Hymer smart battery system - Victron Smart Shunt Installation

[Alman]

So Hymer smart battery system makes connection of any battery / electrical additions complicated. I just got Victron SmartShunt for my Hymer Grand Canyon S 4x4 with the Hymer smart battery system where the charge goes to the AGM battery first but the draw of current is from the LiFePo4 first. My question is where and how can I install the Victron SmartShunt on the Hymer GCS? I will really appreciate a response especially from anyone who has done it already.

 

[autorouter]

I think the question is, what exactly do you want to know? If you place the shunt to measure all the amps going in/out of both batteries, that will give you the Ah state of charge (SOC) of the combined system.

You then have the problem of what settings to put in, to make the SOC accurate. Lead-acid and lithium have different 'Peukert exponent' and charge efficiency values. I'm sure it's possible to calculate what values you need, but I don't know of any available app or spreadsheet that does this. It would depend on the relative sizes of the two battery types. Or you could just have a guess, it probably won't be far wrong.

The alternative is to just put the shunt on one of the batteries, maybe the lead-acid one, because that's what you'll be looking at if you're low on power. Or even get two shunts, one on each battery.

 

[Alman]

I think the question is, what exactly do you want to know? If you place the shunt to measure all the amps going in/out of both batteries, that will give you the Ah state of charge (SOC) of the combined system.

You then have the problem of what settings to put in, to make the SOC accurate. Lead-acid and lithium have different 'Peukert exponent' and charge efficiency values. I'm sure it's possible to calculate what values you need, but I don't know of any available app or spreadsheet that does this. It would depend on the relative sizes of the two battery types. Or you could just have a guess, it probably won't be far wrong.

The alternative is to just put the shunt on one of the batteries, maybe the lead-acid one, because that's what you'll be looking at if you're low on power. Or even get two shunts, one on each battery.

Thanks. The way the Hymer system works is all the charge and connections are in the AGM battery. But they have a battery managment system that draws from the LiFePo4 to run all DCs up and down till it gets low then it draws from the AGM. That way the AGM gets to last many more years - they say possibly to 10 years and more due to the very little discharge on it and constant charge (all charging goes to the AGM which then tops the LiFePo4 after its fully charged). Thats what makes the Hymer system so complicated to modify.

 

[autorouter]

The way the Hymer system works is all the charge and connections are in the AGM battery. But they have a battery managment system that draws from the LiFePo4 to run all DCs up and down till it gets low then it draws from the AGM. That way the AGM gets to last many more years - they say possibly to 10 years and more due to the very little discharge on it and constant charge (all charging goes to the AGM which then tops the LiFePo4 after its fully charged). Thats what makes the Hymer system so complicated to modify.

I agree it's a complicated system. If you wanted to add more storage, and maybe an inverter, maybe go for an entirely separate lithium battery, with its own inverter/charger and maybe a separate B2B for it.

You could arrange for the inverter to charge the hybrid system though its existing charger. It wouldn't take much charge as it would only be feeding the 12V habitation electrics. Then you can run any devices like microwave, coffee machine, hairdryer from the inverter and the new battery. A bit more complicated but doable.

I have a similar separate system in my MH. A standard 12V hab battery with charger and split charge relay, plus a big 48V lithium battery with inverter/charger and B2B. You probably won't want the 48V idea, but might look at the separate battery/charger/B2B idea.

 

[Hoovie]

One option is to get 3 smartshunts
I have one on the Lithium, one on the Lead and one on the overall Lead+Lithium Hybrid bank. It can be interesting to see what each battery bank is supplying and how much work each is doing.
You can see a side-by-side history of the batteries

(PS. I have used the 'Hybrid' Monitor on a standard bank and have used different models and sizes of Lithium batteries so the number comparisons between the monitors in my case may not seem to tie up).


They also provide an instant point-in-time comparision

As Autorouter rightly points out, Lead and Lithium have different charge and discharge characteristics that need to be configured in the Smartshunt and when you are running both batteries you need to decide which one is the primary in terms of use (which will be Lithium until it is used up and then Lead. If you never tend to draw past the Lithium, then configure for Lithium).
By having a separate monitor on each battery bank you are able to configure each one appropriately to get the right results. The overall Lead+Lithium Hybrid Monitor will be generally right but can go out when using the van in an atypical way (drawing more battery power then usual, dipping into the Lead).

