Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Batteries & Chargers => Topic started by: Vts99 on May 31, 2016, 02:48:01 pm
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Hi all I had my boats out at weekend and running on standard 12v lead acid batteries as I'm just a newbie to the hobby
Been told I'd be better using lipo batteries to move weight nearer the aft end of the boats to get them planing better as one is a graupner weser fireboat with racing engines in it and the other is the azteka patrol boat but both have minimal space at aft end
Having never used lipo before and heard horror stories . What exactly do I need to change over to these and how many batteries would I need to get decent pond time on them
Also where's the best place to get everything required to change over
Thanks in advance
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OK
LIPO are safe if used correctly . A SLA can be dangerous if used incorrectly .
LIPO come in many different sizes 4 main ones are 1s,2s 3s,4s Each cell is 3.2v so 2s would be 7.2v and for you a 3c would be 11.6v.
Next you will see the some thing like 2c next to the capacity . this means it can be charged at twice its capacity so a 2AH 2C has a max charge rate of 4AH
Next you will see a number like may be 25C next to the voltage number . This means this is the max discharge the bat can handle. So a 1ah 25c could handle max discharge of 25 ah in bursts .
Ok you have not given the AH of your SLA bat. Mast retailers will give the sive and weight of the bat . A 3C 8ah lipo will way about 30% of a 12v 7ah SLA.
Chargers and plugs . Ok 3B charger is A very good charger available in both battery or mains and battery power in . You will need to get leads and plugs that match you new lipo battery for you charger and boat. Be careful the old tamiya plug can NOT handle big current.
Were to buy
There is compont shop .Howes or Hobby King UK. with HK be very very carful that you order from the UK warehouse and not the International ware house or postage and may be import tax will hit you.
john
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Thanks for that . That has helped explain it for me . Was confused with all the extra codes
Graeme
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Hi Graeme
It can be very off putting all the codes and some of the stories about Lipos. I use them in scale model no problems . Only in very fast electrics were there is very high current draw you really need to be hot on the numbers .
John
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Cool going to look at a 7v set for my weser as it has twin 7v motors then 11v set for my patrol boat as it's got twin 12v motors . Just wondering if it's better to run 2 packs in each model wired parallel for longer pond times and maybe a third in the weser once I fit 3rd motor or am I over thinking this now
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Running packs in Parallel is better than one per motor in my opinion.
Only proviso on that is make sure the packs are of a similar charge state when you parallel them.
Otherwise you may get high currents flowing from the higher charged pack to the discharged one.
Fit as much battery as you need ballast, or as your pocket will allow. Its best not to discharge LIPOs down low, so the more capacity you've got, the lower the chances of you running your batteries down too far. Most modern ESCs have protection in for discharge now anyway.
Rgds
Jon
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Thanks for that that's what I was hoping
Graeme
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You should also invest in one of these or equivilant.
http://www.hobbyking.com/hobbyking/store/__65837__TURNIGY_Super_Bright_LED_Low_Voltage_Alarm_Device.html
http://www.hobbyking.com/hobbyking/store/__68815__Turnigy_Low_Voltage_Alarm_Super_Bright_LED_Light_Set_2_x_Red_Green_.html
This one is the best value - use them in all my LiPo powered boats.
http://www.hobbyking.com/hobbyking/store/__18987__HobbyKing_8482_Lipoly_Low_Voltage_Alarm_2s_4s_.html
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Hi
http://www.hobbyking.com/hobbyking/store/__42953__HobbyKing_8482_Cell_Checker_with_Low_Voltage_Alarm_2S_8S_UK_Warehouse_.html
The best voltage alarm is the black ones, checks total voltage and checks each cell.
A little dearer with the extra bits good value.
Also with Lipo batteries a safety charge bag and not leave unattended !!!!!
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How would that work with 2 bats in parallel? will it test one bat or both ?
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NO!!!
Require one for each battery, plugs into the balance lead of the battery.
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OK thank u
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Absolutely. Treat each battery as a separate unit, charging, using, or storing. handel the cells gently, they are fragile, dont bang or drop them, or they are dented thats when you can get problems, parallel the batteries to get better running time, i just bought some 2200mah from ebay at £10 each, good quality name, (checked on google) putting 2 packs into my Southampton tug for the weight of 1 SLA
Mark
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Cool
Looking at getting 4 in the patrol boat just to sink the aft end down and two speed controllers so separating the motors then 4 in fire boat to sink back end and 2 speed controllers so I can run single double or triple screw on it so always have a back up screw too just in case
Graeme
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Why not look into the LiFePo cells instead, inherently safer and a few other advantages. A good comparison here (https://youtu.be/KXLvljqde0M)
Available here (http://www.hobbyking.com/hobbyking/store/__218__85__Batteries_Accessories-LiFePo4.html?gclid=CPin-uv7ic0CFUQGcwod-3cPOQ)
or here (http://www.componentshop.co.uk/batteries/radio-control/li-fe-power-packs)
or many other places.