Can I charge three batteries (Creo main plus two extenders) simultaneously with two Y cables?
- Thread starter YoGe
- Start date
kahn
Well-Known Member
- Region
- USA
- City
- northWET washington
Very interesting question.
I guess you can either buy more Y cables and experiment or try finding a friend who has one to loan out.
Mine is available for a short borrow in Seattle!!!
Since there is some kind of electronic circuits in there somewhere which requires connections to both batteries or neither charges, I can imagine this might not work to trick those circuits. Obviously, this requires experimentation. I don't imagine it would harm anything but just not work.
Thanks for your kind offer. Unfortunately, I am way over on the other coast. I will send an inquiry in to Specialized. I'll let you know what they say.
Do I understand you correctly - if the Y cable is being used it MUST be plugged into both batteries; It cannot be used if I only want to charge up one battery at a particular time?
Thanks for your advice!
Do I understand you correctly - if the Y cable is being used it MUST be plugged into both batteries; It cannot be used if I only want to charge up one battery at a particular time?
Thanks for your advice!
rayray
Well-Known Member
- Region
- USA
Correct. The Y cable won’t work if plugged into only one battery. For anybody reading this who is unfamiliar with these cables though, it’s important to realize that the other end of the Y cable is plugged into the direct/single cable, so all you need to do is remove the Y and you’ll have a single.
I submitted an inquiry on the Specialized site. I'll post back here when I get a reply.
AHicks
Well-Known Member
- Region
- USA
- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
The charger is designed to shut down when the battery reaches a predetermined voltage. With 2 or 3 batteries hooked up, the charger is going to be looking at/monitoring the AVERAGE voltage of the 2 or 3 packs. That in mind, when this average voltage reaches the charger's shut off point, it's going to shut down.
So that "average voltage" in mind, let's consider a couple of scenarios. What would happen if one of these batteries had a bad cell, and the average voltage didn't get high enough for the charger to shut down?
What if you had 3 batteries on, with 2 of them very low, and the 3rd barely discharged?
A cold battery was brought in from outside and set up with 2 others at room temp....
What MIGHT allow a plan like this to work is if all of the batteries involved had high quality BMS systems in place.
Suit yourself, but I think this is a terrible plan.
So that "average voltage" in mind, let's consider a couple of scenarios. What would happen if one of these batteries had a bad cell, and the average voltage didn't get high enough for the charger to shut down?
What if you had 3 batteries on, with 2 of them very low, and the 3rd barely discharged?
A cold battery was brought in from outside and set up with 2 others at room temp....
What MIGHT allow a plan like this to work is if all of the batteries involved had high quality BMS systems in place.
Suit yourself, but I think this is a terrible plan.
Aren't all these factors just as relevant with 2 batteries as with 3? Are you saying I can't use the Y cable in its standard configuration (for 2 batteries) if my main battery is 25% down and the RE is 90% down? Or vice versa?
AHicks
Well-Known Member
- Region
- USA
- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Agree all factors are the same for 2 or 3 batteries. 3 batteries just aggravates (multiplies) the potential for trouble.
What are we really saving with this Y harness plan? The price of an additional charger?
What are we really saving with this Y harness plan? The price of an additional charger?
It's more for the convenience factor. So if I'm on a long-distance road trip, I can charge all three batteries simultaneously without having to lug 2 chargers along and without having to get up in the middle of the night to swap batteries. I want to wake up in the morning with all three batteries charged. But if it can't be done it can't be done.
I wasn't under the impression that charging worked as you describe it. I thought that each battery would be measuring its own charge and drawing power (or not) accordingly. The way you describe it sounds pretty dicey. I'm wondering how reliable the Y cable is going to be even with only 2 batteries. It sounds like to get maximum charge I should use the Y but then when it stops charging I need to yank the Y and then use the original cable to ensure both batteries are topped up?
fooferdoggie
Well-Known Member
right each battery will shut down when it is done the charger who knows? but the system as as the same with bosch you can change two batteries at the same time. but if you're charging on the bike the system charges each battery separately in stages till the last if I remember right. so it does not matter if they are the same capacity. I bet it's the same with yours. but that does not mean it would work with three.
AHicks
Well-Known Member
- Region
- USA
- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
My issue I suppose, is a basic mistrust of the BMS systems. That's me though. In the scenario where you are traveling with 2 batteries you know and trust you are likely going to be fine.
The scenario that scares me is the one where a pizza shop has 6 delivery bikes and they want to charge them all every night, including when the weather is bad (think below freezing temps for instance). They bring their batteries in to charge using 2 chargers and a combination of Y harnesses to do that (say 3 battteries per charger). That's a recipe for disaster I think....the one I was thinking of when responding earlier.... -Al
tomjasz
Well-Known Member
- Region
- USA
- City
- Minnesnowta
Small fanless chargers weigh very little. I have the feeling that trying 3 at once could be disastrous. I'd wait for an answer from a definitive source. I have two Satiators but always keep cheap fanless as backups and group charging. $10-$15 Aliexpress and Banggood.
Then there's Datex2
Biggamebikes
EXPENSIVE!!! COST MORRE THAN A SATIATOR. I'd buy batteries wth 5A charge capabilities and a Satiator...
https://www.facebook.com/DATEx2
docs.google.com
'Although it may seem simple, adding additional batteries to your eBike is a major challenge. Connecting eBike batteries in parallel, without the DATE Dx device, can be EXTREMELY dangerous. For example, if the batteries have different voltages, chemistry, and or state of charge you risk permanent damage or in extreme circumstances explosion or fire!
