Re: [electricboats] Power in and out of battery bank

Great point.  Also, if you're like me and don't necessarily use actual chargers, but instead power supplies used as a 2-or 3-stage charger, consider that as a charger, the power supply needs to be able to handle running in current limit for a long time (most of the charge cycle).  A friend bought a 30amp "charger" for his boat pack but quickly found it would just shut off after long.  I looked into its detail design and the power control chip used and indeed the circuit was doing what it was wired up to do.  In his case, I got this resolved by adding a resistor in one spot that based on the specs of the chip allowed the power supply to run in current limit continuously.  We also found that the subsequent iteration of these "Meanwell" power supply/chargers actual include a switch allowing enabling of 2-stage charging (constant current limit "CI" phase).

 

Also when you are cruising (genset running, chargers delivering and motor pushing), if you really need maximum or some minimum amount of steady power from your genset to the pack, be sure that the pack voltage is BELOW the CV set point for your charger/power supplies.  Listen to the genset and if it starts running easier, there's your clue.  It's very easy to think you're still getting full power to the pack only to find that the voltage rose slightly and now one or more of the supplies starts ramping its current output down.  When this happens you can also experience "motor-boating" or a cycling between full-current, then lower, then full again, then lower again as the chargers drift in and out of the CV ramp.  To avoid this, increase the speed of your motor until the charge voltage drops below the start of the CV ramp.

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Matthew Geier
Sent: Thursday, September 28, 2023 8:41 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Power in and out of battery bank

 

Some battery charges have protection circuits that may kick in if you are drawing down on the battery while the charger is running, as the load looks like a potential battery fault. Many chargers however are fine running a load at the same time. I would check your charger / solar controller documentation. There may even be option settings on the devices for this.

 

 

 

 

 

On Wed, 27 Sept 2023 at 22:16, Matt Foley <matt@sunlightconversions.com> wrote:

They are correct you can't! Not because it will damage the battery, it's just physically not possible. Energy is either flowing in or out. 

 

If the load is greater than the charging source, it will pull from the source(s) simultaneously. If the load is less than the charging source, it will power the load and charge the battery. 

You are fine. Happy motoring. 

Matt Foley

 

Sunlight Conversions 

1-201-914-0466

 

sunlightconversions.com

instagram.com/sunlightconversions/

youtube/sunlightconversions

 

ABYC Certified Marine 

Electrical Technician

 

 

 

 

On Sep 27, 2023, at 4:50 PM, rholden@orcon.net.nz wrote:

Hi All
Very fundamental beginner's question here.

I currently have a 160amp hour 48-volt closed cell battery bank running a thunderstruck 10KW motor and all works well. ( Looking forward to lithium in the future).

QUESTION: If I am charging the battery using solar panels - or in some cases a generator - can I run the motor at the same time?

There a several claims on Google search that you cannot charge and discharge a battery bank at the same time. 
If you are running solar panels ( which I am about to install) - I can't imagine that you switch them off each time you want to run the motor.
Can someone please clarify if I can charge and discharge simultaneously, or will this damage the batteries or create other issues?

The expert help from this group is very much appreciated.

Richard

Re: [electricboats] Power in and out of battery bank

Hi Richard,

A fuse is a good idea.  BTW, industrial motor controllers here in the States usually have a fuse (or breaker) _and_ an 'overload.' Overloads are specialized devices designed to sense the long term heating of the motor's windings and shut off the motor if it's getting too hot.  It might seem redundant but, the fuses and breakers are typically rated well above the maximum current that would burn the motor.  Really they're more to protect the wiring than the motor.  You probably have a fuse and an overload _in_ the controller.

However, fuses and breakers are over_current_ protection.  The overvoltage protection is a different mechanism.  It might be that the overvoltage causes an overcurrent situation, but it's probably not good practice to count on that.  The voltage rating is more related to the wire's insulation breakdown rating than the wire's size.

If you're asking these questions you're probably already well on your way to a good setup.  Fair winds and following seas amigo!

On Thursday, September 28, 2023 at 07:00:32 PM CDT, Richard Holden <richard.holden@softmachine.co.nz> wrote:

Hi

Thanks for all the feedback folks - really appreciated it from down here in New Zealand, and now seems very obvious when explained correctly.

With the comment about driving the motor supply to too high voltage. I was concerned about that and set a 100amp fuse between the motor controller and the battery - and I did once pop that reset fuse in a panic. I figured that the motor could draw 208 amps (10K motor / 48-volt system ? ) - which may kill or maim the close-cell electric car batteries - so I set up the fuse. Not sure if this is a great idea or a fail.

Cheers again - really enjoy the information I get from the experienced minds in this group

Richard

On Fri, 29 Sept 2023 at 06:29, Dave Yamakuchi via groups.io <dyamakuchi=yahoo.com@groups.io> wrote:

Just make sure you're not driving the motor's supply to too high a voltage.  Generally, you won't and often actually can't have this problem.  The only way you might get into trouble is if there's not a proper charge controller with over-voltage protection between the charging system and the motor _and_ you're charging the batteries up to 'full.'

