12-14-2023, 01:53 PM | #1 |
Gone Wild
Join Date: Jul 2012
Posts: 527
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Controller High voltage cutoff preventing lithium conversion
I am converting a stealth 4x4 (basically a club car ds with a front differential attached to the rear motor gearbox) to lithium. I connected it up with a freshly built pack (uncharged prob. around 50% capacity) worked like a charm. I charged the 16s pack up to 3.6v per cell (lifepo4). The cart won't move. It is a series motor and the solenoid would click, but I got no movement. I couldn't figure out for the life of me what I had damaged. I decided to put the old whimpy FLA batteries that I was replacing back in. Cart ran fine.
The only thing I could think of was there must be a high voltage cut off in the controller that is preventing the lithiums from working when they are fully charged. I believe this to be a FSIP controller like this: https://www.cloudelectric.com/v/vspf...r%20manual.pdf There is no mention of a High voltage cutoff in the manual, but I can't figure out what else it could be. I discharged the battery back down to about 50% SOC, and the cart runs. I am currently slowly increasing my bms cell cut off and charging the pack and checking to see if the cart moves. I am trying to determine what voltage is the cutoff and I guess I will set my bms to disconnect from the charger prior to this voltage. 2 questions: 1. At what voltage would you consider the pack to be 85-90% charged? I don't want to lose a ton of capacity because of this. 2. I don't have a way to program this controller or change the high voltage cutoff setting (that I know of). Does anyone have advice as to how I could wire this or what I could do to make this work? Thanks! |
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12-14-2023, 04:03 PM | #2 |
Gone Wild
Join Date: Dec 2020
Location: Melbourne, Australia
Posts: 1,948
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Re: Controller High voltage cutoff preventing lithium conversion
A 48v controller should work up to 60v.
As low as 3.45v (55.2v) will get you above 99% SOC as long as you give the cells time to saturate once the charger transitions from CC to CV mode. Wait for the current to taper off to less than 10% of the CC current. Having said that, even if you charge to 3.6v (57.6v), which I don’t recommend BTW, the voltage will settle to 3.35v (53.6v) within an hour or so after the charger is removed. What is the battery voltage when the cart doesn’t run? |
12-15-2023, 08:17 AM | #3 | |
Gone Wild
Join Date: Jul 2012
Posts: 527
|
Re: Controller High voltage cutoff preventing lithium conversion
Quote:
How much performance would I loose leaving the cells at 3.4v /cell or maybe even slightly lower? What do you typically recommend the cell high voltage be set at? This controller is an oddball controller. I can't find any markings on it other than "Stealth 4x4" stamped in to the side. However it appears to be from my research an FSIP. I don't know what they would have set the high voltage cut off to, but I know with the curtis this could be adjusted in settings. I am wondering if someone (or maybe even the company stealth) lowered the high voltage cut off for some reason? I don't know, but I can't come up with any other reason the cart wouldn't work other than the voltage being too high. Thanks for helping! |
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12-15-2023, 08:21 AM | #4 |
Gone Wild
Join Date: Apr 2008
Location: Western NY
Posts: 2,298
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Re: Controller High voltage cutoff preventing lithium conversion
Most of the components ive found in 48v controllers like capacitors are actually rated for up to 63v this is of course changeable to less depending on limits set in the programming. by default many like curtis is a 20% variance from the nominal setting.
if its a series cart id look at replacing the controller with a 500a 1205m curtis clone... they can be bought on ebay for as little as $120 new shipped... ive used 2 so fa with no issues including the 72v version i just put in my cart. you can program them with a diy cable or a cable from amazon as well. |
12-15-2023, 08:40 AM | #5 |
Gone Wild
Join Date: Jul 2012
Posts: 527
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Re: Controller High voltage cutoff preventing lithium conversion
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12-15-2023, 08:44 AM | #6 | |
Gone Wild
Join Date: Apr 2008
Location: Western NY
Posts: 2,298
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Re: Controller High voltage cutoff preventing lithium conversion
Quote:
With my stock 36 volt motor running on 72 volts I should be able to do about 28 mph minimum increase |
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12-15-2023, 04:07 PM | #7 | |
Gone Wild
Join Date: Dec 2020
Location: Melbourne, Australia
Posts: 1,948
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Re: Controller High voltage cutoff preventing lithium conversion
Quote:
You will still get close to 100% with a 3.4v charge voltage. How are you going to limit the charge voltage? Is your charger adjustable or do you intend on lowering the protection settings in the BMS? The only way to do it correctly is to lower the charge voltage, NOT lower the protection settings. |
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12-16-2023, 03:45 AM | #8 | |
Gone Wild
Join Date: Jul 2012
Posts: 527
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Re: Controller High voltage cutoff preventing lithium conversion
Quote:
Thanks! |
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