BMS for DIY motorcycle starter battery.
- Thread starter Istria
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reg
Winter: New York City Summer: Atlantic Canada
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Thanks for the info. I expect to speak with RELiON in the next while. I'd like to get clarification on this, in particular in relation to bikes.
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The discussion got my interest in what's the starting current of my Yamaha XT225.
This is a scope plot of starter current. Vertical scale is 50A/div. Horizontal scale is 100 ms/div. When the starter is engaged we see an initial short circuit current spike of about 250A. Within 20 ms the initial spike reduces to 50A. Peak cranking current is about 75A.
The Yuasa battery (YTZ7S) is rated at 6.3AH, 130 CCA
This is a scope plot of starter current. Vertical scale is 50A/div. Horizontal scale is 100 ms/div. When the starter is engaged we see an initial short circuit current spike of about 250A. Within 20 ms the initial spike reduces to 50A. Peak cranking current is about 75A.
The Yuasa battery (YTZ7S) is rated at 6.3AH, 130 CCA
reg
Winter: New York City Summer: Atlantic Canada
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I use a Yuasa battery with my Moto Guzzi V7, but different rating. When I purchased a LiFeMgPO4 battery recently, one of the first things that I figured out was that my Yuasa 1 amp charger wasn't going to cut it. Got a Victron IP65 10 amp. I like slow charging AGM bike batteries, so I probably won't use the Victron for that.
I'd love to try an electric dual-sport. They must be crazy responsive.
Very positive 2019 review of your Yamaha dual-sport:
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Zwy
Solar Wizard
How would you know what I'm buying?I ride motorcycles, which means that for me, unlike you, this isn't a theoretical discussion. I guess you won't be buying an electric motorcycle, such as the highly regarded bikes made by Zero, one of which is in my future. Yes, temperature has to be taken into account. So? By the way, how cold do you think it gets in Sicily
View attachment 45103
Now, an electric motorcycle, bicycle or EV is different than using a Li-Ion or LFP battery for starting an ICE. You're forgetting one other aspect of the whole idea, charging system. You need to replenish electrons.
Go for it, I have better things to do with my time than attempting some things which really don't make sense economically, mechanically and electrical.
First Google result:
LITHIUM STARTER BATTERIES
Lithium Batteries with New RE-START (built-in jump-starting) for motorcycles, powersports, cars. Special sizing for Race, Customs. Special Voltage 6V & 16V.
antigravitybatteries.com
Tiktaalik
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Yes I am familiar with them and I have talked to them also. It’s the only battery of its kind on the US market.First Google result:
LITHIUM STARTER BATTERIES
Lithium Batteries with New RE-START (built-in jump-starting) for motorcycles, powersports, cars. Special sizing for Race, Customs. Special Voltage 6V & 16V.
Counting DCS from Australia, that makes two brands who make automotive starter lithium batteries.
Is that it? Any other brands out there?
Zwy
Solar Wizard
So, I click on the description for the batteries and in one part it states Li-Ion, another states LFP. Have to wonder just exactly which one.First Google result:
LITHIUM STARTER BATTERIES
Lithium Batteries with New RE-START (built-in jump-starting) for motorcycles, powersports, cars. Special sizing for Race, Customs. Special Voltage 6V & 16V.
Hedges
I See Electromagnetic Fields!
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Here's a LiFePO4 battery to deliver up to 450A for starting an engine:
www.harborfreight.com
I haven't tried it alone, but I did jump start someone's van it it.
As packaged, a bit inconvenient for your application. There is a sequence of turning it on and pushing another button to get it ready for jump-starting. It turns off after a while.
Obviously you wouldn't have BMS carry starting current (although this one does that, together with reverse-polarity detection.) Just supply starter solenoid from BMS.
For car alternators, they say, "Do not disconnect alternator to 'test' it." What will your motorcycle alternator do if BMS disconnects battery?
How will you deal with freezing weather when battery can't take charging? (There are other more expensive chemistries tolerant of freezing.)
