12 battery

[RDfella]

Project is moving along slowly. Have fitted the modified distributor and was wondering what battery to use. My classic bikes run Yuasa 6N6 or similar within an old black rubber case. I would normally use that option here, but thinking ahead, I plan on eventually fitting a tiny 12v alternator, so might jump to 12v from the outset. So my query is, what size 12v battery fits these bikes ('60 A10 frame)? My preference is for lead / acid as opposed to the totally sealed type. No outstanding reason why, just my old-fashioned attitude!

[morris]

The Yuasa YTZ7S AGM battery mounted on it’s side fits snugly inside the rubber “Lucas” cases if you care for the period look. I have one in for about 5 years now and it’s still keeping it’s voltage well above 12V.
The advantage of an AGM battery is that it can be mounted in any position except upside down.

[muskrat]

+1 for the AGM. Gotem in all bikes.
Cheers

[JulianS]

The YTX7L-BS 12 volt AGM fits nicely in the A10 with wire clip battery retainer. Been using them for years.

[RogerSB]

Fitted a Motobatt MB9U (AGM) in Feb 18 and it's been excellent.
11Ah, CCA 140A. Length: 138mm  x  Width: 76mm  x  Height: 133 or 158mm. I use both the spacers supplied with it = 158 mm for my 1960 A10 GF.

First photo is of battery in situ before adding sidecar lights , indicators, warning light and buzzer electrics. The other is with it all fitted and as you can see it’s a little crowded in there now – but still plenty of room above to fit the seat.

I also made a list of batteries that fit when I was looking for one in 2018. I've added it here in case it may be of some use.

Batteries that will fit A10 (in my order of preference):-
Motobatt MB9U Equiv 12N74B, L:136 x W:76 x H:133, 11Ah, CCA 140A (AGM).
Yuasa YTX7L-BS, 114, 71, 131, 6Ah, CCA 100A, sealed maintenance free Valve Regulated Lead Acid (VRLA), AGM.
Westco YTX7L-BS,  7Ah, L:114 x W:71 x H:131, AGM.
Yuasa YB7-A, 135x75x133, 8Ah, CCA 124A, YuMicron, Capacity Ah (20-HR): 9.5CCA @ -18C: 115, wet.
Aerco 12N7-4B, 135x76x134, 7Ah, wet.
Lucas LYB9B, 130x72x135, 8Ah, wet.
Exide EB7-A, 135x75x133, 8Ah, wet.
Varta YB7-A, 135x76x134, 8Ah CCA 110A, wet.
Numax YB9B, 136x76x139, 9Ah, CCA 95A (Gel).
MF CB7-A, 135x76x132, 8Ah, wet.

[RDfella]

Thanks Roger - handy list.
As mentioned in my opening lines, not the keen on agm's. Have one in my Firestorm - not cheap and doesn't last long. The latter probably my fault for not keeping it charged on a regular basis, but with 18 batteries to keep an eye on (lawnmowers, boats, bikes, classic cars) some get forgotten at times. And I get the impression agm's don't hold their charge as well as wet acid batteries, and then there's the cost - about the same as a family car battery. Not funny when I'm replacing the Honda one practically every year.

[muskrat]

G'day RD.
In my experience AGM's hold their charge much better than wet cells. Temperature has a big part. The hotter the temp the quicker the self discharge. A new AGM has a rate of 2%/month.
My HD had a wet battery and not started for 2 months. Dead battery. Installed an AGM and after 2 months started first press of the button.
Cheers

[Rex]

AGM's holding their charge better than a wet battery is my experience too. Also I find lead-acid batteries don't seem to last like they used to, and a couple of years max is all I get.
Just bought a new AGM battery for the A7. It cost less than eleven quid delivered and apparently is a standard 12V battery size for electric scooters, and fits in the rubber battery case perfectly with just enough space on top for the fuse holder.
Used to buy those Cyclon batteries but they're now a ridiculous price compared to the alternatives.

[RDfella]

Wish I could get batteries for £11! That’s a couple of PP3’s !
Certainly, my experience with AGM’s has not been great so far, but maybe have to rethink my strategy in light of others’ experience.
Both my ride-on mower and Firestorm use sealed batteries – and each costs around £60. After a couple of months standing, the Honda still has life, but not enough to start (can’t remember the batt number and it needs to come out to be read). And of course the mower gets forgotten over the winter, so flat battery in spring means another new one.
Maybe it’s a size thing? I have some largish batteries (800A SAE) and they’ll hold charge sufficient for a start for almost a year (just as well, given their price) and my classic cars are usually good for several months (they have isolation switches).
Another consideration may be charge rate - I believe wet batteries are more tolerant of fast charge. I know from a Sterling alternator booster I have that sealed batteries have to be set at a lower charge rate than wet cell. With the latter, provided you monitor temperature, you can charge at pretty well what you like.

[Rex]

Sorry, my memory's playing up and it was actually £13.50

https://www.ebay.co.uk/itm/MK-ES5-12-12V-4-5Ah-4Ah-Sealed-Lead-Acid-Replacement-ULTRAMAX-AGM-Battery/124072936308?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

[ellis]

Go for the Motobatt you won't be disapointed. Fit and forget.

ELLIS

[Angus]

I know I am tight but I have two of these in parallel in three bikes (Norton for 3 years, A10 just over a year and T100 6 months). The two fit inside the dummy lucas box and they have been great. The A7 has a more expensive mobility battery with more amp hours but it does not appear to give any real benefit for the extra price.
https://www.ebay.co.uk/itm/Powersonic-12v-6v-Sealed-Lead-Acid-Rechargeable-Battery-Leisure-Alarm-Volt/221844097101?ssPageName=STRK%3AMEBIDX%3AIT&var=520727784378&_trksid=p2060353.m1438.l2649

[morris]

You have a point there RDfella. A wet battery can be brought back to life with some careful massage, but an AGM that’s too deeply discharged or charged too violently will carry the scars for the rest of its life.

[BSA_54A10]

Two things to look for with motorcycle batteries
1) AGM so they don't hake apart
2) PVR so they don't self discharge when not in use.

With perminant magnet alternators it should not be a problem but with field enegised alternators the two big problems are too high a charge rate and regulators that draw a small current 24 /7.
Cyclons are fantastic for engines with an El3 dynamo but not so good when an alternator is fitted.
Then you need to look at the rectifiers
Mowers mostly use a 1/2 wave rectifier or just a single diode
As such they send a plused DC back to the battery which boils open cell batteries in no time flat.
In fact no battery likes getting pulsed feed particularly when that pulse goes 0v to 14 V then back to 0 V again