dc2dc charger

[dcs500]

Looking for info on installing a dc2dc charger with my upgrade to lithium batteries in order to be able to charge off of the motor home engine alternator without over loading it. I have 400 Ah of batteries, a renogy 60 amp MPPT charge controller, 400 watts of solar panels. I need to know if the dc2dc charger replaces the renogy MPPT charge controller.

[craigav]

I suppose any setup could be very unique and I am not aware of your setup although:

MPPT (and PWM) controllers are designed to take the power from Solar Panels and control that power in order to charge your battery(s). DC2DC chargers are designed to take power from a source such as your engine's alternator and battery(s) to charge other battery(s) such as your coach batteries. So with this in mind, unless something is installed in a non-conventional manner, the DC2DC charger will not replace your MPPT controller and instead will work along with it. ~CA

[dcs500]

Thanks, thats what I was hoping for. With the dc2dc charger, a LIBIM would not be necessary?

[craigav]

Correct, however keep in mind that the LIBIM likely also has your "Auxiliary Start" (sometimes known by similar but different names) dash switch connected to it that would no longer function, and if I remember correctly (I don't have a BIM LI or otherwise), the LIBIM may also allow your Coach charging to also charge the main engines (chasis) start battery. In any case though, you would not want both the LIBIM and a DC2DC charger active at the same time. So as far as charging the Coach batteries from the engine's alternator, you are correct that the LIBIM would not be necessary and in fact would prevent the DC2DC charger from working as intended. ~CA

[dcs500]

Thanks a bunch. Adding a dc2dc is much less work than doing both the LIBIM and the charger. Hard to get all this good info, even after researching online for 2 days. I appreciate your response. Safe travels.

[EricM22]

Actually, swapping out the BIM for a lithium BIM is the easiest and quickest route. I think it took me a total of 8 minutes. The existing wires go in the exact same place on the new lithium BIM. Quick and easy.

If you get a DC2DC, you'll have to do some rewiring, and you'll lose the ability to press the little button by the ignition to jump the chassis batteries from the house batteries.

You can keep a non-lithium converter and far well. I did when I switched to lithium and the existing non-lithium converter gets my batteries to 97%, and if I press the little boost button on the converter when plugged into shore power it will quickly charge to 100% if needed.

[Rustynuts]

By going with a LiBIM for the reason of keeping the boost function does not matter as you really should not use the Lithium house batteries to try and start your chassis engine and you need high cold cranking amps for the diesel engine. Unless you have a large bank of Lithium with high amperage BMS units, the BMS will most likely shut down to protect the batteries. You could hold the boost button to connect the ban,s and allow the lithium to maybe charge the chassis battery enough to crank the chassis but that might take some time. The way I prepare is I carry a Victron Battery charger and I would start the generator and use the battery charger to charge the chassis batteries. I went with a Dc2Dc charger for mine as the Victron MultiplusII I have installed, it has a 2amp trickle charger just for chassis batteries that keeps them charged all the time.

[dcs500]

From my extensive research on this subject, I've learned from several experts that the non lithium charger from Progressive Dynamics will only charge my 4 lithium 100 Ah batteries to 80 percent unless I use the boost button. How much I would have to use it may be inconvenient. Also, I haven't added a LiBIM as I will be adding a DC2DC charger which is quite easy as I don't need to rewire but will need to add wiring to the chasis batteries and the house batteries which are easily accessible in my Seneca. My factory BIM is a real pain to get to as I would have to remove all 4 batteries to get my fat body into the battery compartment. The advantage of the DC2DC charger is being able to charge the lithium bank without damage to the engine alternator as I travel. And finally I've only used a battery boost on the dashboard once in the last forty years that I've been RVing. So for me one thing outweighs the other as a matter of convenience. I'm a little lazy in my old age. Thanks for your input as it is important for me to get other perspectives. Cheers

[craigav]

Originally Posted by dcs500

From my extensive research on this subject, I've learned from several experts that the non lithium charger from Progressive Dynamics will only charge my 4 lithium 100 Ah batteries to 80 percent unless I use the boost button. How much I would have to use it may be inconvenient. Also, I haven't added a LiBIM as I will be adding a DC2DC charger which is quite easy as I don't need to rewire but will need to add wiring to the chasis batteries and the house batteries which are easily accessible in my Seneca. My factory BIM is a real pain to get to as I would have to remove all 4 batteries to get my fat body into the battery compartment. The advantage of the DC2DC charger is being able to charge the lithium bank without damage to the engine alternator as I travel. And finally I've only used a battery boost on the dashboard once in the last forty years that I've been RVing. So for me one thing outweighs the other as a matter of convenience. I'm a little lazy in my old age. Thanks for your input as it is important for me to get other perspectives. Cheers

Just for awareness as I am not totally clear of your plans. In any case, if you install the DC2DC charger where the existing BIM is (or nearby) then you can use those cables and remove the BIM. It is important to note (which you may already know) that you do not want to keep a functioning BIM in place and a DC2DC charger as well, if you do then electrically speaking the input and output of the DC2DC charger will be shorted together whenever the BIM kicks in (every time you turn the key on for example) and that likely will damage the DC2DC charger and in any case keep it from working, perhaps just blow some fuses, not quite sure but something to avoid. ~CA

[Rustynuts]

Originally Posted by dcs500

From my extensive research on this subject, I've learned from several experts that the non lithium charger from Progressive Dynamics will only charge my 4 lithium 100 Ah batteries to 80 percent unless I use the boost button. How much I would have to use it may be inconvenient. Also, I haven't added a LiBIM as I will be adding a DC2DC charger which is quite easy as I don't need to rewire but will need to add wiring to the chasis batteries and the house batteries which are easily accessible in my Seneca. My factory BIM is a real pain to get to as I would have to remove all 4 batteries to get my fat body into the battery compartment. The advantage of the DC2DC charger is being able to charge the lithium bank without damage to the engine alternator as I travel. And finally I've only used a battery boost on the dashboard once in the last forty years that I've been RVing. So for me one thing outweighs the other as a matter of convenience. I'm a little lazy in my old age. Thanks for your input as it is important for me to get other perspectives. Cheers

If you have solar then program your max voltage at 14.6 (or depending on the battery manufacturers setting) and that will take your batteries to 100% most of the time where your charger falls short.

