Dual Battery (Oilhead)

[Bob_Roller]

I was going through my maintenance paperwork on the bikes this morning .

I saw that the battery in the oilhead is about 26 months old .

Batteries usually last about 30 ish months or so here .

I had the thought of putting two 18 ah batteries in the bike .

There is an empty space just forward of the battery, that would normally have the ABS electro/mechanical unit, it's more than large enough for a PC680 size battery .

Have two short cables made up and connect the batteries in parallel .

I need to get a battery for the Guzzi, so I was thinking of using the battery that's installed in the oilhead for the Guzzi and then get two fresh batteries for the oilhead .

Any thoughts or recommendations on my idea ?

These are the batteries I'm going to use .

http://www.gruberpower.com/12-volt-18-amp-hour-ah-battery

[montmil]

Bob, Since you're talking motorcycle batteries, I have a question regarding the battery in my bare bones 1978 R100S.

The specified battery is a 12V-24A monster that weights slightly less than a small fishing boat's anchor. The battery is currently in good shape but I have no idea how old it is.  

The bike has a headlight plus tail and brake lights. Nada mas. It's equipped with a Dyna ignition system. No heated grips, seat, extra lights, turn signals or siren.

My question is if an R65-sized battery, like the 12V-18A Gruber would be a workable replacement? Less weight and I see no reason it wouldn't power the Bosch starter as well as the smaller battery on my R65s.

[Barry]

Bob

As you'd effectively have a 36AH battery the cranking voltage would not drop so much and that would put less stress on the batteries. I don't know whether or not that extends the life in your climate to double the normal 30 months. In my climate it would. I once put a 40% over sized battery in my car and it lasted 12 years.  

The downside would be you'd have an even heavier boat anchor than Monte.



Monte,

I don't know for sure about Bob's specific battery but the R80ST and GS used an 18 amp hour battery so if it would crank those engines yours wouldn't be much different especially as you guys never have to crank with really cold oil. You could go for a double whammy weight saving and really knock some lbs off by using one of those aftermarket starters that are designed for smaller batteries.

[Bob_Roller]

Monte, it probably would work, until the temps dropped for the winter months .

The concern in my case, is starting the oilhead after it's been sitting outside at work in the temps we have during our short winter .

The standard battery for the oilhead is the same size as the batteries used in our R65's .

Every once in a while when I've put in an 18-20 hour shift with temps in the upper 30's-low 40's F, the battery in the oilhead is just barely adequate to start the bike, that's the main reason to go to dual batteries .

You don't have access to the battery terminals on an oilhead, to jump start it, if the need arises .

I've been giving thought of adding terminals somewhere on the bike so jump starting would be possible .

My Z3 has a positive and negative lugs for jump starting, if the battery is low on charge, they are located in the engine compartment, the battery is in the trunk .



I use a Harbor Freight battery maintainer on the Z3, three weeks of having the alarm armed and the car not driven, the battery is low enough, not to be able to start the engine .

[Barry]

Didn't realise it got that cold in your part of the world. Still it should have been designed to start at even lower temperatures. Lowest temperature I've started in with no bother was -8C (17F).  Thinner oil helps a lot but I guess it's not worth changing for a very short winter.

[Bob_Roller]

My first thought is to use a lighter grade oil, but for the 6 weeks or so that the temps get 'cold', I can't justify the cost, the oil alone is around  the cost of a second battery .

Although it's not very common, temps have gone down to the upper teens F, normal lows are in the area of low 30's F.

I've looked into the newer replacement lower current draw starters, they cost $350US plus about $25US for shipping .

If the starter quits, I won't hesitate to get the lower draw starter .

[tvrla]

I don't know that the Nippon Denso starters take less current than the Valeo. I've used the smaller 18A batteries in my R100s without a problem. If there's a problem starting the bike with an 18A battery, I'd check on the connections or the starter.

[steve hawkins]

Interesting thread.   I had an issue with starting last week after 4 days of commuting into work in sub zero temps and the bike standing all day in the cold.  I barely had enough juice to get here started on the Thursday and had to put her on charge overnight started on the last gasp!  Standard battery.

