New Battery...

[pdw709]

[brian]

Hello Phil,  with two 12v batteries connected in series, you require a 24v charger.

Connect the 24v charger positive to the positive terminal of one battery, charger negative connect to the negative of the second battery.

If you only have a single 12v charger, it is possible to have the charger connected to both 12v batteries at the same time without having to disconnect the inter linking series cable, by inserting diodes into the battery charging leads to block any unwanted cross flow between the batteries during parallel charging.

On my grandsons T2, I have fitted a car cigarette lighter socket to the dashboard with permanent links from this to the battery, to charge the battery, I simply plug in the charger which has a cigarette lighter plug on the end of the charging leads into the dashboard socket.

Mine is a single battery 12v system, but by running two positive and two negative leads from the cigarette lighter socket, connected to each of your two 12v batteries with a diode in each lead, you would simply have to plug your 12 volt charger in and you would be charging the two batteries at the same time.

The charging rate would obviosly be lower taking longer than it would to charge a single 12v battery, but, then you have to swop the leads over to charge the second battery, so the time element would work out the same, faster in fact if you go down the pre wired charging circuit.

Regards,

Brian.

You definately want to stick with the deep cycle batteries, which, despite there additional cost, will give you a much longer life and stand much more abuse than a normal lead acid battery.

[brian]

Smee again Phil.

I forgot to add that any diodes purchased should have a rating of at least twice the working voltage of the circuit and the current carrying capacity of the chargers full output.

:Member ID lesjacksam ( Feedback score of 3636) on ebay is selling 50v 6amp diodes at 99p each, these should handle most DIY 12v charger outputs.

Regards,


Brian.

[pdw709]

Brian - thanks for the advice.

I checked my charger last night and it has a 12V/24V switch so it seems I can charge both in series as outlined.

This forum is great by the way - it would have saved me a lot of time and money if it had been around when I built mine!

Cheers

Phil

[Robert]

Hi Brian,

that's an interesting point about these diodes!
My 36 Volt system consists of 3 pieces of 12 Volt gel batterys, and I need to disconnect them every time I want to charge them with my 12 Volt charger.  
So I would like to add the diodes and plug as you discribed.
I 'll draw a little scheme (as an electronic nitwit) and hope you 'll advise me.

[brian]

Toylander charging circuit for 36V system.Drawing1

I'm trying to post a drawing I have done of your charging circuit, but obviously I have failed but I'll keep trying Robert.

Basicaly, you will need three battery current amperage diodes and two motor current amperage diodes.

Ebay is your friend finding suitable diodes.

Tonight I have found 5amp 50 volt diodes that will probably do for the charger, and 40amp 600 volt diodes which I would think would be of sufficient to carry the maximum motor load for a 36 volt motor system, or even a 24 volt motor system.

I hope that is of some help until I can post my drawing.

Regards,

Brian.

[brian]

Robert, in the mean time, if you let me have your email address, I will email you the circuit, or anyone else for that matter while I try to post the damn thing on here.

Regards,

Brian.

[Tombraider]

Parkside Railways sells a device that will convert a 12v car battery charger into a 24v one. See http://www.parksiderailways.co.uk/ but you need to open it in a differnet browser, eg Mozilla, as their website isn't viewable in Internet Explorer (well maybe it is in IE8).
Mike

[Robert]

Brian,

if you click at the envelope sign under my avatar, you can send me an e-mail.

Robert

[brian]

Hello Robert, (we're going to have to stop meeting like this, people will start to talk(

I have got the circuit diagram on file as a GIF, (whatever that is) and I know I can send it as an attachment to an email, what I can't remember what to do despite having done it in the past, is stick it on the forum.

If I click on the envelope sign, (which looks more like a speach bubble to me), it only opens a page exactly like this page, but which goes to you only, there is no "attachment" facility, unless one of the little boxes enables me to attach the drawing? But I tried all those options trying to post it last night on the forum.

I even tried to go into edit mode in my T2 build thread where I have posted other drawings, to see how I did it then, but of course, there is a time limit to the editing option, so it would not let me open it.

HELP.

Regards,

Brian

[brian]

Having another go at posting the drawing

[attachment deleted by admin]

[brian]

Whoops. managed to post two now and just noticed I have missed a red link wire in the charging circuit.

All the diodes in the charging circuit should be connected together, will re-draw and post now I have remembered how to do it.

Brian.

[brian]

Right then, I think I have managed to correct the drawing and get it posted on here.

I have found all the appropriate diodes on Ebay, the 40A ones are in America, but I have bought stuff from all over the world and never had a problem,

Don't worry that the heavy duty ones are a much higher voltage than you need, it does not realy matter, just make sure that none of the diodes are rated less than twice the operating voltage passing through them, so the charging diodes need to be at least 50v with the amperage to handle the maximum current your charger can give.

When soldering diodes into a circuit, they are very heat sensitive, so get some one to hold the wire you are soldering, with a pair of narrow nosed pliers between the heat source and the diode. A small crocodile type clip, clipped to the wire will serve just as well if you have one and saves the extra pair of hands.

Regards,

Brian.

[Robert]

Hi Brian,

thanks for the drawing!
It's exactly what I needed. 
I'll go out hunting for the diodes and probably come back to you with some more questions, because I'm an electronic nitwit, as you know. 

[Robert]

Hi Brian,

I have been reading and searching for diodes.
Can you please give me some more information on the following points: (maybe the moderator should move the diode talk to a new topic?)

1) do you have an item nr. or seller information etc. from the diodes you found?
2) do these diodes need to be welded on a board?
3) Is the heat production of the diodes a problem?
4) I read that diodes cause an amp drop of approx. 2-5 amp, due to a voltage drop of approx. 0,7 volt.  Is is that correct ?

regards,

Robert