Author Topic: A7 charging issue?  (Read 3162 times)

Offline BSA500

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A7 charging issue?
« on: 31.08. 2012 08:39 »
Hi,
The question mark is there for a reason I shall explain. I have a A7 in daily use and that includes winter(30 miles a day) so lights are quite important. What I have at the moment is a dynamo running at 12 volts pos earth with a 12 amp hr battery and a vreg 2 regulator and a belt drive. The dynamo was rebuilt/serviced last year by beezermac. Now I have been running all summer so I would expect the battery to be charged,not so!!. With the lights off the ammeter just hovers above the 0 in charge from just above tickover. Lights on the ammeter shows discharge -4 and quickly rises to just above 0 from jsut above tickover and stays there. No matter how many revs it goes no higher and if you stop for lights and tickover the lights dim,nice and bright while running,but dim at stops. It seems either battery will not take the charge or the reg will not put out anymore. Any suggestions as where to start??
Andy

Offline iansoady

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Re: A7 charging issue?
« Reply #1 on: 31.08. 2012 10:56 »
That sounds about right if the battery is fully charged. The voltage regulator stops excess charge so unless the battery is flat(tish) there shouldn't be too much going into it. Remember the lights etc are fed from the dynamo side of the ammeter.

The only thing I would be thoughtful about is the lights dimming, although I would expect this to some extent as when the dynamo is charging the voltage in the system is getting on for 14 volts; when at idle it'll be more like 12.
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Offline BSA500

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Re: A7 charging issue?
« Reply #2 on: 31.08. 2012 12:03 »
Surely the battery should have the capacity when fully charged to keep the lights bright for a minute or two at the lights. So does that suggest the battery is unable to except and hold charge?

Offline Dynamo Regulators Mike

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Re: A7 charging issue?
« Reply #3 on: 31.08. 2012 15:53 »
Hello Andy

Don't like to simply knock the competition but the VReg2 can struggle to maintain charge at 12 V. It takes a lot of revs to get the output up to the 14 V or a little more, which is required to fully charge the battery. See http://www.dynamoregulators.com/about.php for more on this subject.

I suggest you monitor your battery voltage and check for any such shortfall in charging voltage.

The VReg2 has been around a long time unchanged (except for its case). With no load there is a 2 A or so discharge at low speeds where the battery is supplying the field in vain. This is a design shortfall. I am constantly surprised how those things keep selling, but you pays your money and you takes your choice. Caveat emptor.

Mike
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Offline BSA500

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Re: A7 charging issue?
« Reply #4 on: 31.08. 2012 17:41 »
I get the feeling you may be right. I don't really suspect the dynamo as when you switch on the lights it quickly balances out and beezermacc fixed it last year *smile*. The belt drive helps as it is the extra wide and spins up the dynamo by 20%. I have removed the battery which is a year old sealed type 12 amp hour and the reading is 12.08 volts not alot considering its summer. I will check the dynamo f&d together etc. I checked with the battery in place and the highest reading was 12.78 volts so hopefully I can rule out one or the other.

Offline BSA500

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Re: A7 charging issue?
« Reply #5 on: 31.08. 2012 19:46 »
Update....
Connected the f&d together and got a healthy output easy 16 volts plus so looks like a new reg,prob the DVR to go with the belt drive from them. Problem is I need to charge up the battery but the only charger I have is the car one which pumps out 6 amps.My bike Oxford charger blew up. I should avoid electrics *conf*

Offline stu.andrews

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Re: A7 charging issue?
« Reply #6 on: 31.08. 2012 20:59 »
A cheap reliable 2/6/12 volt charger is often available from both Aldi & Lidl. I've had one for several years. They can be left attached as the charging current is only 0.6 amp.
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Offline duTch

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Re: A7 charging issue?
« Reply #7 on: 31.08. 2012 22:30 »
Heya Andy,
                 I couldn't see you mention the headlight Wattage, which could be loading up the system??

