Charging problem: Flat battery and under charing dyno

[SteveH]

Need a little advice please.

My A10 Super Rocket is now back on the road but coming home from the monthly BSA-OC meeting I discovered while running up the motorway at night that I had no lights, past the police car I successfully rode, some winter fog and misting glasses made things more interesting, as did the last 2km home in the unlit countryside  .
The Lithium-Iron 6V battery was dead flat  measuring 0 volts ... I have now recharged and I have measured it at 6.3 volts.
So in the weekend I started the bike and measured the charging voltage .... which was only 6.5 volts out of the Lucas Dyno and electronic DVR2 Regulator. Not the 7.2 volts expected. And the voltage varied with rev's, down to below 3 volts at low rev's and up to only 6.9 volts at higher rev's. Surely the charging voltage should not vary?

[Other factors: the dyno belt drive conversion I assume is now running OK and not slipping on the taper fit. The dyno was taken apart by an engineer for me, as he had to tidy up the taper. Because just after I got the bike the driven cog and nut parted company with the taper on the dyno and made a break for freedom, via the timing cover  ].

So what should I do next to solve the mystery of the under and variable voltage charging dyno ..... take it off and check the brushes first I suppose?
Does anyone know what might be wrong.

Thanks, Steve

[duTch]

 Steve for starters I'm no expert, but don't think you should be trying to charge a Lithium battery from the genny....otherwise (sounds) it's doing something positive but as I know FA about DVR's, I'll let someone else have a go

[KiwiGF]

Need a little advice please.

My A10 Super Rocket is now back on the road but coming home from the monthly BSA-OC meeting I discovered while running up the motorway at night that I had no lights, past the police car I successfully rode, some winter fog and misting glasses made things more interesting, as did the last 2km home in the unlit countryside  .
The Lithium-Iron 6V battery was dead flat  measuring 0 volts ... I have now recharged and I have measured it at 6.3 volts.
So in the weekend I started the bike and measured the charging voltage .... which was only 6.5 volts out of the Lucas Dyno and electronic DVR2 Regulator. Not the 7.2 volts expected. And the voltage varied with rev's, down to below 3 volts at low rev's and up to only 6.9 volts at higher rev's. Surely the charging voltage should not vary?

[Other factors: the dyno belt drive conversion I assume is now running OK and not slipping on the taper fit. The dyno was taken apart by an engineer for me, as he had to tidy up the taper. Because just after I got the bike the driven cog and nut parted company with the taper on the dyno and made a break for freedom, via the timing cover  ].

So what should I do next to solve the mystery of the under and variable voltage charging dyno ..... take it off and check the brushes first I suppose?
Does anyone know what might be wrong.

Thanks, Steve

As a start

 Steve for starters I'm no expert, but don't think you should be trying to charge a Lithium battery from the genny....otherwise it's doing something positive but as I know FA about DVR's, I'll let someone else have a go

 Steve for starters I'm no expert, but don't think you should be trying to charge a Lithium battery from the genny....otherwise it's doing something positive but as I know FA about DVR's, I'll let someone else have a go

Yep, as a start clean the brushes thoroughly to see if that helps, and measure field resistance (the dvr2 maker has a minimum recommend resistance figure) and next check field to earth resistance to ensure no shorting there (this might require fiddling with the connections in the dynamo cover to ensure you get correct readings.....not sure). Then “report” back if no joy, as there are other checks to carry out...

I’ve no experience of lithium batteries.....so I’m assuming you’ve investigated they are compatible with the dvr2 etc (can they overheat at low charge? )

[muskrat]

G'day Steve.
I think the problem is the Li battery. I've been led to believe they need a different charging system.
https://tinyurl.com/y42djhmc
Go back to a lead acid/AGM type battery.
Cheers

[Angus]

It may well be the battery type, but also is it not the case that the DVR2 or any regulator will not try to charge a battery that is already fully charged.

