Charging sealed batteries with Alton alternators

jim burgess

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Ok my Norvin has an Alton alternator and sealed Bosch battery. In 3 years I have done about 1500 miles. (I know pathetic but..) When first fitted the ampmeter would show about 2 amps charge and then slowly drop back to about 1/2 an amp. No amount of revs would improve on this. If the dynamo drive was disconected it would then show a steady 2 amp discharge as it fought to run the electronic ignition system. I took it that this showed that the Alton was putting something into the battery and assumed the low state of charge in normal operation just indicated a well charged battery. When not in use I would leave the battery connected to one of Paul Goffs little trickle charge devices.
So last October I did a slow ride in the evening and ended up with a dead engine and battery at the top of a hill, the bike started on the bump down the hill but would not start off the kick starter.
Later that month I had an evening run at dusk, glow worm lights and a scary ride home. All the way through winterI had the battery on trickle charge, not all the time just occasionally.
Last weekend I found I had a totaly dead battery. With a good charge it would run the engine but eventually die, no chance of running lights, this just resulted in a dead engine! Kill switch!
I connected up a lead acid battery I use on the Shadow. When I run the engine I get a good 8 amps charge! The battery charger indicated that this battery was "charged" before I fitted it.
So I have bought another Bosch battery, I am stuffed in this respect as I built the bike to fit that battery and a change will need serious metal work. I mentoned all the above to the counterhand and he said. "the problem is you are not using it enough, (story of my life) you need to turn on the lights and discharge the battery and then recharge it". When I pointed out the low rate of charge from the Alton he went on to say "you need to contact the manufacturer, these battries are designed to be pulse charged, they don't work on the normal sine wave". Now I thought that sine wave indicated AC and I belive batteries need DC, so it sounds like bull shine to me, but I open it up to you learned fellows, what am I doing wrong? How do I put it right? Is there really a "special" way to charge a sealed battery? For those of you in the know I do not accept this as Australian revenge and long range Knut removal, no voodoo answers please? I am an electrical muppet, I can follow a circuit diagram, wire bikes and houses, but I don't get all that stuff about volts/amps and ohms, so construct your replies accordingly please.
Many thanks.
Jim Burgess, Norvin S.O.
 

1660bob

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I would keep away from "maintenance" chargers- I used constant charging from an "Fully Automatic" charger on a mobility scooter and kyboshed two sets of perfectly good batteries in a depressingly short time(one set brand new).I took advice from very knowledgeable and helpful staff at a charity mobility workshop in the North of England (Skelmersdale-recommended!)who told me to "Only charge the batteries as little as possible" They explained that so called maintenance chargers never let up, and ,sensing even a small voltage drop, immediately get to work pumping up your batteries again and again needlessly, night and day, week in week out.The trouble with this is that the batteries themselves can only be charged a finite number of times before they are past it- and they soon are if constantly hooked up to an auto charger. Since then, I manage the scooter batteries by running it almost right down through normal use, and then give them a charge and disconnect the charger-result- the latest set of batteries are as hairy chested as ever 9 months into their life, whereas the last (new, Lucas) set were going iffy after six months, Bob
 