 Cheers, duTch
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Offline Triton Thrasher

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Re: A7 charging issue?
« Reply #8 on: 01.09. 2012 01:59 »
Surely the battery should have the capacity when fully charged to keep the lights bright for a minute or two at the lights. So does that suggest the battery is unable to except and hold charge?

Usually, you cannot keep headlight on in traffic with a 6V dynamo regulated to 12V. Many people use a pilot light with 10W halogen bulb or somesuch, for town work.

The speeded up belt drive and DVR2 may help, or even fix the situation. I haven't used them.

Manormike is right- the waste of 24W (2A) at idle is a daft feature of many electronic dynamo regulators.

Offline BSA500

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Re: A7 charging issue?
« Reply #9 on: 01.09. 2012 10:21 »
I am ordering a new charger today as we don't have a decent Lidl and no Aldi within 50 miles there's nothing down south *smile*. The headlight wattage is 55/60 and I have an led rear lamp, but that's not the issue as I have run the bike all summer with no lights and still the battery is no where near charged. The vreg coupled with the belt drive copes to a point as I said it quickly balances when lights are on from just above tickover but no more extra to top up the battery.

Offline saltbox Alf

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Re: A7 charging issue?
« Reply #10 on: 01.09. 2012 12:25 »
Jut as an after thought , I run a DVR2 reg but still have chain drive to dyno, but i had a similar problem re charge rate. After sorting all the bullet conectors to see if they were making well, all seemed fine, still the problem! just as a rueling out I put another ammeter in place, spare one kicking around the w/shop and lo and behold proper charging rate and battery keeping charged, I think the old ammmeter had gone high resistance in it guts somewhere *dunno* However I am pleased with the DVR2, does what it say's on the box.
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Offline warmshed

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Re: A7 charging issue?
« Reply #11 on: 02.09. 2012 08:33 »
You need to get a meter and measure the voltage of the battery and also when engine is running, or it will just be guesswork. I have a DVR2 and without lights,  it gets up to 14.6 volts at around 2000+ RPM.
Don't forget that running a 55 watt headlamp with a pilot bulb (noted the LED rear lamp) you leave very little output to charge the battery and the dynamo will have problems maintaining the correct voltage to the battery or the headlamp. 
Once charged a good 5AH battery should in theory,  have sufficient capacity to run a headlamp for an hour, in reality you can expect a good 30 mins, so the stops at the traffic lights should not present a problem.

Batteries as they age or have been abused, can give a good terminal voltage (but normally slightly lower) but will have seriously reduced capacity, that's why the best way to test a battery is with a load tester.

Offline Triton Thrasher

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Re: A7 charging issue?
« Reply #12 on: 02.09. 2012 09:23 »
I'd try a 35W halogen bulb and switch to pilot lamp wherever there  are street lights.

Ammeters are rather notorious for failing. You don't really need one. If the lights brighten when you rev off idle, that's all the test you need on the charge system when you're on the road.

Offline BSA500

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Re: A7 charging issue?
« Reply #13 on: 02.09. 2012 10:46 »
quote from a previous reply of mine

 "I checked with the battery in place and the highest reading was 12.78 volts so hopefully I can rule out one or the other."

and another

"Connected the f&d together and got a healthy output easy 16 volts plus"

So it looks like the reg is playing silly buggers. Yes the lights will brighten off idle but it stops short of putting out enough to charge the battery so when I stop for any reason they dim straight away. I also have a 12 ah battery on board so if charged correctly this should not be an issue. My ride to work each day is mainly A roads rarely dipping below 45 mph. And it should have a healthy charge right now as I don't ride with lights on in summer.


Offline Triton Thrasher

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Re: A7 charging issue?
« Reply #14 on: 02.09. 2012 11:33 »
Lights going very dim at idle can be flat battery, which can be a bad battery which will not charge, or can be a battery which is isolated from the charge circuit or has high resistance between it and the circuit, such as at a bad connection.

I had a Boyer reg which regulated to too low a voltage. I phoned them and they didn't believe me, which wasn't much help.