Which DC to DC controller

[EdRedBird]

Looking at the first 4 renogys here

Amazon.co.uk : renogy dc to dc charger

Now the 60A (blue one) is apparently loud (hearsay youtube) I have noise sensitive passengers so I would rule that one out
The 50A MPPT one I have seen the set up and did not hear a thing myself on youtube .... However Solar panels are 2 years down the line (budget)
And I figure I can upgrade the DC-DC unit later if I place it handy

That leaves the 20 and 30A ones......
It will charge slower ? But how much slower is to slow?

Startoff will be a bank of 2 AGM batteries (again budget and later upgrade - Again if there is a price argument 20% to go for Lithium straight away I am all ears/eyes)

Looking at 12 V coolbox eventually fridge
4x 3w ceiling lights
Microwave / induction hob (800w)
Coffee machine

 

[ManTheVan]

I don’t know about renogys, but in answer to your question, I can recommend ones made by Sterling. Ours is 30A and together with the LiFePO4 110Ah battery and a decent Victron MPPT solar controller, means we have never had to use EHU.

Our setup is different though, as we have a 3-way fridge and gas hob, no microwave. We can use an induction hob via inverter, but never had the need.

 

[autorouter]

That leaves the 20 and 30A ones......
It will charge slower ? But how much slower is to slow?

For a battery below about 80%, the calculation is simple. A 30A B2B will put in about 30Ah per hour of driving. The B2B puts out its full output, as shown on the label. When it gets to 80%, the amps tails off, so it's not so easy to calculate. But as a rough guess you could estimate it's about half the amps on average. So 15Ah per hour of driving for a 30A B2B.

The charging process is not 100% efficient, but since charging is at 14.5V and discharging is at about 12.5V, that is mostly where the inefficiency goes, so the amps calculation is reasonably good.

 

[RogerIvy]

Votronic and Victron also make some really good Dc-Dc chargers

 

[Otter Spotter]

Sterling are good too

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[Tombola]

you say bank of agm abtteries but what total ah are you charging.
noise from a b2b surley isnt gonna be louder than your engine and road noise.

general rule you want your charger to throw in as much as poss, 5% is bad, 10% is low, 20% is ok 30% of battery ah is good, after that you are talking lithiums that can take pretty much anything you throw at it.
remember its all about what goes into your batteries from whatever source, If you are travelling, will your solar also be pumping in, and you alternator ?
30 a is a good all rounder

 

[EdRedBird]

autorouter so.... above 80% the higher current starts to have effect....
Hypothetically a 100Ah battery which is down rp 20% would need 2h at 30Ah to get up to 80% and another 3 to get up to 100 ish?
At 60% that would half these times ?

Presuming you are not drawing on the batteries while driving ...because well you are driving those times are not shocking.....
It is more going to be calculating how much I am drawing when I stand still

 

[EdRedBird]

Tombola Solar is a bit away yet. I will run a dud wire to connect pannels at a later date but that is at LEAST a year away

 

[autorouter]

@autorouter so.... above 80% the higher current starts to have effect....
Hypothetically a 100Ah battery which is down rp 20% would need 2h at 30Ah to get up to 80% and another 3 to get up to 100 ish?
At 60% that would half these times ?

2 hr at 30A is 60Ah, which as you say would take it up to 80%. The other 20% (20Ah) would take longer than the theoretical 30A for 40 minutes because the amps would tail off, but probably less than 2 hours to reach 100%.

A 60A B2B would halve all the times, as you say.

There's another consideration. For 200Ah of AGM batteries, the max amps advised is about C/5, where C is the capacity,so that's about 200/5= 40A. Lithiums will take a higher charge rate, C/2 or even C.

I don't know about Renogy, but on my Sterling 70A B2B there is a setting for half power (35A) that might be kinder to smaller lead-acid battery banks if you want capacity for expansion in the future.