My setup is not like Autorouters, and not quite like the Hymer either - I have the two running in parallel under load; the Lithium charges primarily more than the Lead (much more important IMO as it is the Lithium you will be drawing on most, so that is what you want to recharge most) and then disconnects to let the Lead have as much of the chargers output as it can handle.
I also have Lead-Carbon rather than standard Lead-Acid. Lead-Carbon is fine with a PSOC (Partial State of Charge) so if you are deep-discharging the full bank and don't have the chance to do a full recharge, focusing on the Lithium and holding off on the Lead-Carbon is not a problem for it. If you deep-discharge and then the recharge is on the Lead and you don't have the opportunity to fully charge it and so the Lithium isn't getting charged (as the Hymer system would seem to work as you describe it), you don't get to really benefit from the Lithium batteries until you are in a situation where you are able to charge everything fully. If camping off-grid extensively, this could be a real downer

PS. My personal preferance and recommendation is to get the Victron BMV Monitors over the Victron Smartshunts, especially if you have or intend to get a Victron Cerbo. The BMVs have programmable relays (the Smartshunts have none) and those relays can come in very useful in the future. You can always add a Bluetooth module to a BMV-70x, but you can't add a relay to a Smartshunt.

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[Alman]

I agree it's a complicated system. If you wanted to add more storage, and maybe an inverter, maybe go for an entirely separate lithium battery, with its own inverter/charger and maybe a separate B2B for it.

You could arrange for the inverter to charge the hybrid system though its existing charger. It wouldn't take much charge as it would only be feeding the 12V habitation electrics. Then you can run any devices like microwave, coffee machine, hairdryer from the inverter and the new battery. A bit more complicated but doable.

I have a similar separate system in my MH. A standard 12V hab battery with charger and split charge relay, plus a big 48V lithium battery with inverter/charger and B2B. You probably won't want the 48V idea, but might look at the separate battery/charger/B2B idea.

I am actullay thinking of replacing all of the current setup with a new Victron 24V system. Is it possible to share what you replaced and conncected when replacing the Hymer system with the 48V system?

 

[autorouter]

I am actullay thinking of replacing all of the current setup with a new Victron 24V system. Is it possible to share what you replaced and conncected when replacing the Hymer system with the 48V system?

OK here's my take on it, may not be what you want but maybe some useful ideas there.

The main problem is that all the present habitation circuits, and any future additions, run from 12V DC. My Hymer has a 12V distribution/fusebox - a Schaudt Elektroblock EBL101 - that feeds all the habitation circuits, with a 12V lead-acid battery. The battery is charged from a mains charger built into the EBL, and from a split charge relay built into the EBL while driving. I don't have any solar, yet. In general the original system works fine, but is obviously limited in battery storage.

I wanted to add more battery storage for longer time off-grid, and also an inverter for microwave, coffee machine, etc.

The EBL mains charger is 18A at 12V, which is only just over 200W. This is about the maximum level of power that any of the 12V devices needs. I wanted to install a 3000W inverter, which would pull at least 250A from a 12V battery. My view is that any current over 100A needs serious wiring and a severe looking at to see if it's really necessary. Going to 48V cuts the amps down to 63A, which is a bit more comfortable. Batteries for domestic solar installations are mostly 48V for this reason.

Wiring in a 3000W inverter/charger and over 3kWh of batteries is always going to need almost completely separate wiring, even if you decide to stick with 12V. And it would also need a separate high-power B2B to charge from the alternator. Once you get away from standard 12V you can choose 24V or 48V. Since there's the same problems for both, I went for 48V. So I kept all the original Hymer system, and added the 48V system.

The only contact between the two systems is that the inverter powers the EBL 12V mains charger when there is no EHU connected. The EBL thinks it's on EHU most of the time, because it's always getting power from the inverter when it's switched on.

The system is a Victron Multiplus 2 3000 48V inverter charger, connected to a Pylontech US3000 48V 3.5kWh lithium battery, equivalent to about 290Ah at 12V. There's a Sterling BB124870 B2B charger which takes 70A at 12V from the alternator to charge the battery while driving.

Originally I had everything controlled by a Victron ColorControl GX panel, which interfaced nicely with the inverter and the battery BMS. Victron have collaborated with Pylontech to make sure everything works fine. I have since changed it to a Vistron Cerbo GX controller with separate screen. The ColorControl panel worked fine, but didn't have enough memory to run the special version of the software that has geeky additions for more control. I also added another battery to make it 7kWh (equivalent to nearly 600Ah at 12V).

The Sterling B2B was actually the only one I could find to output 48V from an input of 12V, but it works fine so I'm happy with it. If you go for 24V there is more choice.