Hey ya'll. Just another one here working on another GS500Cafe - Mod.
Wondering if any of you legends could help suggest/tell me what i could use for a replacement battery.
Im attempting to get something smaller that i can shelf away under the seat. I know some others have got a nice little tidy LITHIUM to stick under there. BUT im a compete rook when it comes to electricals and i've never replaced any batter in the past, so dont know where to start :confused:
Thanks in advance !
Max
You could use an
Antigravity Lithium battery. It contains a BMS (Battery Management System), so you don't have to know anything about electrics, apart from (+) positive terminal is Red and (-) negative terminal is Black. And you can mount it in any configuration - even upside down, not that you would want to do that.
The two models I would recommend are:
https://antigravitybatteries.com/products/starter-batteries/restart-oem/atz7-rs (https://antigravitybatteries.com/products/starter-batteries/restart-oem/atz7-rs) - $130
...and the more expensive but thinner: (2.25")
https://antigravitybatteries.com/products/starter-batteries/small-case/ag-801 (https://antigravitybatteries.com/products/starter-batteries/small-case/ag-801) - $180
NOTE: There may be thinner models. I didn't spend a lot of time comparing the various models.
Disclaimer for using Lithium batteries in motorcycles:
- Make sure that the engine is in good condition and starts easily. Due to the much smaller capacity, a Lithium battery won't stand up to the rigors of continuous cranking when trying to start a problem engine. Use a bigger capacity lead-acid battery for that task.
- Use only Lithium specific Motorsport Chargers to charge this battery! (No lead-acid chargers.)
Quote from: MaxyMax on December 23, 2020, 12:32:54 AM
Hey ya'll. Just another one here working on another GS500Cafe - Mod.
Max
Welcome! Pics please...
First of all thanks for taking the time to holla back.
Thanks for the clarification, here i was thinking i had to get the same battery , or a specific model for my bike.
But im getting the idea now , that a battery is a battery , pretty much ( as long as voltage is right ect )
as you said (+) & (-)
Definitely some good suggestions there .
i also read that a guy has been using UPG 85938 Ub1213 in his bike, said its pretty crap replaces it every year or so if he doesnt use his bike much. but said its really cheap and also small to fit in tight places.
So possible , another option there possibly . Not as good as a lith, but great on a budget
have been filming my build, will def show when i make a little more progress
LiFePO4 aka "lithium iron" (note the "r") batteries are roughly compatible with standard vehicle charging systems like in your GS and are much smaller for a given capacity than a lead acid battery.
BUT! There are a lot of other issues. These batteries are very bad at starting a vehicle when it's cold. I mean under about 50f. The usual recommendation is to let them headlight run for a minute before you start it so the battery warms up, which has the obvious downside of also draining the battery. This leads to the other big caveat. While they are typically safe to charge with normal vehicle charging systems, they require special care to get them to completely charge. A GS500 has a notoriously bad charging system to begin with, so even one in perfect condition will fail to charge a LiFePO4 battery more that about 90%, and then only when the bike is running over about 3k rpm. Of course if your charging system is in less than perfect condition, like a typical 20 year old motorcycle, then it will likely fail to charge a LiFePO4 more than maybe 75% or worse.
Sure some will tell you that new KTM motorcycles have LiFePO4 batteries and do fine but those are not 20 years old and we're designed specifically for those batteries. And KTM owners still complain about poor starting when cold.
Point of all of this is, changing battery chemistry is a real rabbit hole and will make the bike less reliable and likely require a lot more work than just swapping the battery. If it was a 250cc dual sport with a kick starter I might think it was a decent idea, or a show queen that wasn't likely to be used for transportation. This is my opinion after being stranded and having to carry a jump pack everywhere when I had a LiFePO4 battery on my GS with a well sorted charging system.
I've used a LiFePO4 battery for 3 months (before stripping the bike for mods) and have had no problems with the battery. On my bike, the BMS stops the charging process at 98% of full charge (14.55V). 100% full is at 14.6V for LiFePO4. I have battery measuring equipment for most battery chemistries, including LiFePO4 and I'm quite happy with a 98% charge as I think it's better for a battery to not be fully charged. However, according to the article linked below, a LiFePO4 battery can be safely overcharged to 4.2 volt per cell, which is 16.8V for 4-cell batteries, like the ones we use for motorcycles.
https://www.powerstream.com/LLLF.htm (https://www.powerstream.com/LLLF.htm)
Of course, one can measure the charge voltage of a GS500 rectifier/regulator. If I remember correctly, mine measured 14.6V. That means on my bike, a LiFePO4 will potentially be fully charged, depending on what the BMS cut-off is set to.
my fully functioning stock r/r put out 14.2v max at the battery terminals. I believe the range is 13.8-14.2 iirc. And that's with no dropping from terminal or wore corrosion, which is nearly impossible.
