Flat starter battery

Whilst on EHU tonight I've connected a separate 6A charger to SB via my inverter to give it a boost. So a charger powering a charger of sorts! 🤔
 
What I notice now that I have the charger connected via the EBL is that it's only charging LB at 13.05v, whereas connected direct to LB charges at 13.6v. I wasn't expecting any difference. 🤔
 
wildebus said:
Nice setup. However ...

There is something you need to watch out for with this though .... the 9A B2B that charges the SB from the LB will raise the SB Voltage up of course.
When it increases sufficiently, it will hit the threshold for the 30A B2B to then switch on and start charging the LB from the SB, and that will stay active until the off-voltage threshold is met.
The result is that your 9A charge INTO the SB will end up being a 30A charge OUT OF the SB! Net difference... you will pull around 20A out the Starter Battery while the intention was to put 9A in, plus you will have all the energy losses in both B2Bs (each around 85% efficient). On mains you will just waste pennies, but on Solar, you will waste precious harvesting power.

You can get round this to a degree with the Victron Kit by using the remote input of the 30A B2B so it only comes on when the engine is running or maybe just the ignition/Acc line (you wouldn't want to use a trigger generated by the Solar Panel as the solar will still be active when you are driving).
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Totally agree with the above,but that’s not the case.it’s been running flawlessly for over 6 months as it was designed to.i use the battery monitor and charge controller as a bms in tandem...the 9A DC/DC power is supplied from the mppt only when the LB is in absorption state,then the battery monitor will only switch on the 9A DC/DC charger when the LB is above 98% SOC and the starter battery hasn’t reached 14V(engine not running).
unless these parameters are met the charging doesn’t take place.
as for the 9A triggering the 30A and causing cycling,this is not the case as 9A is set @ a storage voltage of 13.22V for the SB and the engine detection settings for the smart alternator are 14.10V tigger on.done this install on my mates boat for his bow thruster batteries last year without Any issues.
this is all sounds a bit complex,but is so simple utilising the existing controls that you have in place! Just an extra £35 for the additional victron 9A dc/dc charger.
ps... all the victron kit apart from the dc/dc chargers are all connected to Venus GX for remote monitoring and control,so I know it functions when I’m away from the van!.
 
So in other words, you configured it in order to avoid that issue ;) Good Stuff


Just one question... where did you buy a Victron 9A DC/DC charger for £35? that is one hell of a discount!
 
wildebus said:
So in other words, you configured it in order to avoid that issue ;) Good Stuff


Just one question... where did you buy a Victron 9A DC/DC charger for £35? that is one hell of a discount!
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I always install victron kit....when doing off grid & grid tie systems,so I get very good discount on victron products!👍🏻
 
xsilvergs said:
Interesting, Orion Tr 12 - 12 - 9.

What could I use one of these for?
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The TR-Smart units can be used as Power Supplies as well as Chargers. This means that you could use them as a DC-DC Converters between Battery/Charging Systems and the Motorhome electric outlets and provide a steady set voltage rather than the variable ones experienced as battery SoC drop and as chargers come on (always thought delivering a steady voltage is heathier then delivering between 15V to potentially down to 11.5V (if inverter in use))
I was thinking to do this with the 12/12/30A unit I have up for sale (instead of selling it) but it's a bit of an expensive unit for just that function (it is a shame that Victron don't make a normal 12/12 DC-DC Converter to go alongside the 12/24 and 24/12 converters .
So that is one use. The 9A one is probably a bit small for that kind of purpose however and you won't find one for sale for close to £35 either ;)

I might try the above using a Ablemail AMC 12-12-30A B2B as that can also be programmed as a charger in the same way (although have to use a PC rather than Smartphone App)
Downside of course is that you are 1) introducing another component that will always be on and using some power and a potential point of failure.
 
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Same here

Screenshot (8).png
 
it will be the caravan site that has good stuff - but also some pretty misleading stuff in there, so for that reason is blocked from linking,
 
Have we tracked down a good description of EBL operation that doesn't get blocked yet?
 
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wildebus said:
it will be the caravan site that has good stuff - but also some pretty misleading stuff in there, so for that reason is blocked from linking,
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Which part is mis-leading? Do you mean how the EBL is designed to function? Thanks.
 
Phantom said:
Which part is mis-leading? Do you mean how the EBL is designed to function? Thanks.
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I mean there are some articles on that website that are misleading - and plain incorrect - and Philip has taken the decision to block the site for that reason as I understand it.
What it says about the EBL I have no idea.
 
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