Disabling Sargent EC500 charging of lithium leisure battery.

[Stewen]

…. Whilst retaining full charging of Lead Acid vehicle battery when on EHU.

I have a shiney new Roamer 230A seatbase smart 4 battery which replaced 2 AGM’s under a bench seat.

Charging was already in place & working well with the AGMs by way of Victron IP22 mains charger, Victron Orion XS50 dcdc charger and Victron mppt solar charger , all connected directly to the Leisure battery. The Sargent solar controller is disconnected inside the EC500.

Charging of the lead acid vehicle battery is by way of a Vanbitz battery master and this works as intended in keeping the VB topped up.

When on electric hookup the Sargent charger is manually turned off to prevent it from charging the LB in error.

However, whilst doing the lithium install this past week or so (which involved larger cables, fuses and different cable runs & generally moving the victron stuff around to gain under bench space previously occupied by 2 AGM batteries and with no leisure battery connected , the vehicle battery ran right down as the Sargent panel defaulted to the VB to run itself. It was switched off but still monitors batteries in the background. I presume.

So, last night I hooked up to mains and switched the charger on and this morning the VB is fully charged. All good.

My reason for posting is this. Once everything is up and running & back to normal, IF I need to give the VB a full charge I can set the charging to “normal” in the control panel (EC430) settings and then the panel will charge whichever battery is selected, so, in this case, Vehicle battery. But we dont ever want the Sargent PX300 charger to charge the leisure battery by mistake (human error/old age) because its not suitable for the Roamer.

Also, if the mains went off, whilst the VB is selected, the Sargent system would then run the hab side from the selected VB Not good. One (me) would have to first realise the mains was off, then remember to turn the Sargent charger off, switch the battery selected to LB, so that if the power came back on the Sargent could not charge the LB ( as thats the one selected) then with power back on, change back to VB and turn the charger back on !

I called Sargent to ask if there is any way for the EC500 to permanently block charging of the LB and only charge the VB whilst leaving the battery selector on the control panel to aways be set to LB…. They said, unsurprisingly, not possible within their system.

So, I thought about installing an inline diode to only allow current to flow into the Sargent system & block any charge current coming into the LB. I’m not sure of the correct spec. Diode though. The feed from the LB to the sargent is via the original 20A fuse and the PX 300 charges at max 20 Amps I think.

Or, a relay somewhere that breaks the LB charge feed when the Sargent charger is on but still allow the LB to power the hab side.

I may well be overthinking this but if anyone had any thoughts on a possible solution it would be appreciated.

Apologies for this long winded post!

Tia

 

[headlight]

Stewen why do you "never want the Sargent PX300 to charge the leisure battery" ?
The PX300 has 14.4v charge and 13.6v float and no desulfation stage, what damage have Roamer said it will do ?
It won't fully charge a LifePo4, maybe 90%, but won't damage it.
I have left my PX300 in situ and it is still powered on the odd occasion we are on hook up.
I have a Fogstar 230AH LifePo4 and checked with both Fogstar and Vanbitz that this was OK to do and my set up has been in place for 9 months now and the couple of nights I have been on hook up have caused no issues.

 

[TCG]

Stewen in your post you state "The Sargent solar controller is disconnected inside the EC500." but then you are concerned that the PX300 will charge the leisure battery.
When i fitted my kit i completely removed the PX300 and the sargent solar charger. so now the EC500 does not control any charging but any means.
just leave it to the Victron Multiplus, Mppt Solar and Orion B2B... ours has been done like this for 4 years and not had any issues

you can turn off charging via the EC430

 

[Stewen]

Thanks Guys, I did say I might be overthinking this a bit. From your responses I conclude that I was definitely worrying too much!

I think my main concern was charging the vehicle battery from almost flat, which is why I’m keeping the PX300. It doesn't happen often thankfully.

I suppose I can just switch on the PX300 as & when its needed.

The Victron mains charger is plugged into its own dedicated mains socket.

Thanks again for allaying my concerns!

 

[TCG]

Thanks Guys, I did say I might be overthinking this a bit. From your responses I conclude that I was definitely worrying too much!

I think my main concern was charging the vehicle battery from almost flat, which is why I’m keeping the PX300. It doesn't happen often thankfully.

I suppose I can just switch on the PX300 as & when its needed.

The Victron mains charger is plugged into its own dedicated mains socket.

Thanks again for allaying my concerns!

get rid of the PX300 and get yourself a battery master (from this site with fun discount) that will take care of your starter battery

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[Stewen]

get rid of the PX300 and get yourself a battery master (from this site with fun discount) that will take care of your starter battery

Thx, I already have one & from here

Its great for trickle charging, I agree