Note: it's really the same problem if you don't have a good controller charging the batteries even _without_ the motor.  Charge applied to a 'full' battery can overcharge and damage the cells.  The charge controller/balancer makes sure your cells don't get overcharged.  That's one of it's jobs.

As an example: On MinnKota 12V trolling motors, the Max voltage allowed is 13.6V  This is actually lower than the 14+ volts some chargers will apply to fast charge a 12V battery.  This would be a problem.  IDK the max allowable for _your_ motor, but if you're charging with potentially more power than the motor can draw, you can end up significantly higher than the nominal 48V.  Just make sure your motor is cool with whatever might happen worst case...

On Thursday, September 28, 2023 at 01:24:47 AM CDT, Thierry <thierry.lequeu@gmail.com> wrote:

Just to clarify: you can!

There's no problem charging the battery and using the motor at the same time.

The only risk I see is that if the motor is regenerated (charged via the motor) and via a charger, the battery voltage may rise without "control", and even then... the charger will stop, and if the motor's speed controller is properly adjusted, regeneration will stop too!

--

	Richard Holden Systems Administrator
	+64(0)21-763-862
	richard.holden@softmachine.co.nz
	www.softmachine.co.nz

Re: [electricboats] Power in and out of battery bank

A fuse will interrupt if the current is too high, it is not a device to avoid overvoltage. A low or even zero current is quite possible in a case of a too high voltage.

You should evaluate what amuont of overvoltage the motor controller is able to take without damage. Then select a proper charger to prevent a voltage higher than this threshold at the output of charger (or any other source).

_._,_._,_

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Re: [electricboats] Power in and out of battery bank

Some battery charges have protection circuits that may kick in if you are drawing down on the battery while the charger is running, as the load looks like a potential battery fault. Many chargers however are fine running a load at the same time. I would check your charger / solar controller documentation. There may even be option settings on the devices for this.

On Wed, 27 Sept 2023 at 22:16, Matt Foley <matt@sunlightconversions.com> wrote:

They are correct you can't! Not because it will damage the battery, it's just physically not possible. Energy is either flowing in or out. 

If the load is greater than the charging source, it will pull from the source(s) simultaneously. If the load is less than the charging source, it will power the load and charge the battery. 

You are fine. Happy motoring. 

Matt Foley

Sunlight Conversions 

1-201-914-0466

sunlightconversions.com

instagram.com/sunlightconversions/

youtube/sunlightconversions

ABYC Certified Marine 

Electrical Technician

On Sep 27, 2023, at 4:50 PM, rholden@orcon.net.nz wrote:

Hi All
Very fundamental beginner's question here.

I currently have a 160amp hour 48-volt closed cell battery bank running a thunderstruck 10KW motor and all works well. ( Looking forward to lithium in the future).

QUESTION: If I am charging the battery using solar panels - or in some cases a generator - can I run the motor at the same time?

There a several claims on Google search that you cannot charge and discharge a battery bank at the same time. 
If you are running solar panels ( which I am about to install) - I can't imagine that you switch them off each time you want to run the motor.
Can someone please clarify if I can charge and discharge simultaneously, or will this damage the batteries or create other issues?

The expert help from this group is very much appreciated.

Richard

_._,_._,_

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Re: [electricboats] Power in and out of battery bank

Hi

Thanks for all the feedback folks - really appreciated it from down here in New Zealand, and now seems very obvious when explained correctly.

With the comment about driving the motor supply to too high voltage. I was concerned about that and set a 100amp fuse between the motor controller and the battery - and I did once pop that reset fuse in a panic. I figured that the motor could draw 208 amps (10K motor / 48-volt system ? ) - which may kill or maim the close-cell electric car batteries - so I set up the fuse. Not sure if this is a great idea or a fail.

Cheers again - really enjoy the information I get from the experienced minds in this group

Richard

On Fri, 29 Sept 2023 at 06:29, Dave Yamakuchi via groups.io <dyamakuchi=yahoo.com@groups.io> wrote:

Just make sure you're not driving the motor's supply to too high a voltage.  Generally, you won't and often actually can't have this problem.  The only way you might get into trouble is if there's not a proper charge controller with over-voltage protection between the charging system and the motor _and_ you're charging the batteries up to 'full.'

Note: it's really the same problem if you don't have a good controller charging the batteries even _without_ the motor.  Charge applied to a 'full' battery can overcharge and damage the cells.  The charge controller/balancer makes sure your cells don't get overcharged.  That's one of it's jobs.

As an example: On MinnKota 12V trolling motors, the Max voltage allowed is 13.6V  This is actually lower than the 14+ volts some chargers will apply to fast charge a 12V battery.  This would be a problem.  IDK the max allowable for _your_ motor, but if you're charging with potentially more power than the motor can draw, you can end up significantly higher than the nominal 48V.  Just make sure your motor is cool with whatever might happen worst case...

On Thursday, September 28, 2023 at 01:24:47 AM CDT, Thierry <thierry.lequeu@gmail.com> wrote:

Just to clarify: you can!

There's no problem charging the battery and using the motor at the same time.