The DATE Dx solves this: You can now combine batteries that have different chemistries, voltages, outputs, and or state of charge. The device will manage everything and protect your ride.
The DATE Dx devices are weatherproof. You can place the device anywhere you wish. Ensure the device cannot be knocked or damaged while riding so avoid installing the device where this type of damage could occur."
Then there's Datex2
Biggamebikes
EXPENSIVE!!! COST MORRE THAN A SATIATOR. I'd buy batteries wth 5A charge capabilities and a Satiator...
https://www.facebook.com/DATEx2
𝐃𝐀𝐓𝐄𝐱𝟐 gets the 𝗕𝗘𝗦𝗧 𝐔𝐏𝐆𝐑𝐀𝐃𝐄𝐒 for your 𝐁𝐈𝐊𝐄. 🚀🚀Period.
𝐏𝐑𝐎𝐏𝐄𝐑 upgrades for your 𝐁𝐈𝐊𝐄! All the 𝐃𝐀𝐓𝐄𝐱𝟐 products come with 24/36 months premium warranty at 𝐏𝐄𝐀𝐂𝐄 𝐎𝐅 𝐌𝐈𝐍𝐃 All the 𝐃𝐀𝐓𝐄 𝐁𝐅𝐱 motors are 𝐃𝐀𝐓𝐄 𝐌𝐱𝟑 TEMP-protected out of the box The 𝐃𝐀𝐓𝐄 𝐌𝐱𝟐 is the optional but recommended way to visually show the controller's temp We are not just yet...
docs.google.com
'Although it may seem simple, adding additional batteries to your eBike is a major challenge. Connecting eBike batteries in parallel, without the DATE Dx device, can be EXTREMELY dangerous. For example, if the batteries have different voltages, chemistry, and or state of charge you risk permanent damage or in extreme circumstances explosion or fire!
The DATE Dx solves this: You can now combine batteries that have different chemistries, voltages, outputs, and or state of charge. The device will manage everything and protect your ride.
The DATE Dx devices are weatherproof. You can place the device anywhere you wish. Ensure the device cannot be knocked or damaged while riding so avoid installing the device where this type of damage could occur."
Last edited:
tomjasz
Well-Known Member
- Region
- USA
- City
- Minnesnowta
Thanks for the update
m@Robertson
Well-Known Member
- Region
- USA
The potential for consequences here are rather worse than has been discussed so far.
Anyone who has parallel'd two or more batteries together knows that, upon connecting the batteries together with your 'y', you must have all packs at about the same voltage. Like, within a half volt. Less if possible (your typical adjustable charger or lab power supply allows you to regulate to one 10th of a volt pretty easily).
Why is this? Because electricity flows in both directions across a connecting cable. When two batteries at different voltage levels are connected, the two will equalize voltage via the higher voltage pack flowing current into the other until the two are equalized. This happens instantly.
Think on how that might be a bad thing for just a sec
For sure you want to only use those cables exactly as Specialized says you can. They've thought these consequences thru and done something to mitigate them. Don't try to reinvent this wheel.
Anyone who has parallel'd two or more batteries together knows that, upon connecting the batteries together with your 'y', you must have all packs at about the same voltage. Like, within a half volt. Less if possible (your typical adjustable charger or lab power supply allows you to regulate to one 10th of a volt pretty easily).
Why is this? Because electricity flows in both directions across a connecting cable. When two batteries at different voltage levels are connected, the two will equalize voltage via the higher voltage pack flowing current into the other until the two are equalized. This happens instantly.
Think on how that might be a bad thing for just a sec
For sure you want to only use those cables exactly as Specialized says you can. They've thought these consequences thru and done something to mitigate them. Don't try to reinvent this wheel.
fooferdoggie
Well-Known Member
this is how simple systems work. but at least with bosch the batteries are not connected together. they are separate and the motor uses each one in turn like if I have a 100% battery and a 30% battery the motor will use the 100% battery till it gets to 30% then it will use each battery and switch off and keep them within 5% I think charging works the same if you have them on the bike or one charges then the other and they both charge at the same time the last percent.The potential for consequences here are rather worse than has been discussed so far.
Anyone who has parallel'd two or more batteries together knows that, upon connecting the batteries together with your 'y', you must have all packs at about the same voltage. Like, within a half volt. Less if possible (your typical adjustable charger or lab power supply allows you to regulate to one 10th of a volt pretty easily).
Why is this? Because electricity flows in both directions across a connecting cable. When two batteries at different voltage levels are connected, the two will equalize voltage via the higher voltage pack flowing current into the other until the two are equalized. This happens instantly.
Think on how that might be a bad thing for just a sec
For sure you want to only use those cables exactly as Specialized says you can. They've thought these consequences thru and done something to mitigate them. Don't try to reinvent this wheel.
I would have thought that my reaching out to Specialized to clarify the point, and reposting their advice here, would have made it abundantly clear that I am not trying to "reinvent the wheel". Just seeking information, and accepting the information as provided.
In case it has not been made clear: I intend to follow the advice I received from Specialized and I advocate everyone do the same.
Cheers!
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