Gregory Bender

Batteries

Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models

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Motorcycle batteries generally fall into three technology categories: lithium ion, valve regulated lead acid, and flooded wet cell.

Lithium ion batteries

Please see the follow-up information at the bottom of this section.

Lithium ion batteries are the latest readily available battery technology. Lithium Ion batteries are extremely light weight and deliver a lot of electrical power. These benefits come at a cost. Indeed, lithium ion batteries are more expensive than other batteries, but nice things cost money.

The real drawback I see is the overall lack of reliability of lithium ion batteries. I don't know very many people who have them, but the failure rate has been unacceptable amongst those I know who have installed them (near 100%). I know that Shorai has been good about replacing their failed batteries. But, that doesn't do much good when your battery fails out in the middle of nowhere and you have to figure out how to get back to civilization. The failures tend to be instant without any pre-warning whatsoever: running fine one minute and then dead on the side of the road the next (and totally unrelated to the performance of the charging system).

I'm hoping the early lithium ion troubles are nothing more than the teething pains of bringing a new technology into a harsh environment. Personally, I'm going to wait a lot longer until reliability is a very distant memory.

Follow-up

At this time, I do not recommend the use of lithium ion batteries.

Valve regulated lead acid batteries (also referred to as dry cell, gel, sealed lead acid, SLA, absorbed glass mat, AGM, etc.)

Please see the follow-up information at the bottom of this section.

Comparison of various valve regulated lead acid batteries

Thanks to Kevin Hahn of Scrambler Cycle for sending me the link to this information.

In a nutshell, Bug Dr from Texas compared 5 different valve regulated lead acid batteries (listed here in alphabetical order):

Feel free to read through the entire comparison, but the MotoBatt was the clear winner.

Big Crank ETX30L

Charlie Mullendore of Antietam Classic Cycle has informed me that the Big Crank ETX30L battery fits (Battery Mart sells them). Here are the details:

  • Battery Mart Part #: ETX-30L
  • Capacity: 26 Ah
  • Type: AGM
  • Length: 6.63 inch
  • Width: 5.19 inch
  • Height: 6.88 inch
  • Cold Cranking Amps: 400 CCA
  • Shipping Weight: 23.00Lbs
Big Crank ETX30L battery. Applicable to Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police motorcycles.
Big Crank ETX30L battery. Applicable to Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police motorcycles.

Photo courtesy of Battery Mart.

Deka/Marathon MAR-8AM-U1R (made by East Penn Manufacturing)

Charlie Mullendore of Antietam Classic Cycle has informed me that the Deka/Marathon MAR-8AM-U1R battery fits (Battery Mart sells them). These batteries are popular with owners of the Mazda Miata. Here are the details:

  • Battery Mart Part #: MAR-8AM-U1R
  • Capacity: 25 Ah
  • Type: AGM
  • Length: 7 34 inch
  • Width: 5 18 inch
  • Height: 7 14 inch
  • Cold Cranking Amps: 320 CCA
  • Shipping Weight: 25.00Lbs

The one drawback I see to these batteries is the use of post terminals. I prefer a battery that accepts a 6 mm ring terminal. I find it easier to fit the hold down bracket as well as additional electrical components.

Marathon MAR-8AM-U1R battery. Applicable to Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police motorcycles.
Marathon MAR-8AM-U1R battery. Applicable to Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police motorcycles.

Photo courtesy of Charlie Mullendore, Antietam Classic Cycle.

Odyssey brand batteries

A great battery choice recommended by John Ulrich is the Odyssey PC925MJT with 380 cold cranking amps and 925 cranking amps for 5 seconds. It can be installed on it's side and fits well in the battery tray. Battery Mart and Battery Sales are two online locations with (historically) competitive pricing (thanks to Charlie Mullendore of Antietam Classic Cycle and Howard Blank for the links to the online stores).

George Dockray was kind enough to send me a couple of photos of his PC925 installation. He glued rubber sheet to a piece of 34 inch plywood for the base to get it out of the way of the bolt heads and base tabs.

George Dockray's installation of an Odyssey PC925 battery. Applicable to Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police motorcycles.
George Dockray's installation of an Odyssey PC925 battery. Applicable to Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police motorcycles.

Photo courtesy of George Dockray.

George Dockray's installation of an Odyssey PC925 battery. Applicable to Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police motorcycles.
George Dockray's installation of an Odyssey PC925 battery. Applicable to Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police motorcycles.

Photo courtesy of George Dockray.

Greg Field reports that the Odyssey PC545 and Odyssey PC680 batteries fit and function well.

My first Odyssey PC925 lasted three years before it cracked and leaked a small quantity of battery acid onto my battery tray and transmission. Odyssey sent a replacement. The replacement lasted three years before it died. For USD $180.00, I expected a lot more out of a battery than case cracks and a three year lifespan. I wish I could strongly recommend Odyssey batteries, but my experience with them has left me disasstisfied. Of course, other people have gotten much longer life out of their Odyssey batteries and I suspect that the hot climate in Arizona greatly decreases battery life. All the same, I am not willing to pay USD $180.00 for acid leaks and a three year life span.

More generic VRLA batteries

Carl Krall introduced me to the idea of using a VRLA battery removed from a portable jump start product sold by Harbor Freight.

Following Carl's lead, I installed the Harbor Freight battery in my Ambassador and it is working very well so far (installed ).

Sealed Lead Acid battery inside Harbor Freight item number 62306.
Sealed Lead Acid battery inside Harbor Freight item number 62306.

Photo courtesy of Harbor Freight.

Sealed Lead Acid battery inside Harbor Freight item number 62306.
Sealed Lead Acid battery inside Harbor Freight item number 62306.

Photo courtesy of Carl Krall.

Follow-up

I recommend the use of valve regulated lead acid batteries. They have a much better track record than lithium ion batteries for longevity and performance, and are far less likely to emit fumes or leak acid than flooded wet cell batteries. Furthermore, if one does start to fail, you can likely nurse it enough to get back home (unlike lithium ion batteries).

Flooded wet cell batteries

Please see the follow-up information at the bottom of this section.

Garden tractor batteries (flooded wet cell)

I used to be a proponent of the very inexpensive lawn and garden tractor batteries such as the Interstate SP30R Battery with 290 CA and 230 CCA or the Walmart EverStart U1P-7 garden tractor sized battery with 350 CA and 275 CCA available from Walmart. However, these batteries have low cranking power and vent corrosive gases. I was never completely satisfied with them. But, if you are on a budget, these will definitely get the job done inexpensively.

Group 51 batteries (flooded wet cell)

Charlie Mullendore of Antietam Classic Cycle has informed me that the AC Delco 51R-60 battery fits. Here are the details:

  • Cold Cranking Amperage (CCA): 450
  • Cranking Amperage (CA): 530
  • Length: 9.31 inch
  • Width: 4.94 inch
  • Height: 8.69 inch
  • Weight: 28 pounds

Group 55 batteries (flooded wet cell)

The Group 55 battery size is pretty much discontinued by everyone. If you do find one, it may be very old. My recommendation is that you do not waste your time trying to find one of these. However, I've kept the information on them below for reference.

Based on recommendations from Robert A. Greene and Mark Etheridge of Moto Guzzi Classics, I have now chosen to use an AC Delco Group 55-6 year battery with 535 CCA. I picked one up from my local auto parts distributor. A NAPA Group 55 battery may also work, but doesn't fit as well as the AC Delco.

If your local auto parts house just has to have a vehicle to look up a part, try any of the following:

  • 1993 - 1995 Kia Sephia
  • 1987 - 1990 Jeep Wrangler
  • 1978 - 1980 Ford Thunderbird

As for installation, I was able to use the stock battery hold-down bracket and the long L-shaped bolts. I did have to modify the battery a bit, though, in several places. Along the bottom of the battery there is an extra chunk of plastic that is usually used to clamp the battery to the battery tray in cars, etc. This extra chunk got in the way of the four tabs on the battery tray. Some quick work at the bench grinder got rid of those (I just love grinding on a battery with power tools!). Also, on either long side of the top of the battery, I whittled away some extra plastic so that the hold-down bracket would fit snug. I just used a razor blade for this work. Since this is a top post battery, I found some adapters at the local parts store that worked well for mounting my ring connectors.

I am very happy with this battery. The starter cranks much faster and the lights are less susceptible to dimming with engine speed. This upgrade was well worth the extra money and minor modifications.

Follow-up

I do not recommend the use of any flooded wet cell battery.