My mosfet r/r does 14.6v with uprated wiring and redundant connectors eliminated. Identical r/r in my Bonneville only does 14.4v. for regular batteries in most motorcycles 14v is more than enough but not for LiFePO4.
Quote from: mr72 on December 23, 2020, 01:52:07 PM
my fully functioning stock r/r put out 14.2v max at the battery terminals. I believe the range is 13.8-14.2 iirc.
Sounds like you've had some bad luck with Lithium Iron batteries and I can fully understand why you're feeling apprehensive about them. But my experience is the opposite, and just as well, because there is no turning back to Pb on my Street Tracker. I've removed the battery box and it just won't suit the ST style to have a bulky battery anymore. For that reason I made sure that the Lithium Iron battery was working fine before I started modifying my bike.
Referencing the link I've posted above:
A fully charged LiFePO4 cell is 3.6V (4-cell = 14.4V) and a fully depleted LiFePO4 cell is 2.5V (4-cell = 10.0V). From that I calculated that 14.2V represents about 95% charge and that is quite acceptable. Therefore the stock GS R/R voltage should be fine for keeping a LiFePO4 topped up while riding.
The only time that I can foresee problems is when a battery of too small capacity is being used. My battery is 3.8A/h and I would consider that to be on the small side, but I know about batteries and how to care for them - even the exotic chemistries like LiFePO4. I also have a LiFePO4 charger which I will use when the battery hasn't been used and charged for a while.
The reason I brought this up is to hopefully help others avoid making a frustrating mistake. LiFePO4 batteries can be fine or a motorcycle once you understand the risks and tradeoffs. But when someone is just choosing based purely on cosmetics of a smaller battery, I think more explanation is in order. Not everyone seriously thinks things through all the way. And I find GS500 owners to be more likely to need a reliable bike, more often using them for transportation without a ton of extra money to throw at them.
Let's be honest. A GS500 is not really the ideal candidate for a cafe build or restoration. Nobody seeks one out. Usually you wind up with one because it was cheap and available, then you start thinking you can turn it into a project. But rarely will someone plan a project and seek a GS500 as the basis for it.
But mostly the op claims to be inexperienced with electrics, which is not a great candidate for a LiFePO4 conversion. IMHO.
Sure, you had every right to point out the pitfalls and the op needed to be made aware of it. I fully agree that there would be cases where a LiFePO4 battery is not be a good substitute for a Pb battery. On the other hand, I think people should also hear about examples where it did work out well and not be put off by stories of doom and gloom.
You make a good argument that a GS500 is normally not the ideal donor bike for a cafe racer or restomod. However, judging by all the pictures of modified GS500's on the web, I'd say they are quite popular for exactly that, despite being a beginner's bike. Not everyone has the means to upgrade to a beter bike and would rather modify the bike that they already have. I chose to modify my current GS500F because I fell in love with the nimble handling and potential for upgrading when I still had my previous '89 GS500E.
Hopefully the op is now aware of the hazards and will make an informed decision regarding the battery.
I will add that it's fine to charge a lithium motorcycle battery with a conventional charger.
What you don't want to do is leave the charger on the battery in float mode because then you end up with a 20-30% charged battery.
So charge up and then promptly disconnect. (Or buy a lithium specific charger if you want to leave a charger connected)
Shorai's website will help you find a battery of comparable CCAs to the stock GS500 battery. It will obviously be smaller but will perform similar to what you are used to. Lithium batteries like the Shorai are superior in almost every way to other battery chemistries except in COLD WEATHER they are a PITA. They will work fine but you have to know how to warm them up. Turn the headlight on for 20 seconds before you hit the starter button.
Other than that they will outlast and outperform all other batteries. You can abuse them for years and years. You can crank on them until they seem dead, wait a few minutes and they will still have a few strong cranks left in them. Other battery chemistries get weaker as the voltage drops.
In the end I went back to sealed gel batteries because I don't have time to deal with the cold weather starting behavior when I'm late for work the 6 months out of the year its too cold to just hit start. And 3 lbs of battery isn't going to make any difference for my riding style.
If you have a heated garage, always keep the battery on a trickle charger, don't live in a climate that gets below 45 degrees Fahrenheit, or don't ride for transportation, the cold weather behavior of lithium motorcycle batteries will be a non-issue and will be the last battery you ever buy for the bike.
I wish I had been ablemto tolerate the LiFePO4 batt long enough to discover the upside. I put it in in November and got stranded so many times because it was cold, I gave up. With an LED headlight, it wouldn't warm the battery. And with carbs at time it takes more cranking than a less than perfectly charged battery can take. But my LiFePO4 was undersized...
Now, on my fuel injected Triumph it might work fine. Starts on like 1 turn every time. And the fuel pump would probably warm it up. But I just bought a new AGM for it. Why fix what's not broken?