AGM or Lithium battery upgrade question

[Flick]

I just had an idea on how to bring the charging system on our bikes up to modern standards. It looks like the voltage regulator on the back of the alternator is interchangeable with a BMW 325i. This will bring the charging voltage up from 13.2v to 14.2v. This will let me run a maintenance free AGM battery, or a lithium battery. The concern I am having is can the Ecu's handle the increased voltage? I will obviously need Frankenduck's 50 Amp alternator conversion to handle increased load on the charging system, I don't think that the 30 Amp on my K75 will cut it. I would like to run this lithium battery: http://www.shoraipower.com/s-101398-K75S.aspx

So what does the asylum think of my plan?

[wmax351]

Seems expensive...

My Formula SAE Racing team uses one of the lithium batteries on our car. Its the multi cylindrical cell type. It runs a modified GSXR 600 engine, with a Motec ECU. We had nothing but problems with it last season. They're light, but fragile. One deep cycle/overcharge and their toast.

I'd say don't fix what ain't broke. Maybe do AGM, with the alternator mod. The ECU and all other sensitive electronics are voltage regulated.

[Flick]

I was attracted to the fast recharge times and lighter weight of lithium, but not 100% sold on longevity. I am waiting to hear back from that battery maker about how this battery responds to over voltage and under voltage situations. They claim that they make their own square cells that are more power sports friendly. If I don't get reasonable answers back then I will run just use an AGM battery.

I am the kind of guy that likes to see how far I can push the limits of a machine. Right now I am working on this charging system mod, an ECU remap, cafe/street fighter conversion, fuel cooling system, suspension upgrade, and looking into getting higher performance cams and pistons. That is just the short list.

[frankenduck]

Since I always upgrade my bikes to the 50A alternator I don't know what the voltage is regulated at on a 32A alternator but it's already at 14.1-14.2V or so on the 50A alternator.  I've done this upgrade to numerous K75s/K100s as have scads of other people and nobody has had any issues that I know of so as far as I'm concerned there's no need to mod any of the electrical system for a system that's regulated at 14.1 or 14.2V.

You can run an AGM battery like an Odyssey PC680 with the stock 32A alternator and everything is fine and the battery lasts a very long time.  That's what I had in my K75RT for years. No issues.

FYI: The early K bikes (up to 1990 at least) came with a rather wimpy ground cable running from the negative battery terminal to the left side of the transmission.  In later K bikes it's much beefier.  From what I've seen most of these have been upgraded to the newer ground cable but there's still a few bikes out there with the old one.  If you still have the older one then I'd recommend upgrading that, especially if you're installing a 50A alternator.

[Flick]

I have only been getting 13.5V, and I couldn't find any where that says what the voltage should be. Many bikes I have worked with from the early 90's are regulated at 13.6V, so I assumed that our bikes were too. I guess I just need to order a 50A alternator and I will be happy. Thanks Duck

[frankenduck]

Just my .02 but there's really no need to upgrade from the 32A alternator unless you intend to run something with a high power draw like a pair of 55W aux lights.  The 32A alternators are more than up to the task of running a K75 or K100 and keeping the battery charged.

[Flick]

Just my .02 but there's really no need to upgrade from the 32A alternator unless you intend to run something with a high power draw like a pair of 55W aux lights.  The 32A alternators are more than up to the task of running a K75 or K100 and keeping the battery charged.

I am planning on 55/100w headlight on relays, gps, radar detector, heated gear, phone charger, chatterbox (plugged into 12v), and an air horn. The air horn draws ~30A. This setup put a huge strain on the 27A system on my Triumph, and it was carbed, I would feel more comfortable with a 50A system.

[johnny]

greetings flick...

you can always install a weedeater engine generator...

j o

[wmax351]

Just my .02 but there's really no need to upgrade from the 32A alternator unless you intend to run something with a high power draw like a pair of 55W aux lights.  The 32A alternators are more than up to the task of running a K75 or K100 and keeping the battery charged.

I am planning on 55/100w headlight on relays, gps, radar detector, heated gear, phone charger, chatterbox (plugged into 12v), and an air horn. The air horn draws ~30A. This setup put a huge strain on the 27A system on my Triumph, and it was carbed, I would feel more comfortable with a 50A system.

The horn, if relayed, isn't an issue (unless you are in NYC or a few other places, then I'm not so sure).

The real power draws are going to be your heated gear and headlight. But even that is only 100w for the light, 50 for vest, 50 for pants, 20 for gloves. The other farkles aren't that big a deal.

Other thing is that the K bike has a true alternator, with a field coil, rather than a permanent magnet rotor, which allows high power output at lower RPM.

If the triumph was a permanent magnet one, it may have not put out full power at low RPM.

[frankenduck]

I assume you're using a Stebel Nautilus Compact horn.  That draws 18 amps, not 30.  And you don't use it 100% of the temporary so it's only a temporary load which won't run down your battery.

What heated gear are you planning on using and how much power does it consume?

Radar detector, GPS and Chatterbox are all negligible loads.

[Flick]

I assume you're using a Stebel Nautilus Compact horn.  That draws 18 amps, not 30.  And you don't use it 100% of the temporary so it's only a temporary load which won't run down your battery.

What heated gear are you planning on using and how much power does it consume?

Radar detector, GPS and Chatterbox are all negligible loads.

I have 16.5A of heated gear (I don't like the cold). I like using a Wolo model 410 airhorn. The horn is a 3 trumpet system made for cars, it is louder than the stebel. I wired it in parallel to the stock horn with a relay. It had a draw of nearly 30A, and became a running joke that my horn was bigger than a friend of mine's ninja 250's starter (25A).

[Lawrence]

Just a little reality check here.  Looking over the wiring diagram in the 1985 K100RS owner's manual, I couldn't find any indication the headlight circuit uses a relay. Is this correct or did my old eyes miss something?

[Flick]

You can make a subharness from 2 relays, some wire, and connectors. Or you can order one premade from places like Eastern Beaver http://easternbeaver.com/Main/Products/H4_Kits/h4_kits.html

[frankenduck]

Lawrence, you are correct.

Flick, you left out fuses.

Lieberry topic on Headlight Relays