Lithium conversion easiest route DC2DC vs BIM

[johnelway]

Hi,
I have a 2019 sunseeker 2290 with 2 AGM batteries. i want to convert to lithium but i want to be sure about what i need to change.

1- onboard Converter/charger : I already checked and it's compatible with a simple jumper to change the charge profiles to lithium.

2- Solar system : My solar controller Lithium compatible so i only need to change the battery type to lithium.

3- BIM solenoid : This is the biggest question. I currently have a bim-160 that is doing everything about the alternator charging to/from both house and chassis battery. I know that if i don't change anything, my alternator will probably die if my house li battery ask for too much power... i also know that the bim-160 will not trigger the charge since the li battery voltage will be too high.

The Question : What is the best way to convert this part to lithium?
- Change the BIM to LI-BIM 225?
- Disable/disconnect the BIM and install a DC to DC charger.
- Is it possible to keep the actual setup and only add the DC2DC charger in parallel with a switch?
- What is the easiest way to install the DC2DC charger?
- What are the pros/cons of each way?


Thanks a lot for any help provided

[TitanMike]

Originally Posted by johnelway

Hi,
I have a 2019 sunseeker 2290 with 2 AGM batteries. i want to convert to lithium but i want to be sure about what i need to change.

1- onboard Converter/charger : I already checked and it's compatible with a simple jumper to change the charge profiles to lithium.

2- Solar system : My solar controller Lithium compatible so i only need to change the battery type to lithium.

3- BIM solenoid : This is the biggest question. I currently have a bim-160 that is doing everything about the alternator charging to/from both house and chassis battery. I know that if i don't change anything, my alternator will probably die if my house li battery ask for too much power... i also know that the bim-160 will not trigger the charge since the li battery voltage will be too high.

The Question : What is the best way to convert this part to lithium?
- Change the BIM to LI-BIM 225?
- Disable/disconnect the BIM and install a DC to DC charger.
- Is it possible to keep the actual setup and only add the DC2DC charger in parallel with a switch?
- What is the easiest way to install the DC2DC charger?
- What are the pros/cons of each way?


Thanks a lot for any help provided

I would disable the BIB and install a DC-DC charger. Disabled BIM's can still be used for "Emergency Start" and the DC-DC charger does a far better job of charging house batteries than the "On-Off Cycling" operation of the BIM's
A DC-DC charger will provide the same charging profile for your LiFePo4 batteries as a converter while a Li-BIM merely charges for a short period at alternator voltage, then shuts off for a while and repeats. A DC-DC charger will provide a steady output at LiFePo4 charging voltages even when alternator output is down around Float voltage levels..

A DC-DC charger is often less $$$ thn a new Li-BIM.

[johnelway]

Originally Posted by TitanMike

I would disable the BIB and install a DC-DC charger. Disabled BIM's can still be used for "Emergency Start" and the DC-DC charger does a far better job of charging house batteries than the "On-Off Cycling" operation of the BIM's
A DC-DC charger will provide the same charging profile for your LiFePo4 batteries as a converter while a Li-BIM merely charges for a short period at alternator voltage, then shuts off for a while and repeats. A DC-DC charger will provide a steady output at LiFePo4 charging voltages even when alternator output is down around Float voltage levels..

A DC-DC charger is often less $$$ thn a new Li-BIM.

Thanks a lot for confirming my thoughts.

2 more questions.

1- disabling bim. How do I do this? Disconnect ignition cable? Any more stuff to disconnect?

2- installation of the DC DC? I install it in parallel completely with new cables from truck battery?

I was thinking of replacing my actual pwm solar controller with a renogy DC to DC 50amp with mppt. Since I have only 4 x 100 watt of solar panel in parallel. It will be compatible and my setup.
That way, I'll upgrade my solar controller plus adding the DC 2 DC charger at the same time.

https://ca.renogy.com/50a-12v-dcc50s...ger-with-mppt/

Good idea?


Thanks

[rk06382]

Originally Posted by johnelway

Hi,
I have a 2019 sunseeker 2290 with 2 AGM batteries. i want to convert to lithium but i want to be sure about what i need to change.

1- onboard Converter/charger : I already checked and it's compatible with a simple jumper to change the charge profiles to lithium.

2- Solar system : My solar controller Lithium compatible so i only need to change the battery type to lithium.

