Hi John,
We chose Pure Lead batteries for all of our systems simply because when you look at all the batteries available, they are the safest.
We chose Northstar Batteries because they are the most forgiving to leaving in a partial state of discharge, they are the most efficient of all the Lead Acid Batteries we have looked at, and Northstar is committed to refinining their technology to be the best.
However, even Northstar batteries require balancing. Most issues arise from the batteries from the suppliers coming from different batches which could be months if not years apart. Plus if you don't have a method to balancing a battery pack then one bad battery requires replacing the whole pack.
The cost of ownership of an electric or hybrid vessel is directly related to the cost of the batteries and how often they must be replaced. Most batteries are replaced every 4 to 5 years. My first battery balancer installed on my boat, Kapowai, enabled Deka batteries to last over ten years, which resulted in half the cost of ownership of the batteries.
Considering the replacement cost, including installation time, whether you do it yourself or have it done professionally, is about $4,000 or so, that translates into cost of ownership being around $1,000 per year for the batteries for the average installation. Double the life expectancy of the battery, and that cost of ownership of batteries drops in half to perhaps $500 per year but best of all defers battery replacement for a decade or more.
Not only does a balancing system extend the life of the batteries, it also limits the decline of amp hour capacity.
As you can imagine, if you follow the charge requirements of a battery then you will get maximum battery life. If you install batteries in series, every time the battery is charged and discharged it will go out of balance and the amount it will go out of balance is incremental. There are some lucky cases. I installed 12 x 2 Volt, 1200 amp hour Lifeline batteries (24 volt) on my brothers boat 7 years ago and they are still perfectly in balance with no balancer. These batteries were custom built and did come from the same batch so it is possible that good batteries can last a long time, but my experience looking at other installations sees that this is not the norm. Most batteries go out of balance early in their life when installed in series. Once they are out of balance they no longer follow the charge requirements of the manufacturer. Weak batteries will be over charged and strong batteries will be undercharged and the whole stack starts to age early. Basically, unless you are very lucky, any batteries installed in series without a balancer will start the self destruct process on the first charge cycle.
But there are no commercially available battery balancers on the market today that accomplish everything a balancer / monitor requires. So we built our own…
In 2018 Electroprop will start selling a battery balancer, monitor and charging system that will be the most advanced system of its kind…. well unless someone else comes up with something better in the meantime or I have missed it in my research of available products.
Here are a few of the highlights:
1) Monitor every battery for temperature and voltage. Loads, charging sources and diversion load logic is based on individual battery condition. If any one battery goes over 14.7 volts, then balancing begins, then diversion loads are enabled, then charging sources start shutting down until the voltage comes back within acceptable limits.
2) Display temp and voltage on display on monitor plus over Bluetooth and Wifi ( for redundancy and so we can communicate our info over Wifi, to allow bluetooth to communicate other info to tablet or phone)
3) Android functionality with Apple coming soon
4) Sequential load management based on priority
5) Diversion Load Management
6) Charge Source Management
7) Up to 16 channels of Load, Diversion and Charge Management
8) 20 amps of balancing or get home mode with either AC or DC charging sources This enables the use of a high power DC generator. Balancing currents need to be a percentage of overall charging currents to protect batteries from over voltage conditions.
9) Control of Circuits from phone or tablet…. turn fridge on a couple of hours before getting to your boat, or lights on from the dock so you can read the combination lock
10) up to 65 amps of charging a 48 volt battery plus up to 75 amps of charging a 12 volt house battery….. that is a total of over 4.5 KW. This high power output enables the use of AC generators to make an AC hybrid.
11) very high efficiency
12) installed in a waterproof enclosure with aluminum heat sink
13) text alerts like if the bilge pump was activated etc.
14) fully customizable to the needs of your boat and your lifestyle.
The current build will include
AC and DC distribution, all charger modules, and DC converters in a box that measures 19 x 19 x 12 inches. If that is two big for someones boat, it can be custom build into a variety of smaller boxes.
James Lambden
The Electric Propeller Company
625C East Haley Street,
Santa Barbara, CA
93103
805 455 8444
james@electroprop.com
www.electroprop.com On Nov 4, 2017, at 12:16 AM, 66b6dcd5b59507e7d751ea81382ea1f6 wrote:
