I’d suggest asking what cells he is using in the battery. 13S18P will be VERY heavy. I’m using a 12S12P and it weighs ±8Kg.
I’m quoted at 11.5kg for the battery - me being 80-82kg (depending on what time of day or mood you get me in!) I’m worried about overall weight.
I asked what cells he is using and he provided me a link to his manufacturing facility so seems to be own brand chinese manufactuer 2000mAh - see below pic
That’s the problem with using cells that are worse quality. With Samsung 30Q (14S12P) cells you could get a battery that weighs in at around 7.5-8kg which makes quite a big difference when carrying the board and it would have the same amount of run time.
Thanks for the heads up!
Not looking for any more headaches in a project that has already had many
Ya I’m worried about the weight alright but I think the price may be too good to turn down on my first board build. Is the main concern the weight for carrying around (distance from car to water etc.) or the weight to get to foil?
Flipsky motor.
If its carry about then I may live with it for my first board
I find cutting weight wherever you can is worth it.
My first board with small battery weighed in at around 15kg. My newer board is around 21kg with a heavier battery and I definitely feel the difference.
Now I’m on a mission to go as small as I can so it’s easy to transport and foil better.
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Hi ,
Following this thread with great interest…
The assembly of an own pack seems a bit risky with my limited knowledge.
Maytech has a battery solution as well I noticed…:
12s12p 36ah Samsung 30Q battery pack with 150A BMS
They offer it for $1200 and with a 5A charger for $40
what are your thoughts on this offer?
As someone who also doesn’t feel comfortable building a battery, I’d say that’s a pretty fair price (assuming the shipping rate is also fair and the batteries are genuine Samsung 30Q).
For reference, a similar battery from one of the established companies (Lift, Fliteboard) is over $3,000. Theirs are about 10% higher capacity, but that doesn’t justify a 200% price increase.
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Is the Maytech battery waterproof or open?
Eileen posted this 4 days ago: #Maytech 12s12p 36ah Samsung 30Q battery pack with 150A BMS #12s12p #battery #batterypack #samsung30q #samsung #efoil #efoiling #efoils #electrichydrofoil | By Eileen | Facebook
I requested an offer yesterday…
Datasheet Samsung 18650 30Q:
min charging current 0,5C,
thats 1.5A or 18A for a 12p Pack.
I dont think, it is a good idea to drive the cells beyond their specs.
Neither during discharge, nor while charging
If it can handle 18A what’s wrong with the 5A charger?
Oh ya, I saw that. It doesn’t look waterproof and the pack dimensions look all kinds of wrong.
I totally agree on that, however missing the knowledge to conclude that myself…
It is what she offered in response to my price request…
also: “the battery can be soldered according to your need”
which made me curious what is wrapped in that blue foil we saw in the vid…
I will ask some more questions and wait for her response…
How exactly are you driving the cells beyond their specs? The minimal charge current spec means nothing. You could charge a 12P pack with 1A if you want, it’s just going to take a VERY long time to charge.
Its the high current charge rate that matters as that’s where heat is generated and things become unstable.
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I dont know, what happens, i am no LiIon expert.
I only know, the datasheet says: min charging current 0,5C. I am sure, there is a reason.
Maybe charging 10 hours with 0,1C destroys the cell chemistry? Who knows…
When my pack become unbalanced (12s10p li ion) i manually charge each group using the balance plug, I use only 1A which means less than 0.1A per cell and there is no damage only taking forever to charge
EDIT
idea comes from this guy
0.5C - 1C are the guidelines for std charging. When you trickle-charge a battery the current goes right down to 0.1A sometimes. The slower you charge a battery the closer you will get it to the correct voltage.
More important than C rate for charging it the the temperature rate for charge and discharge. If you can keep it cool in the specs range, you can always go above the Charging rate that is why reliable BMS is very crucial. Advance BMS firmware gathers temperature,SOP (State of health based on cells cycles and history mainly) SOC and calculates the SOP (State of power) and communicates with the load (lets say motor controller or ECU) to let the load know how much power it can sink or deliver in real time if load violates the broadcasted limits it shuts down! This how EV batteries can reach 10 years life cycle with around just 10% loss of capacity.
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