Going to work in the dark and coming home in the dark, with lights on, with the trip being generally slow throw traffic, and the alternator is not really giving enough juice to charge the battery at those low rpms.  At least not enough to replace that harge lost with starting.

A long run at reasonable rpm would have sorted it, but who wants to be doing 50 mph in -4 deg Celcius? I was certainly not dressed for it.  I do not think I exceeded 30 mph and that was cold enough!

Rev. light

[montmil]

Brother Light...  Add a BatteryTender Jr. to your personal Santa Wish List.  [smiley=deal2.gif]

[Bob_Roller]

I don't know that the Nippon Denso starters take less current than the Valeo. I've used the smaller 18A batteries in my R100s without a problem. If there's a problem starting the bike with an 18A battery, I'd check on the connections or the starter.

I checked all of the electrical connections, the copper is still it's original color, hasn't even tarnished yet .

I think my main problem, is that I use 20w50 oil all year long, I can't justify the cost of the lighter weight oil for the short cold season we have here .

Four quarts of Spectro oil cost around the same as the second battery .

A supervisor in the parts department at work, has an R1200GS, he works 6 PM to 6 AM, has made the comment that after sitting outside all night, the starter is quite slow on the few mornings that the temp was in the upper 30's F., as compared to the warm temps .

Currently at 0800, it's 38 F., 3C. .

[tvrla]

A trick in the cold country is to leave a bare light bulb burning under the hood in the garage. It generates enough heat to make starting easier.

But your bikes are outside... would it be possible to have an extension cord powered light bulb resting on the engine?

Another hint to make starting easier at low temps is only short bursts of the starter. This will also allow the fuel drawn up (mostly liquid) to vaporize some before the next burst.

Another solution is to carry another battery in the luggage and jump the bike with it. Just do that during the month and a half of cold weather.

Oh, and one other thing - remember not to rev the engine right at first. Some guys like to blip the throttle thinking that's the way to warm up the engine - only trouble is the oil is really thick and not lubricating very well yet till it warms up and thins down. It's also extremely hard on the oil pump - puts a LOT of strain on it.

Best thing is to keep it running at slightly above normal idle - just enough to keep it from dying.

[Bob_Roller]

The nearest power outlet is probably 300 feet away .

There's no way to jump start the bike, the battery is not accessible under the fuel tank .

The oilhead is fuel injected, once it fires off, it's no problem .

By the time I get my gloves and backpack on, etc . it's a minute or two before I get moving, I have a two mile stretch at 45 mph to get the engine warmed up, before getting on the expressway .

This just a battery capacity issue, large displacement engine, heavy oil, small battery .

If I could install the large battery the airhead 1000cc bikes have, I wouldn't have an issue, but the design of the bike doesn't allow it .

I'm going to order the batteries this week, maybe get them installed next weekend .

[Bob_Roller]

Got the dual battery setup installed in the oilhead this afternoon .

As usual, things didn't go very well from the beginning .

The space for the ABS module, is 1.75 inches narrower at the bottom, than it is at the top .

Had to resort to a piece of wood as a shim ( 2inches thick, 6 inches wide and 5.5 inches long), to get the battery up high enough to clear everything in the way .

A bit of work to get the correct hardware to install the cables on the batteries, the holes  in the cable ends are about three times as large as they need to be for a motorcycle application .

The starter has never turned this fast before, definitely accomplished what I set out to do .

Also got the airfilter replaced, as long as I had the fuel tank off .

[Bob_Roller]

The dual battery,has definitely cured the starting issue .

Also the bike has had problems with the engine stalling and stumbling upon first cold start of the day, that's not evident anymore .

I left the bike sit outside all night, no problems what so ever starting this morning, 40 F., 4 C. .

I was told that the oilhead bikes were quite sensitive to battery voltage and didn't run well if the battery was not at it's best .

[Bob_Roller]

Resurrected this thread .
Well, two years later and the starter is sounding a bit sluggish and the battery maintainer doesn't stop charging the batteries, never gives a full charge indication .
Just ordered two more batteries this afternoon .
So, I didn't get any more extended battery life with two batteries installed .
Just replaced the filter and oil yesterday, went to full synthetic Mobil 1 V-Twin 20w50 and no noticeable increase in starter speed .