Dual Factory Batteries WITH Lithium/Solar..

[sunflower111]

Hi guys,

I have facotry dual batteries under my drivers seat (2010 MWB Transit in Australia)...

I have just mounted my 200watt solar panel and need to connect via the Renogy 50amp DC/DC charger with MPPT..

Now I know that you cannot have lithium with AGM as a dual battery set up... so my question is this....

CAN I hook up the renogy charger to the main starter battery under the seat and leave the Auxilliory battery in place.. OR do I need to remove the second battery and reconnect those to the lithium battery?

Has anyone left these two factory batteries in place and installed a lithium house battery for the solar in a camper conversion?

If i lieft it this way it would leave just my back charging port off if the aux battery and all lights/fridge etc would run off the lithium?

[johnporter11]

As far as I'm aware you can use any kind of house battery. There is a setting on the Renogy to choose lead/acid, AGM, or lithium.
I have the 50A like yours but I have it set to charge a lead/acid EFB battery bank.

[sunflower111]

As far as I'm aware you can use any kind of house battery. There is a setting on the Renogy to choose lead/acid, AGM, or lithium.
I have the 50A like yours but I have it set to charge a lead/acid EFB battery bank.

thanks john, I do see that and am aware of that. It's the factory dual battery that's my concern. I know you can only leave them if they're "linked".. like the second battery is actually part of the same system... not a second like "house battery"...

they are linked enough is what i'm asking, like people leave them there and add the system off the main one? Even if the "link" is turning on and off with the engine?

[johnporter11]

As far as I'm aware you can use any kind of house battery. There is a setting on the Renogy to choose lead/acid, AGM, or lithium.
I have the 50A like yours but I have it set to charge a lead/acid EFB battery bank.

thanks john, I do see that and am aware of that. It's the factory dual battery that's my concern. I know you can only leave them if they're "linked".. like the second battery is actually part of the same system... not a second like "house battery"...

they are linked enough is what i'm asking, like people leave them there and add the system off the main one? Even if the "link" is turning on and off with the engine?

Ah OK, you're talking about the two vehicle batteries. Of course, they only become linked when the engine is switched on (you can hear the relay). The OEM setup is AGM.

[johnporter11]

I'm a bit confused about your question.
I have a vehicle with two AGM batteries under the seat, one a starter battery and the other an auxiliary which deals with radio, central locking, etc. My understanding is that when ignition is off the starter battery is disconnected from the auxiliary (to safeguard it from being discharged accidentally). After the engine is started the two are linked via a relay. Correct me if I'm wrong, but I believe the rear battery under the seat is the starter battery, but I'm not sure.
My Renogy B2B is fed from the rear battery. The charging side of the Renogy is connected to the leisure batteries, in my case two lead/acids. So these batteries are charged by both the engine and the solar.
All the 12v systems in the habitation side of the van are fed from those two leisure batteries. They can be lead/acid, AGM, or Lithium.
The two AGM's under the seat work away on their own, managing the original van electrics.

[dumper]

No solar on mine but I have the Sterling b2b charging two leisure batteries the only wiring to van is to the Sterling and all the earth wires go back to the leisure batteries the van battery’s look after the van only .

[sunflower111]

I'm a bit confused about your question.
I have a vehicle with two AGM batteries under the seat, one a starter battery and the other an auxiliary which deals with radio, central locking, etc. My understanding is that when ignition is off the starter battery is disconnected from the auxiliary (to safeguard it from being discharged accidentally). After the engine is started the two are linked via a relay. Correct me if I'm wrong, but I believe the rear battery under the seat is the starter battery, but I'm not sure.
My Renogy B2B is fed from the rear battery. The charging side of the Renogy is connected to the leisure batteries, in my case two lead/acids. So these batteries are charged by both the engine and the solar.
All the 12v systems in the habitation side of the van are fed from those two leisure batteries. They can be lead/acid, AGM, or Lithium.
The two AGM's under the seat work away on their own, managing the original van electrics.

Yes! This is the setup I have as well, and understand the back battery is the main starter battery, so the Renogy DC/DC connects to that!

Sorry for the confusing question! I'd been told for so long you coulnd't link the AGM and the Lithium batteries, and been told that my second battery was just connected to the AUX... I didn't understand that they were actually connected! So my auto electricain says to me.. you can keep it if they are connected, but you have to take it out if they aren't.. he obviously doesnt seem to know whats going on in there either depsire looking at it...

So- the question I guess is... ARE they connected/one system.. even if they turn of and on with the ignition... I can simply hook up my leisure lithium battery to the starty battery via the RENOGY and just leave the second auxiliory to do its thing?

[Altransit]

The two van batteries are connected from the second that you switch on the ignition, you should hear the 'thunk' of the relay. They are both used for starting and remain connected for charging whilst the engine is running.
They will disconnect immediately you turn off the ignition, and will also disconnect if you switch on the ignition and don't start the engine (after a minute or so)

[johnporter11]

And Renogy gives you a choice of settings for lead/acid, AGM or lithium to charge your leisure battery(s) because they all have different charge patterns.

[dumper]

And Renogy gives you a choice of settings for lead/acid, AGM or lithium to charge your leisure battery(s) because they all have different charge patterns.

The Sterling is the same .

[bortaf]

I'm a bit confused about your question.
I have a vehicle with two AGM batteries under the seat, one a starter battery and the other an auxiliary which deals with radio, central locking, etc. My understanding is that when ignition is off the starter battery is disconnected from the auxiliary (to safeguard it from being discharged accidentally). After the engine is started the two are linked via a relay. Correct me if I'm wrong, but I believe the rear battery under the seat is the starter battery, but I'm not sure.
My Renogy B2B is fed from the rear battery. The charging side of the Renogy is connected to the leisure batteries, in my case two lead/acids. So these batteries are charged by both the engine and the solar.
All the 12v systems in the habitation side of the van are fed from those two leisure batteries. They can be lead/acid, AGM, or Lithium.
The two AGM's under the seat work away on their own, managing the original van electrics.

Yes! This is the setup I have as well, and understand the back battery is the main starter battery, so the Renogy DC/DC connects to that!

Sorry for the confusing question! I'd been told for so long you coulnd't link the AGM and the Lithium batteries, and been told that my second battery was just connected to the AUX... I didn't understand that they were actually connected! So my auto electricain says to me.. you can keep it if they are connected, but you have to take it out if they aren't.. he obviously doesnt seem to know whats going on in there either depsire looking at it...

So- the question I guess is... ARE they connected/one system.. even if they turn of and on with the ignition... I can simply hook up my leisure lithium battery to the starty battery via the RENOGY and just leave the second auxiliory to do its thing?

No they are not connected in one system, the DC50s seperates them, that's it's job.
The 2 vehical batterys are connected to each other when IGN is on but the DC50s sepeates them from the leasure battery, in effect you now have 3 sepertae batterys when IGN is off and 2 when it's on.
I have the same set up in my ambulance (except i also have 2 other split charge systems in place but thats a WHOLE other long long storey) lol and it works fine, ive run it with both SLA and LiFeP04 without overcharging ect ect.
The only downside to the DC50s is "if" you have solar it limits the Dc to Dc charge to 25A, if you dont have solar (either switch it off or dont actualy fit it) it'll give the full 50A via the Dc to Dc, i have solar so i switch it off when driving


Crap vid of my instal here
https://youtu.be/lUXsCeIiKt0

[johnporter11]

To do this, I've put a breaker on the positive feed from the solar into the DC50 (instead of a fuse). It's over my shoulder just behind the driver's seat (because that's where the DC50 also is, just 50cm from the vehicle batteries).