# 24 volt batteries



## Ziggythewiz (May 16, 2010)

That would be pretty huge, like 300+ lbs ea. What is the project?

Outside of heavy industry a 24V pack is usually made out of 12, 8, or 6V batteries.


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## bug man nrg (Aug 30, 2012)

it is a boat .i am doing a warp9 with 144 volts .i have found 24volt batterie's but they have less amps than a 12 volt car batterie


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## major (Apr 4, 2008)

bug man nrg said:


> it is a boat .i am doing a warp9 with 144 volts .i have found 24volt batterie's but they have less amps than a 12 volt car batterie


Hi bug,

I'm not sure why you want 24V batteries, but they can be obtained from places which build and sell batteries for forklifts and such. 300 Ah would be a small one for them, but I think in the range, especially if you are looking to buy 6 of them. They would give you high quality, long life and serviceability at the cell level.

Your best Ah/$ would come with 6 volt golf cart batteries due to volume of manufacture. I think those would be available near 300 Ah.

Regards,

major


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## bug man nrg (Aug 30, 2012)

i am looking at the Interstate or deka for this set up .this boat has two Volvo IC engines in place .i have pulled the engines out and i am getting the mounts made .i need 144 volt to each motor.
we put 12 bags of sand where we would like the batteries to sit in the boat before we pulled the engines and the only that we found was that the boat was 2" deeper in the water so when the engine are out and the warp9,s are in place then we will be ok .
My thinking is that if i use 24 volt batteries then i need 6 per motor to make 144 volts not 12 12 volts per motor


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## onegreenev (May 18, 2012)

Your post says you need 144 to each motor so I am to assume you need or want two packs of 144 volt batteries. If that is the case then you need to put in 24 bags of sand to get a better idea of your actual weight and displacement in the water. Be sure you don't overload the boat. You can you know. As for getting it to plane with that much weight, well it seems like it would be best to keep it a displacement hull and not go too fast rather than try to haul 3,200 or more of excess lead out on plane. 



3,250 lbs of lead for two 144 volt packs using 6 volt golf cart batteries. 
or 3,600 lbs of lead for 12 24 volt batteries for two 144 volt packs of forklift batteries.


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## major (Apr 4, 2008)

bug man nrg said:


> My thinking is that if i use 24 volt batteries then i need 6 per motor to make 144 volts not 12 12 volts per motor


Hi bug,

Invalid reason. It doesn't save anything. The 24 volt batteries will be twice as large as the 12 volters so the total mass and space requirements will be the same essentially. You really should reduce your battery requirement to a total required energy in kiloWatt hours (kWh). For your nominal calculations, use kWh = voltage times Ampere hours = V * Ah. No matter how you divide up you total voltage (6 * 24V or 12 * 12V), the ending energy (kWh) is the same or 144V * Ah.

Also, is there a reason you says "per motor"? You can use a single battery for both motor drives.

major


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## onegreenev (May 18, 2012)

> Also, is there a reason you says "per motor"? You can use a single battery for both motor drives.


Yes but two motors will drain that 144 volts faster than one?


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## major (Apr 4, 2008)

onegreenev said:


> Yes but two motors will drain that 144 volts faster than one?


Not if the total battery energy is the same.


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## Ziggythewiz (May 16, 2010)

No, two motors would drain the 300AH faster than one.


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## major (Apr 4, 2008)

Ziggythewiz said:


> No, two motors would drain the 300AH faster than one.


What don't you understand about "total energy" 

Two motors each with 144V and 300Ah = 2 motors both on 144V and 600Ah. Total energy = 2 * 144V * 300Ah = 86.4 kWh.
Total energy = 144V * 600Ah = 86.4 kWh.

Same total energy, same run time, same battery mass and space. Just one set of batteries instead of two.


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## bug man nrg (Aug 30, 2012)

i see the 24 volt and the 12 volt side by side and it is not twice the size they look almost the same size the 24 volt is a bit bigger .My problem is the ah on the 24 volt is less than the 12 volt
what is with that ???


