Battery to battery or alternater to battery

Discussion in 'Tech/Mech General' started by SteveandDenise, Nov 15, 2013.

  1. SteveandDenise

    SteveandDenise Funster

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    Hi All

    I am thinking of fitting a B to B or A to B charger.

    One seems to be a simple small box/relay the other seems to be a more complex bit of kit with sensors for temp on the alternater and battery and the cost varies a lot.

    Any advice appreciated

    Steve :Smile:
     
  2. Steve

    Steve Funster Life Member

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    The Sterling one I was looking at was some what more involved when it came to fitting, if you have easy access to the alternator then its not so bad but does more or less become a fixed item and if removed at a latter date would require more work. The b2b is a lot simpler, 2 wires in 2 wires out. The chap that I talked to at sterling's did ask what I wanted if for and he said that for the normal 50amp use a b2b was the best option, but for greater power and control the a2b would be more suitable. By the more power he said for battery capacities over 200ah and charge rates of 75+amps. As I have found out to my expense if you go for a b2b or an a2b fit all the temperature sensors recommended or you will cook the alternator.
    Steve
     
  3. Terry

    Terry Funster

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    Go for a simple relay(£10 ish) and beef up the cable :thumb::BigGrin:
    terry
     
  4. jonandshell

    jonandshell Funster

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    We have an A2B charger. It's brilliant.
    Would I fit one again? No!

    When I bought ours, we wanted more than the standard 45 amp B2B. I had no option but to go for the A2B unit.

    B2B units up to 100 amp are available now. That is what I would have gone for had I had the choice at the time.:cry:

    I recommend you identify your alternator size, take away 40 amps, and go for the size of B2B that most closely matches the alternator output you have left.:thumb:

    As an example, we have a 150 amp alternator, I would buy the 100 amp B2B. The spare 40 amps you will need to run your vehicle's engine management etc..

    Don't worry about going large on the charger, your existing leisure battery will only get what it wants. You will then have spare capacity for a bigger battery bank in the future. Remember the most benefit is gained from these chargers when you use quality lead acid deep discharge batteries. At best, traction monoblocs, nearly as good, Banner Energy Bulls.:thumb:
     
  5. SteveandDenise

    SteveandDenise Funster

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    B2B

    Thanks for the coments we have 2x110 leisure batteries with solar 130w which has been fine all year with no ehu apart from the HAIR DRYER 1800w (genny) but was thinking of a 2000w inverter as that is the only time we need 220 volts.

    My wife has tried all the small wattage ones and you know how it is they dont do the job properly!

    It sounds like a 100 amp B2B may be the answer.

    Thanks
    Steve:Smile:
     
  6. jonandshell

    jonandshell Funster

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    Before you rush out and buy though, do be cautious about the size of your vehicles's existing cable from alternator to starter battery.
    This might be too thin to carry the alternator's maximum output current for prolonged periods.:Eeek:
    My suspicion is that Just looking's alternator failed due to excessive heat build up in the alternators rectifier bridge and output post.
     
    Last edited: Nov 15, 2013
  7. SteveandDenise

    SteveandDenise Funster

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    B2B

    Thanks Jon

    The van Is a two year old Fiat 3.0 I will have a look at the alternater if I can find it it's bad enough trying to see the engine (A class) and also take a look at the wire used be for I do any thing.

    Steve
     
  8. jonandshell

    jonandshell Funster

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    In fact, thinking back to my A2B install, the standard Ford cable was just 16 mm sq.
    Taking into account the length of the original cable, beefing it up would have been necessary, even if fitting the simpler B2B system.
    Fitting the A2B forced the cable to be changed to 35mm for correct operation.
    With the heavier alternator output cable, there have been no heat issues, despite prolonged periods of over 2 hours of maximum current output.
    Definetly a check work carrying out before installation.:thumb:
     
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