Installing Redarc BCDC to charge LifeP04 in Trailer. 20A or 40A ? Can a OEM ‘06 Alternator support 40A? (1 Viewer)

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Finally getting rid of the 75 Group 31 AGM and replacing it with a BattleBorn 105AH LIFEP04 battery in the trailer. I will probably never install a 2nd battery in the trailer so wondering which BCDC to get. 40A or 20A. I know the 20A should charge the battery fine however from what i read the 40A will charge much quicker and would allow me to potentially add another battery in the future. So my question.... WIll a new OEM ‘06 alternator support charging both a group 31 AGM battery under the hood as well as support the 40A Redarc charger ?

thank you all.
Sean
 
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I've done a fair amount of research and while I went with a different company for my dcdc charger, I think they work somewhat the same.

To answer your question the BCDC charger will not interact with the charging of your starter battery. Its only function is taking the current from the starter battery, and boosting it up to 20a or 40a and using that current to charge the second battery. Thats a very explain it like i'm five explanation, but I hope that makes sense.

Meaning the secondary battery will only begin charging once the starting battery is charged, so your alternator is connected to the starting battery, and then your BCDC charger is connected to the starting battery which is then connected to your secondary battery, and the BCDC charger has all of the logic to maintain, and monitor your LiFePo4 battery.

To answer your second question the 20a will charge the second "House" battery as long as its the same chemistry, but the 40a will potentially be double, and by that I mean I think its an "Up to" sort of wording.

so you can get "Up to" 20a of charge or you can get "Up To" 40a of charge.

I hope this helps and let me know if you have any more questions!
 

REDARCRyan

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Tacoma, WA
Finally getting rid of the 75 Group 31 AGM and replacing it with a BattleBorn 105AH LIFEP04 battery in the trailer. I will probably never install a 2nd battery in the trailer so wondering which BCDC to get. 40A or 20A. I know the 20A should charge the battery fine however from what i read the 40A will charge much quicker and would allow me to potentially add another battery in the future. So my question.... WIll a new OEM ‘06 alternator support charging both a group 31 AGM battery under the hood as well as support the 40A Redarc charger ?

thank you all.
Sean
Hi Sean,

I'd recommend the BCDC25D, unless you're consuming a ton of battery life and need rapid charging during short durations from site to site. Also, some clarification from the other comment the BCDC will kick on once it registers the starting battery in the vehicle reaches 13.2v, it will then begin charging the AUX battery at 25a per hour, while varying charging profiles in order to perfectly top off that battery. It can also handle dissimilar battery types although it's not generally recommended. It also has solar priority so if you have solar it will prioritize the incoming power first and supplement the remaining through the BCDC. You'll want to mount the BCDC as close to the BattleBorn as possible to eliminate voltage drop and ensure maximum power is transferred to the aux battery.

As for your alternator, rule of thumb is that about half of the alt output is for vehicle accessories. For example, if it's a 100a alternator 50a is available so a BCDC40D would be acceptable but near the limits of the alternator.

So to conclude, the lithium battery will give you about 80% of it's Ah for usage. This means have about 84Ah's ~ish to use without starting your vehicle to charge if you don't have solar leaving you with a dead battery. If you have solar, you can expect about 6Ah for every 100w's in panels you have in direct sunlight. Keep in mind, BCDC can handle as much solar as you throw at it within 32VOC.

If you have any other questions, please don't hesitate to shoot me a message or an email : rthurston@redarcelectronics.com
 
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LOVE Redarc!!! those guys are badass and their support is unparalleled and their BCDC's are far superior that anything on the market......I have a BCDC 2410 thats charging two 100aH's AGM batteries wired in to a 24v config and have had ZERO issues. I have a 200w solar panel that charges while im parked......you can not go wrong with RedArc!!!!!
 

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