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Teleman's avatar
Teleman
Explorer
Nov 08, 2021

LiFePo battery upgrade question

I ordered a 200AH LifePo battery to replace my two 100AH lead acid batteries and also a compatabile converter which takes care of charging the battery with shore or generator power but what about charging the battery with the alternator? Does the battery's BMS take care of everything and therefore no need to change or upgrade the alternator? Sorry if this is a dumb question!
  • pianotuna wrote:
    . . . Can it be limited to 20 amps if need be? . . .
    This could potentially be an important feature consideration. It'll be interesting to see if the 124a alternator has the headroom to handle the additional ~40a load for the long haul.
  • otrfun wrote:
    pianotuna wrote:
    . . . Can it be limited to 20 amps if need be? . . .
    This could potentially be an important feature consideration. It'll be interesting to see if the 124a alternator has the headroom to handle the additional ~40a load for the long haul.

    I'll have to look into it. I was originally looking at a 25A unit but that would have been inadequate for 400 watts of solo panels, which I plan to install next spring.
  • pianotuna wrote:
    Teleman,

    That is a good decision. Can it be limited to 20 amps if need be? It is a far superior make.

    Another reason to have a bypass circuit is for a "poor mans" boost switch. If the chassis batteries are dead, you would be able to get some amps into them from the "house" bank. Don't have it "active" when starting. The Li bms will NOT like it.

    If the alternator did fail, then that bypass circuit could be used to keep the engine running a lot longer while getting to a service center. Of course the Redarc ought to be turned off to do this.

    What kind of switch do you use? I take it using the house battery boost switch as is isn't recommended? I carry a jump start battery pack too.
  • Teleman wrote:
    otrfun wrote:
    pianotuna wrote:
    . . . Can it be limited to 20 amps if need be? . . .
    This could potentially be an important feature consideration. It'll be interesting to see if the 124a alternator has the headroom to handle the additional ~40a load for the long haul.

    I'll have to look into it. I was originally looking at a 25A unit but that would have been inadequate for 400 watts of solo panels, which I plan to install next spring.


    That would not be a switch. It would be a feature on the dc to DC charger.
  • pianotuna wrote:
    Teleman wrote:
    otrfun wrote:
    pianotuna wrote:
    . . . Can it be limited to 20 amps if need be? . . .
    This could potentially be an important feature consideration. It'll be interesting to see if the 124a alternator has the headroom to handle the additional ~40a load for the long haul.

    I'll have to look into it. I was originally looking at a 25A unit but that would have been inadequate for 400 watts of solo panels, which I plan to install next spring.


    That would not be a switch. It would be a feature on the dc to DC charger.

    Sorry that wasn't meant for you. Since edited.
  • Teleman wrote:
    pianotuna wrote:
    Teleman,

    Another reason to have a bypass circuit is for a "poor mans" boost switch. If the chassis batteries are dead, you would be able to get some amps into them from the "house" bank. Don't have it "active" when starting. The Li bms will NOT like it.

    If the alternator did fail, then that bypass circuit could be used to keep the engine running a lot longer while getting to a service center. Of course the Redarc ought to be turned off to do this.

    What kind of switch do you use? I take it using the house battery boost switch as is isn't recommended? I carry a jump start battery pack too.


    Hi Teleman,

    I use this type:

    https://www.napaonline.com/en/p/NW_786125?impressionRank=3

    I like it because I store it with the "key" hanging on a string. It would be nearly impossible to turn it on by accident. Maximum load up to 300 Amp @ 24 Volt DC.

  • pianotuna wrote:
    Teleman wrote:
    pianotuna wrote:
    Teleman,

    Another reason to have a bypass circuit is for a "poor mans" boost switch. If the chassis batteries are dead, you would be able to get some amps into them from the "house" bank. Don't have it "active" when starting. The Li bms will NOT like it.

    If the alternator did fail, then that bypass circuit could be used to keep the engine running a lot longer while getting to a service center. Of course the Redarc ought to be turned off to do this.

    What kind of switch do you use? I take it using the house battery boost switch as is isn't recommended? I carry a jump start battery pack too.


    Hi Teleman,

    I use this type:

    https://www.napaonline.com/en/p/NW_786125?impressionRank=3

    I like it because I store it with the "key" hanging on a string. It would be nearly impossible to turn it on by accident. Maximum load up to 300 Amp @ 24 Volt DC.


    OK thanks.
  • Teleman wrote:
    pianotuna wrote:
    Teleman wrote:
    pianotuna wrote:
    Teleman,

    Another reason to have a bypass circuit is for a "poor mans" boost switch. If the chassis batteries are dead, you would be able to get some amps into them from the "house" bank. Don't have it "active" when starting. The Li bms will NOT like it.

    If the alternator did fail, then that bypass circuit could be used to keep the engine running a lot longer while getting to a service center. Of course the Redarc ought to be turned off to do this.

    What kind of switch do you use? I take it using the house battery boost switch as is isn't recommended? I carry a jump start battery pack too.


    Hi Teleman,

    I use this type:

    https://www.napaonline.com/en/p/NW_786125?impressionRank=3

    I like it because I store it with the "key" hanging on a string. It would be nearly impossible to turn it on by accident. Maximum load up to 300 Amp @ 24 Volt DC.


    OK thanks.

    Do you place it between the staring battery and the charger or the charger and house battery? How did you mount it?
  • Hi Teleman,

    I was able to mount the three I use near the drivers seat in the wall. It makes it quite convenient for switching while I'm trundling down the road.

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