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## major (Apr 4, 2008)

bug man nrg said:


> i see the 24 volt and the 12 volt side by side and it is not twice the size they look almost the same size the 24 volt is a bit bigger .My problem is the *ah on the 24 volt is less* than the 12 volt
> what is with that ???


Bingo  That is what I am saying. Compare kWh, and you will find that the size and weight is about the same for the same kWh.

A 12V 100Ah battery holds the same energy as a 24V 50Ah battery and therefore will be about the same size.


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## Ziggythewiz (May 16, 2010)

major said:


> What don't you understand about "total energy"
> 
> Two motors each with 144V and 300Ah = 2 motors both on 144V and 600Ah. Total energy = 2 * 144V * 300Ah = 86.4 kWh.
> Total energy = 144V * 600Ah = 86.4 kWh.
> ...


I mean if he has a 144V 300 AH pack powering two motors it will last half as long as if he has (two separate) a 144V 300 AH pack for each motor. I'm sure that's what Pete meant as well, I was just pointing out that it's the AHs that get drained, not really the Volts. 



bug man nrg said:


> i see the 24 volt and the 12 volt side by side and it is not twice the size they look almost the same size the 24 volt is a bit bigger .My problem is the ah on the 24 volt is less than the 12 volt
> what is with that ???


Batteries are usually designed with some size and weight in mind for a specific application. For example, with marine and golf cart batteries they are designed so you can pick them up without killing yourself, so a 6V, 8V, or 12V each weighs about 60 lbs. Because they have a similar weight they have a similar amount of lead in them and similar total energy, which equates to less AH for the higher voltage packages.


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## major (Apr 4, 2008)

Ziggythewiz said:


> I'm sure that's what Pete meant as well, I was just pointing out that it's the AHs that get drained, not really the Volts.


It would have helped if you had included Pete's quote in your post #10. I though you were disagreeing with my post #9.

All this confusion would be cleared up using energy (kWh) instead of volts and Ah.

I asked why he was using 24V batteries and why he was using 2 strings. Neither of those strategies alone gets you better performance or range.


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## Ziggythewiz (May 16, 2010)

Bug man, what are your performance goals? Are you trying to match the awesome EV boat vids that have been done recently, or just putting around the lake?

If you need good performance and range, you'll probably need lithium so as not to become a submarine project.

Also, what motors are you planning to use? On the water it's likely one big motor will do as well as two smaller ones, and have less weight.


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## bug man nrg (Aug 30, 2012)

this is to go fishing in.
There is one down here in Florida and i would like to do the same thing .
This is not for speed 
fish come to the sound of the motor not to a ic engine


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## PStechPaul (May 1, 2012)

I found some really high capacity batteries in a recent search, but I think they are mostly single cells or perhaps up to 4 cells in a pack:
http://interstatepowercare.com/PDF/LM_OPzS_Flooded.pdf

As always, keep the Peukert value in mind. If you drain one pack at 1C you will get only about 1/2 the rated Ah. With two packs at 1C each will be 1/2C and you will get more than twice the rated Ah and thus more than twice the run time, but at the considerable cost of twice the weight.


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## bug man nrg (Aug 30, 2012)

I am a new to this EV thing but i would like to know what i am doing on the fab side i have that in hand i build 1000hp street & race cars in the shop but this ev thing is kicking my butt.
OK what do i end up with if i have 6x24 volt 110 Ah per motor ??
http://www.facebook.com/pages/Emerald-Performance/194777241351


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## major (Apr 4, 2008)

bug man nrg said:


> OK what do i end up with if i have 6x24 volt 110 Ah per motor ??


Show me the 24V 110Ah lead acid battery you propose, please.


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## Ziggythewiz (May 16, 2010)

bug man nrg said:


> Iwhat do i end up with if i have 6x24 volt 110 Ah per motor ??


Voltage adds in series. Ah adds in parallel. So if you have 6 24V 110Ah batteries in series that will be a 144V 110Ah battery pack with a sticker rating of 15.8 kWh. How much of that is usable depends on the battery specifics. 

