12v Battery for TS250/1 Supa 5

Forums Technical Two Stroke: Help needed 12v Battery for TS250/1 Supa 5

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    • #15675
      Pete Lamb

      Does anyone have a battery model number for a TS250/1 when changing to 12volts with a VAPE charging system?


    • #15678
      Ollie Harris

      I expect your current 6v battery is a 6n11a.
      A YB5L is the same dimensions, but 12v.

      A YB5L will fit, however is a fairly low capacity battery at 5Ah (compared to the original 11Ah). Shouldnt be a problem, as the vape kicks out much more electrical power compared to the original dynamo, and the ignition is self generating.

      The 250 has a good amount of room in the battery box, so if you take some dimensions you should be able to fit a larger battery. The Tayna website isnt bad for selecting a battery based on dimensions – https://www.tayna.co.uk/motorcycle-batteries/yuasa/?ordering=&A-8=12&A-10=Wet (note that the link is for “Yuasa” brand batteries. I’m not saying Yuasa is the brand to get, but it’s useful for getting the battery code. To be fair, all brands seem equally rubbish nowadays)

    • #15679
      Andrew Staley

      I would agree with Ollie above, especially in that all brands seem equally rubbish nowadays and it’s the luck of the draw if you get a good conventional lead-acid one that lasts.

      If you are going with a smaller 12v YB5, you could cut down on power usage by fitting a 12v Ultra-bright LED parking light bulb in the headlamp (BA9S) which is brighter than using a dipped headlight with a conventional bulb if you are using the headlight as a day riding light. (Available on eBay)

      If you are feeling flush you could fit a Lithium battery – I put a JMT YB5 on my Supa5 with Vape Powerdynamo and it worked fine.
      It is the same size (120wide x60deep x92high) as the 6v original so fits in the space, only weighs 420grams and they tend to maintain their charge if not being used, like over winter perhaps, in fact they don’t recommend trickle charging them.
      If you do need to charge it however, you should use a specific charger so factor that in!!

    • #15689
      Luke Duller

      Don’t forget that power = voltage x current and so a 12V 5Ah battery will store (as-near-as-damnit) the same amount of energy as a 6V 11Ah. Nominally, 60Wh for the 12V vs 66Wh for the 6V. As Ollie says, the ignition is self-generating and really the battery is only used if you want to be able to have the lights on or charge your phone whilst the engine is stopped.

      Anyway, I use 12V 7Ah sealed lead acid (SLA) batteries on all my 12V bikes, like the ones sold for burglar alarms, etc. They are spill-proof, can theoretically be mounted in any orientation and are physically much smaller per Ah than a wet battery. Even with the Powerdynamo regulator and coil mounted there as well as a 12V 7Ah battery, I have a decent-sized space for tools, etc. in the battery box on my Supa 5.

      I have been told by someone much more knowledgeable than me that the fairly crude charging regulation found on motorcycles is less than ideal for an SLA battery’s lifespan, but in practice I seem to get a good couple of years out of one and, when they can be bought on eBay for £15, that’s good enough for me! Another advantage is that, if you shop around online for a good price, it seems they can be sent in the post, ready to go, unlike wet batteries these days.

    • #15691

      Just for info Tayna deliver filled lead/acid batteries.
      They plug the vent and use a sealed plastic bags etc.
      Tayna provide straightforward excellent service and provide both brand names and cheaper alternatives. A Yuasa from Tayna won’t be a fake which is always a possibility from some eBay sellers.

      For what it’s worth I’ve a Yuasa 6N12A-2D (6V 12Ah) battery fitted to my 6V TS250/1. This battery is a different size to the standard battery and is a nice fit in the battery compartment across the frame rather than in line. So far, about two years, I’m happy and fully expect it to go on for a few more years. Every time I’ve bought a cheap no name battery from eBay it’s not lasted and been a waste of money.
      All battery technologies require a specific charging protocol to maintain them in good health with a long life. Unfortunately the charging systems of most vehicles is a basic “apply maximun voltage at all times”. This is not a correct charging protocol for any type of battery and the type of battery which copes best with this is Lead/Acid, because it is basic and robust.
      I know Bynnzi has not has luck with Motobat AGM batteries on several of his bikes.

    • #15700

      Jjust a thought, you could always use two 6V batteries in series to give 12V. This was standard for, I believe, the MGB for space reasons. If you use two standard 6V 11Ah batteries you will end up with 12V 11Ah. If your 6V battery is in good order then you only need to buy another. There’s loads of room in the battery compartment.

    • #15712
      Pete Lamb

      Thanks for the replies.

      I bought a 6ah battery, which fitted the battery compartment easily. I had plenty of spare depth and height, but width limited the choice. It all seems to work well, and copes with the additional load of my heated vest with the main lights on too. The vape unit seems to cope with the load.
      As a new MZ owner, I’m getting to know the bike and I’m enjoying the ride. I just need to sort out the uneven running. It stutters at marginal throttle settings and surges on overrun quite badly. Some of it probably just a characteristic of the bike and the BVH carb?


    • #15713
      Ollie Harris

      The surging is a known quirk of the 250
      I don’t know the 250 series well, but I’ve heard of people having reasonable success with changing the pilot jet
      Ive also heard some have changed the length of the induction hose
      I don’t know the details, so it might be worth posting a separate topic on this forum, or on one of the Facebook groups, as there’s bound to be someone who can help.

    • #15716
      Pete Lamb

      Thanks Ollie

      I am playing with carb settings at the moment.
      If it persists I’ll start a new topic.


      • #15718
        Keith Angus

        Your battery should be fine. Bear in mind that the much later Saxons, with a decent alternator, had a 5.5 Ah battery as standard. I have fitted 9 Ah, but the battery is not a problem given a good generator. My bikes do not need LED bulbs to maintain good charging.

        As for the surging, it seems to be a carburettor problem as much as anything else. Turn the tickover down as low as you can get away with. Some folks set it to the minimum, which means the bike won’t tick over, and you just have to keep your hand on the twist grip when stopped. On my Saxon it is very low – the tacho pointer doesn’t move off the bottom stop which should mean it’s lower than 500 rpm. (The handbook says 1250 revs, but I can’t see why.) You may be able to get a better carb. Some of the German suppliers offer a modern Bing carb set up for older MZs, but the cheapo Chinese copies of “better” carbs are generally reported to be rubbish. It seems to me that the cure is a good carb and electronic ignition, allowing a low tickover.

        When I had my 250/1 I just lived with it. The other problem can be bogging down if you try to bang open the throttle while below 3000 rpm. On the hill I used to live on in Wales that meant I had to grind to a stop and start all over again. If I hit the bottom of the hill at just over 3000 revs I could sail up it.

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