T-Pain Is On A Boat: Re: [Electric Boats] Re: Batteries wired in series

I have long sought out an inherently safe, low cost charging solution so we could compete in the marketplace. I have tried several times to make a battery monitoring system that monitored voltage and temperature. Every time we tried it cost too much for the average boater. This time round I have found a way to do it that is cost effective and we will start including it in our systems in the very near future.

Every time a string charger works it incrementally takes the batteries in the string out of balance. As soon as the string is out of balance, the individual batteries are being ruined. It is incremental over time. Once the batteries are out of voltage by .1 of a volt, they are no longer following their charge algorithm. The weaker batteries get overcharged and the stronger batteries get undercharged and the whole string of batteries is ruined prematurely. String chargers on average are getting 4 years out of their batteries. Balance the batteries and you could get double the life. There is huge inherent value in balancing and monitoring batteries and any balancing / monitoring solution will pay for itself within 4 years by completely avoiding a battery replacement.

Electroprop's Plus system based on multiple Mastervolt chargers does every thing with 4 chargers and dedicated temp sensors, plus universal input, but cost 5 times that of one 48 volt charger. Hence 10 unregulated chargers or more will be sold in the US for every inherently safe charging system sold. I do not think that the boat owners know what they are getting into when they buy an unregulated string charger. It is almost a guarantee that at the end of the battery life that one of the batteries in the string will be subject to an over voltage event and potential thermal event. When I talk to customers and vendors about this issue, I get kind of a blank look back. It is obvious that they just don't believe there is a problem, cause otherwise I don't think they would be buying or selling these units.

As a marine electrician, I have seen battery problems first hand on board boats. This is not a problem just for electric boats. In fact it is more of a problem with diesel boats that leave their batteries in parallel on charge. Series strings allow individual monitoring of each battery and, if monitored, are much safer than 12 volt batteries in parallel. Electric boats therefore have the opportunity of increasing the safety of boating… if battery monitoring and balancing is properly looked after. If you don't believe me that most boats have battery problems, go in the back door of your marine battery supplier and take a look at the batteries that are coming out of boats. They are leaking acid, huge corrosion on the terminals, and some of them have been completely destroyed.

This just does not have to be this way. We are in the year 2016 and we can do better than this. Cost should not be the only driver in determining a system. Safety and Value over time should weigh in heavily as well.

I am a huge proponent of electric boats and think we can build systems that are both cost effective and safe.

There are probably 500 or more unregulated string chargers on boats in the United States right now. All of these chargers pose a risk to the boats they are mounted in. This system will be able to be installed on these unregulated charging systems, and balance and monitor these battery banks, and prevent a thermal condition from arising.

Much of the technology that we have adopted for our sailing systems comes from the golf cart or electric bike industries. The reason why we need to be vigilant is because our boats need to be built to higher standards because we are reliant on them floating and not having electrical problems. We live with our systems… our systems are in our living room, our bedroom and our kitchens. Our electric propulsion systems can only bring us home safely if we know when we leave the dock that the batteries are good. There is no room for error in building an electric boat system and the standards have to be much greater than outdoor recreational vehicles.

What many boat owners don't realize is the battery pack is only as good as the weakest battery.

Knowing the resting voltage of each individual battery is very informative to how much energy is left in the battery pack. It is also an easy way to spot a weak battery in the system.

This new system is a very elegant solution with minimal parts, size of components, or complexity while offering extensive information on each battery in the pack.

This system will protect the battery from overcharge and low discharge and has the potential of extending the battery life through balancing.

It basically puts goal posts in, for the batteries to operate within.

If you balance a battery it extends the life of the battery considerably….many times more in value than the cost of the balancing option.

___________________________

Electroprop's new E-BMS works with any String Charger by monitoring the center-taps and distributing power to lower batteries to keep up. The E-BMS Interrupts power to the String Charger in the event of a voltage or temperature event by latching out the charger and displaying a check battery light. The E-BMS can be added to an existing string. If done before the batteries are too far out of balance, it will add years to the life of the battery bank.

Our new E-BMS will feature:

2 amps of balancing current,

individual 12 volt monitors for each battery with upper and lower relays.

Isolated Power Source so one switch can turn off all four monitors at the same time.