 

[Bart]

I've been looking as well at the renogy dc/dc chargers as my Stirling b2b 60a has packed in and I'm reluctant to spend another 400+ quid on a top brand for it to fail after approx 6 months use in total since we bought it 3 years ago. So I am thinking on trying the 60a Renogy one, BTW aren't dc-dc chargers and b2b chargers the same thing but just different names are used??

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[jp11]

I have the Renogy DCC50S. It's 50A and also has an in-built MPPT controller, so you'd be already set up for your solar.
No noise from the thing at all. I have two 100AH EFB batteries. They haven't had a mains charger on them since they were new. Been running it for three months.
Apparently if runs at 50% when there is solar input also. I've put a breaker just behind the drivers seat, so I can isolate the solar if I feel the need. My battery bank is sitting at 13.8V this evening. When travelling, I run a 12v compressor fridge.

 

[RogerIvy]

Apparently if runs at 50% when there is solar input also.

I thought it was 25A solar and 25A alternator. Is that not the case?

 

[RogerIvy]

BTW aren't dc-dc chargers and b2b chargers the same thing but just different names are used??

Yes. The "B2B" was in many ways a UK name (Sterling started it?).
DC-DC may have been named as such in America.
Not sure where EU (Votronic?) fits in with the nomenclature.

I guess DC-DC is more accurate name than B2B. In fact, it's not the starter battery that charges the leisure anyway, it's the alternator. So DC-DC better describes the charging system.

 

[autorouter]

The "B2B" was in many ways a UK name (Sterling started it?).

I think they produced an 'Alternator-to-Battery' charger for boats, that involved modifying the alternator a bit. When they produced a charger that didn't require the mods, they called it a B2B. A lot of electrical terms are not good descriptions - inverter, relay, shunt, bus or even 'battery' for example.

 

[jp11]

I thought it was 25A solar and 25A alternator. Is that not the case?

Yes, 25 would be 50% of 50. The solar would depend on how much was available?

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[EdRedBird]

2 hr at 30A is 60Ah, which as you say would take it up to 80%. The other 20% (20Ah) would take longer than the theoretical 30A for 40 minutes because the amps would tail off, but probably less than 2 hours to reach 100%.

A 60A B2B would halve all the times, as you say.

There's another consideration. For 200Ah of AGM batteries, the max amps advised is about C/5, where C is the capacity,so that's about 200/5= 40A. Lithiums will take a higher charge rate, C/2 or even C.

I don't know about Renogy, but on my Sterling 70A B2B there is a setting for half power (35A) that might be kinder to smaller lead-acid battery banks if you want capacity for expansion in the future.

Considdering 1 of these these compared to 2 agm
<Broken link removed>

 

[gerry mcg]

How would the Victron Orion-Tr get on with a Schaudt EBL119? (What model is the one to get for a non smart alternator van ? The non isolated one? (they do isolated and non-isolated )
Or is the Votronic 1212-30 /50 the easiest to get on with the EBL.
A Sterling 1260 seems to be the best option wrt availability and I am really looking for >30A charging rate to utilise the high current that a 200Ah lithium can take to reduce recharge time and Sterling 1260 seem to be the ones with a high Current.
it seems the Sterling B2B don’t interface with the EBL, so am i correct in that the EBL has (or uses) a split charge relay that needs to be disabled if i bypass the EBL

 

[Tasape]

Eza are supposed to be very good

 

[autorouter]

What model is the one to get for a non smart alternator van ? The non isolated one? (they do isolated and non-isolated )

In all the MHs I've ever seen, the leisure battery and the starter battery are connected together at the negative terminals, ie both connected to the chassis - and so is the alternator negative. So the non-isolated version is fine. If you already have an isolated version, it can be used by connecting the negatives together.

 

[autorouter]

Have a look at this thread. It's for the EBL99, but the EBL119 has exactly the same split charge relay arrangement:

Renogy dc dc mppt with schaudt 99

Hello guys :) I need help to connect the dc-dc mppt charger, cause I don't know how bypass the ebl 99 :( Can someone explain me, what do I need do?

www.motorhomefun.co.uk

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[steveh57]

I have two Victron Smart Orion 12 12 30A non isolated in parallel, seemed to me way to go with 220ah Lithium and the fridge pinching over 10A at times whilst driving.They can run hot if airflow is inadequate, which de rates them above 40c, I added a heat conductive mounting plate and a 12v fan in front of each, certainly keeps them cool now. Each has their own dedicated wiring loop from starter to leisure battery , I also have one of them switchable remotely to take strain off the alternator when other vehicle electric loads are high.

