Re: [electricboats] Electric Motor for 40ft Sailboat

Also very helpful to physically separate these 2 battery "banks" reducing the chance that one could touch BOTH + and – "hots" together.  My boat has 2 groups of modules forward and 2 groups aft, with one group port, one starboard, with the pack voltage nom. 42v (12s lithium ion, 700ah).  If I were to go 96v in this way, it would make sense to segregate the port modules

From the starboard modules and arrange as you describe.  There's no way one could physically reach ones arms across the boat to touch the -42v and +42v at the same time.  I could totally use the same chargers I currently use, just have one charger for each bank.  I have oodles of contactors that would suit.  About the only additional investment then for me would be a 96v motor and controller…and with my Briggs & Stratton ETEK brush motor now a veteran of 22 years (and 4 brush sets), I can see a time where this might be a happening!

 

Thanks.

 

www.evalbum.com/492

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Randy Cain via groups.io
Sent: Thursday, July 10, 2025 4:26 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Electric Motor for 40ft Sailboat

 

Yes, 96vdc can be bad stuff. The bipolar approach mitigates the danger. First, use an isolated system where neither the positive or negative rails are used as the ground (it's normal to have the negative rail connected to the ground in 12v, 24v, 36v and 48v systems). Then, make certain that both rails are disconnected by the disconnect switches, contactors and circuit breakers, not just one rail. Then, connect the midpoint of the battery as the ground reference and safety ground. A bipolar 96v system is then just as safe as a 48vdc system. 

Re: [electricboats] Electric Motor for 40ft Sailboat

Yes, 96vdc can be bad stuff. The bipolar approach mitigates the danger. First, use an isolated system where neither the positive or negative rails are used as the ground (it's normal to have the negative rail connected to the ground in 12v, 24v, 36v and 48v systems). Then, make certain that both rails are disconnected by the disconnect switches, contactors and circuit breakers, not just one rail. Then, connect the midpoint of the battery as the ground reference and safety ground. A bipolar 96v system is then just as safe as a 48vdc system. 

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Re: [electricboats] Electric Motor for 40ft Sailboat

In this case wiring safety compliance is absolutely paramount. 96v DC is absolutely lethal.

Also BMS contactors must also be safety type to assure welded contacts are mitigated. MOSFETs are much safer as their dominant failure mode is open circuit

Best regards

Lee Eldridge

0427874796

On 1 Jul 2025, at 21:05, Randy Cain via groups.io <randylcain=gmail.com@groups.io> wrote:



A single 96v charger works. The requirement to focus on is that it be isolated, that neither the positive or negative are connected to the case's safety ground. I use a Batrium BMS across the full 96v battery and it controls both positive and negative contactors (no mosfets). I also use active balancers. 96v devices aren't as common as 48v but isolated 96v are available. 

Re: [electricboats] Maximum input voltage for outboard?

Just an update...  Solar system is back on (buyer who wanted just the boat had to drop out), and the price is reduced to $14,000.

 

Jim

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Re: [electricboats] One cell out of whack. Replace it or stay with it.

Beautiful accurate write up. BMS of quality protect cells first. Them implement user settable functions

 

Best regards

Lee Eldridge

0427874796

On 2 Jul 2025, at 02:50, Anton via groups.io <iamyouranton=gmail.com@groups.io> wrote:



I have used a JK BMS, and several other brands of BMS, and their main function is to disconnect the battery before damage happens. Your BMS is not doing that. It should do that regardless of any interaction between the BMS and charge sources  or discharge loads, any CANbus or other signal level stuff that is intended to control anything else should be irrelevant to the BMS simply disconnecting the battery before anything bad happens. Cell balance is only there to balance the cells when things are working properly, if one cell goes high, the BMS should simply disconnect the battery from everything. 

To reiterate, you definitely want your charge sources to be set up correctly, your discharge cutoffs in your inverter or other loads to be set up properly, it serves both the keep weird stuff from happening when the battery disconnects but also as a double safety, the BMS *must* disconnect when any cell goes low or high regardless of any other set points or parameters. 

So, your BMS is not functioning correctly, and you need to figure out why. 
As suggested, definitely double check the cell voltages against what the BMS is telling you with a quality DVOM, but also do a thorough review of all your connections, I have a bell going on in the back of my head that maybe your charger is hooked up to the batteries directly in such a way that the BMS disconnect is not disconnecting it. 
If that is not the case, maybe the BMS settings are set to a too high cell voltage. In any of the BMS I have used, cell voltage overrides any other settings, if one cell goes high or low, it doesn't matter what the overall voltage settings, delta, etc are set for, if one cell goes high or low, it disconnects that battery, that is the whole purpose of any BMS.

There was some noise on the forums in the past about JK BMS firmware being wonky and settings changing to lithium ion settings when it was disconnected from the battery, but I haven't experienced that. Make sure your BMS is running the latest firmware. 

Also worth noting, while testing, do not take your eyes off the meter while charging! It can go from resting voltage to high enough to damage the battery in minutes, from 3.4 to high enough to damage the battery in seconds. Do not leave it unattended until you have figured out what is not right. 
Having driven that one cell up to 4.25v, it kay be damaged, but for the purpose of trouble shooting the BMS, use that cell, it can be the canary in the coal mine and be sacrificial while testing. Once you have things working right, you can capacity test the whole battery assembly and find out if that cell is dragging the whole pack down enough to warrant replacing it. 

Re: [electricboats] One cell out of whack. Replace it or stay with it.

Good luck Peter.

Say, I don't think you shared a diagram of your wiring and so we're pretty much assuming or guessing how things are connected.  If you have one, can you share it?

Thanks.

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Peter Knowlton via groups.io
Sent: Wednesday, July 2, 2025 5:46 AM
To: electricboats@groups.io
Subject: Re: [electricboats] One cell out of whack. Replace it or stay with it.

 

Thanks for all the responses. Very helpful. Comments and suggestions give me plenty to do to figure this out. Will be working on this over the next few days. If worse comes to worse I have some "extra" cells so if I need to swap out.... I hope it's not the BMS, but I suppose it could be. Just don't know how you could have a BMS where the cells' overload protective settings (3.65v) are triggered, except for one particular cell, which allows that cell to runaway. That can happen in a BMS?

 

Peter

[electricboats] Enpower M3336 Controller Wiring help needed.

I have a Enpower M3336-9650  Controller I am trying to hook up to a AC Induction Motor. The wiring diagram I have shows KS1 the power input connected to B+ which is 96 volts. I have tried this and the contoller does not power up or make any sounds or beeps. Anybody in this group have any experience with this contoller?

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