Split charge systems

Hi

Currently have fitted a T max split charge battery system, however I’ve now had to replace 2 x relays which causes the leisure battery to drain , as it’s smaller than the main one

So wish to remove it and thinking of fitting a VSR relay , been looking at the following but can’t see the difference , do u think the amps are suffice please and do u think it’s a better system to fit or maybe something else

https://simplysplitcharge.co.uk/index.php?route=product/product&product_id=276

https://simplysplitcharge.co.uk/Split-Charge-Systems/Relays?product_id=642

https://simplysplitcharge.co.uk/Split-Charge-Systems/Relays?product_id=644

alternator is 150 amps, Aux battery 75 amp and main one 100amps

have 2 x battery volt meter gauges inside the cabin so don’t need the T may display unit so can remove it

many thks

My experience is most things factory can go worng, anything add on will go wrong.

lynall said:

My experience is most things factory can go worng, anything add on will go wrong.

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Many thks and indeed know where ur coming from, can’t put up with that T max relay anymore with them keep failing , have heard the VSR is supposed to be a lot better , originally went for the T max as it had the voltage displays for both batteries but now I have independent gauges in the dashboard I don’t need that either

so thought then I can remove all that part of the loom , simplifying it and just leaving the large battery cables

Plus still have the hydraulic crimper so that’s paid for itself already

gstuart said:

do u think the amps are suffice please and do u think it’s a better system to fit or maybe something else

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How much power are you pulling from the aux battery? That's the important thing you need to know.
If you're pulling 200 Amp, then the split charge starts to supply power to recharge the aux battery, effectively the split charge will be supplying the aux battery load, and charge the aux battery at the same time.
So how much power you feed the aux battery is dependent on load imposed on the aux battery at the time of charging.

Relay contacts tend to burn on DC, especially if they're disconnected when large currents are flowing. Sometimes it's better to go with a solid state relay SSR, as there's no contacts inside to arc and burn out.

Nodge68 said:

How much power are you pulling from the aux battery? That's the important thing you need to know.
If you're pulling 200 Amp, then the split charge starts to supply power to recharge the aux battery, effectively the split charge will be supplying the aux battery load, and charge the aux battery at the same time.
So how much power you feed the aux battery is dependent on load imposed on the aux battery at the time of charging.

Relay contacts tend to burn on DC, especially if they're disconnected when large currents are flowing. Sometimes it's better to go with a solid state relay SSR, as there's no contacts inside to arc and burn out.

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many thks,

is only for when I use things like lights , fridge etc , nothing like a winch etc

so I’ve seen this , do u think it would be ok please, as I know ur extremely knowledgeable, once this is all sorted I’ll eventually get round to fitting a solar panel on the roof and then fit that awesome regulator

https://www.12voltplanet.co.uk/vict...sitive-relay-battery-combiner-1224v-120a.html

plus as mines a euro 3 , reg 2005 I assume then mine is t a smart alternator, know it’s controlled by the ecu but has a steady 14.5 Vdc , read that the smart alternator go down to 13.4Vdc etc so would assume by that a VSR will be ok

plus with it being a victron should be a far better quality than the previous T max, if it’s not suitable would u mind showing me one of these solid state relays plse,thks

thanks again

I would say a split charge relay is better than a voltage sensing relay, if you have the choice

gstuart said:

so I’ve seen this , do u think it would be ok please, as I know ur extremely knowledgeable

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You can't use a VSR with a smart charging alternator, which a D3 has IIRC.
It says this on the item description.

Nodge68 said:

You can't use a VSR with a smart charging alternator, which a D3 has IIRC.
It says this on the item description.

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hi

many thanks, I saw that but mines a euro 3 and wondered that about a smart alternator, know it’s controlled by the bcm , so is that what defines a smart meter then please

so I assume I’ll then have to get a battery to battery type then , haven’t found a SSR yet

thks again

B2B is the best option, just pricey

kermit_rr said:

B2B is the best option, just pricey

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many thks and indeed coming to that conclusion after the sound advice

it’s just finding one that isn’t very expensive , got so fed up with the T max eating relays got to get a better system , maybe it’s because it had a smart meter that’s why they keep failing , had 2 x fail already so won’t be a third that’s for sure , taken just the relay out and left the rest in situ so shouldn’t be too bad of a job to wire a new one in

just a case of finding it’s replacement now

Nodge68 said:

You can't use a VSR with a smart charging alternator, which a D3 has IIRC.
It says this on the item description.

