How to Protect Your Controller from In rush Current | Pre-Charge Resistor Install

Hey everyone. In today's video we are going to be looking at failures caused by in-rush current and how to prevent them with pre-charge resistors!
Pre-charge resistor we sell: emotobros.com/...
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Website: emotobros.com
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[@PeaceChanel]

Thank You for All that you are doing for our Planet Earth.... Peace.. Shalom.. Salam.. Namaste .. 🙏🏻 😊 ✌ ☮ ❤ 🕊

[@KyleGotSkill]

IF you just bought a Chi 72v battery please watch this! If you do not you will blow up your controller. I know, I did it and E-Moto Bros helped me with this exact issue. You guys helped me with this exact issue/fix when the battery company would not. I've had zero issues since I did this configuration. You guys were very helpful in your emails and I felt like you guys actually cared about the issue. You guys already updated your site with this video as well. the Battery company still hasn't updated their website with any warnings about this issue, assuming that would mean they take some responsibility. Either way huge thanks and props to you guys for the fast turnaround on the replacement controller. I will always be a customer of E-Moto bros!

[@Danielxperez14]

Seriously! I have stock battery with no bypass and mine had this issue, they sent a new one out this week and I’m so excited to start riding again! Their customer support is 5/5 unmatched!

[@kchortu]

PUT A SWITCH IN THE RESISTOR LINE. If you put a momentary switch that is normally open so all you have to do is push it then when you let go it takes that resistor out of the circuit

[@permanentlypatriotic]

Can this be installed if you have a breaker delete? My CHI battery has a QS8 connector which bypasses the breaker.

[@jonlock7150]

Have you had any issues? I had to delete my breaker also

[@permanentlypatriotic]

not a single one. works great!@@jonlock7150

[@kyleerhard9284]

I have been running no breaker Qs8 plug with zero issues for about 3 months now. ( 72v 38ah, compact with bac 400p

[@JJ-nq7pg]

Have you had any controller failures without this mod being added thanks

[@gigabane7357]

I am new to all of this and am actually looking at protecting my solar array but my mind wanders all over to get full comprehension. If you do this to bypass the breaker, does that not mean that there is now constantly power going to the bike? just not high powered. is it enough power to actually make the bike move by accident?

[@surronzak8154]

Thanks a lot for telling us

[@lr7974]

Just an opinion but you should probably have an inline fuse on the resistor line that takes a carfuse. not only will it protect things with a short on that wire but also blow if someone tries to pull a lot of current on that wire if they didn't turn on their breaker.

[@emotobros]

I think that is a very good suggestion. I would recommend using a high rated slowblow fuse though to ensure current spikes from first connection don't blow the fuse frequently under normal operation.

[@jrwrenchmore4096]

Would a 5A 250v slow blow be sufficient? I have installed the resistor and would like to add a fuse for piece of mind but am not sure what fuse to run. Thanks.

[@Danielxperez14]

Do you recommend I do this with my stock battery? I want to save up for a aftermarket battery but probably not this year

[@Overmotor]

You mentioned that some batteries have a soft start function. I have an EBMX 72v 57ah. Do the EBMX brands have that function built in that you know of?

[@emotobros]

I believe that EBMX batteries is what ASI used to intially determine this was an issue so I'd guess that they do not have the feature or at the very least isn't setup. I'd note that we do see less issues with that battery in comparison to CHI as far as which causes this issue more.

[@Overmotor]

@@emotobros Good to know! You guys are lifesavers and if a $10 device & 20 minute install will help preserve my BAC4000 then that's worth it to me!

[@sagesends]

Have you guys had problems with your breakers melting? The OEM breaker is rated for 100 amps but with 12kW plus we're way over that. mine melted completely so i deleted it (yes, i know that's sus, but im sure if i put another one in it will just melt again)

[@fezdlix9709]

What the most amps you can run on a stock breaker?

[@fearlegit2858]

Do you guys have the link to this product? (The one I found was sold out)

[@lithiumbizkit]

Is this an issue with KO Nano + Chi 60v51ah with QS8 + breaker delete?

