T-Pain Is On A Boat: Re: [Electric Boats] LiFePO4 Battery Pack

Friday, August 21, 2020

Re: [Electric Boats] LiFePO4 Battery Pack

Hi Pat,

No, a 16s battery system should not damaged your Torqeedo motor I don't think. The 4.0 can use either their 48V battery or two of their 24 V batteries in series. You are correct about the nominal of the 48V battery, but the nominal Voltage of the 24V battery is 28Vs. When two are used in series for the cruise 4.0, that should give a nominal voltage of 52 volts.

Best Regards,

Eric Crouch

On Aug 21, 2020, at 12:40 PM, sw v1opps@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:

If your handy can make your own
Ant bms will send all data to your phone

On Friday, August 21, 2020, 10:22:42 AM PDT, oak oak_box@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:

Pat,
My Torqeedo 4R has a voltage reading on the throttle display.
It's crude - but that is actually not a terribly bad indication of how much you have left...
You need to know what the lower voltage level is that you're comfortable taking your batteries to.
Then you need to do a couple of runs to see how long it takes at a constant wattage to get there.

Good luck finding a good source for a 48V bank. I've been experimenting with ebike battery sets - but they're only up to 50AHr max, and aren't intended to put out the high wattage that you could use with your Torqeedo 4.0R (up to 4000W - which is about 85A at 48V. The ebike batteries aren't intended to provide more than 30-50A in short bursts). For my small 13' boat, I can manage with that, and it's a really nice, affordable package. For your 24' Pontoon boat, you really probably do want a full 100A pack. Though you could consider an ebike pack as an emergency limp home backup.

John

On Friday, August 21, 2020, 12:12:08 PM CDT, forums@greensdomain.com [electricboats] <electricboats@yahoogroups.com> wrote:

Hello Everyone,
Back near the end of April, I posted a question about my 10 year old AGM batteries that were showing signs of their age. (The motor is a Torqeedo Cruise 4.0R and the boat is a 24' pontoon used on small inland lakes). I received many useful responses and decided to order a 16-cell LiFoPO4 pack from a supplier on Amazon. At order time, the delivery date was scheduled for mid-June. When that time approached, I received an email saying they were delayed and wouldn't ship until July 5^th. The next email said July 22^nd. Then August 4^th. I ended up cancelling the order (even though they said they would ship August 10^th to the 14^th. I told them to let me know when they were ready to ship and I would promptly place a new order. Well, here we are on August 21^st and I haven't heard a thing. On Amazon, it says new orders would be delivered in September. At least I haven't lost any money as my credit card was never charged other than a temporary hold being placed on the card which expired a few weeks later.

I was hoping someone on this group could provide a trusted supplier where I could order what I want and actually expect to receive it before the snow flies!
Here's what (I think) I want:
-A LiFepo4 battery pack to be used with my 48 volt motor
-Approximately 100 Ah capacity
-Some way to monitor charge level (e.g., a BMS with a Bluetooth connection to a smart phone, or some sort of a "Gas Gauge" display or meter)
-A built in BMS that protects the cells from undercharge, overcharge, and unbalanced cells.

I recently looked at Torqeedo's offering. At around $5,200 USD (plus some "required" accessories and shipping), it is the most expensive pack I have seen, but it also confused me. Most of the packs I have looked at seem to use 16 cells so the nominal voltage is around 52v, but the Torqeedo pack says its nominal voltage is 44...4v and the low voltage cutoff is 36v. Can anyone explain why they would do that? Should I be worrying that a 16-cell LiFePO4 pack will damage my Cruise 4.0R?

Thanks,
Pat