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By infamous I meant everyone has heard of them and many seem to accept they are something special enough to justify the outrageous UK cost which implies a minimum 10 year life to be economically viable. I knew that Odyssey say they are AGM's of a sort but they advise a charging regime which differs from a generic AGM hence I used it as a good example of why it's not necessarily safe to assume batteries of a given chemistry or construction will always conform to the generic stereotype. I think they do say there is something special about the construction so that may explain why they differ.

Hi,

Planing on a long ride this weekend to a Tech-Day. Plan on replacing the steering head bearings! YAY!
Also would have liked to address the charging issue at the same time, but I don't have the tools or understanding to test things. It could be as simple as dirty connections or worn brushes.

However-
I'm currently accepting suggestions regarding charging systems : )
I've now noticed that the charging process simply takes longer. Maybe it's simply a slow battery maintainer thing, not really a charger - probably explains the low cost. When I've ridden recently before dawn and back after dusk using full lights and often high beams, the battery dies after about 4-5 hours which is about two or three days of commuting to work. The few hours at home don't seem to be enough to recharge the battery (a new AGM).

So while it's probably some worn out parts, I'm thinking of upgrading to a more modern and powerful charging system anyway.
I want a stronger charging system because I'd like to someday add more lights, be able to charge my phone, camera batteries, etc. Maybe use smaller lithium batteries or even have dual plugs. Also would there be issues with the AGM battery? I don't know why but the more I read here the more it seems that anything is possible and I know nothing about anything.

It seems that the Enduralast and Omega are the favorites and neither is really a bad or wrong choice.

Would be love to hear some experiences or opinion.
For example I think an expert on ADVrider named Anton L(something) that has or had a R100R chose Omega. All the searches bring up old threads, sometimes years old, so I don't know if he still has it or what, but I respect his opinion. Others have chosen Enduralast, also long time experts. So I just don't know. There seem to be pros in both camps.

Personally, since they both seem good,
I thought that the Omega being closer to the original set up was good if only because diagnosing a problem seemed the same or similar with what seem to be just beefier, more powerful versions of the same parts. Also one can push start a bike with a weak battery and I think Omega will then charge it - I might be wrong on that. My understanding is Enduralast needs a strong or at least higher minimum battery to work with or it won't work at all. Then again if both are doing their job right, why would a battery be weak?

Enduralast seems more modern and has fewer moving parts (which I like) so carrying spares is not required.
I just don't know.

Anyway I appreciate your interest and any input.
Thanks.

Anton has his own web site with some good information on charging systems.
http://www.largiader.com/articles/charging/


I can't help with the aftermarket systems but I do a daily very short commute and the standard system charging an AGM at the correct voltage copes fine without any top up charge but I have no electrical accessories and mostly use a 20W halogen in lieu of the head light. The charge light goes out at idle and stays out. If a bike starts instantly then replenishing that starting draw is not the issue so if the battery is now known good it must be that your running electrical load is in excess of what the standard system can provide and you do need an aftermarket system.

I know nothing about the modern batteries and what is best for this or that. I want to visit the charging system and basic logic.

If some of these modern batteries require some regimen to be properly charged, how does one alter the original charging system to accomplish that unusual requirement?

If the modern batteries are finicky about how they are charged up, then maybe that explains why a battery that is superior, in theory, behaves so poorly in practice on our BMW.

Back in the day, the batteries supplied by BMW were awful. They didn't usually last long and were very expensive. Some did last a long time, but not many in normal use by the normal rider.

BMW just used batteries from Germany, or at least designed by German companies. I don't know who made them in reality, but I think that I didn't see any stickers to claim China or other. Do you really think that BMW was going to send out a press release saying, "The batteries that we sell with the bikes are crap and we don't know what to do about it."

Instead, they came up with an elaborate procedure to assure that they were properly charged the first time and then they would last. Reading the procedure, it was obvious to me that they chose to send out a charging procedure that was so time consuming that nobody would follow it, and they didn't.

We set up to follow the wasteful procedure, well knowing that our volume would either prove or disprove its efficacy. It failed and was no better than what was the usual procedure of filling it up and putting it on a medium to slow charger.

Mostly we sold the cheaper and far better Japanese batteries. Some of our customers bowed to the alter of BMW and had to have "original approved" parts from BMW. OK, we can assist you in wasting money. We always informed customers of our opinion, but they were free to ignore it. We made most of our money from those that ignored our advice anyway.

We found that the most important factor in battery life was the charge voltage. If it was too low, then the battery just didn't get charged up fully. If it was too high, then the acid could get boiled out. This charge voltage varied according to the riders habits. The problem was the rider that rode back and forth to work every day 5-10 miles round trip and then took off on the weekends to do a 800 mile tour. The Japanese batteries tolerated that far better than the Varta.