If you have one of those battery packs for each motor, you would have a sticker rating of 31.6 kWh, but there's no reason to have them in separate battery packs, instead of just 1 144V 220Ah pack.


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## major (Apr 4, 2008)

bug man nrg said:


> OK what do i end up with if i have 6x24 volt 110 Ah per motor ??


Simple math: 144V * 110Ah = 15840Wh = 15.8kWh => 21 hp for one hour run time on each motor.

Real world: 110Ah * 0.7 (Peukert factor) * 0.8 (DoD) = 61.6Ah

144V * 110A = 15.8kW * 85% (eff) * 1.34 => 18 hp

Time = 61.6Ah / 110 A = 0.56 hours = 34 minutes

So I expect you could run each motor at 18 hp for 34 minutes.


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## bug man nrg (Aug 30, 2012)

i am looking at some 12 volt 200Ah 
http://www.thepowerstore.com/product.asp?ID=2316
and the 24 volt
http://sell.bizrice.com/selling-leads/459995/deep-cycle-solar-battery-24V-100Ah.html
tell me if is the right way or not
http://www.facebook.com/note.php?note_id=158005490989717


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## bug man nrg (Aug 30, 2012)

So what is it i need Ah or volts???


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## major (Apr 4, 2008)

Thank you for telling what batteries you're talking about.

1.)


bug man nrg said:


> i am looking at some 12 volt 200Ah
> http://www.thepowerstore.com/product.asp?ID=2316


That is a 12v, 200Ah deep cycle lead acid battery. It looks like a really nice one, but is available in England and conversion to US$ would be around $600 each without shipping across the ocean.

2.)


bug man nrg said:


> and the 24 volt
> [URL]http://sell.bizrice.com/selling-leads/459995/deep-cycle-solar-battery-24V-100Ah.html[/URL]


That is a 24V, 100Ah Lithium Iron Phosphate Battery from China. The price is not indicated nor the availability to the US market. I have not heard of this product or company. You take a big risk sending money to China.

3.)


bug man nrg said:


> tell me if is the right way or not
> [URL]http://www.facebook.com/note.php?note_id=158005490989717[/URL]


That is a deal for four 12V, 150Ah lead acid batteries at $1600 apparently from a domestic source. Equals $400 each. This is likely the most "real" deal of the three you list, but they list the weight at 300lbs. That would be 75lbs for each of the 12V, 150Ah batteries. That sounds fishy to me.

1.) 12V * 200Ah = 2400Wh per battery. Or $250/kWh
2.) 24V * 100Ah = 2400Wh per battery. ?
3.) 12V * 150Ah = 1800Wh per battery. Or $222/kWh

These prices per kWh sound high to me. The first google hit for Trojan golf cart battery brought up a place at $160/kWh with free delivery. As for your option #2, Lithium would be nice for lower weight per kWh and longer cycle life, but expect to pay 4 times the price per kWh.

I hope this explanation shows you why I keep saying to reduce it to kWh. You can always add batteries in series to increase voltage and add batteries in parallel to increase Ah. But the kWh per battery does not change. Look for the price per kWh and weight per kWh to compare different battery deals and then multiply by the number of batteries you need to get the voltage and capacity (or total kWh) for the battery pack.

I suggest you visit several battery retailers in your area. Places which sell to a wide variety of users including golf carts, not just automotive cranking batteries. Talk to the owner or knowledgeable person and tell them of your application. See what they recommend and what they will warranty. When you buy that much battery, chances are you'll need the warranty for at least one of them.


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## major (Apr 4, 2008)

bug man nrg said:


> So what is it i need Ah or volts???


kiloWatt hours (kWh)


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## Ziggythewiz (May 16, 2010)

major said:


> 75lbs for each of the 12V, 150Ah batteries. That sounds fishy to me.


Specs similar to a marine battery. Since these are for a solar application, I doubt they'd handle high amps well.


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## Carl55 (Jun 9, 2012)

If I correctly understand what I have read on this site a 70 amp hr lithium equals a 100 amp hr lead acid. So, going with high dollar lead saves little money. In this case less than $1500. Something to think about.

