New member..battery charging advice required please :)

Discussion in 'Off Grid Living' started by poppydogpaul, Feb 13, 2016.

  1. poppydogpaul

    poppydogpaul Monkey

    Hi all :) ....I'm sure this topic creates a 'yawn' factor for those in the know...I'm a carpenter ;) so any advice would be appreciated...

    I'm currently building a self build motorhome...the base vehicle is an ex govt minibus so is utilising 2x 12v mercedes 110 ah lead batteries (in parallel..24v)....for starting, 4 small fluro lights and to power a fitted ebespacher diesel heater (blown air). I have also aquired 2 x banner 12 v 110ah lead batteries for a future planned 24v leisure circuit.

    Due to financial constraints and work commitments the bus has been left for approx 3 months with total inactivity.

    My long term plan is to have the diesel heater and the lights wired over to my banner 24v leisure circuit with an inverter...(I'm considering solar to supply this eventually with an inverter...apart from the forementioned power requirements I am only running a small dvd player/screen and laptop charger...all cooking is lpg and a woodburner is en route!)

    So here are my initial questions...all four batteries were accepting charge just fine before my recent neglect...( banners are in the boot disconnected...merc starters are fitted in place). I need to move the bus to a permanent site offering shore power asap (narcissist site owner) a charger is yesterday. For about £40 I can purchase a simple 12v charger isolate the cells...get the van running (hopefully)...then worry about decisions of permanent installed intelligent chargers later....or is this a risk?...Is it worth the investment now in a 24v intelligent charger that will hopefully give the batteries best chance of a recovery charge? then be fitted in lace for maintenance (in the UK 'Ctek' brand..8 stage intelligent charger keeps being recommended...a £250 spend|! ..gulp!)

    I'll have shore power at the new site so a cheap fan heater will suffice as spring is approaching...and big decisions can be made as funds allow....

    I'm just concerned about buying twice...possibly ruining my current cells with a cheap charger in order to get the van started...or missing out on the opportunity of possibly a charger/inverter now which would manage charging the leisure circuit in the future...I'm hoping transferring the heater and lights away from the merc starter cells will mean my alternator can cope with charging those....

    I fully appreciate those with tech knowledge will possibly be slapping their heads at the mo...that is why I'm here asking questions....I have what I have to work with at the moment ;)

    Thanks in advance for responses....kind regards :)
  2. Dunerunner

    Dunerunner Brewery Monkey Moderator

    First, Welcome to the forum/
    Second, two 12V batteries connected in parallel are a 12V source. Connected in series, the voltages are additive. Think of it as two 12foot 2X4's side by side... still 12 foot but stronger, more capacity; compared to the same two 12 foot 2X4's tied end to end, now 24 feet but with the same capacity as a single 12 foot 2X4.

    Solution/// Disconnect all batteries and reconnect them in parallel. Then charge as one 12V bank, all at the same time. They should recharge within a few days. Make sure they are not sulfated and that the cells are filled with distilled water to the proper level. That should get you started.

    Here is a charger that should do the trick... Battery Tender 021-0123 Battery Tender Junior 12V Battery Charger: Automotive
  3. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    Remove from vehicle, check that both batteries are of the same type, lead acid etc.

    Check each cell for proper electrolyte level, check the specific gravity of each cell. If any cells are way out of whack , Lead–acid battery - Wikipedia, the free encyclopedia , with the others then figure you have a bad cell, yes any cell charge level can be checked with a meter but you need to know how.

    Charge each battery with a quality charger that has a trickle down charge rate. At the end when the battery reads about 13.50 on a good meter check the electrolyte levels again and take the specific gravity of all cells again.

    Record all readings for future reference of battery condition.

    One bad cell in a string is ruin your whole day.

    Batteries are a source of stored power, they can be deadly and will blow up if you are not careful and follow standard safety rules.

    Lead Acid Battery Maintenance | Safety Tips for Servicing
    Last edited: Feb 13, 2016
    Dunerunner likes this.
  4. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    If it were my setup, I would be looking for a nice MPPT Charge Controller, since you plan on Solar, down the Road, anyway.... and then use it to maintain BOTH Battery Banks, via Isolating Power Diodes. Since you will have Shore Power, you can get a nice Transformer to do the local Line Voltage, to MPPT/CC Input, Transformation, and thru a Bridge Rectifier. Then when you get Solar, you can just switch between the Shore Power Input, or the Solar Input, to MPPT/CC as needed. Basically the Battery Bank that is the lowest Voltage, will take most of the Power from the MPPT/CC, until it comes up in voltage, to equal the other Battery Bank, minus the .7Vdc drop of the Isolating Diodes. By using the Settings in the MPPT/CC, you can maintain the System, at whatever Float Voltage you desire, and ALWAYS have a Hot Battery for Engine Starting, no matter what the state of the House Battery Bank is. Now we can see what CS has to say...
  5. arleigh

    arleigh Goophy monkey

    My own system is 6 volt batteries pared and each on it's own switch so that I can regularly test each pair at random including each solar panel, and the wind mill .
    I can switch out any battery pair or solar panel that is not performing, so they do not draw down the rest.