My old bike has no regulator, just a permanent magnet alternator and rectifier. Battery over-charging is the regulator, and alternator windings are switched in when lights are enabled. I put in an AGM battery and build a shunt regulator.
450 Peak Amp Portable Lithium Ion Jump Starter and Power Pack
Amazing deals on this 450A Jump Starter And Li-Ion Power Pack at Harbor Freight. Quality tools & low prices.
www.harborfreight.com
I haven't tried it alone, but I did jump start someone's van it it.
As packaged, a bit inconvenient for your application. There is a sequence of turning it on and pushing another button to get it ready for jump-starting. It turns off after a while.
Obviously you wouldn't have BMS carry starting current (although this one does that, together with reverse-polarity detection.) Just supply starter solenoid from BMS.
For car alternators, they say, "Do not disconnect alternator to 'test' it." What will your motorcycle alternator do if BMS disconnects battery?
How will you deal with freezing weather when battery can't take charging? (There are other more expensive chemistries tolerant of freezing.)
My old bike has no regulator, just a permanent magnet alternator and rectifier. Battery over-charging is the regulator, and alternator windings are switched in when lights are enabled. I put in an AGM battery and build a shunt regulator.
Ok, here's the deal - precisely because of threads like this. And I ride with LFP (or at least did).
Step 1: Commercially, you pick an LFP starter bat based on a totally fake spec called Pb/Eq. You choose your new lfp battery to match what the oem bike manufacturer called for in lead acid. Forget CCA's and all that.
(If you are diy'ing, then you must use high-rate cells like non-counterfeit Headways, A123's, anything "nanophosphate" and the like) Cells from inside a Miady battery are straight out.
Step 2: The smart ones - if they have the space and budget - will +1 it in size and step to the next size larger - or as large as will fit in the battery bay.
Step 3: Don't leave loads on for hours. These cells are very high-rate, but low in capacity if you look at it from the normal C/20 standpoint.
CHARGER: Don't mess around. Many of these batteries don't have a bms, or if they do, understandably don't do balancing. Yes, the Shorai's have an external balancing port if you want to do that.
So how do you balance these naked batts? With a Tecmate-Optimate Lithium (LFP) charger.
This is the 5A version. They also have a 10A version. Wish they made them even larger!
tecmate.com
Yeah right - how?
@snoobler might dig this:
Tecmate-Optimates don't run a standard CC/CV. Instead of a steady CV, they pulse it. Don't go nuts - I'm not talking about desulphation right now. Just the charge profile. Not fast enough like a true PWM, nor slow like a hysteresis. Put an AM radio next to it, and you can hear the differences. Or watch your voltmeter bounce.
The way that works is that during the rise-time of the pulse, more energy is able to make it into the lagging cells just prior to the unbalanced overall "pack voltage" CV limit is reached where current input is very low - and ineffective at balancing on a series-connected pack-level.
As the leading edge of each pulse more or less "sneaks in" a charge to lagging cells, they balance out. Is it a perfect balance? NO. But it gets you into the ballpark.
The other part of the game is one of DUTY CYCLE protection:
By pulsing, when cells go high, they are not held at that high state of charge long as the leading edge sneaks in a charge.
This actually works for BOTH chemistries such as LFP or AGM. In the case of agm (which I did long before LFP arrived), pulsing the CV when the agm's cells were badly balanced internally, when one cell goes high, it doesn't immediately gas-out! So same kind of reason for LFP (minus any gassing obviously) using the pulsing CV - duty cycle protection.
I'm a HUGE fan of Tecmate-Optimate. But I won't go into all the other stuff they do unless asked. Like temperature checks so as not to charge when it is freezing. There's more, but I'll stop. Their marketing is cute, but I got to talk to engineers years back.
Seems like any mention of a high-priced British designed Optimates goes haywire fast with cheaper alternatives, but this thread caught my attention.
Step 1: Commercially, you pick an LFP starter bat based on a totally fake spec called Pb/Eq. You choose your new lfp battery to match what the oem bike manufacturer called for in lead acid. Forget CCA's and all that.
