12v Battery Recommendations

[gregwils]

I have opted to convert my electrical system to 12v. I installed a 120W alternator from Lacey a few years ago, but did not convert it to 12v. I need to purchase a 12v battery - already have the coil . I was thinking I would get a higher quality AGM, but not certain about the physical size. I was curious if anyone had a recommendation. Thanks.

[gregwils]

After a little research, I think I am going to go with a Yuasa YB14A-A1. It's not an AGM, but the dimensions are pretty much the same, 14 Amps, same terminal type. The positive post is on the same side as the negative, where with the original spec battery the posts are on opposite corners.

I haven't made the purchase, so if anyone has a better suggestions, I would appreciate you sharing. Thanks.

[ducwiz]

See my post from 2014: http://www.motoscrubs.com/forum/viewtopic.php?f=3&t=1723&p=12614&hilit=yuasa#p12614

But: for me, an AGM battery seems the better choice, because it has a near-zero self-discharging rate. For the same reason, I also recommend a LiFePO4 (= LFP) Lithium type. You can store these batteries without charging for many months, and they still keep 80-90 % of their capacity. This is not possible with a lead-acid battery, standard or gel type, which you have to re-charge every 4-6 weeks. The LFP has further advantages in particular:

- it is very light, only ~30% of a lead-acid batt. comparable in size
- the nominal Ah capacity can be much smaller, as ~90% of the stored energy can be used at the nominal voltage; in case of lead-acid it's ~40% only

Hans

[gregwils]

Thanks Hans. I would love to use a lithium battery, but am running a RR163 Electrex R/R and Electrex's website states "Our regulator/rectifiers MUST NOT be used with Lithium-ion batteries". I am not sure what is unique about the R/R, but I don't have the background to feel comfortable deviating from the mfg's recommendatoin.

[ranton_rambler]

My 175 has an Exide ETX7L, which is 6Ah capacity. It’s an AGM battery running with Electrex reg-rec. I am told that Lithium batteries have very specific charging requirements which the Electrex units can’t provide.
I don’t recall there being very much choice in smallish 12V batteries when I was looking.

[LaceyDucati]

Hi

The most used 12v lead acid battery in Ducati singles is the Yamaha RD400 battery which is a perfect fit in the standard rubber tray, 12N5.5A-3B. I use a YTX7L-BS in my Mk3 which fits the original rubber tray and just needs something like a 20mm spacer on the side to position and secure the position in the tray. The YTX battery is black and the stickers often peal off leaving them looking fairly period from a distance. Lead acid batteries take more abuse and are cheaper, I just like to keep things simple.

Regards

Nigel

[ranton_rambler]

I think your YTX7L will be the same size as mine. A bit smaller than the original 6V battery I think.
I never got round to sorting the proper strap so it’s got some cable ties holding it down.
As I have plenty of time at the moment (being furloughed from work) I suppose I could do it.
Ian

[ducwiz]

Thanks Hans. I would love to use a lithium battery, but am running a RR163 Electrex R/R and Electrex's website states "Our regulator/rectifiers MUST NOT be used with Lithium-ion batteries". I am not sure what is unique about the R/R, but I don't have the background to feel comfortable deviating from the mfg's recommendatoin.

About lithium-ion batteries:
Different chemistries for lithium-ion batteries exist, see https://www.mpoweruk.com/lithiumS.htm. Misconceptions and incomplete or even false informations about the different battery types are present on the internet. A clear distinction has to be made, especially between the Li-ion types used in laptop computers, moble phones etc., and the LFP battery (see bthe following).
The only type we can use as a 1:1 replacement for the usual lead-acid types (FLA, SLA, AGM) ist the Lithium-Iron-Phosphate / LiFePO4 or LFP battery. It has a cell voltage of 3.2 volts. All other Li-Ion batteries feature 3.6 - 3.7 volts, hence cannot be used in automotive vehicles with their 6 or 12 volt power systems without severe modifications.
Comprehensive comparisons of lead-acid and LFP batteries are given here


here
https://www.gliderpilotshop.com/lfp_vs_lead_acid?___store=glider_en
and here
https://www.batterycontroller.co.uk/pages/comparativa-batterie-lifepo4-li-ion-e-piombo-acido

The japanese Shido company https://www.afam.com/en/electricity/shido-lithium-ion-batteries/ offers many 12 volt LFP batteries, i. e. https://www.tayna.co.uk/motorcycle-batteries/shido/?ordering=Price-Asc&A-29=1.6,2.4

Hans

[gregwils]

Wow, thank you again Hans. A wealth of information in the charts and links, more reading to do. Thank you Nigel and Ian too.

[ducwiz]

Finally, I must make three important remarks:

- LFP batteries do not like overvoltage, see https://www.landportbv.com/en/brands/landport/landport-lfp-lithium/. Hence, your bike's voltage regulator should be a precise one and in good condition. It would be unwise to run an LFP battery in a n/c model with the old "black brick" R-R. This might lead to destruction.
- modern "smart" battery chargers often have a "desulfation" or "revitalization" mode. Here, voltage pulses much higher than 15 Volt are applied to the battery. This most likely will also harm the battery. Check your charger if it has this mode and deselect it, or use a simpler device.
- LFP batteries are irreversibly damaged when discharged below ~10 Volt, so take care to keep them in an appropriate charge state.

Hans

EDIT: Just found this page: https://www.boschautoparts.com/en/powersport/batteries/lihium-ion-batteries
It gives a lot of useful info about their LFP battery, series but at the same time is an example of very bad merketing and desinformation of customers: They do not even mention "LiFePO4" at least once !