[bsa-bill]

Not sure about li-ion batteries but presume they are like certain other types (Cyclon) and will not recharge if they get too far down with the modern type of charger, I have managed to get a charge into them using an  old type lager metal bodied type (that may come with round pin plug) in kill or cure situations, (the cure may be temporary)

[duTch]

 I'm curious about the 6V Li-Ion battery, ie; brand and rated Ah capacity and how long you've been using it....?

  As far as I'm aware Li-Ion cells or polymer packs are usually 3.7v nominal voltage fully charged @4.2V, so to achieve '6V' would need to be two in series with fancy circuitry = 7.4 nominal/8.4V fully charged and to bulk it out pack them in parallel (eg;my Metabo drill is rated at 18V, but in the Batt.Pack consists of 10 x 18650 cells>5 in series/2 parallel <- I think it's called '2P5S or 5S2P', giving a charged pack of 21.0V). The charger shat itself, so I pulled the packs apart for a dekko, and the cells out and now recharge them in 3 special 4 cell chargers, so I now know enough to be as dangerous as the average bear

  It may be a complete different setup, but worth checking up on....

 **Edit; I just had a look at an email from Jaycar and they're flogging LiFePO4 Deep Cycle batteries so re-read the original post which clearly says Li-Iron, not Li-Ion , but still reckon it needs a different charge system ;
 https://www.jaycar.com.au/6-4v-4-5ah-lithium-deep-cycle-battery/p/SB2200

[SteveH]

Thank you all for your advice everyone, I'll start with an inspection and clean. And testing the resistance.
It might take me a while to report back as my electrical expertise is only a little above "it's invisible and can bite you".
No sight yet of the famous "Lucas Smoke" that electrical equipment runs on (if you ever see that the smoke has got out, the device will cease to function).
Cheers, Steve

[BSA_54A10]

If it really is a Lithium battery get rid if it.'You are playing with fire, quite literally.
Incorrect charging can lead to the battery shorting internally then they burst into flames.
They can not be extinguished, all you can do is pour water over the bike to stop the whole thing burning down in front of you.
Cyclons will work best followed by any one of the sealed AGM batteries.

[coater87]

If it really is a Lithium battery get rid if it.'You are playing with fire, quite literally.
Incorrect charging can lead to the battery shorting internally then they burst into flames.
They can not be extinguished, all you can do is pour water over the bike to stop the whole thing burning down in front of you.
Cyclons will work best followed by any one of the sealed AGM batteries.

 I completely agree with this, lithium batteries have their place but its not in our bikes.

 Danger, Danger, and not in a funny way either.

 AGM is the way to be, clean, inexpensive, almost endless size choice and they dont burn things to the ground.

 Lee

[Kickaha]

If it really is a Lithium battery get rid if it.'You are playing with fire, quite literally.
Incorrect charging can lead to the battery shorting internally then they burst into flames.

Some of them like the Ultrabatt have their on onboard battery management systems which take the charging problems out of the equation

[SteveH]

Getting back to trying to solve that flat battery mystery ...........
In the weekend I tested the Dyno output (by bridging the D & F plugs and earthing to the Dyno case) and got a healthy 18V + at 3,000rpm ... so I take the dyno output to be good.
But I measured only 6.2V at the 6V battery, both at rest and while charging / motor running. The Ampmeter showed no noticeable charging (it does show discharge with lights on, so it is working).
Therefore I think, is my DVR-2 not working? How do I check this?
Your thoughts please ......................
Thanks Steve

[mikeb]

did you do anything about that Li battery Steve? not good on our  bsas.
if you have a wet or agm battery and you are sure you have the DVR2 connected well (ie check the ground, the volts at the input and output terminals) then I'd say that you did just test the DVR2. and found it wanting.
but i would double check the connections to it first.

[SteveH]

Thanks Mike, I checked the connector plug and the battery connections, all good. Assume earth connected.
Hmmm yes perhaps a new battery would be clever.
Cheers,
S

[SteveH]

Mike, If replacing the DVR-2 and battery, might be a good time to move to 12V. Yes?
Any thoughts / considerations?