Carl


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## Ziggythewiz (May 16, 2010)

I'd say 70 ah lithium equals about 150 AH lead...and lasts at least 2x as long. I'm not aware of any lead that can deliver it's sticker at even 1C, or any that last 2000-5000 cycles.

And then there's the time spent watering and replacing lead packs...that may have some value to some people.


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## bug man nrg (Aug 30, 2012)

OK guy how do you get the KWH i need to get this thing to work 
When this is done i will take on the car thing


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## major (Apr 4, 2008)

bug man nrg said:


> OK guy how do you get the KWH i need to get this thing to work


I thought I explained that. You multiply V times Ah, like I did here:



major said:


> 1.) 12V * 200Ah = 2400Wh per battery. Or $250/kWh
> 2.) 24V * 100Ah = 2400Wh per battery. ?
> 3.) 12V * 150Ah = 1800Wh per battery. Or $222/kWh


Obviously divide by 1000 to go from Wh to kWh.

*also see post #22.


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## major (Apr 4, 2008)

bug man nrg said:


> OK guy how do you get the KWH i need to get this thing to work


O.K. Are you asking how many kWh you need? That is an entirely different question. I thought you were asking how to calculate kWh for a battery.

You can see some of this in post #22. kWh is the energy in the battery. That determines how far or how long you can go on a charge. kW is power. One kW = 1.34hp. Power determines how fast you go. Or vice versa. 

So you need to know how fast the boat is going and how much power it requires. That is a big unknown for us. I hope you know. Once you do have the power and the run time, you then calculate the energy needed (kWh). Similar to what I did here: 


major said:


> Simple math: 144V * 110Ah = 15840Wh = 15.8kWh => 21 hp for one hour run time on each motor.
> 
> Real world: 110Ah * 0.7 (Peukert factor) * 0.8 (DoD) = 61.6Ah
> 
> ...


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## bug man nrg (Aug 30, 2012)

O.K. Are you asking how many kWh you need? That is an entirely different question. 
yes i am .i only need to do this one time due to cash flow
WHAT IS THIS 
http://www.evassemble.com/index.php...oducts_id=18&zenid=21krkc6p31de9hc909t0v7vav0


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## PStechPaul (May 1, 2012)

bug man nrg said:


> WHAT IS THIS
> http://www.evassemble.com/index.php...oducts_id=18&zenid=21krkc6p31de9hc909t0v7vav0


Looks like an expensive LiFePO4 battery.


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## major (Apr 4, 2008)

bug man nrg said:


> > O.K. Are you asking how many kWh you need? That is an entirely different question.
> 
> 
> yes i am .i only need to do this one time due to cash flow
> ...


Hi bug,

The link is a source for LiFePO4 cells. They are 3.2V 10Ah for $15.50 apiece. That equates to $484/kWh or about 3 times the cost of lead acid battery. For the total energy you have been talking about, you would need more than a thousand of those cells.

But more importantly, you need to figure out the boat's power and energy requirements. Some of the figures bounced around here are on the order of $15,000 for the battery pack and maybe $10,000 for motor and controls. With that level of investment, you need a plan and a design instead of taking shots in the dark at batteries.

Regards,

major


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## bug man nrg (Aug 30, 2012)

is this any thing i need to get or not ???


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## Carl55 (Jun 9, 2012)

WHAT IS THIS 
http://www.evassemble.com/index.php?...9hc909t0v7vav0

There is a build thread on here using those, but I do not recall who. Maybe somebody will.


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## Ziggythewiz (May 16, 2010)

bug man nrg said:


> is this any thing i need to get or not ???


Yes you need batteries. What you use or where you get them is up to you.





Carl55 said:


> WHAT IS THIS


You tell me. Can't tell what you're referring to. You'll have to link to something more specific than a vendor's homepage.


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## PStechPaul (May 1, 2012)

What's this:





 
*This* is goodbye...


