2B and hope that there aren't wild voltage swings on the alternator output. Put the cheapest lead acid battery you can find (with reasonable max charge current) as a buffer between the alternator and B2B...

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[CazPaul]

Im not sure how old the gels are, ive got 2 lever arch files of records and gone back to 2011 and not founf a bill for leisure battery yet. I also know the previous owner always took ehu.

Our x2 140AH Deta gels are original March 2005 Van registered in Germany, we just lasted in late September northern England 6 days without EHU and they were still on 12.7 when we were leaving, x2 80watt original fit solar and PWM regulator.

I would leave it as it is Jon unless there is a problem and you are running out of power. I never want owt doing unless there is a need for it.

 

[jongood]

Our x2 140AH Deta gels are original March 2005 Van registered in Germany, we just lasted in late September northern England 6 days without EHU and they were still on 12.7 when we were leaving, x2 80watt original fit solar and PWM regulator.

I would leave it as it is Jon unless there is a problem and you are running out of power. I never want owt doing unless there is a need for it.

I do have a problem Paul, I'm running out of power in a couple of days. I realise we re a little power hungry but there's some money in the budget and I want to make the vehicle suit our requirements not the other way round. Interestingly when I had the Clou and the Arto side by side the clou was generating about 3 amps when the Arto was generating about 5 from 200watts.

 

[jongood]

The main purpose of the B2B in this situation is to effect smart charging. A directly connected dumb alternator knows nothing about bulk/absorbtion/float and will reduce battery life by overcharging. It probably just gives 14.4V, so would act like an eternal absorbtion charger. If it is a smart alternator it probably does a better job.

So if you have a dumb 12V alternator, you have a few choices to make. Connect directly and hope the battery doesn't overcharge, connect via a B2B and hope that there aren't wild voltage swings on the alternator output. Put the cheapest lead acid battery you can find (with reasonable max charge current) as a buffer between the alternator and B2B...

Ive got a bank of 24 volt batteries (chassis) and the leisure batteries that are not connected to each other. My logic with a B2b has been to boost the charging by effectively using both alternators to charge the leisure batteries?

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