Help with BTB Charger wiring please.

[Don Quixote]

I have a B2B fitted it connects direct from vehicle battery to B2B to hab batteries. As I have no idea how the Sargent system works I have to leave it there, but cannot see why direct fitting would not work.

 

[Revolvor]

Hi John, what problems do you see in installing a battery to battery..
To me it would just be another charging source, ie from alternator.. and I can't think how that would interfere with the sergeant. ..
I've read @PhilandMena post above about Sargent not been compatible with his ..I'm sure they could say why and what the issues are...
Obviously you need to be sure but I can't think why not..
Ta Andy

I have a B2B fitted it connects direct from vehicle battery to B2B to hab batteries. As I have no idea how the Sargent system works I have to leave it there, but cannot see why direct fitting would not work.

My problem is incorporating a B2B Charger into a system that already has an EC225 EHU Charger.

My understanding that in a simple system it is possible to charge a Vehicle Battery and Hab battery simultaneously, from the vehicle Alternator. In order to isolate the Hab battery when the engine is not running, the “link” between the two batteries is via a Battery splitting Relay, controlled by the Alternator D+ terminal, or a Voltage sensing relay.

In an ideal world, fitting a B2B charger would mean removing the link, and wiring the B2B charger to both batteries. A BTB charger cannot work correctly if there is already a direct link between the two batteries.

However with the Sargent EC225 fitted, there is an added complication:

I have spent a lot of time on my back, under the van, trying to trace where all the wiring goes to and from and it seems that the link between the Vehicle and Hab batteries goes through the EC225, so if I remove the link from the EC225 to the Hab or vehicle batteries, then they will then not charge from EHU.

I assume that the EC225 needs a signal from the Alternator D+ terminal in order to switch off the 12v circuits when the engine is running, in line with legislation. I also assume that the 12v supply to the fridge is controlled via the D+ signal, plus a relay.

John

 

[andy63]

'''My problem is incorporating a B2B Charger into a system that already has an EC225 EHU Charger.'''

hi john, ive had a look at the download available off the sargent site on the ec225 unit and from what I can see the vehicle battery does not receive a charge from the mains charger (the charger supplies the 12v leisure load and charges the leisure batteries giving priority to the 12v load )...from memory im sure this is the case as I fitted a battery master type device to a van with the ec225 unit to ensure the start battery did receive a charge from the leisure batteries when they were been charged either by the mains charger , or solar..that worked ok..

so what im saying is I don't think there is an existing charging link through the ec225 from the mains charger for the start battery or to the leisure battery from the alternator...... you could check that easily enough with a meter , by checking the battery voltages in each case..
john has indicated in the post you quoted above that he has a b2b device fitted along side the sargent ec225 unit without making any modifications, which would seem to indicate it should work.
the link to the download if you haven't already got it, if the linkt doesn't work its on sargeants site. Broken Link Removed
hope you get sorted.
ta andy

 

[PhilandMena]

Isn't the EC225 and the EC 328 two different animals ?

 

[Abacist]

I also think that they are different - I have the EC 325 in my 2010 AT Savannah and a friend has the EC 400 in his 2011 AT Savannah

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[PhilandMena]

I have the EC500 Power Supply Unit.

 

[andy63]

Isn't the EC225 and the EC 328 two different animals ?

Sorry posted a link for wrong one but the right download is available from the Sargent site..
There are differences ...sorry..
Ta andy

 

[andy63]

http://sargentshop.co.uk/Technical-Data/Self-Help/EC225-/-EC325-Power-Control-System
Hope this one works but on phone and it quite often doesn't..should take you to the download for the ec225..
Ta andy

 

[Revolvor]

.......so what I'm saying is I don't think there is an existing charging link through the ec225 from the mains charger for the start battery or to the leisure battery from the alternator...... you could check that easily enough with a meter , by checking the battery voltages in each case..

Andy, thanks for your reply. It never ceases to amaze me how much time people on the forum are prepared to spend in helping others!

I think I am getting somewhere! There are two wires g0ing to the +ve terminal on the leisure battery:
A heavy gauge one (brown/blue) and a lighter gauge (red) that immediately branches into three fused wires - 15A (red), 10A (red/black) and 5A (red/blue).
I disconnected them and monitored voltages with the EHU on/off, and engine running/not running.

The red wire seemed to be an "output" and registered zero volts at all times.

However, there was a voltage present on the brown/blue wire, both when the EHU was connected, OR the engine was running.

I then examined the EM50 unit, mounted on the floor behind the driver's seat., and found this has a 20A fuse labeled "Split Charge Supply" and another 20A fuse labelled "Fridge".

Tomorrow, I will pull the 20A Split Charge Supply" fuse and repeat the exercise of checking voltages at the battery connections.

That should then allow me to make full use of a CtekD250!!

If it all works, I will post on the forum.

Thanks to all, John

 

[Revolvor]

I think I am winning! Pulled the fuse in the EM50, and that seems to be what I want ...... Power from the EHU charger, but nothing when the engine is running. Hopefully that leaves the way open for me to fit a solar panel and Ctek D250
John

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