What kind of battery for vintage motorcycle?

[McLovin]

I thought this would be easy, but seems not so.
For a 73 BMW R75/5, need a new battery.
A lot of people recommend the Odyssey battery, which seems to be an AGM battery.
Seemed simple.
But then others said while the battery is good, it needs to have a special charger. Regular chargers like my Deltran Battery Tender Plus that I use for all my cars don’t properly charge at the higher voltage that AGM batteries need, and you’ll get shortened life.
Ok, I guess I can spend $125 for a specialty charger just for the motorcycle.
But then people also say the old BMW charging system also doesn’t charge at a high enough rate while you’re riding. And at a *minimum* you need to install an adjustable voltage regulator (and properly adjust it).
Now that’s pushing my limits.
What batteries and chargers do you guys use on your vintage bikes?

[flatbutt]

FWIW my R80RT had a crap charging system. I used the YUASA.

[Baz]

I'm not any expert so take it for what it's worth - maybe 2 cents -

I think it was just an AGM for my Ninja and not sure if I have ever changed my R75/7 battery yet.

I just use standard battery tenders and they seem to work just fine on all my bikes.

One thing I did get for my bikes were wiring loom quick connectors for easy attachment of a battery tender/charger.

[McLovin]

Yeah, I have those on all my vehicles. None of them get driven daily, so I like to keep them charged.
Making batteries last has always been a thing with me. For my cars, I usually get 10-12 years out of Interstate batteries. I think it’s because I regularly put them on the chargers.
Motorcycles are another story. Even on chargers, I don’t usually get more than 3-4 years. (But maybe that’s because I’m buying inexpensive batteries for the bikes).
For the BMW, I think I’ll just go with Batterymart. For the price, if I can get 3 years out of it, I’m good.

[McLovin]

I looked on the bike, and the previous owner put this battery in, he put the date on it and it’s exactly 3 years old. It actually still works, but on cold days when the bike is dead cold, barely (one warm, it’s fine).
So 3 years for $50, not bad.

[zakthor]

Agreed. Don't let the perfect be the enemy of the good. You're overthinking just buy a regular battery. Motorcycle batteries are tiny and inexpensive and only last a few years, no point investing in something crazy.

[Baz]

100% agree - good call guys!

[Rot 911]

Just get a regular AGM battery for it. Airheads don’t need anything special. Keep it on a trickle charger and you should get a few years out of the battery.

[Rot 911]

Originally Posted by afterburn 549

I have been using Lithium for years in the old Harley.
They weigh 3 lbs.
It will crank over 225 lbs of compression EZ

I think McLovin is trying to avoid buying a special battery charger. And his BMW is low compression. The cheapest AGM he can find that will fit in the battery box will do the job nicely.

[908/930]

The other problem with the AGM is your bike's alternator output voltage was not really set up for it, likely on the low side for voltage. If you are paying much more than a regular FLA not sure if there will be any gain.

[E Sully]

When I finished restoring my '72 Kawasaki H2 I bought a standard lead acid Yuasa. It was disappointing, so I picked up a Motbatt AGM. It has been working great so far. Of course my electrical needs are minimal since there is no electric start.

[Cajundaddy]

Regardless of battery choice, a $27 NOCO smart charger is useful to extend the life of every vehicle battery you own. It will easily pay for itself over time. These days I would probably choose an AGM battery for a vintage bike and connect it to a smart charger every month or so for a complete refresh to 100% capacity.

https://www.amazon.com/vdp/0fc6f6a412054811bcdbbafea6e478d9?product=B07W46BX3 1&ref=cm_sw_em_r_ib_dt_HFxoN2Tsfyigq

[McLovin]

This is the one I’ve used on all my cars and prior motorcycles (with “regular” batteries) for years.
There seems to be some disagreement as to whether it works with an Odyssey battery

[gtc]

Many chargers these days are AGM compatible. No need to spend a bunch of money.

Here's a battery tender for example:
Battery Tender on Amazon

[cstreit]

AGM's dont require anything special. They are a drop in replacement.

I have used a seals lead-acid an an AGM on my '71 Norton - both worked fine.

[island911]

Originally Posted by gtc

Many chargers these days are AGM compatible. No need to spend a bunch of money.

Here's a battery tender for example:
Battery Tender on Amazon

There it is.

Float charger rather than a trickle charger.

The float turns off at voltage, and on again when needed.

[varmint]

Lithium ion battery tucked in the hump.

[greglepore]

$19 and have it on 3 cars and a mower...https://www.amazon.com/gp/product/B07MCTXFC7/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[Baz]

Spa day yesterday for my bikes and discovered the battery in my R75/7 was kaput. So I just ordered one of these - an AGM:



$65 delivered, from Amazon

Should be a perfect fit according to my measurements.

[Baz]

This is the old one I'm replacing.....