K11 Owners Group

Ernie-NH · Posted: Wed Nov 24, 2010 6:52 pm Post subject: Battery winter storage ???

Hi guys...

OK... here's the question: I have three 12v batteries, ( ie: one for each bike ) Can I wire all three in parallel and attach a Battery Tender to keep these fresh for the next 4 to 5 months while we all hibernate ?? Personally I dont see why not, given the capacity of the Marine Battery Tender... any thoughts ??

Happy Thanksgiving all............// Ernie in NH

ps: next year its EVERYBODY to Shogs house for "deep fried turkey" and ALL the fixings..... eh?
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Flying Duck · Posted: Wed Nov 24, 2010 7:10 pm Post subject:

Short answer: It would work but it's probably not a great idea because the batteries are different.

Recommendation: Bring them inside your house where they'll be at room temp and rotate the charger every few days.

Better yet, get a couple of Battery Tender Juniors so each bike has it's own charger. Inexpensive and good quality.
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drikko · Posted: Wed Nov 24, 2010 7:38 pm Post subject:

It will work provided they are all in good nick to begin with and make sure you charge them fully on their own first. I agree though probably best to buy a little battery tender for each.
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K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB

DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.

'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde

Ernie-NH · Posted: Wed Nov 24, 2010 8:17 pm Post subject:

Hello all...

You're probably all right about the "3 Juniors" being best... but the reason I asked the question is that my neighbor's boat ( in the Marina ) uses 3 12v batteries on a parallel harness to run everything while they're out and on anchor. These batteries are in turn 'charging' from the engine's alternator when running. Installed in the engine compartment is a Switch "on/off" Marine Battery Tender connected to the shoreline plug to look after the batteries when not sailing. So, I says t myself, why not for my 3 batteries as well... I do think however that the 3 marine batteries are somehow different ( ie: capacities in aH ) and much larger in size to be sure...

Ok... it was worth asking, and I value your collective opinions...

Very best regards...........// Ernie in NH
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AMA,, American Deaf Bikers
Airhead Beemers Club
'11 G650gs
'95 K1100LT
'76 R100/7

drikko · Posted: Wed Nov 24, 2010 9:33 pm Post subject:

So on boats if the batteries are actually wired together then they must be exactly the same size ie AH rating and in similar condition ie you never replace one, if one dies you replace all 3.

If they are different sizes then they should be isolated. A good marine battery isolator separates them all electrically except for charging. Very similar to a 4WD dual battery setup. Bigger boats often have one battery for starting the engine use only, the isloator will charge this battery first before any charge goes to the house batteries. Your neighbour may well have 2 house batteries, one for all the nav equipment and the other for all the other stuff, light, fridges, tvs etc. If however he has all 3 wired together and they are different sizes then he may well be in for trouble out on the water when he most needs it to be working!
_________________
K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB

DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.

'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde

drikko · Posted: Wed Nov 24, 2010 9:38 pm Post subject:

Oh and BTW, there used to be a theory that you shouldn't sit a battery on concrete. This is no longer the case as they are all made out of plastic. It used to be the case when they were made out of rubber or bakelite about 60+ years ago. It is no longer relevant.
_________________
K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB

DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.

'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde

SugarHillCTD · Posted: Wed Nov 24, 2010 10:05 pm Post subject:

Ernie,

I am a past and probably a future member of the RV.net forum, since we have had 2 truck campers and will be looking at another one in the next couple years.

The common knowledge is that if an RV has more than one 12v battery, they should be of the same age. Otherwise, once paralleled the newer battery will be "drained down" by the older battery to
that older battery's state.

As others indicated- I would charge them separately. As you know I have 3 bikes in our garage. I just move the "intellicharger" from one bike to the next every weekend.

John
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John & Cathy

'92 K100RS4V Pearl White SOLD
'04 K1200GT
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Scott_Anderson · Posted: Wed Nov 24, 2010 10:18 pm Post subject:

Ernie-NH · Posted: Thu Nov 25, 2010 6:25 am Post subject:

Good morning all AND Happy Thanksgiving !!

Re the "batteries"...... after reading 'drikkos' responses and John's comment on battery age, your ARE right ! The batteries MUST be identical in 'capacities' and 'age' ( which mine are not ) or the poorer, older, lesser capacity battery(s) will deplete the newest.... in effect aging it out quicker. From a physics point of view I have yet to reason why that might be the case BUT I'm not going to jeopardize my $120 to $160 batteries. So I'll just make up a "Winkin/Blinkin/Nod" standing array of little Battery Tenders to babysit my batts whilst I snooze by the stove 'til winter passes.

Thanks again for your collective input..... very much appreciated.

Best regards all............// Ernie in NH
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'76 R100/7

drikko · Posted: Thu Nov 25, 2010 6:32 am Post subject:

Remember the battery depleting thing only applies when they are getting drained ie under load, so I still would quite happily put 3 different batteries on the charger in parallel provided they were just being trickle charged over winter and you charged them all up separately first.
_________________
K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB

DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.

'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde

SugarHillCTD · Posted: Thu Nov 25, 2010 8:11 am Post subject:

drikko,

I've got to research that a bit. Even on a trickle charge I wonder (but do NOT know for sure) if there isn't a tendency for 2 or more batteries to draw down to the lowest one?

