Good afternoon all! New to the site and hoping someone can assist me? I have a 2023 Renegade Explorer and i am converting from AGM to Lithium battery.
My current system has two 280AH agm d8 batteries. I have a victron multiplus 12/3000/120 , Victron Cerbo GX, Victron MPPT solar controller 100/30 , I have a Victron GX touch monitor inside the coach and the whole coach is equipped with the firefly control system.
I ordered a single 628 AH Wattcycle lithium battery. My question is: What else do i need to do to make this conversion? i know I need to re configure the inverter to lithium, Can this be done through the firefly system or will i need the interface cable to use a laptop? i have been told i need a shunt? Again will the firefly system and cerbo GX do what a shunt will do? And I have been told i need a Dc/Dc charger to protect the truck alternator?
Anyone familiar with this stuff please… I’m all Ears.
Sounds fun. So everything already installed and working on AGM?
The Cerbo & VRM can make changes to your MP using VEconfig & laptop. Unless you have a communicating battery, a shunt configured as a battery monitor will talk to the Cerbo to keep tabs on the battery for SOC. A DC/DC keeps alternator loading under control, and it can help with voltage droop on long wires from your alternator. I have read where people have interfaced Firefly to the Cerbo, didn’t look like a newbie task tho.
Sounds great. I installed a brand new system on a Renegade Verona last year. The Firefly and the Cerbo do not integrate to my knowledge. I know a tech guru who can integrate other multiplex systems like Silverleaf but not Firefly. If it is all working fine you shouldn’t need to mess with it. Sometimes you lose functionality in the multiplex when you change out the factory inverter(often Magnum) but sounds like you have a Victron already so you would have dealt with those problems already.
You will need to change all your chargers parameters according to the battery manufacturers recommendation. And unless the WattCycle has Victron comms you will need a smartshunt or BMV(are you sure you don’t already have one?). The Multiplus can be configured through VRM like @MiPaul said or you can use your laptop and a MK3 connection. Some people find this simpler. Download VictronConnect, plug in the cable, and it will find the inverter. The MPPT can be configured using the VictronConnect app on your phone through Bluetooth.
Lastly, you do not absolutely need a DC to DC charger but it is the better way correctly charge lithium batteries from your alternator. As a simpler and less expensive alternative you can swap out your existing BIM(Battery Isolation Manager) that is more than likely installed in that rig and replace it with a LI BIM(Lithium Battery Isolation Manager). You quite simply disconnect the BIM and install the Li BIM in its place. It has the same shape and terminals. No programming or configuring at all. This will protect your alternator from overheating(the biggest concern when changing to lithium) and it will preserve the starting battery trickle charge and boost feature that the factory BIM has. You will lose these functions with a DC to DC charger. The disadvantages is it will not ever fully charge the batteries like a DC to DC since it is simply relying on the alternator only for its charging voltage. This is how your AGMs are currently being charged anyway. Your solar and your shore power charging through your Multiplus will provide a thorough and complete charge anyway so often the LI BIM makes a lot of sense.
Here is what the BIM looks like if its what they installed in your rig. These are made by Precision Circuits and so is the LI BIM.
So after reading and watching tons of articles and videos I opted to purchase a victron Orion 1400 dc/dc charger, eliminate the existing bim thingy, also orders up a victron smart shunt for the other end of this puzzle.
Should have everything this week so with any luck I can mastermind this whole thing this weekend
Just to highlight the point I made earlier. You will lose the starting battery trickle charge and boost feature included in the BIM. These are pretty nice features. Just want to make sure you saw that.
Well I’m back! So I got everything installed and I thought I was in business. The coach has been in the garage with the main disconnect off and the battery has been holding at about 60% for over a week so that was all good. Last night I decided i would plug into shore power and charge that lithium to 100% and then put the coach outside in the sun to see what kind of longevity I would get running the refrigerator with solar. So I plugged into shore and everything looked good. The battery was charging and all was good. this morning I went out to the garage and indeed the lithium was at 100% , But I had an alarm on my victron monitoring board saying that the system had overcharged to over 25Volts! the charger had turned itself off. and the shunt history shows that once the battery got to 100% the voltage spiked to 25 volts and stayed there all night. Looks like the battery shut itself down. Biggest problem is that it looks like my firefly touchscreen is fried. I can say with confidence that changing over to lithium is definitely not a plug and play thing.
I cant understand how my multiplus could charge to 25 volts?
Okay, Update, today we started investigating to see what happened. here is what we know so far, The battery mfg says that the battery should be charged to 14.6 volts, That is the voltage that we set the multiplus for max charge, what we discovered via the smart shunt data history is that the battery actually shut off at 14.2 volts. when this happened the charger went runaway and shot up to 25 volts. the result of this so fat is: it fried my firefly touch screen, looks like it fried the Generator circuit board and my power awning does not work. I may find some other stuff that was damaged (hope not)
Today after figuring this out we changed the max charge parameter in the multiplus to 14.2 volts. We rand the battery down a bit and then plugged into shore power and this seemed to solve the runaway problem. When the battery gets to 100% the charger backs off and it seems to hold right there.
my fear now is that if my battery is being charged and it reaches it high heat threshold or its cold threshold and turns off the same thing may happen?
I still dont understand how a 12 volt charger can go rouge and charge to 25 volts like that.
this is an expensive endeavor at this point. The firefly touch screen is almost $400 and I do not have a clue what the generator board may be, I may be able to figure out the awning?
14.6V on a 4 cell LiFePO4 pack is 3.65V per cell, assuming they are completely in balance. That’s the absolute max of the cell, not a point to charge to.
I charge to 3.45V, discharge to 2.9V on 8 cells that my Cerbo can monitor.
I still don’t understand the 25V thing. When a battery BMS lets go, it usually breaks the ground connection. Guessing here, but that missing ground reference might have caused something silly? Can a 12V MP charger even make 25V? Are you sure it wasn’t the Orion XS1400 that chimed in with the extra voltage?
You lost me there, at this point I’m leaning toward diagnosing the damage to the generator and pulling out the lithium and going back to Agm. Chalk it up to if it’s not broke don’t fix it.
If you have a detailed circuit schematic or some pics of the connections please share. The 25V spike should not have happened but perhaps something in the existing installation is foxing one of the charging devices. Do you know for sure if it was the shore power charger or the 1400XS that spiked the voltage?
I understand your frustration but your experience is not normal. Lithium conversions are by far superior to lead acid are not that big of deal as some out there make them out to be. I would hate to see you abandon such a potentially excellent set up. I recommend finding a tech in your area that is familiar with Victron products. Your installation is not complex. It may be something simple. Diagnosing and advising through this forum is very limited.
Do not step back, show us your system in details. The disconnecting akku triggert something.
This is also the reason to install a victron system carefully and program the components each with the critical datta (battery limits) so in the case “communication loss” all components can work standalone.
Maybe your control switches partly of if the akku disconnects due to OVP.
Another good homepage to get knowledge is the guy with the nordkyn boat project. He wrote 7 articles with a good summary and technical overview about mobile Li systems.
AKKU is a technical term, mainly used in Germany I think, that basically means a rechargeable battery. OVP means over voltage protection. Specifically the over voltage protection used by the BMS(battery management system) of your LFP(LiFePo4) batteries. Perhaps we would do well to have a “glossary of terms” page on this site.
