Just finished upgrading 2021 NA to three 460ah LI - OMG!

[the_fu]

Every coach more or less has some form of battery isolation set up. Some more so than others. Some have simple relays, some have timer based systems for engaging and disengaging the batteries and charging systems, and some have more complicated algorithms in computer based systems.

 

[Rustymayes]

SO my 2022 Dutch Star has a Victron charger inverter I believe. Would the BIM be integral to the Charger/inverter or a separate component? My standard Lead acid batteries are in good shape still but when they begin to fail I will be looking to take advantage of the latest technology to upgrade the batteries and the DC/DC charger. Great thread!

 

[MemoriesByTheMile]

According to the manufacturer of a BIM:
“The Battery Isolation Manager isolates the two battery systems, Chassis & Coach, in a Motorhome. This prevents loads in one system from discharging both. It also connects the two battery systems together during charging. Both batteries are charged if either is being charged. The Coach Battery is charged while driving down the road, and the Chassis Battery is charged while plugged into Shore Power at a camp ground.”
This is from precision circuits inc.

Lithium Battery Isolation Manager | Precision Circuits Inc

The Lithium BIM (Li-BIM) isolates the two battery systems, chassis, and coach, in a motorhome. This prevents loads in one system from discharging both. It also connects the two battery systems

www.precisioncircuitsinc.com

 

[the_fu]

SO my 2022 Dutch Star has a Victron charger inverter I believe. Would the BIM be integral to the Charger/inverter or a separate component? My standard Lead acid batteries are in good shape still but when they begin to fail I will be looking to take advantage of the latest technology to upgrade the batteries and the DC/DC charger. Great thread!

The modern Newmar coaches use a slew of Silverleaf modules to monitor and manage many different things. There is a module in the dash that monitors the engine data (is it on, RPM, etc) as well as route the turn signal video signals. This information is used by another Silverleaf module to open and close a solenoid to separate or join the two battery systems - aka "Bridge" them. Side note, this module in my dash was actually bad when I bought the coach and my batteries were not charging when driving - Silverleaf tech at first thought it was the module controlling the solenoid but it was not bridging because this module was not giving engine status to other module. Complicated systems these coaches

 

[Rustymayes]

According to the manufacturer of a BIM:
“The Battery Isolation Manager isolates the two battery systems, Chassis & Coach, in a Motorhome. This prevents loads in one system from discharging both. It also connects the two battery systems together during charging. Both batteries are charged if either is being charged. The Coach Battery is charged while driving down the road, and the Chassis Battery is charged while plugged into Shore Power at a camp ground.”
This is from precision circuits inc.

Lithium Battery Isolation Manager | Precision Circuits Inc

The Lithium BIM (Li-BIM) isolates the two battery systems, chassis, and coach, in a motorhome. This prevents loads in one system from discharging both. It also connects the two battery systems

www.precisioncircuitsinc.com

I admit that I have more reading to do. I was under the impression and understanding that the chassis batteries would be charged with the engine running down the road and the coach batteries would be charged by the inverter/charger when on shore power. Maybe I am confused by what Chassis batteries are and coach batteries are. I call the chassis batteries the two in the engine bay that are start batteries and the coach batteries are the deep cycle batteries that powers the coach thru the inverter. Actually I don't understand why both batteries would not be charged always at the same time.

 

[the_fu]

I admit that I have more reading to do. I was under the impression and understanding that the chassis batteries would be charged with the engine running down the road and the coach batteries would be charged by the inverter/charger when on shore power. Maybe I am confused by what Chassis batteries are and coach batteries are. I call the chassis batteries the two in the engine bay that are start batteries and the coach batteries are the deep cycle batteries that powers the coach thru the inverter. Actually I don't understand why both batteries would not be charged always at the same time.

Your understanding of which batteries are called what is correct. The computer in your coach monitors what activity is happening (driving or stationary) and what charging device is active (alternator, generator, inverter/charger) as well as what the voltage is for each of the battery banks (chassis and coach) and then decides what is the best course of action. When the coach is underway, the batteries are bridged and the alternator charges both sets of batteries. The problem with LI batteries is that they will pull a large load from the battery to charge and this is stressful for the stock alternator, shortening its life or killing it altogether. The answer to this if you move to LI batteries is to either get an upgraded alternator (which is ideal as your batteries will charge faster while driving) - or get a DC-DC converter that limits the current from the alternator to the batteries and gives them only what the alternator can handle.

I know its a lot, but if everything is working to your liking right now - this is all academic.

 

[Larry D]

I was looking today and my 2020 Ventana already has the LiBim 225 installed so that simplifies it a bit.