Kind of like water finding its lowest point- OK that was a poor example Laughing

But you are probably correct.

John
_________________
John & Cathy

'92 K100RS4V Pearl White SOLD
'04 K1200GT
IBA Several-SS1k, BBG, 50CC NYC to S.F.

drikko · Posted: Thu Nov 25, 2010 8:22 am Post subject:

OK so yes that will happen. All batteries have what's known as their internal discharge rate. This is measured in milliamps (mA). The more old and or stuffed a battery is the higher it is. What is actually happening is not a current discharge per se but the chemical barriers get worse so the battery discharges slowly but surely. They just measure it in mA so you can estimate how long it will stay charged without any connections at all.

So if you have multiple charged batteries in parallel on a float charger that are different ages etc then if the charger can supply enough current to exceed the combined internal discharge rate then all will be OK, they'll all stay charged. So it depends on the condition of the batteries and the maximum float charge ability of the charger.

You know what the charger can do but not necessarily the condition of the batteries.

Clear as mud I know Smile

_________________
K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB

DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.

'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde

Ernie-NH · Posted: Thu Nov 25, 2010 11:08 am Post subject:

WOW....! I'm certainly glad I opened this 'can of worms' !! I guess the degree of sulfonation within each is what perhaps impacts the 'draw down rate' as each battery ages.... but now that I think of it, it would be fun to scope this out from a chemical point of view and then see just how effective the dielectric actually becomes as the plate surface coating increases... since its the 'fluid/plate' interface that provides the current we seek.(in either direction, charge or dscharge ). Sounds like something we could actually do and quantify... Great idea !

Regards all..........// Ernie in NH
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'11 G650gs
'95 K1100LT
'76 R100/7

Ted · Posted: Thu Nov 25, 2010 12:22 pm Post subject:

Doesn't battery tender make a 4-port charger? Personally I would buy a Battery Tender Jr. then just rotate the batteries - one week on A, then a week on B, then a week on C, repeat Smile

Since I already have a battery tender Jr ($20 shipped on sale, look around!) I just put it on for a few days every few weeks.
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Ted

KOG#1

Ernie-NH · Posted: Thu Nov 25, 2010 12:53 pm Post subject:

Hi Ted...

I think I'll just buy three Battery Tender Jr.s put 'em on a power strip, hook one to each battery and then go snooze until April... The rest of the BS was just thinking about thesis material for students...

Enjoy the holiday with a meal and a good cigar !!

Very best regards......// Ernie in NH
_________________
AMA,, American Deaf Bikers
Airhead Beemers Club
'11 G650gs
'95 K1100LT
'76 R100/7

robleyd · Posted: Thu Nov 25, 2010 7:25 pm Post subject:

If you happen to be a subscriber to the Internet BMW Riders' Technical email list, there was a discussion on batteries there a few weeks ago that might be of interest - well, parts of it, anyway Very Happy

http://www.lists.ibmwr.org/mailman/private/bmw-tech/ and log in, then see the thread listings for October and November, anything with battery in the subject.
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David, owner of:
1996 K1100 LT

drikko · Posted: Fri Nov 26, 2010 2:04 am Post subject:

At $20 each you bet, that's the best option for sure!

The draw down is pretty easy to measure and yes in a flooded cell it's sulphination that is a major cause. This is one reason why AGM batteries last longer. I only run AGM batteries in my yacht as wet batteries are dangerous as you are healing over. If you get rolled and the acid comes out, the mixture with salt water can produce some fairly toxic gases, I'm not any good and chemistry but it's something to do with the sulphuric acid and the salt in the water.
_________________
K1100RS '97
Laverda RGS 1000 '84
Jim Young Trailer Sailer 5.7M WB

DISCLAIMER:- Anything I say may have been when I was drunk so please don't take it personally.

'Bigamy is having one wife/husband too many. Monogamy is the same.'
Oscar Wilde

Bob T · Posted: Fri Nov 26, 2010 12:45 pm Post subject:

FWIW...Motorcycle superstore has the BT Jr on their Super Deal of the Day for $19.99...
Today only....

http://www.motorcycle-superstore.com/DoTd.aspx?SiteID=em_DOD_11_26_Text&WT.mc_ID=35967&WT.i_e_dcsvid=1534401358
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Bob T.
'96 K1100RS
'95 K1100RS - Totaled
'01 Triumph TT600
'83 Suzuki GS1100E

Ernie-NH · Posted: Fri Nov 26, 2010 5:11 pm Post subject:

Hey Bob.....

I'm on it x 3...!!

Thanks...............// Ernie i NH
_________________
AMA,, American Deaf Bikers
Airhead Beemers Club
'11 G650gs
'95 K1100LT
'76 R100/7

Flying Duck · Posted: Fri Nov 26, 2010 5:38 pm Post subject:

I have these on all of my battery tenders:

http://cgi.ebay.com/ebaymotors/PPL-001-Powerlet-BMW-BASIC-Plug-_W0QQcmdZViewItemQQhashZitem2e97ca171aQQitemZ200115099418QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_1004wt_687
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE