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02-14-2018, 09:06 PM | #1 |
Not Yet Wild
Join Date: Sep 2015
Posts: 25
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Regen braking with lithium-ion batteries
I can’t wrap my head around this one. I am installing 14 cell lithium ion battery (Nissan leaf battery) into my Yamaha G29 Drive. I’ve got an Altrax controller in the cart, upgraded solenoid and much heavier wires. Is it safe to have the regenative brakes on or should I turn them off? Can the single trans brake handle all the weight while braking? I know the batteries need to be balanced while charging and I am installing a battery managent system. I just can’t get the regen into my head. Just looking for some insight from anyone that has a setup like this. Thanks.
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02-15-2018, 10:18 AM | #2 |
Gone Wild
Join Date: Jan 2017
Location: Miami, FL
Posts: 1,061
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Re: Regen braking with lithium-ion batteries
I have regen enabled on my cart with a leaf pack. No issues. I think that since regen doesn’t really add all that much power back to the pack it’s a non-issue from a cell balancing perspective. I’m not a Yamaha guy, but would venture to guess that with the substantial weight reduction of the lithium pack, your trans brake should be fine.
PingEye3 has done quite a few lithium conversions on Yamaha carts at his club so he would be able give you the best info on the subject. Sent from my iPhone using Tapatalk |
02-15-2018, 10:59 AM | #3 |
Over This Interview Is...
Join Date: Jun 2012
Location: AZ
Posts: 17,449
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Re: Regen braking with lithium-ion batteries
It's fine, even with the Rxv, which uses tons of regen braking. A typical allowable charge rate on lithium cells is up to 3C intermittent, in a 100ah pack, that would mean it can briefly absorb power at a rate of 300 amps. I don't know the specs on the leaf cells tho. As long as your bms provides over voltage protection, you are fine.
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02-15-2018, 11:02 AM | #4 |
Gone Wild
Join Date: Sep 2012
Location: Charlotte, NC
Posts: 9,329
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Re: Regen braking with lithium-ion batteries
This would actually be an interesting question for Alltrax engineers that perhaps one of the dealers can ask.
Does the Alltrax controller "Overvoltage" limit applies during Regen? The problem with most BMS is that they are designed to disable the charger in case of overcharging, not stop the Controller from operating. Alltrax has a setting on their BMS section for "Overvoltage Protection in Case their BMS communication is Lost" that would seem redundant if the Controller was already monitoring the Overvoltage based on the regular setting. In either case I think the maximum charging current for the Leaf batteries is 120 amps, so I would limit the "Max Battery Regen current" to 120 amps. |
02-15-2018, 11:19 AM | #5 |
Not Yet Wild
Join Date: Sep 2015
Posts: 25
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Re: Regen braking with lithium-ion batteries
That you everyone for the responses. It seems like most people agree it shouldn’t an issue. The cart doesn’t run in regen very long ever. Short burst. And setting the max regen below 120 amps make seems too. I didn’t thank of that. Thanks again for he info.
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03-06-2018, 06:10 PM | #6 |
Gone Wild
Join Date: Jul 2017
Location: West Columbia Texas
Posts: 1,036
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Re: Regen braking with lithium-ion batteries
Have you picked a BMS and or charger yet?
I just bought my leaf cells today and I'm still back and forth with ZEVA about their new BMS16 v2 it comes out in 2-3 weeks. I'm having a hard time getting responses from TC charger though. I was given a quote but no one that wants to bill and ship me the charger :-/ |
03-10-2018, 05:36 PM | #7 |
Not Yet Wild
Join Date: Sep 2015
Posts: 25
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Re: Regen braking with lithium-ion batteries
I broke down and bought a chargery.com BMS. It was pricy comparing to a lot of other systems but I’m really happy with how it is working. It has a lot of functions and I haven’t even begun to get into everything yet.
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03-10-2018, 10:06 PM | #8 |
Gone Wild
Join Date: Jan 2017
Location: Miami, FL
Posts: 1,061
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Re: Regen braking with lithium-ion batteries
Dope looking setup
Sent from my iPhone using Tapatalk |
08-11-2018, 08:07 AM | #9 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: Regen braking with lithium-ion batteries
You still like the Chargery? I just ordered one for my 14S. I bought it specifically because I could pick the over voltage and balance voltage start and I want to never charge the pack to FULL voltage.
Any advise for stuff to watch for on the Chargery? |
08-12-2018, 11:56 PM | #10 |
Gone Wild
Join Date: Jan 2013
Location: Saint Petersburg, FL
Posts: 2,089
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Re: Regen braking with lithium-ion batteries
And the OP asked about regen. I set my max regen amps to somewhat less than 2C. The lithium batteries should handle 3C charge current. With the weight reduction, my little 75 amp regen is akin to standing on the drum brakes... I like it a lot and happy to be refilling my pack!
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