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## Carl55 (Jun 9, 2012)

Ziggythewiz said:


> Yes you need batteries. What you use or where you get them is up to you.
> 
> 
> 
> ...


Sorry was trying to quote bugman but it did not work. Maybe this will.


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## bug man nrg (Aug 30, 2012)

Ok guys we went out in the boat with the set at 144volt on each motor and it works well .we only went out four miles or so but the other boat that came out with us was there in case he had to tow us back but all was well on the water. 
Your help on this one help a lot i did not think it would work this good .I still do not understand it yet bet it will take a wile to get my head around it .we had a talk with Deka and interstate on getting better batteries around 400Ah each at 24 volts we will let you know what come's out of this 
Mack 
Emerald Performance


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## bug man nrg (Aug 30, 2012)

I had a look at this and i think it works
Unfortunately, this question cannot be answered without knowing the size of the battery bank and the load to be
supported by the inverter. Usually, this question is better phrased as "How long do you want your load to run?", then specific
calculations can be made to determine the proper battery bank size.
Formulas and Estimation Rules
1. Watts = Volts x Amps
2. Battery capacity is expressed by how many Amps for how many hours a battery will last - Amp-Hour (A.H.) capacity
3. For a 12-Volt inverter system, each 100 Watts of the inverter load requires approximately 10 DC Amps from the battery
4. For a 24-Volt inverter system, each 200 Watts of the inverter load requires approximately 10 DC Amps from the battery
The first step is to estimate the total Watts (or Amps) of load, and how long the load needs to operate. This can be determined
by looking at the input electrical nameplate for each appliance or piece of equipment and adding up the total requirement. Some
loads are not constant, so estimations must be made. For example, a full-sized refrigerator (750-Watt compressor), running 1/3
of the time would be estimated at 250 Watts-per-hour.
After the load and running time is established, the battery bank size can be calculated. The first calculation is to divide the load (in
Watts) by 10 for a 12-Volt system or by 20 for a 24-Volt system resulting in the number of Amps required from the battery
bank.
Exam ple of Load Calculations
Suppose you were to run a microwave oven for 10 minutes a day, which draw about 1000 Watts, despite their size. To keep it
simple, think of the inverter as electrically transparent. In other words, the 1000 Watts required to run the oven come directly
from the batteries as if it were a 12 VDC microwave. Taking 1000 Watts from a 12-Volt battery requires the battery to deliver
approximately 84 Amps.
(1000 Watts ÷ 12 Volts = 84 Amps)
A full-sized refrigerator draws about 2 Amps at 120 Volts AC. By multiplying 2 Amps x 120 Volts, you find out the refrigerator
uses 240 Watts. The batteries will need to deliver 20 Amps to run the refrigerator (240 Watts/12 Volts = 20 Amps). Typically,
refrigerators operate about 1/3 of the time (1/3 "duty cycle"), or 8 hours a day. Therefore, the A.H. drain will be 160 A.H.
(8 hours x 20 Amps = 160 A.H.).
After the load and running time is established, the battery bank size can be calculated. The first calculation is to divide the load (in
Watts) by 10 for a 12-Volt system or by 20 for a 24-Volt system resulting in the number of Amps required from the battery
bank.
Example of Input Calculations
1. Total Watts = 1000 W
2. Amps from 12-Volt battery = 1000 ÷ 10= 100 Amps DC
3. Amps from 24-Volt battery = 1000 ÷ 20= 50 Amps DC
Next, the number of DC Amps must be multiplied by the time in hours that the load is to operate.If the load is to operate for 3 hours:
For a 12-Volt battery: 100 Amps DC x 3 hours = 300 A.H. For
a 24-Volt battery: 50 Amps DC x 3 hours = 150 A.H.
Now, the proper type and amount of batteries must be selected. Traction batteries, (also called deep cycle or golf cart type),
should be used in order to be able to handle the repeated discharge/charge cycles that are required.
Choosing the Correct Number of Batteries
This is a little more difficult due to the rating method used by the battery manufacturers. Also, because of the nature of the
battery, the higher the discharge rate, the lower the capacity of the battery.
Battery Capacity Hours of Di scharge
100 20
90 10
87 8
83 6
80 5
70 3
60 2
50
1
Most batteries' A.H. capacity is stated for the 20-hour rate of discharge. This means that a battery has a 100 A.H. capacity if it is
discharged over 20 hours, or at about 5 Amps-per-hour (100 A.H. / 20 hours = 5 Amps DC). However, this s