 

[the_fu]

I was looking today and my 2020 Ventana already has the LiBim 225 installed so that simplifies it a bit.

So that version of a BIM is a pretty clever approach to the issue. Instead of using a computer, it is an electromechanical switch with a timer that connects and disconnects the batteries. This video I found interesting as he takes apart one of these devices and explains it. This is not how things work on the New Aire and other Luxury Newmar that implement the Silverleaf system.

 

[Larry D]

Looking at finalizing battery order today and I have a questoin please. There are two Epoch 460 Amp 12 V batteries. Both have blue tooth, are heated, have hot and cold shut offs. The significant differences are the newer one has Victron Coms, are individually fused and will to 300 Amp continuous discharge. Also there is about a 30% price difference. Am I missing something else? I have had a Cerbo set up in the past and don't see where the coms would be a deciding factor for me. With the smart shunt and bluetooth plus the panel from the Mangum Invertor I think I will know battery status. If I were changing invertor that may change my opinion but as it stands now I am leaning to the less expensive batteries and they have twice the duty cycle specs. Thanks for your input in advance. Regards

 

[Rustymayes]

Your understanding of which batteries are called what is correct. The computer in your coach monitors what activity is happening (driving or stationary) and what charging device is active (alternator, generator, inverter/charger) as well as what the voltage is for each of the battery banks (chassis and coach) and then decides what is the best course of action. When the coach is underway, the batteries are bridged and the alternator charges both sets of batteries. The problem with LI batteries is that they will pull a large load from the battery to charge and this is stressful for the stock alternator, shortening its life or killing it altogether. The answer to this if you move to LI batteries is to either get an upgraded alternator (which is ideal as your batteries will charge faster while driving) - or get a DC-DC converter that limits the current from the alternator to the batteries and gives them only what the alternator can handle.

I know its a lot, but if everything is working to your liking right now - this is all academic.

Thanks for the clarification and confirmation of my understanding of the way the systems work. I have plenty of experience similar systems on my big boats but have yet to delve into the Li battery technology.

 

[the_fu]

Looking at finalizing battery order today and I have a questoin please. There are two Epoch 460 Amp 12 V batteries. Both have blue tooth, are heated, have hot and cold shut offs. The significant differences are the newer one has Victron Coms, are individually fused and will to 300 Amp continuous discharge. Also there is about a 30% price difference. Am I missing something else? I have had a Cerbo set up in the past and don't see where the coms would be a deciding factor for me. With the smart shunt and bluetooth plus the panel from the Mangum Invertor I think I will know battery status. If I were changing invertor that may change my opinion but as it stands now I am leaning to the less expensive batteries and they have twice the duty cycle specs. Thanks for your input in advance. Regards

My take and speculation on what I have researched is that the Canbus connection to get actual SOC from the battery BMS is definitely more helpful than that of the calculated number. On top of that, the enclosures of these batteries are much more accessible for repairs or future upgrades or changes. The BMS quite likely is not the same in both batteries - in fact in the more expensive battery, its BMS heat sink is exposed outside for better cooling of the components. The more expensive battery also is better sealed from the elements (IP54 vs IP67). The discharge for short bursts is higher. This could be helpful in bridging situations for low chassis batteries (not likely dead, but low), and also it is not clear what cells are used in the lower cost battery - The more expensive one uses really good Eve cells. Not throwing shade on the lower cost version. I went with the best because my expectation is this will be at least 10 years in my coach. That difference, on three batteries, amounted to $180/year in that scenario. Also, check for discount codes out there. I did not pay the listed price. Check with Epoch for more specific differences.

 

[the_fu]

One more thing, in multiple battery configurations, I think the BMS, because they are linked and can communicate, may balance the charge better between batteries. Might not be an issue in the early years, might make a difference later on. I don't know - again speculation on my part.

 

[Larry D]

Thank you-

 

[MarkMaxPayne]

With my factory installed Lithionics, I too rely on the Lithionics BMS for SOC info. I have a Victron battery shunt installed, but it does drift a little from what the Lithionics BMS says. When they don't match I override the Victron and tell it what the Lithionics BMS claims to be true as it should know the real SOC.

Best,
-Mark

 

[Larry D]

My last system had multiple batteries and all Victron equipment-Orion DC charger, smart shunt, two Smart Solar charge controllers (1180 watts on the roof) , cerbo GX, mx 50 display panel and 3000 watt invertor. I also used the bluetooth connection to the batteries to "correct" the system SOC weekly. Never off a lot where it mattered in the short term but it could have possibly become a problem over time.