[Kevin Cooper]

Originally Posted by dcs500

Looking for info on installing a dc2dc charger with my upgrade to lithium batteries in order to be able to charge off of the motor home engine alternator without over loading it. I have 400 Ah of batteries, a renogy 60 amp MPPT charge controller, 400 watts of solar panels. I need to know if the dc2dc charger replaces the renogy MPPT charge controller.

Suggest you go to AZExpert’s latest YouTube video on a possibly better way than a DC2DC charger. It is what he installed in his own Patriot Beaver.

[mplan]

FYI, Victron is coming out with a 50amp 12V DC to DC charger, supposedly lots of enhancements over the 30amp version. I’m waiting to get my hands on one.

[Rustynuts]

Originally Posted by Kevin Cooper

Suggest you go to AZExpert’s latest YouTube video on a possibly better way than a DC2DC charger. It is what he installed in his own Patriot Beaver.

Yes he installed the LiBIM that has been discussed here which is what I started out with when I changed to Lithium but I quickly found that it wasn’t very efficient, won’t charge a Lithium to 100% and truly only charges 42% of the time you are driving. I switched to a Victron 12-12-30 and even with its overheating and charge rate DEG ration from the overheating, I saw a much better charge rate than with the LiBIM. Here is a good blog that explains the pros and cons between the LiBIM and the DC2DC Charger.

https://explorist.life/how-to-charge...le-alternator/

[Rustynuts]

Originally Posted by mplan

FYI, Victron is coming out with a 50amp 12V DC to DC charger, supposedly lots of enhancements over the 30amp version. I’m waiting to get my hands on one.

I have the Victron Orion XS 12-12-50 on Pre-Order and was last told I should see get it with in a month. From what I have read and seen, it’s much better than the 12-12-30.

[dcs500]

I'm confused. I haven't installed a LiBIM or other BIM. The original equipment has not been removed. Pic included. Are you saying that I have to remove the factory unit when adding a DC2DC charger? My plans are, after I just installed the new 4500 series Progressive Dynamics converter with the switch for FL, AGM, or Li ,to install four new Lithium 100 Ah batteries. I already have solar panels on board. I'm exploring the best set up for my needs. I'm taking Rustynuts advice to install a DC2DC charger so that the engine alternator will not be overloaded while driving and charging the house batteries. As I understand it, I simply have to install the DC2DC charger with a connection to the ignition and don't need to remove the existing factory monitor in the pic. I am getting bits of info for this. I have a 2018.5 Seneca. If I need to remove the existing unit pictured, please let me know. This is getting frustrating. Thanks

[mplan]

Originally Posted by Rustynuts

I have the Victron Orion XS 12-12-50 on Pre-Order and was last told I should see get it with in a month. From what I have read and seen, it’s much better than the 12-12-30.

I placed a pre-order with Exploristlife.com. They have an excellent blog post with instructions on how to wire it since the first release comes only in the non-isolated version.

[craigav]

Originally Posted by dcs500

I'm confused. I haven't installed a LiBIM or other BIM. The original equipment has not been removed. Pic included. Are you saying that I have to remove the factory unit when adding a DC2DC charger? My plans are, after I just installed the new 4500 series Progressive Dynamics converter with the switch for FL, AGM, or Li ,to install four new Lithium 100 Ah batteries. I already have solar panels on board. I'm exploring the best set up for my needs. I'm taking Rustynuts advice to install a DC2DC charger so that the engine alternator will not be overloaded while driving and charging the house batteries. As I understand it, I simply have to install the DC2DC charger with a connection to the ignition and don't need to remove the existing factory monitor in the pic. I am getting bits of info for this. I have a 2018.5 Seneca. If I need to remove the existing unit pictured, please let me know. This is getting frustrating. Thanks

Yes, that is what I am saying. While I agree with others that a DC2DC charger is advantageous and provides for an optimal charge for LifePo4 battery(s) (and other advantages), it is also true that simply replacing the BIM with a LIBIM as a simpler solution and retains your aux start function.

In any case, while you don't have to physically remove the BIM you do need to disable it. Which in part of why I was suggesting to install the DC2DC charger in (or very near) the location in your image as a "replacement" of the existing BIM. Again, you don't want both a functional BIM and DC2DC charger active at the same time. ~CA

[dcs500]

Okay, thanks. How do I disable the BIM? Do I disconnect the battery cables and remove the ignition wire, etc?

[craigav]

Originally Posted by dcs500

Okay, thanks. How do I disable the BIM? Do I disconnect the battery cables and remove the ignition wire, etc?

Yes, that is exactly what you would need to do. Which circles back around to the reason for my suggestion to install the DC2DC charger there as you can re-use those same wires for the DC2DC charger, (ignition signal and an input and output cables) instead of running new wires and keeping in mind that the existing wires need to be disconnected anyway. ~CA

[dcs500]

So all the other wires are just disconnected? Like the sig wire and gen set wire? Anything else I should know? I appreciate all your info, I just need to have all the details. Thanks