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## major (Apr 4, 2008)

bug man nrg said:


> Ok guys we went out in the boat with the set at 144volt on each motor and it works well .we only went out four miles or so but the other boat that came out with us was there in case he had to tow us back but all was well on the water.
> Your help on this one help a lot i did not think it would work this good .I still do not understand it yet bet it will take a wile to get my head around it .we had a talk with Deka and interstate on getting better batteries around 400Ah each at 24 volts we will let you know what come's out of this
> Mack
> Emerald Performance


Kool  What batteries do you have? V and Ah? What controllers (with Warp9)? What was your speed and current draw? What are you doing for chargers? Got photos?


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## bug man nrg (Aug 30, 2012)

we had to go back to 12 volt and we got all the parts from http://evolveelectrics.com/
GPL-8DL (DUAL PURPOSE) batteries we got a good price on


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## bug man nrg (Aug 30, 2012)

JepthaTalon
A car battery can be used on a boat, but a battery made for the marine industry can give you better service. They are made to match the load requirements of a boat, they are usually sealed and leak-proof, and are often a dual purpose high load deep cycle type. The AGM batteries are the boater's choice.

yes i know but when you get 24 x12 volt batteries for $400 you go with it to see how it works


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## bug man nrg (Aug 30, 2012)

how come's there is no kind of charging for this EV thing .we have to take a Honda geni out with us and that sucks


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## major (Apr 4, 2008)

bug man nrg said:


> how come's there is no kind of charging for this EV thing .we have to take a Honda geni out with us and that sucks


Charging at home the night before works great for me


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## bug man nrg (Aug 30, 2012)

this boat will not fit out side the house


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## major (Apr 4, 2008)

bug man nrg said:


> this boat will not fit out side the house


I don't know how to read you. Are you telling us you outfitted a large boat to battery power and have to place or means to charge the battery


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## bug man nrg (Aug 30, 2012)

it is not that big 30 foot that had to volvo engine,s at one time now it has 2 warp 9s


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## major (Apr 4, 2008)

bug man nrg said:


> it is not that big 30 foot that had to volvo engine,s at one time now it has 2 warp 9s


So where do you charge and what charger do you use?


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## bug man nrg (Aug 30, 2012)

at the dock but you go out on the water we take the geni with us and charge when we are fishing and sipping on a bud


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## major (Apr 4, 2008)

bug man nrg said:


> at the dock but you go out on the water we take the geni with us and charge when we are fishing and sipping on a bud


What is the size and model of the battery charger?

What is the size or output rating of the Honda generator?


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## bug man nrg (Aug 30, 2012)

What is the size and model of the battery charger?
the charger came from Elcon PFC 2000+ 
(Optimized For 120VAC)
What is the size or output rating of the Honda generator? 
Honda EU2000i


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## major (Apr 4, 2008)

bug man nrg said:


> What is the size and model of the battery charger?
> the charger came from Elcon PFC 2000+
> (Optimized For 120VAC)
> What is the size or output rating of the Honda generator?
> Honda EU2000i


Hi bug,

You fail to mention if you have one or two of those chargers. That charger will deliver 10 Amps to the 144V battery string. So it would take 25 hours to charge one set of batteries if they were completely flat (discharged). Using one charger for both battery strings would take over 2 days to charge.

How often do you charge? How do you know your State of Charge (SoC)? How do you know how much charge you use? Do you have an ammeter to tell the current draw when you're underway?

The Honda generator if run for 5 hours will only put about 10% of a full charge into the batteries. 

major


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## bug man nrg (Aug 30, 2012)

it is the only we have right now we are working on bigger things for this boat soon


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