Help sizing Renogy DC to DC charger for caddy 110a alternator

[sun seeker]

Hello there i have a caddy 1.9tdi 2009
I've just got a renogy 100ah lithium battery and 20a DC to DC charger in the black friday sale but now thinking should i have gone for the 40a charger instead as obviously it will charge the battery twice as fast.
the renogy battery has a 100a BMS and has a Maximum continuous charging current of 50 A

Would the 40a charger be ok for the caddy alternator rated at 110a?
i don't want to over work the alternator to much but if it can handle the 40a charger id go for that one.

the limited research i've done suggests to match your DC to DC charger to the alternator idling amperage
i'm not 100% but what i can find the alternator idles at 50% its rated output so my caddy alternator should idle at 55a.

Many thanks james

 

[Dellmassive]

I've just got a renogy 100ah lithium battery and 20a DC to DC charger in the black friday sale

- good man

now thinking should i have gone for the 40a charger instead as obviously it will charge the battery twice as fast.

- very true

the renogy battery has a 100a BMS and has a Maximum continuous charging current of 50 A

- yep true

Would the 40a charger be ok for the caddy alternator rated at 110a?

- yes, if its rated at 110A then it can produce 110A, but thats MAX, id be looking to run it at 75% max, (I've killed an alternator from drawing too much for too long . . . it will get very hot then the regulator pack will fail)

i'm not 100% but what i can find the alternator idles at 50% its rated output so my caddy alternator should idle at 55a.

- the voltage output will be controlled from either the van (LIN bus) or the VREG on the alternator - depending on the system on the van.



so basically, go for it.

you can even get the 50A unit that has solar MPPT built in.


with the BT-2 Bluetooth unit connected to it you can adjust the output current limiter as you like . . . ( via the Renogy Home APP)

so 10,20,30,40,50A as you like - its well sweet =]


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https://amzn.to/3lfpVUH

and . . .

Renogy Bluetooth Module BT-2 : Amazon.co.uk: Business, Industry & Science

Renogy Bluetooth Module BT-2 : Amazon.co.uk: Business, Industry & Science

amzn.to

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more info here:

Dellmassive’s "How I Done It" blogs.

-- Dellmassive`s -- "How I Done It" -- thread -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

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[CJW]

with the BT-2 Bluetooth unit connected to it you can adjust the output current limiter as you like . . . ( via the Renogy Home APP)

so 10,20,30,40,50A as you like - its well sweet =]

Sorry to jump on this thread, but am I to understand you correctly @Dellmassive that the Renogy home app allows you to set the current applied to the battery during charging? For example, a DCC50S powered by the alternator could be limited to a 20A / 30A bulk charge to an AGM battery? Many thanks.

 

[Dellmassive]

@CJW

Yes correct.

You can set the charge limit via the app...

And max voltage.

And chemistry type


.

 

[CJW]

@CJW

Yes correct.

You can set the charge limit via the app...

And max voltage.

And chemistry type

Marvellous - what a great piece of kit! I really like it, and now I can throttle the current to my stopgap 95ah AGM battery to not exceed 0.3C. When money allows I can can get the full 50A to a Renogy lithium. Perfect. Thank you @Dellmassive.