    My system is built in a shop trailer, and the battery bank is below deck so it can breathe, and gasses do to enter the shop at all.
    I keep baking soda and water handy for cleaning the terminals, and distilled water for topping off each cell as they need it.
    The nice thing about using 6 volt batteries ,
    Golf cart batteries are designed for high out put
    6 volt allow me to run things that are 6 volt ,but if required can rewire in series for any combination I need and IMO perform better than 12 or 24 volt batteries.
  6. AD1

    AD1 Monkey+++

    Guys he may have. 24 volt system since its anX Gov vehicle
  7. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    Might you be speaking of the Formula Wheel?
  8. HK_User

    HK_User A Productive Monkey is a Happy Monkey

    Maybe TMI.

    Of course we could add in Eli the Ice Man.
    Dunerunner likes this.
  9. ghrit

    ghrit Bad company Administrator Founding Member

    Let us not forget that's all DC -- And yes, I'm still awake enough to know it's all about batteries here --
  10. ghrit

    ghrit Bad company Administrator Founding Member

    AC is very similar as long as reactance is considered. (BYKT, I think.)
    Dunerunner likes this.
  11. Dunerunner

    Dunerunner Brewery Monkey Moderator

    Resistance in AC and DC is the same as long as it is pure resistive. Introduce a coil or capacitor and you introduce reactance and that requires some more advanced math.
  12. poppydogpaul

    poppydogpaul Monkey

    Hey all..thankyou for the replies! good to find an active forum/community where I'm assuming people won't judge my lifestyle choices quite as much as my parents do :whistle:...I hope to find the time to contribute more here, I've lived out of campers/this bus for 3 years now..and 5 years tv free:)

    So the detail already provided here has managed to expose my lack of electrical knowledge...I'll clarify (hopefully without muddying the waters more)...I'm going to need guiding through this with patience....(think of attempting to teach a blindfolded monkey how to knit)...:ROFLMAO:

    Yep as an ex govt bus its a 24v system (with the exception of a convertor to a 12v cigarette lighter on the dash)...hence why I sourced the 2 banner cells as I thought it would be easier to establish a 24v leisure circuit to power existing lighting and hot air blower.

    'C tek' are a norweigan firm I believe...I sent off a detailed email last week to their technical team (I'm throwing that word out there loosely!)....highlighting my exact set up and asking which of their products they suggested....the response was errm, reserved. "Depends what batteries you want to charge (you have these details) quickly you want to charge them (you have these details)...and what your intended load will be (repeat as necessary)....."

    So attempting to research with the people who are charging between £150-£800 for 'intelligent' chargers drew a blank...lets hope their products are slightly more clued up than the staff ;)

    I've checked the cells and fluids seem correct,...I could probably borrow a 12v 'trickle' charger and get them up to speed individually...was just concerned that they may have suffered from idling and a charger that offered multiple charge modes/monitoring and desulphation may be worth the investment now. Heads up...Idiot question...."could a bog standard old school trickle charge at the moment harm them?".

    ps...thanks for the amazon would appear that you guys and girls across the pond seem to have vast choice of toys to buy compared to the UK....and what you pay in $$$...we pay the same figure in £££! :eek: ( questions to reviewers of certain UK amazon offered chargers pointed me to ctek after they criticised trickle...and 'only' 3 stage intelligent chargers).

    Math of any sort makes me break out in a cold sweat...I do appreciate the input....just providing a caveat so folks don't get offended that I'm not engaging intelligently with it....... "buy this and clip it on that" is where I'm at with electrical knowledge right now. If you need me to build a 'home' out of govt cast off buses, reclaimed pallets...vintage wine crates...and random ideas....I'm good to go (y) ....(except the 'sparky...hurts when you touch it dangerous bit').
    kellory, Dunerunner and HK_User like this.
  13. poppydogpaul

    poppydogpaul Monkey

    Quick update...I had a conversation today with a London based supplier of chargers/inverters...they stock ctek brand...and many others. He sounded interested, and informed (lots of tapping on calculator buttons whilst I spoke..I don't think he was doing the monthly accounts :unsure:)....

    His conclusion was to buy a decent charger (£220) that could send charge to the two banks...initially from shore power...then add a split relay later. He was adamant on my need to buy an 'intelligent' charger of that price bracket. He was totally dismissive of solar for UK use and suggested until he saw reasonably priced panels/controllers with effective output for this country..he wouldn't stock them, suggest them...or sell them. His solution seemed quite straightforward...I'm concerned about irritating fellow campers by having to start my engine every few days to replenish the leisure circuit if I'm on a site with no shore power....hmm.

    Hey Dunerunner. Thankyou for your input so far (y)...I have considered the generator route, it appears a really straightforward solution...its a big bus so I could find space...just concerned about the noise (on a quiet campsite)...and reliance on more purchased fuel....I was hoping that solar could provide an alternative so I could hear local birdsong :)....but appreciate a decent genny would be retailers in the UK only seem to suggest its useful for battery top up. I have 4 metres of roofspace spare!....

    Thanks....I checked this out on Amazon I suggested before...$799 there or £799 here ....must be a coincidence ;)
    Last edited by a moderator: Feb 15, 2016
  14. Dunerunner

    Dunerunner Brewery Monkey Moderator

  15. GrayGhost

    GrayGhost Monkey+++

    Looks like that monkeys have you're in good company here.

    Welcome to SM!
    HK_User, ghrit and Dunerunner like this.
  16. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

    You can also make a quiet generator even quieter, with the use of an insulated box or cover. (Leaving plenty of clearance for heat and exhaust of course)
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