redbloke1956

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Hi Jim, some of this may sound like gobbledeegook but if you filter out that which is over your (our) head then you should get some valuable info from it on SLA (sealed lead acid) batteries.
Figure 1: Typical SLA Battery Construction​
When an SLA battery is being discharged; the lead (Pb) on the negative plate and the lead dioxide (PbO2) on the positive plate are converted to lead sulphate (PbSO4). At the same time the sulphuric acid (H2SO4) is converted to water (H2O).
In a normal charge, the chemical reaction is reversed. The lead sulphate and water are electro-chemically converted to lead, lead dioxide and sulphuric acid. During a full charge cycle any gasses produced need to be re-combined in a so called ‘oxygen cycle’. Oxygen is generated at the positive plates during the latter stages of the charge cycle, this reacts with and partially discharges in the sponge lead of the negative plates. As charging continues, the oxygen produced also re-combines with the hydrogen being produced on the negative plate forming water. With correct and accurate cell voltage control all gasses produced during the charge cycle will be re-combined completely into the negative plates and returned to water in the electrolyte.
If an SLA battery is over-charged, the excess cell voltage will result in the conversion of electrolyte into large amounts of hydrogen and oxygen gasses which cannot be recombined by the normal processes. A pressure-release valve will open and vent the excess gas, resulting in the loss of electrolyte and a loss of capacity.
If the battery is undercharged; the low cell voltage will cause the charge current to diminish to zero well before full capacity is reached. This will allow some of the lead sulphate produced during discharge to remain on the plates, where it will crystallise, which also causes a permanent loss of capacity.
It is also important to remember that SLA batteries have a self discharge rate of approximately 5% per month. This is less than most other forms of rechargeable batteries, but has to be considered. Manufacturers recommend recharging when the battery reaches about 70% of its capacity (approximately 2.1 volts per cell). They use this to calculate the maximum life of the battery, but this is very difficult to implement in a real world application.
So let us look at different charging techniques: -Constant Voltage Charging: this method is the most commonly used for SLA batteries as the individual cells tend to share the voltage and equalize the charge between them. It is important to limit the initial charging current to prevent damage to the battery. However, with a single fixed voltage, it is impossible to properly balance the requirements of a fast charge cycle against the danger of overcharge.Constant Current Charging: this method can be used for a single 2V cell but is not recommended for charging a number of series connected cells, a battery, at the same time. This is because some cells will reach full charge before others and it is very difficult to determine when the battery has reached a fully charged state. If the charge is continued at the same rate, for any extended period of time, severe overcharge may occur to some cells, resulting in damage to the battery.Taper Current Charging: this method is not really recommended for charging SLA batteries as it can often shorten battery service life due to poor control of the final fully charged voltage. However, because of the simplicity of the circuit and subsequent low cost, taper current charging is often used to charge a number of series connected batteries that are subject to cyclic use. When using this method it is recommended that the charging time is either limited or that a charging cut-off circuit is incorporated to prevent overcharge.Two Stage Constant Voltage Charging: this method is a recommended for charging SLA batteries in a short period of time and then maintaining them in a fully charged float (or standby) condition.​
Each of the above has its advantages and disadvantages, but using a simple charger design may not be cost effective in the long term. Checking battery condition and replacing batteries with lost capacity is very costly and environmentally unfriendly. So designing a charger to maximise the life of the SLA battery is very important.
Another important factor that has to be considered when charging an SLA battery is temperature. As the temperature rises, electrochemical activity in a battery increases, so the charging voltage should be reduced to prevent overcharge. Conversely as temperature falls, the change voltage should be increased to avoid undercharge.
I hope some of this helps mate.

Kevin
 

Martyn Goodwin

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Dump the SLA and lead acid batteries - migrate to Lithium Ion - holds its charge for well over a year plus an almost flat discharge curve with a steep waterfall at the end. Perfect for Alton equipped Vins
 

dave g6xnc

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Get yourself an Optimate trickle charger and leave it permantly connected, I have used one for years with a "gel" battery no probs. You will probaly find that you get a slight discharge through the diodes on the alternator which is normal and if not ridden regurlerly will result in a flat battery.
 
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redbloke1956

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Non-VOC Member
Dump the SLA and lead acid batteries - migrate to Lithium Ion - holds its charge for well over a year plus an almost flat discharge curve with a steep waterfall at the end. Perfect for Alton equipped Vins
Sounds like a plan Martyn, but Li-Ion batteries also have there own limitations: If dicharged too far they may not accept a charge again, They can go into thermal runaway with excessive temperatures, life is shortened if fully charged, over charging also produces issues.
To run a Lithium Ion battery system correctly requires a fairly complex/expensive charging system.
Can you tell me how yours has been going and for how long please mate.

Regards
Kevin
 

redbloke1956

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Get yourself an Optimate trickle charder and leave it permantly connected, I have used one for years with a "gell" battery no probs. You will probaly find that you get a slight discharge through the diodes on the alternator which is normal and if not ridden regurlerly will result in a flat batery.
Hi Dave, I have come across dozens of new and near new Gel Batteries that would not accept a charge from any charger once run flat, one day I tried connecting another charged battery in parallel with one of the "dead" batteries (without charger) and it accepted a few milliamps, this value rose to only 10's of milliamps over an hour or so, at which time I then reconnected the "dead" battery to the charger and it came good and accepted a charge? That one has me stumped but has worked twice since......go figure!!!!

Kevin
 

dave g6xnc

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I was talking normal use, once flat you've had it, that's why I use the optimate since no probs. I fitted a flashing LED on my GS and when not used for a time this going 24/7 it had the undesired effect on the battery!, this was an Exide not a Chinese copy.
 

timetraveller

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There is another problem with Lion batteries which is not generally known but which might affect their use on our bikes. Typicaly a loss of about 4% per year of the original capacity is experienced, which is very good compared with some other battery technologies, but this is exacerbated by high temperatures. The standard position of a battery behind the engine on our twins is going to be a relatively hot spot. This loss of capacity is also worsened by the batteries being stored at high temperatures while fully charge. Storing them at high temperatures is not something which is going to concern those of us in nothern climes but those who live where temperatures get to 30 degrees and stay around there for months might want to consider whether Lion technology is the way for them to go.
 
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