12 volt battery for A7

[Robert Leigh]

I think the time has come to renew the battery on our Ulsteroid. I have been using a YB14-A2 motorcycle battery, but I am wondering if I can go to a YB12 with satisfactory results. I would be pleased to know other peoples' experience with 12 volt motorcycle batteries before I shell out. I do want to use the starter motor. I know that a very small battery will suffice for ignition only.

[Steve Jones]

Depends on how much space you've got but I've got these on both my cars running on 12v. https://www.tayna.co.uk/mobility-batteri...12-25-y-g/

The one in the Trials Chummy has been there since 2007, has never been removed, never been re-charged and just works. The one in the Ulster similarly since 2013. That they're a gel battery is a plus point as the one in the Chummy is mounted on its side and a bonus is that they can't spill if things go very wrong!

Steve

[andrew34ruby]

What is the advantage of these motorbike batteries? 12 or 14 or even 28 amp hours seems very little capacity. I use a 12volt Bosch S4 001 type 063. 44 amp hours.

[Robert Leigh]

That looks too big for a standard A7 6 volt battery hole, otherwise appears to have an excellent performance, particularly the life you have got from them. It appears to have twice the capacity of my present motrorcycle battery and a better CCA, but I was thinking of going down to 12 Ah rather than up to 28 Ah and wonder if anyone has experience of this.

[Alan]

I used a 12Ah battery on my special years ago. Only real problem is lack of capacity for driving at night. So I guess it depends what set up you have and what you plan to do.

[Steve Jones]

Neither the Chummy or the Ulster have standard A7 battery boxes but a friend has one of these batteries in his trials car and that fits (just) into the battery box in his car. Both my cars have fully re-built dynamos with rewound 12v field coils and armatures. Whilst the cranking capacity of all the above batteries is on the low side, this is offset by them cranking via a 6v starter motor. Neither car does much, if any, night driving but the Chummy has sometimes been driven for distances with the lights on in murky winter trials weather without issue.

Steve

[Dave Mann]

On a visit to a local battery supplier for a battery for our daughter's VW Beetle I thought I spied a new Seven battery only to be told it was a 12 volt battery for some modern, a quick check revealed it would fit an RN battery box and was 40AH. So I ended up getting two batteries. That was two years ago and it is still giving good service in both day and night driving.

[Malcolm Parker]

The RL saloon has the standard battery box with a small 12 volt battery of the type used in Bedford Rascals.  It fits perfectly.



The Ulster has a smaller battery box and has a 12 volt 24Ah battery of a type used on a Motto Guzzi 1200cc motorcycle.  It does the job admirably but I have never used the Ulster for night-time driving.   If you have a proper 12 volt dynamo and regulator the smaller capacity battery seems okay.   There is no point having a large capacity battery if the charging system is incapable of filling it.

[Robert Leigh]

Thanks to all for helpful information. I will probably go with a 12 Ah battery. I think the dynamo will cope with my 35 watt H4 headlamps and the rest LED; I may change headlamps to LED also.

[Bela]

I'll convert to 12V with dynamator (45A) next time.  Here in D hazard warning is  a standard and the headlights are going for H4. The size of the batterie box in  my special  is 172 x 162 x 300 mm (l x w x h). I decided to buy this one  with 30 Ah :
https://www.ebay.de/itm/YBX3009-Yuasa-SM...Sw7hReVwqA.