[@emotobros]

Inrush current is bad for all systems from all manufacturers so I'd imagine it's likely not good for the KO Nano. That being said, I'm unsure if this is a common issue with KO products or not.

[@surronzak8154]

isn't there a way to use that with a qs8 anti spark ? As the circuit breaker is a curent bottle neck and takes room, would need 2 connectors for the bike, 1 QS8 and one to plug first with this device. I never switch the breaker of, only keys so my controler capacitors are always full ? I have the QS8 lines ready to install.

[@surronzak8154]

I think I figured it out, do I just need to put this device on the plus before the controler in a connector and one negative wire from negative controler to the connector, and 2 smal wires on the battery + and - to the connector, connect précharger first and then QS8 . Good so ?

[@emotobros]

You should not ever remove the breaker. It is a needed component for safety. In the case of a fail-short the connector could weld itself together and you will not be able to disconnect the battery without the breaker. Additionally, the QS-8 is not a replacement for a pre-charge circuit or a breaker.

[@slingman1981]

cant reach your merch site

[@crankysloth1833]

So this just makes a battery bypass more safe?

[@emotobros]

Yes and no. It makes a bypassed battery more safe for your controller. Indirectly, this increases the overall safety of your controller by reducing the liklihood of the controller failing short with a bypassed battery hooked up. A bypassed battery still does not have overcurrent or undervoltage protection though so if a short still occurs there is nothing to stop it.

[@jakeonthelake2114]

Is it an option to include this in a setup with qs8 connections and no breaker? I have a battery on the way with qs8 connection and now I’m unsure if that was the best option to choose.

[@surronzak8154]

I think so, but you will have 2 connectors, 1 QS8 and a small one for this device

[@lr7974]

This only works with a breaker in place. Without it when you connect the qs8 which is always on. With a breaker in place when you connect the path via the resistor will slowly charge your caps and bring your controller up to working voltage then when you throw the breaker the current starts to flow through the main path

[@jakeonthelake2114]

@@lr7974 that’s what I kind of figured. So aside from purchasing a breaker that takes a little more amps to pop and installing it im going to have to leave my computer unprotected for the time being?

[@lithiumbizkit]

Same situation here. I have a 60v51ah compact from Chi with QS8 coming and a little worried about running it on my KO Nano controller. Remove breaker and the QS8 is antispark. Still a little nervous about no longer having a breaker.

[@jakeonthelake2114]

@@lithiumbizkit I’m more concerned about not having protection from the in rush current provided by the bms. May just have to purchase a larger breaker

[@woodser1765]

Question is why ASI does not have this protection already?

[@BM-zm1jl]

He explained it in the video

[@motocrisis]

Not sure if it’s possible for the controller to provide that type of protection. The resistor is bypassing the circuit breaker thus allowing a trickle of power from the battery to charge the capacitors in the short amount of time between connecting the battery to the bike and flipping the breaker to the ‘on’ position.

[@emotobros]

It is not standard to implement a precharge circuit into a DC controller or inverter. In applications using lithium batteries a BMS should always be used. To be clear, a BMS serves this function in addition to overcurrent and undervoltage protection as well. Some BMSs to not have a precharge circuit as not all are built equal. The battery is the best candidate for protections becuase it is the energy source itself and would cover anything downstream. In order to save space for more cells and have a higher output at lower cost companies like Chi batteries have decided cut this out. The real question that should be asked is why battery manufacturers would prioritize battery capacity/output over neccessary safety features.

[@lr7974]

@@emotobros what battery bms’s have proper inrush/over current/over voltage/under voltage/temperature protections ? Does ebmx bms’s retain all the oem battery safety measures?

[@lr7974]

I just un bypassed a stock battery that someone screwed with. Unfortunately the bms has issues now I swapped in another bms and the battery looks ok but now I have to order an expensive bms to fix this battery. Not a fan of people bypassing bms’s