(If you are diy'ing, then you must use high-rate cells like non-counterfeit Headways, A123's, anything "nanophosphate" and the like) Cells from inside a Miady battery are straight out.
Step 2: The smart ones - if they have the space and budget - will +1 it in size and step to the next size larger - or as large as will fit in the battery bay.
Step 3: Don't leave loads on for hours. These cells are very high-rate, but low in capacity if you look at it from the normal C/20 standpoint.
CHARGER: Don't mess around. Many of these batteries don't have a bms, or if they do, understandably don't do balancing. Yes, the Shorai's have an external balancing port if you want to do that.
So how do you balance these naked batts? With a Tecmate-Optimate Lithium (LFP) charger.
This is the 5A version. They also have a 10A version. Wish they made them even larger!
TecMate – OptiMATE Lithium 4s 5A
tecmate.com
Yeah right - how?
@snoobler might dig this:
Tecmate-Optimates don't run a standard CC/CV. Instead of a steady CV, they pulse it. Don't go nuts - I'm not talking about desulphation right now. Just the charge profile. Not fast enough like a true PWM, nor slow like a hysteresis. Put an AM radio next to it, and you can hear the differences. Or watch your voltmeter bounce.
The way that works is that during the rise-time of the pulse, more energy is able to make it into the lagging cells just prior to the unbalanced overall "pack voltage" CV limit is reached where current input is very low - and ineffective at balancing on a series-connected pack-level.
As the leading edge of each pulse more or less "sneaks in" a charge to lagging cells, they balance out. Is it a perfect balance? NO. But it gets you into the ballpark.
The other part of the game is one of DUTY CYCLE protection:
By pulsing, when cells go high, they are not held at that high state of charge long as the leading edge sneaks in a charge.
This actually works for BOTH chemistries such as LFP or AGM. In the case of agm (which I did long before LFP arrived), pulsing the CV when the agm's cells were badly balanced internally, when one cell goes high, it doesn't immediately gas-out! So same kind of reason for LFP (minus any gassing obviously) using the pulsing CV - duty cycle protection.
I'm a HUGE fan of Tecmate-Optimate. But I won't go into all the other stuff they do unless asked. Like temperature checks so as not to charge when it is freezing. There's more, but I'll stop. Their marketing is cute, but I got to talk to engineers years back.
Seems like any mention of a high-priced British designed Optimates goes haywire fast with cheaper alternatives, but this thread caught my attention.
Lurkers: Don't go cross-application crazy thinking this pulsed-CV is a replacement for a true balance!
This strategy was originally aimed at small cell-count batteries like 6-cell agm's. Or small 4s1p maybe 4s2p LFP batteries.
The more actual cells you have, the easier it is for a lagging cell to "hide". This would be the case with huge prismatics. One attempt with my general purpose GBS prismatic bank, and yeah, gonna' leave the CV/Pulse technique to small cell-count batts.
This strategy was originally aimed at small cell-count batteries like 6-cell agm's. Or small 4s1p maybe 4s2p LFP batteries.
The more actual cells you have, the easier it is for a lagging cell to "hide". This would be the case with huge prismatics. One attempt with my general purpose GBS prismatic bank, and yeah, gonna' leave the CV/Pulse technique to small cell-count batts.
Currently looking at this myself - for cars though (<2L turbo, low compression). A lot of people have done it.
The way i'm thinking is you need 2 positive terminals - 1 goes to the starter, 1 goes to the rest of the car.
The starter +ve bypasses the BMS (fuse to manage risk)
The car +ve has all the usual & the BMS - so you can use a regular 100A BMS to charge/discharge, balance & manage.
But you need a BMS that interrupts the +ve & not the negative, cant find one of those.
The way i'm thinking is you need 2 positive terminals - 1 goes to the starter, 1 goes to the rest of the car.
The starter +ve bypasses the BMS (fuse to manage risk)
The car +ve has all the usual & the BMS - so you can use a regular 100A BMS to charge/discharge, balance & manage.
But you need a BMS that interrupts the +ve & not the negative, cant find one of those.
I have recently made the proposed battery. 4x 32700 liitokala LFP cells 6500mAh.
I decided not to use a BMS for this battery for now, because I am going to use it as an experimental battery. I might add a BMS for it later. Until then, I will charge and discharge it with care while experimenting.
I decided not to use a BMS for this battery for now, because I am going to use it as an experimental battery. I might add a BMS for it later. Until then, I will charge and discharge it with care while experimenting.
Lithiummoto
New Member
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- Jan 2, 2022
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- 5
Well, if this thread is still active, and why would'nt it be ??
Let me just say, I've been making LFP starter batteries for 10 yrs now, so, what ever needs starting, I can do it.
Naturally, its going to cost you more than if u do it yourself, but, thats not the issue here as people didnt know where to get something made.
The link is to me; lithiummoto.com
I'm in florida but, can ship worldwide.
not selling, just telling.
contact me if you are in need.
Let me just say, I've been making LFP starter batteries for 10 yrs now, so, what ever needs starting, I can do it.
Naturally, its going to cost you more than if u do it yourself, but, thats not the issue here as people didnt know where to get something made.
The link is to me; lithiummoto.com
I'm in florida but, can ship worldwide.
not selling, just telling.
contact me if you are in need.
Attachments
For even more fun, follow this thread from our friends over at ADVRIDER starting in 2012 by _cy_ and STILL going!
www.advrider.com
For you battery nerds, you'll note that _cy_ was also part of the gang over at CandlePower Forum, who with a small band of enthusiasts, got manufacturers to make "protected" cell boards on their cylindricals to be a now-standard addition. Real lithium-battery nerd history.
Motorcycle Batteries .. AGM, GEL, Wet, Lithium Iron Phosphate (LiFePO4)
Motorcycle Batteries .. AGM, GEL, Wet, Lithium Iron Phosphate (LiFePO4) Let's examine the most popular battery types, how to charge, advantages,...
www.advrider.com
For you battery nerds, you'll note that _cy_ was also part of the gang over at CandlePower Forum, who with a small band of enthusiasts, got manufacturers to make "protected" cell boards on their cylindricals to be a now-standard addition. Real lithium-battery nerd history.
Playing devils advocate...
The only thing you have told us is that you have a business & that you can do it. You have not contributed knowledge or insight into the conversation or challenges. IMO it is a marketing post.
Lithiummoto
New Member
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- Jan 2, 2022
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ok, sorry for not saying what should be readily apparent after years of lithium starting batteries being used.
BMS's should be used, LFP is safe, YEs, hi C rated cells are out there, yes, u can make your own, everything can be had on alibaba if u look long enough. I guess its better for someone ELSE to mention your name . But, no one knows my name, so.....what do i do ?
I doubt anyone would be interested anyway as most here "just cluck their thick tongues and suggest oh so very delicately when they link to other sites that do the same thing...., oops, I'm quoting Anthony Perkins... hmm, If anyone has a legitimate question, i can answer it. ok, i promise not to sell to anyone on this forum.
BMS's should be used, LFP is safe, YEs, hi C rated cells are out there, yes, u can make your own, everything can be had on alibaba if u look long enough. I guess its better for someone ELSE to mention your name . But, no one knows my name, so.....what do i do ?
I doubt anyone would be interested anyway as most here "just cluck their thick tongues and suggest oh so very delicately when they link to other sites that do the same thing...., oops, I'm quoting Anthony Perkins... hmm, If anyone has a legitimate question, i can answer it. ok, i promise not to sell to anyone on this forum.
Ha! common sense anyone?
In terms of Hi-C rated LFP, is there specific packaging that the industry is going towards?
i.e. Pouch cells are where its at for starting & have a good track record, some prismatics are *starting* to emerge - but no long term data.
Also what I find fascinating are the design issues with the application - vibration is INSANE as wearing & killing all sorts of components, casings, capacitors. Is there anything from a safety perspective that you see as a challenge/issue?