The only risk I see is that if the motor is regenerated (charged via the motor) and via a charger, the battery voltage may rise without "control", and even then... the charger will stop, and if the motor's speed controller is properly adjusted, regeneration will stop too!

--

	Richard Holden Systems Administrator
	+64(0)21-763-862
	richard.holden@softmachine.co.nz
	www.softmachine.co.nz

_._,_._,_

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You receive all messages sent to this group.

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Re: [electricboats] Power in and out of battery bank

Just make sure you're not driving the motor's supply to too high a voltage.  Generally, you won't and often actually can't have this problem.  The only way you might get into trouble is if there's not a proper charge controller with over-voltage protection between the charging system and the motor _and_ you're charging the batteries up to 'full.'

Note: it's really the same problem if you don't have a good controller charging the batteries even _without_ the motor.  Charge applied to a 'full' battery can overcharge and damage the cells.  The charge controller/balancer makes sure your cells don't get overcharged.  That's one of it's jobs.

As an example: On MinnKota 12V trolling motors, the Max voltage allowed is 13.6V  This is actually lower than the 14+ volts some chargers will apply to fast charge a 12V battery.  This would be a problem.  IDK the max allowable for _your_ motor, but if you're charging with potentially more power than the motor can draw, you can end up significantly higher than the nominal 48V.  Just make sure your motor is cool with whatever might happen worst case...

On Thursday, September 28, 2023 at 01:24:47 AM CDT, Thierry <thierry.lequeu@gmail.com> wrote:

Just to clarify: you can!

There's no problem charging the battery and using the motor at the same time.

The only risk I see is that if the motor is regenerated (charged via the motor) and via a charger, the battery voltage may rise without "control", and even then... the charger will stop, and if the motor's speed controller is properly adjusted, regeneration will stop too!

Re: [electricboats] Power in and out of battery bank

I first wrote about doing this back in 2005 or so.  I converted my boat to electric in 2003 www.evalbum.com/492 .

In 2005 I hauled it out and repaired bottom damage, etc, got it prettied up, then got it out on the river.  Then I did a 90 mile round trip on the Columbia River to the Cathlamet Wooden Boat Show.  With just about 300ah at 36v onboard, there's no way I could make the trip on shore power alone.  And I didn't think I'd be able to recharge at Cathlamet or anywhere else on the river.  So I brought some gasoline, a Honda EU2000i genset and 2 chargers.  Going downstream I realized that one of my chargers wasn't working, so I only had one running (generating just 20amps to the pack) going downstream.  To make time, I was probably cruising at 40amps.  And so, the pack saw a net loss of 20amps.  By the time we reached the boat show the pack was down about 150ah---and I couldn't recharge at the docks.  My wife brought me a spare charger and so, going back upstream I had 40amps of charge current.  If I was using just 40amps, the net current was zero and the pack voltage unchanging.  But to make it upstream at any rate, I used about 55amps.  After several hours of this, we rolled into a marina for the night (again, no charging available and didn't want to annoy folks with my genset) at this point maybe 230amp-hours down.  The next morning, things were still not ideal (bad tides) and so initially was still using power despite the genset and chargers.  But things improved and so it eventually was clear I'd make it back, barely---nearly 300ah used from the pack on the trip.  As I recall, the genset/chargers provided about 800ah on the trip.

 

Anyway, bottom line is you need to know your pack's state, what your genset/chargers are capable of and what power levels you'll need for your trip.  Plan it out and give yourself extra time.  The slower you can run the boat and make progress, generally, the less energy it will take to go the distance.  It's more complicated with current flow---i.e. with a 2kt current you wouldn't want to slow your motor to the point that you go 2kts on the water.  Still, do the calcs, bring the fuel, bring spare parts as needed and hope that your genset/charger keeps running.  Plan for contingencies for the case of those things failing---i.e. keeping enough pack energy to get to the next (or the last) harbor or perhaps having solar or wind power available---or cell phone and a wife who could bring parts J.

I like to power in and out of marinas (or towns) on just electric.  Knowing it's 4 hours at 3knots vs 3 hours at 4knots, needing to get to the destination in 3 hours dictates the faster rate---at least for the main part of the trip.

It's fun to watch the Amp gauge.  Start up the genset, plug in the chargers, watch 40amps going into the pack and seeing the bump in pack voltage is nice.  Then heading out, current drops as you pick up speed until the current direction flips.  If starting out, your pack is likely already full, so you either let the charger(s) respond to that or you'd want to increase boat speed to draw more current until the net current goes to zero or negative.

It's all pretty obvious really.

 

Enjoy.

 

-MT

 

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Thierry
Sent: Wednesday, September 27, 2023 11:25 PM
To: electricboats@groups.io
Subject: Re: [electricboats] Power in and out of battery bank

 

Just to clarify: you can!

There's no problem charging the battery and using the motor at the same time.

The only risk I see is that if the motor is regenerated (charged via the motor) and via a charger, the battery voltage may rise without "control", and even then... the charger will stop, and if the motor's speed controller is properly adjusted, regeneration will stop too!