Individual battery display notifies of relay condition per battery. (CHARGING CUTOFF / LOAD CUTOFF)

Programmable Low Voltage Cutout for loads

Programmable HIgh Voltage Cutout for Charging Source

Charger will not run until batteries have been checked

GFCI protection for each charger

Individual battery temperature sensing will be an option.

Estimated box size is a 7 x 7 x 4 box.

It will be a tremendous value to a boat with potential for extending the life of a battery bank by years, simply by guaranteeing the battery gets the proper charging voltage.

This system is a safety system designed to interrupt a string charger before a battery can experience a thermal event .

The BMS Interrupts charging and latches out charger when any one battery goes over a set point, that you enter, according to your temperature compensated charging voltage plus suggested delta voltage of .2 volts. (CHARGE 14.7 / LATCH OUT 14.9)

The Balancer prevents premature failure of the battery bank by equalizing the voltage of the individual batteries so they remain on their programmed algorithms. If one battery bank can't keep up with rest of them, it is time to replace that battery.

The earlier you start battery balancing the better. Battery Monitoring prevents overcharging and consequently gassing the batteries electrolyte off and in some cases fusing and shorting plates out.

We can build a monitoring system for 6 volt batteries at this time but unfortunately there is no balancing option available for 6 volt batteries.

For best results use new batteries.

We can make our electric boats the safest, most efficient, most reliable, longest range electric boats possible.

Thanks,

James

James Lambden

The Electric Propeller Company

625C East Haley Street,

Santa Barbara, CA

93103

805 455 8444

jlambden: Skype

www.electroprop.com

james@electroprop.com

On Apr 28, 2016, at 1:50 PM, 'Jason (Electric Boats) Taylor' jt.yahoo@jtaylor.ca [electricboats] <electricboats@yahoogroups.com> wrote:

My bank is 16x lithium cells in series.
I am using a BMS for individual cell monitoring which can interrupt charging if one cell goes over max voltage and cutback on throttle at a low threshold and kills throttle completely at a lower threshold.
While the BMS isn't smart enough to provide individual cell voltages, I have wired my battery boxes for remote BMS and voltage monitoring. So each battery box has a waterproof 5-pin connector on it which is lead to a panel at my Nav-station. From there, I wired up each of the 16 BMS cell modules and the volt meters. This lets me easily see the blinking lights of the cell-modules to see which are in error or shunting as well as the voltages of each cell on the meters.

As a safety measure, I have used small 1A self-resetting fuses (really not expensive and often sold in packs of 5, 10, 25) at the pos and neg of each 4-cell pack. This should prevent any cable connection mix ups from frying anything.

/Jason

--
Jason Taylor
v:514-815-8204
e:j@jtaylor.ca

On Apr 28, 2016, at 11:43, James Lambden james@electroprop.com [electricboats] <electricboats@yahoogroups.com> wrote:
I have worked on 48, 72 and 96 VDC systems for 10 years.

The only time I have ever felt DC electricity was on a 48 volt boat. My arm was sweaty and I came in contact with the shunt and felt a tingle. I don't know of any cases of anyone ever being shocked by 48 volt DC and having any serious consequences.

I have studied these systems for years and I think the biggest hazard with low voltage DC systems is when the batteries fail at the end of their life while connected to a string (48 volt ) charger. One battery will fail before all the rest and this battery will steal the voltage from the other batteries as the resistance of the failed battery goes high. I consider a 48 volt battery charger on a 48 volt battery to be an unregulated charger and very dangerous. It is very likely that at the end of the batteries life, when charged by a string charger, that one of the batteries will experience a thermal event, start boiling its electolyte, put Hydrogen gas into the boat which we know is very explosive, and more problematic that that, potentially go thermal and catch the boat on fire. This is even more of a problem on batteries connected in parallel.

The other big issue that I have with these unregulated charging setups is the batteries go out of balance. This happens incrementally every time you charge with a string charger. As soon as the battery is out of balance by .1 of a volt, the battery life gets shortened. There is a definite knee in the life of the battery that starts when balance is out. Most batteries last 4 years with one of these string chargers when they could last 8 to 10 years with a balancing setup. With battery banks costing $2,000 and a days work in changing and disposing of them, I have to ask myself why are people going this route. Overall its expensive, time intensive and dangerous.

The other issue is as soon as the batteries start going out of balance, improper charging causes the batteries to lose amp hour capacity and that is usually a straight line event with time. It takes 3 to 6 months to destroy a battery pack, half way into that unbalanced cycle, the batteries will have half their power. Batteries suffer greatly from imbalance because now they are not receiving their proper charge voltage. The weakest battery gets too high a voltage and all the rest of the batteries get undercharged, and the whole battery bank fails prematurely.

We have moved to one charger with dedicated temp sensor per battery. The cost of perfect battery management costs $2,500. With shunt and screen its close to $3,000. Each battery charger can affect a charge enable relay for any string charger on the system including solar. In most applications the system pays for itself in 4 years by avoiding costly premature battery replacement

Part of my job is to bring this technology to as many people as possible by reducing the price. I have started on a project that will monitor each of the 12 volt batteries and when one of those goes over 15 volts the system de-activates a charge enable relay and turns off the string charger, and provides a warning. This is the bare bones essential that should be in every system. We think we can accomplish this for under $200 including a screen where you can see all 4 battery voltages. After we build the minimum safety system, we will be turning our attention to a system that balances as well. I know the vast majority of new boat motor sales are going for an inexpensive system but if you look at the cost of ownership, you might be surprised what you are getting yourself into when you choose an unregulated string charger for your charging setup.

If you have an unregulated 48 volt battery charger, the responsibility is yours to make sure your batteries are remaining in balance. Don't wait for a thermal event or a gas off event. As time goes by, check your batteries more often. When you see an imbalance of more than .1 of a volt, you need to balance your bank.

You want to keep your boat safe, your crew safe, and avoid costly, unnecessary battery replacement. The best way at this time to charge a battery is with a dedicated battery charger with dedicated temperature sensor. If you want to charge at the string level (48, 72 96 ) then you need to monitor each individual battery if you want an inherently safe system. The key to safely charging batteries is to monitor all batteries in a system, and affect a charge enable relay based on individual battery health.

You want to know the condition of your batteries before you leave the dock. Amp hour counting battery meters do not compensate for less capacity of the bank over time. If you don't know the strength of your battery bank, you could be leaving the dock with an empty battery and never even know it.

A simple way of knowing the health of your battery bank is look at the resting voltage with no charger or load on the battery. If you batteries are resting at 12.4, there is most likely only half the remaining capacity left in them. If your batteries are going out of balance, it will also show up in the resting voltages.

Look after your batteries, and your batteries will look after you!

James
James Lambden
The Electric Propeller Company
625C East Haley Street,
Santa Barbara, CA
93103

805 455 8444
jlambden: Skype

www.electroprop.com

james@electroprop.com
On Apr 28, 2016, at 7:48 AM, Hannu Venermo gcode.fi@gmail.com [electricboats] <electricboats@yahoogroups.com> wrote:
Most welders and plasma systems work around 30-40 volts.
The EU low voltage directive is set at 80V DC for a reason.
And I´m somewhat conversant with electrical stuff, as I build and design (industrial type) CNC systems.
No argument that 62 V is unpleasant.
Just that neither 48, nor 80V, is really dangerous, nor 220V single phase (with RCD and or GFI).
380V 3-phase is not particularly dangerous, unless its high power.
But, 400V DC is dangerous and needs to be tested to make sure its off.
Moral:
High voltage DC is very dangerous.
The commonly accepted and legal limit is 80V DC.

And most especially on these high power devices where power is tens to hundred kW plus, such as boats and cars.

Anecdote:
We connected 380V, 100 amps, live wires, on our extension cords.
With a running 50 kW diesel generator.
It ran upto 4 industrial cnc machines at a time (on lowered accelerations, due to limited total power).
We ran the genset 10 hours a day 3 months straight, and needed to fill the tank once (1000 l iirc).

But yes, we had industrial engineers and technicians, with experience (about 14 of 18 were engineers).
Its not amateur stuff.
I would not connect live 50 kW stuff, myself.

We could not get the power company to turn on the power for 3+ months.
T.I.S. wins, again..

On 28/04/2016 15:43, Chris Hudson clh5_98@yahoo.com [electricboats] wrote:
I work in the electrical field. We have 125 volt battery banks with the center of the bank grounded. Accidentally coming in contact with the +62.5 or the -62.5 volt side to ground gives a wicked shock. A hit across the heart at that voltage could be deadly. Don't underestimate our "low" voltage systems.

Sent from myPhone
--   -hanermo (cnc designs)  