 

[Bolti]

Sorry don't really know how these things work.
But if the dc-dc charger sucks every amp it can from the alternator are these things not detrimental to the alternator. Asking as I have had mine fail, 3 year old van.

 

[steveh57]

The DC DC charger limits the max current draw from the alternator to it’s specified input, without it in the scenario where you have a Lithium battery, thick cabling via a SCR, the current draw then is unlimited ( fuses excluded ) until the battery is charged at which point it stops abruptly. Often one gets away with it because of the resistance of the narrow gauge cable fitted to the SCR in many vans limits the current flow.

Vans with a smart alternator should already have a B2B of some capacity fitted as standard.

I believe an alternator is usually happy to output 50% of it’s rated capacity for long periods.

 

[RogerIvy]

…and alternators do sometimes fail because they have a fault, not because you’ve overloaded them.

 

[Bart]

Yes. The "B2B" was in many ways a UK name (Sterling started it?).
DC-DC may have been named as such in America.
Not sure where EU (Votronic?) fits in with the nomenclature.

I guess DC-DC is more accurate name than B2B. In fact, it's not the starter battery that charges the leisure anyway, it's the alternator. So DC-DC better describes the charging system.

I think they produced an 'Alternator-to-Battery' charger for boats, that involved modifying the alternator a bit. When they produced a charger that didn't require the mods, they called it a B2B. A lot of electrical terms are not good descriptions - inverter, relay, shunt, bus or even 'battery' for example.

Thanks, I was pretty sure they were the same thing, but just wanted confirm before I buy a dc-dc charger as apposed to buying a b2b charger, lol, either was I'm buying the right item ^^

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[EdRedBird]

autorouter This might be a silly question but
Starter Pos to B2Bin
Starter Neg to B2Bcommon
B2Bout to Leisure +
B2Bcommon To Leisure neg

Now any fusebox / load i put on the leisure battery.....
I can take that of the B2Bout and Common not?
No need to run a (2) cables back from the leisure ?

 

[autorouter]

This might be a silly question but
Starter Pos to B2Bin
Starter Neg to B2Bcommon
B2Bout to Leisure +
B2Bcommon To Leisure neg

Now any fusebox / load i put on the leisure battery.....
I can take that of the B2Bout and Common not?
No need to run a (2) cables back from the leisure ?

Yes, that's exactly how distribution/fuseboxes like CBE, Sargent and Electroblock are normally powered. You'd normally wire a fuse near the leisure battery that will be adequate for the B2B (charging) and the loads (discharging). For my EBL it's a 50A leisure battery fuse.

 

[EdRedBird]

Yes, that's exactly how distribution/fuseboxes like CBE, Sargent and Electroblock are normally powered. You'd normally wire a fuse near the leisure battery that will be adequate for the B2B (charging) and the loads (discharging). For my EBL it's a 50A leisure battery fuse.

I have a 70A CB for in between start and B2B
I also have a 50A CBfor in between B2B and Leisure (though they recommend 60 in the manual)

I am thinking Bus just outside the B2B and from this bus to
1 Circuit breaker -> leisure battery and from the bus to another
2 Circuit breaker -> blade fusebox

 

[jp11]

My set-up using Renogy 50A B2B/solar (DCC50S).
Drivers seat would be just in the foreground of the picture. Two leisure batteries behind the black panel. Sorry, the picture is slightly complicated by the inverter wiring. My plan was to have everything closely linked together, and all out in the open to avoid cooling issues (everything within half a metre, and solar panel connection directly overhead).

 

[jp11]

I should have added, the vehicle battery in the Transit is under the drivers seat.

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