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@Nodge68

hi mate

so contacted ctek with relation to what solar panels etc I can use , there saying the D3 doesn’t have a smart alternator , know ur extremely knowledgeable with regards to this , know the D4 has one with regards to how the battery chargers which is different to the D3

Nothing like getting confused, lol

without sounding too naive, shirley the type of alternator shouldnt matter with respect to connecting solar

Some others I’ve been looking at ,

https://www.tayna.co.uk/battery-chargers/ctek/d250se/

https://uk.renogy.com/12v-40a-dc-to-dc-on-board-battery-charger/

https://uk.renogy.com/12v-20a-dc-to-dc-on-board-battery-charger/

kermit_rr said:

without sounding too naive, shirley the type of alternator shouldnt matter with respect to connecting solar

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it’s the actual charger I’m trying to pin down, as in if the dc to dc will work with one that hasn’t got a smart alternator

Indeed that’s what I’m hoping with regards to solar , as when I finally get the split charger installed if I then later on decide to fit solar that it will be ok to add to that already installed controller

apologises and hope I’m not being pedantic and honestly I’m so grateful for the help as god knows I need it, lol

thks again

gstuart said:

so contacted ctek with relation to what solar panels etc I can use , there saying the D3 doesn’t have a smart alternator , know ur extremely knowledgeable with regards to this

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The D3 alternator is ECM controlled, so is a semi-smart system. It doesn't use a separate battery controller module as the smart systems do, but the D3 alternator still has intelligent output control.
The D3 ECM knows exactly how much energy is being used by the vehicle electrical system, and how much extra energy is needed to charge battery, and regulates alternator output accordingly.

This can cause issues when additional batteries are installed, as the ECM software isn't expecting an additional battery in the system, so increases alternator output to maintain battery voltage, presuming the vehicle battery isn't working correctly.
The second battery controller you're using will simply switch the aux battery in and out, as and when it needs changing or not, which will vary the load on the vehicle alternator, potentially upsetting the system in the process.
I suspect that the voltage is suddenly climbing when your aux battery charge controller cuts out, which is what is responsible for the relay contacts burning.

If the relay in your current system is a replaceable relay, then it's probably best to fit a remote SSR instead, as those don't have contacts to burn out.
I use SSRs in my solar projects, as they handle high disconnect voltages just fine.

Nodge68 said:

The D3 alternator is ECM controlled, so is a semi-smart system. It doesn't use a separate battery controller module as the smart systems do, but the D3 alternator still has intelligent output control.
The D3 ECM knows exactly how much energy is being used by the vehicle electrical system, and how much extra energy is needed to charge battery, and regulates alternator output accordingly.

This can cause issues when additional batteries are installed, as the ECM software isn't expecting an additional battery in the system, so increases alternator output to maintain battery voltage, presuming the vehicle battery isn't working correctly.
The second battery controller you're using will simply switch the aux battery in and out, as and when it needs changing or not, which will vary the load on the vehicle alternator, potentially upsetting the system in the process.
I suspect that the voltage is suddenly climbing when your aux battery charge controller cuts out, which is what is responsible for the relay contacts burning.

If the relay in your current system is a replaceable relay, then it's probably best to fit a remote SSR instead, as those don't have contacts to burn out.
I use SSRs in my solar projects, as they handle high disconnect voltages just fine.

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that’s a brilliant explanation thank u so much and now makes a lot more sense , see I knew u were extremely smart and knowledgeable

so for example would this one work ok please as it seems the dc to dc work better than VSR’s and like u said previously some of the other ones shouldn’t be used on the smart systems

https://www.tayna.co.uk/battery-chargers/ctek/d250se/

main reason for the CTEK is because I have a charger by them and they have a very good name with build quality etc , also seen many utube sites of overland guys that use them

yes the relay in mine is a unit on its own, that makes a lot of sense with regards to having a sudden surge with amperage as it switches from main to Aux battery

funny enough I haven’t found a SSR yet , but was just wondering if that CTEK would work ok plse and if there is any contacts used inside

thanks so much once again.

So been looking at this one again, because it has a Bluetooth App feature where I can monitor both batteries and solar panel via my iPad , which is a big advantage to me being able to see it from indoors

https://uk.renogy.com/dcc50s-12v-50a-dc-dc-on-board-battery-charger-with-mppt-new-version/

However have seen it has a standby usage of 60Ma , car already uses 22Ma in sleep state , so if I’m working this out correctly and say round it off to 100Ma that would only be 0.01Vdc

100 watt panel spec , of course that’s on a good day but think it will be large enough for my use


Maximum Power at STC: 100W Cell Efficiency: 21.00%
Optimum Operating Voltage (Vmp): 18.6V Open-Circuit Voltage (Voc): 22.3V
Optimum Operating Current (Imp): 5.38A Short-Circuit Current (Isc): 5.86A
Operating Temperature: -40°F to 176°F Maximum Series Fuse Rating: 15A
Solar Cells: 33 Cells Maximum System Voltage: 600V DC (UL)
Weight: 14.3lbs/6.5kg
Dimensions: 42.4 X 20.0 X 1.38 In(1076 x 509 x 35mm)

gstuart said:

yes the relay in mine is a unit on its own, that makes a lot of sense with regards to having a sudden surge with amperage as it switches from main to Aux battery

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Do you have the pinout for the relay?
A standard SSR will have 4 terminals, but are much more robust in design, and function too.
I use this one in my solar projects, and for general DC switching.
https://www.ebay.co.uk/itm/UK-stock...=p2349624.m2548.l6249&mkrid=710-127635-2958-0