Help with BTB Charger wiring please.

Discussion in 'Solar Power' started by Revolvor, Oct 14, 2015.

  1. Revolvor

    Revolvor Funster

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    I have posted a few times about my desire to install Solar and a BTB charger, and have nearly decided what to do.

    I will have a dedicated Solar Charge Controller, connected to the Leisure Battery, and not make use of the existing wiring from the EC225. Would I still need a "Battery Master" if I have a BTB Charger? Will the two work together?

    However, I am still not sure how to modify the wiring to allow a BTB charger to work correctly.

    I sent the following to Sargent Tech Support, but have had no reply.

    Is anyone on the forum able to help?

    "I have a 2008 Autotrail Excel 600B, fitted with a Sargent EC225 Power Supply and EC100 Control Panel.
    I wish to add a “Battery-to-Battery” charger, to enable quicker/more efficient (4-stage) charging of the leisure battery when it is being charged by the Alternator.
    In order for the BTB charger to work, I will need to remove the existing input from the Alternator to the leisure battery. I assume this is controlled by some sort of split-charge or voltage-sensing relay, but may also go through the EC225.
    However, I will still want there to be a 12v supply to the fridge when the engine is running, and also for the Leisure Battery to charge, via the EC225, when on EHU. I assume that the EC225 also needs a signal to switch-off the 12v supplies (lights/sockets etc) when the engine is running, to comply with regulations.
    Are you able to advise me of the modifications to the wiring that I will need to make to enable the BTB charger to work correctly? Are you able to supply any wiring diagrams – more comprehensive than the one in the EC225 Instructions?"

    Thanks,
    John


     
  2. Abacist

    Abacist Funster

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    I am surprised that you expect a firm like Sargent to attempt to supply what you want to someone who obviously does not know what they are doing and presumably for free! If they tell you to do X, Y and then Z and you electrocute yourself, burn your van to the ground or blow a battery up they would be putting themselves at risk of a claim from you or your insurers. Think about it, how are they supposed to know if your van has already been tampered with such that it is no longer standard.

    I have learnt enough from this forum to know that I don't know much about 12 volt electrics and the potential to cause a bad fire is great. Why risk one of your biggest investments? Get someone who knows what they are doing to do it and pay for the peace of mind!
     
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  3. DavidG58

    DavidG58 Funster

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    tough but true, 'cruel to be kind' and all that, not just this OP but I see loads of questions for advice that IMO they are not proficient to undertake
     
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  4. andy63

    andy63 Funster

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    Hi John. .as far as I know there is no conflict in installing the btb charger and battery master.
    The btb charger will ensure efficient charging of the leisure battery from the alternator and a device like the battery master will ensure a trickle charge to the start battery once the leisure battery voltage reaches a predetermined voltage regardless of the charging source .ie solar ,alternator or mains charger..
    In your letter to sergeant you mention removing the existing wiring from alternator to leisure battery..again I think that that wiring will have nothing to do with the sergeant unit as I think that only deals with charging the leisure and start batteries from a mains source and not via the alternator ,so if that wiring is in place it's been added and may be via a voltage sensing relay and a btb would be a more effecient option..
    I've looked at the Stirling btb charger wiring dig and looks straight fwd.ie basically connecting the two sets of batteries together via the btb unit..
    I have fitted a few battery master devices and they are straight forward and simple..
    Hope someone can give you a bit more help with the battery to battery charger
    Ta Andy.
     
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  5. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    If you use a CTEK D250S Dual it will solve all your problems. It is a MPPT solar regulator AND B2B charger in one unit, it also splits the solar charging between leisure and engine batteries.

    D.
     
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  6. Techno

    Techno Funster Life Member

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    Very interesting and educational video


    Antipodean demo
     
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  7. Techno

    Techno Funster Life Member

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  8. Techno

    Techno Funster Life Member

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    Even the user manual does not specify the solar capacity.
    I doubt it will perform as well as my dedicated mppt regulator but still impressive kit and a no brainer if starting from scratch. Also a no brainer compared to sterling and their prices.
    http://www.ctek.com/Archive/ProductManualPdf/SMARTPASS_EN.pdf
     
  9. Techno

    Techno Funster Life Member

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  10. Techno

    Techno Funster Life Member

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    double post
     
  11. Techno

    Techno Funster Life Member

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  12. TheCaller

    TheCaller Funster

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    It's rated as a 20A charger, so I suppose that's the practical maximum. They recommend a 30A fuse in the solar panel supply cable. Multiple panels must be connected in parallel because it's maximum input voltage is 23V.

    It's a cracking bit of kit. Ideal if you are starting from scratch & so straight forward compared to most alternatives.
     
  13. Techno

    Techno Funster Life Member

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    That just backs up my assumption that it is not as efficient as a dedicated MPPT as my own has exceeded 22 amps from 300 watts. I still question where roadpro got a figure of 340 watts when it is not in the user manual
     
  14. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    I'm fairly certain the 20A figure is the B2B rate (increased by using the smartpass unit alongside). Having since checked it is indeed quoted as 20 Amps charging current, safe to assume this is for both B2B and solar functions but while Andy's setup may exceed this level many users setups will not.

    D.
     
    Last edited: Oct 17, 2015
  15. Techno

    Techno Funster Life Member

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    Yes I agree. I believe the solar is rendered open circuit with the engine running.
     
  16. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    Dunno mate but I know it works well as I've been using one on our camper for a couple of years with no problems and no flat batteries.

    D.
     
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  17. Revolvor

    Revolvor Funster

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    Well …. two very different tones in replies to my post! Firstly thanks to the constructive replies from @Techno100, @dave newell lvs and @andy63.

    @Abacist – not sure what sparked that off! There are 100’s of posts on this forum from people that “do not know what they are doing” … that’s why they posted the questions. There are also 100’s of posts promoting the idea of DIY projects such as fitting Solar Panels and more. The fact that some of the professionals on the forum such as Techno100, Dave Newell and Eddie Vanbitz are prepared to give technical advice suggests that even they agree that some projects are practical with good DIY skills.

    I joined the forum a year ago and have learnt so much from the posts by members. Since then I have learned about the difference between MPPT and PMR solar controllers, Battery-to Battery charging, 4-stage charging of 12v batteries, best practice for location of fuses, wire gauges and much much more.

    A good way to learn about a subject is to ask others with experience, and that is what I am doing. Just for the record, official Autotrail advice is to contact Sargent for issues with wiring. Over the past year I have had a number of email exchanges with the technical department at Sargent, and they have been extremely helpful with advice on technical matters, one being fitting solar panels, which they do not supply.

    I am a professional engineer, with I believe a deal of common sense, and have no intention of compromising the wiring of my motorhome. By asking questions I was trying to get the information to decide whether what I wanted to do was practical for me to perform, or if I should seek professional help.

    John
     
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  18. Techno

    Techno Funster Life Member

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    I learned plenty too thanks to @dave newell lvs
    I was not familiar with the CTEK range and I'm quite impressed.

    Prices vary wildly but even list prices are good
     
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  19. Techno

    Techno Funster Life Member

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    I've found the D250S @ £169 and the Smartpass @ £136 inc delivery so only £305 for the set.

    Also the MXS 25 Charger @£173 for 500ah battery banks
     
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  20. andy63

    andy63 Funster

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    Couldn't agree more with your thoughts..
    At the end of day it's work on your own van and if you are prepared to have a go with help available then that's how you learn..
    I've made mistakes but generally if the right information is available and you are prepared to take time and make the effort you get there..
    Andy
     
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