3- BIM solenoid : This is the biggest question. I currently have a bim-160 that is doing everything about the alternator charging to/from both house and chassis battery. I know that if i don't change anything, my alternator will probably die if my house li battery ask for too much power... i also know that the bim-160 will not trigger the charge since the li battery voltage will be too high.

The Question : What is the best way to convert this part to lithium?
- Change the BIM to LI-BIM 225?
- Disable/disconnect the BIM and install a DC to DC charger.
- Is it possible to keep the actual setup and only add the DC2DC charger in parallel with a switch?
- What is the easiest way to install the DC2DC charger?
- What are the pros/cons of each way?


Thanks a lot for any help provided

I modified my RV Custom Products SDC-107 Battery Control Center for my Battle Born LiFePO4 in 2019. Before I modified the BCC the higher voltage of the LiFePO4 batteries were causing the BCC to try to charge engine battery all the time. see chart below:



I get up to 90 amps of charge from my alternator. Two factors that limit the amperage to the LiFePO4 batteries are the lead-acid engine battery & the size of the battery cable from the alternator to the coach batteries.

We boondock for two days at a time and it is nice to get an extra 90 amp charge as we drive to our next site. I only start the gen to test it.

I recommend the LI-BIM 225 as 90 amps is like having a 1200 watt solar panel array. The largest DC2DC is 40 amps.

I replaced my Converter/Charger with my Inverter/Charger. I set the float voltage to 13.25v

[TitanMike]

Originally Posted by rk06382

The largest DC2DC is 40 amps.

Renogy now has a 60 amp DC-DC charger as a stand-alone and the DC-DC Charger/MPPT solar controller provides 50 amp on both sources, alternator or Solar.

[roblombardo]

I chose the Li-BIM, thinking it would deliver higher current than the DC to DC option. I'm not sure one is better than the other though. I know I've seen more than the 40A rating of the DC charger via the BMV-712 shunt, but I don't always have the app on obviously, so who knows what the max would be. When the Li-BIM off (cool down) time is considered, hard to say the better option? The BIM does preserve the battery coupling function (both directions). You likely can retrofit in the same space as I did if you go the Li-BIM route. See attached photo.

[johnelway]

Originally Posted by roblombardo

I chose the Li-BIM, thinking it would deliver higher current than the DC to DC option. I'm not sure one is better than the other though. I know I've seen more than the 40A rating of the DC charger via the BMV-712 shunt, but I don't always have the app on obviously, so who knows what the max would be. When the Li-BIM off (cool down) time is considered, hard to say the better option? The BIM does preserve the battery coupling function (both directions). You likely can retrofit in the same space as I did if you go the Li-BIM route. See attached photo.

Of course the Li bim can be retrofitted into the same exact place since I already have a bim 160.

But I chatted with precision circuit and they did not recommend me the bim 225 for my setup... They recommend me to go with a DC to DC charger.

[johnelway]

Originally Posted by TitanMike

I would disable the BIB and install a DC-DC charger. Disabled BIM's can still be used for "Emergency Start" and the DC-DC charger does a far better job of charging house batteries than the "On-Off Cycling" operation of the BIM's
A DC-DC charger will provide the same charging profile for your LiFePo4 batteries as a converter while a Li-BIM merely charges for a short period at alternator voltage, then shuts off for a while and repeats. A DC-DC charger will provide a steady output at LiFePo4 charging voltages even when alternator output is down around Float voltage levels..

A DC-DC charger is often less $$$ thn a new Li-BIM.

Thanks Titan Mike.

I decided to disable the bim and install a dc2dc charger.

How can I disable the bim but still be able to use the emergency start boost function?

[TitanMike]

Originally Posted by johnelway

Thanks Titan Mike.

I decided to disable the bim and install a dc2dc charger.

How can I disable the bim but still be able to use the emergency start boost function?

Someone posted a quick method on this forum a while back. As I recall it was fairly simple, like merely breaking a component off the circuit board but maybe they'll jump in and give the exact method.

Even if BIM is removed the solution is as adding a continuous duty solenoid to connect Positive battery leads connected to both house and chassis batteries. Then find the control wire from existing boost button.

[eric1514]

Originally Posted by johnelway

Thanks Titan Mike.

I decided to disable the bim and install a dc2dc charger.

How can I disable the bim but still be able to use the emergency start boost function?

I used to think about how to modify my BCC if I was to install a DC-DC charger and retain the emergency start function but in all my years of RVing in all the different motorhomes I've owned, I have never, ever used that feature. Personally I don't think I'd sweat it much. If I was really concerned I'd carry a long set of jumper cables.