Ariel Owners Motorcycle Club

Hi folks,
Here's a question that I feel I should have an answer to, but thus far has eluded me:

Why is it that the Lucas magdynos on my bikes can happily maintain the charge of the batteries and cope with the lights being on without problem, but are unable to charge the battery if it is pretty much flat ?

My VB has an original solenoid type regulator, while my Panther has a somewhat more recent electronic type. Both refuse to charge a flattish battery.

Would be interested in an explanation

Cheers,
Bevan

Some electronic regulators require a minimum volt in the battery to initiate the charging cycle usually about 4.5v

What type of batteries are fitted ?

I have recently had problems with the Yuasa battery on my daughter's Yamaha MT125 (She's a Police Traffic Officer and they are being encouraged to take their bike tests !).

She left the bike unused for a couple of weeks and the battery appeared to be flat. It then wouldn't charge on any of my chargers (one 'high tech' and two simple things).

I bought a new, identical battery and the same thing happened after being left unused on the bike.

I contacted 'Tanya Batteries' and was advised as follows:

"Hi,

Many thanks for your message.

Wow, I can see from this voltage that the battery has suffered a high electrical drain.

We tend to find if a battery is discharged too low, then when attempting to re-charge the battery, the charger will run a current through but the battery will not retain its charge as it will not recognise it as a battery.

So following the next steps will “trick” the battery into regaining a charge, in most cases.

Please try the following to re-charge your battery:

1. Connect flat battery to any other battery with jump leads.

2. Leave for 10 mins and then connect charger to flat battery at same time.

3. Turn on charger and charge like this for 1 hour.

4. Then take off jump leads and charge battery normally with charger for minimum of 12 hours.

If the unit gets hot or starts to give off a bad smell please stop immediately.

5. 12.73v will be 100% charged.

Leave disconnected and monitor the voltage over a 24 hour period to see if/when the voltage drops off, and provide us with these readings.

We will then be able to ascertain how to proceed under the warranty.

If we can be of any further assistance, please don't hesitate to contact us.

Kind regards,
Jay"

I connected the Yuasa battery to a spare car battery and did as advised - and it worked. Better, I fetched the original 'dead' battery and it came back to life via the same trick.

These are modern glass mat batteries, so if you are using one of those (as I am on my VH) then this might be worth trying.

If, however, its an old-style lead-acid battery this probably won't help.

Bob.

Useful bit of information!

Yes, very usefull to know ! Thanks for that tip.

and I like this bit :
If the unit gets hot or starts to give off a bad smell please stop immediately.

hi dynamos or alternator are not for changing flat batteries they for keeping a fully charge battery top up , if you try charging a flat battery you will overheat the dynamo or regulator

Bevan,
There is a multitude of battery chargers available. Finding one that will recover a battery whos' voltage has dropped below critical minimum is another matter.
I have been using this one : https://www.mdsbattery.co.uk/accumate-6 ... arger.html for a number of years now and have recovered several with only 1 or 2 volts left in them. Suitable for: Wet, AGM, Gel and VRLA types
I have one connected to my VB on 6V 24/7 and another on my 1933 Austin 10 on 12v 24/7. The VB has a 6v MotoBat which is Glass Matt I believe.
They are on Ebay UK at a slightly higher price than this link but you can sometimes find them a few pounds cheaper.

Gary

Don't let your battery go dead flat firstly and if it's left that way it will sulphate up and develop a high resistance and doesn't take a charge. It may also become shorted out if left a considerable time if the sulphate (white) build up is excessive. I've recovered a couple of dead ones recently by putting a 12 volt into a six volt CAREFULLY. with jumper leads. It may sizzle briefly and then take a slow charge. Charge and discharge a few times. It now runs the headlight for at least 20 minutes so is close to normal. If the battery is old or been dropped don't bother.
With AGW or paste batteries a high rate of charge will create bubbles that are permanent. The electrolite doesn't flow. If the battery gets hot when charging chuck it. This is with a "proper" high Tech charger. You have a limited choice of chargers for 6V batteries these days so don't overcharge it with a "primitive" charger that can cook it . Having acid over the bike is a no no. Many of the OLD type do gas a lot . Set the regulator so it doesn't over volt the battery. IF it's the earlier 3rd brush type it's more difficult. Pre say 1937. Nev

I can tell you that what Tanya Batteries advised works. I had a flat 6v AGM battery and connected it to a good one and this 'tricked' my Optimate charger into charging both batteries. I am not recommending the procedure but it worked for me.
Dennis