If you only ride short rides and don't pay attention to keeping the rpm up over 3500, then you need a charge voltage around 14.3-14.4 and not less. If you only rode on the freeway with all trips being over 20 miles, then you could get away with only 14.0-14.1.

For old lead acid batteries there is far more to it than laid out here. Some of it is on my website.

For any battery, you need to know about proper battery terminal crimping. BMW contractors didn't. BMW had no inspection procedure for the wiring quality in those days. I know because I was there in the assembly line. You need to know about dielectric grease and how to use it. None was used on any BMW motorcycle and we paid for that in greatly increased repairs.

Few knew how to measure the charge voltage and few cared either. My bank deposits just got larger. I thank you because I am still spending the money today.

This information is only for historical reference and may not apply to anything today. Sorry if this just wasted your time.

I think the charge voltage is still the relevant issue. I believe the reason I can keep the battery charged even on short commutes is because I set the voltage regulator at 14.5 volts cold (14.3 volts hot). It did increase water loss but not excessively. With that set up and a lot of battery care I got 12 years out of a Varta wet cell. It also happens to suit a modern AGM battery if perhaps at the low end of what's needed for some batteries.

I wonder if relatively low charge voltage ex factory is a German manufacturing thing because I've seen a critique of Mercedes charging systems which said they routinely set the voltage too low. It prompted me to measure the voltage on my old 190e and sure enough it's lower than ideal at 13.8 volts cold falling as low as 13.5 volts when hot. Perhaps not so much of a problem flat out on the German autobahns but not where it should be. And not something I can change as easily as on the bike.

The problem with these low charge voltages is if you take the total population of automotive users as a whole the majority have no clue what the state of charge of their batteries is. They think as long as the engine starts the battery must be fine which is just nonsense in terms of achieving proper battery life.

I know little about modern cars but I'm told that some BMW's now have very sophisticated charging systems even to the extent of charging only on the overrun to save energy and requiring reprogramming when the battery is changed so that appropriate charging regime is applied. Failure to carry out this reprogramming results in premature battery failure.

I plugged my battery tender into my Odyssey battery before leaving on a month long holiday in the US. 4 days into my holiday my shed burned down with my R90S, Toyota ute and my neices car as well as all of my carpenter and mechanic tools. The fire brigade said it was an electrical fire. The devastation was so bad that nothing could be recycled and I'm still cleaning up 2 months later to build a new garage. I don't think I'll ever leave a battery on for a duration and I'll charge my batteries away from everything else!

Was this a tender specifically designed for Odyssey batteries, or a Battery Tender brand charger?

Bamboo812 wrote:Was this a tender specifically designed for Odyssey batteries, or a Battery Tender brand charger?

Good question. a "battery tender" has become a generic term, while a Battery Tender is a specific product from a specific company. Yuasa now makes a competing product which I assume is also a quality product, but others are of very varying quality.

Bamboo812 wrote:Was this a tender specifically designed for Odyssey batteries, or a Battery Tender brand charger?

It was a battery tender, not specified for an Odyssey. I'll watch things a lot closer in the future, to bad about the past.

barryh, yes, you are right. We rarely found a 12 system on a BMW motorcycle to have the charge voltage up to 14.0. We made a special set-up for adjusting the mechanical regulator on the /5 and later. Once you know how, it is easy, but could be dangerous. We had a special overhead fuel tank set up to feed the engine while we would gently bend the spring to raise the voltage. We had a fan to cool the cylinders, but we could do the adjustment in short order and be done before it heated up much. We usually had one other person on stand-by holding a fire extinguisher.

One must remember that a lead acid battery starts to decline the day it is charged. If treated properly, it is a nearly straight line degradation until its death. Basically, the capacity declines and that means that the charge rate must also go down equally. If it is always charged up at the 10% of original amp hours, soon that becomes a much larger percentage. That means heat and boiling the acid to water and hydrogen in the air. That can explode easily. Ask anyone who has been around one that blew up. It is like a small stick of dynamite with resulting damage. It is because of this that a trickle charger is so much safer.

My preference for charging is a charger of medium capacity, say around 8-10 amps. Then I plug that into a variac and adjust it go give me the charge current I prefer. A simple variac is an adjustable transformer that takes the 117 VAC input and allows out put from zero to 135 VAC. One also needs a good DC ammeter in the line to the battery.

Variacs became unpopular some 25 years ago and I was able to afford a few. I will be selling them on eBay soon. They are again in demand and I was surprised. A small one is enough for a charger.