Battery Wars

[wesnewell]

Late to the party, but here's my option.
30 5000mah Turnigy 4S 20C hardcase packs configured as 20s6p for 74V nominal. 2220Wh. Cost under $700. Now all you need is a way to charge it.That can be done lots of ways from parallel charging all 30 bricks at once, which would be a real pita and time consuming, to charging the whole pack at once using a bulk charger and 6 battery medics to balance the whole pack. Cheapest realistic charger would be the 900W bms charger which would take about 4 hours to charge the whole pack for $88. Or for $250, their 2000W charger that would charge it in 2 hours. I think either of these would be lots faster than the little 2-5A charger you get with a ping. I wouldn't waste time or money on bms boards or parallel boards. I would use 6x balance leads to parallel at cell level. That will cost maybe $10 more.

 

[cwah]

Late to the party, but here's my option.
30 5000mah Turnigy 4S 20C hardcase packs configured as 20s6p for 74V nominal. 2220Wh. Cost under $700. Now all you need is a way to charge it.That can be done lots of ways from parallel charging all 30 bricks at once, which would be a real pita and time consuming, to charging the whole pack at once using a bulk charger and 6 battery medics to balance the whole pack. Cheapest realistic charger would be the 900W bms charger which would take about 4 hours to charge the whole pack for $88. Or for $250, their 2000W charger that would charge it in 2 hours. I think either of these would be lots faster than the little 2-5A charger you get with a ping. I wouldn't waste time or money on bms boards or parallel boards. I would use 6x balance leads to parallel at cell level. That will cost maybe $10 more.

For me a bms is a must have with such option unless you want to get the hassle to always check the cells, unplug and parallel packs every time you charge with associated risk and always fear to hit LVC or charge too high

 

[wesnewell]

I don't know where you get the idea you have to unplug and parallel anything to charge without a bms. You don't. You can balance charge any series using battery medics and a bulk charger. As for LVC, well there's one in the controller if you should ever run the pack that low.

 

[llile]

Late to the party, but here's my option.
30 5000mah Turnigy 4S 20C hardcase packs configured as 20s6p for 74V nominal. 2220Wh. Cost under $700.

Hmm - these are cheaper. Thanks!

Now all you need is a way to charge it. I wouldn't waste time or money on bms boards or parallel boards. I would use 6x balance leads to parallel at cell level. That will cost maybe $10 more.

Well, you can do that, but it won't be allowed to park in my garage. I think the money saved on not installing LVC/HVC and using a cheap charlie charger would be offset by the huge fire extringuisher you'd need to carry around. For my money, and fire insurance rates, Method's paralleling LVC/HVC boards would be needed to promote healthy and peaceful sleep. Best quality charger too. The rest of the nuts and bolts add up fast over $1000 by the time you buy good bulk chargers, power supplies, Andersons, and so forth, thus:

Methods:								
HVC Breaker Board			http://www.methtek.com/2012/07/26/hvc-breaker-potted-into-aluminum-housing/		                                 1	@	$120.00	 =$120.00
LVC Boards			http://www.methtek.com/2011/11/12/lvchvcparallel-boards-10/		                                                                3	@	$50.00	= $150.00
Parallel expansion boards			http://www.methtek.com/2012/05/04/parallel-boards-6s-5s-4s/		                                                  3	@	$10.00	= $30.00
Balance Tap Jumper			http://www.methtek.com/2012/05/10/jumper-6s-5s-4s/		                                                                        3	@	$3.00	= $9.00
Extension			http://www.methtek.com/2012/05/10/extension-6s-5s-4s/		                                                                                 3	@	$2.00	 = $6.00
Mouser:								0
Anderson PP75 Housings			http://www.mouser.com/catalog/catalogusd/645/1562.pdf		                                                        48	@	$1.47 =	$70.56
Anderson PP75 Contacts			http://www.mouser.com/ProductDetail/Anderson-Power-Products/5915-BK/?qs=sGAEpiMZZMtjzVbpKqo2YZRH3O%252bLIhj71A28q2e7a8A%3d		48	@	$0.62	= $29.76
Hobbyking:								0
iCharger 3010B 10S			http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=11597			                                                     $176.75
Turnigy 1200W 24V 50A power supply			http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=22820			                            $142.35
								0
Shipping					                                                                                                                                                                                            $340
misc					 	                                                                                                                                                                                            $50

 

[llile]

Alright I have made my decision. All this talk of Lipo, IMHO, is moot. If I go with a new battery pack, it'll be from Cell Man, but if I just add to my existing pack, it'll have to be Ping to match.

Turnigy LIPO is cheap, but the videos in the next three posts say why I'm not getting a LIPO without doubling it's cost with LVC/HVC electronics and the best charger money can buy. Even Boeing can't figure out how to keep LIPO batteries from catching on fire, and they are freaking rocket scientists. The more I look into this, the more scared of LIPO I become. You racers can keep them.

Cell Man wins the battery war. Ping gets a close second, similar in cost but heavier per WH.


http://em3ev.com/store/index.php?route=product/product&path=35&product_id=106



Lipo without protection electronics is out. Here is the reason:

 

[llile]

http://www.youtube.com/watch?v=M6xVZzZES-A

 

[llile]

http://www.youtube.com/watch?v=yc8NTkUKJ8k

 

[wesnewell]

Yep, any idiot can start a fire with lipo. They can also explode LA batteries, and even lifepo4 batteries. Been using lipo for over 2 years without as much as a puffed cell. I have 2 forms of protection. First is a cheap voltmeter. Second is LVC in the controller which I set to 86V for my 24s pack. Just yesterday I hit controller LVC about 2 blocks from home for the first time since going to 24s. Still had 9% soc. I don't need to squeeze more than that out of it.

 

[llile]

Yep, any idiot can start a fire with lipo. They can also explode LA batteries, and even lifepo4 batteries. Been using lipo for over 2 years without as much as a puffed cell. I have 2 forms of protection. First is a cheap voltmeter. Second is LVC in the controller which I set to 86V for my 24s pack. Just yesterday I hit controller LVC about 2 blocks from home for the first time since going to 24s. Still had 9% soc. I don't need to squeeze more than that out of it.

Glad to see you've got it under control! I would not want to end up like the folks int he video.

 

[llile]

Cell Man is able to make custom battery packs very reasonably. Right now he is quoting on a 24S2P 40AH 75 volt battery pack, split into two pieces. Cost is less than if I bought two 24S1P batteries, as it only needs one BMS.

Cell Man Batteries

 

[dnmun]

you can use a lipo BMS on the lipo packs just like you would with a lifepo4 pack. that will protect it and they are cheap too.

 

[sabongi]

Can you recommend any lipo BMS´s?

 

[dnmun]

i like the one that agnius found for 10S. sacko just bot a 24S lipo BMS for $73 from them.

http://www.bestekpower.com/888v24spcmbmspcbforli-ionli-polymerbatterypack/PCM-D131.html

you can choose the LVC and HVC for the BMS when you order. i would recommend 2.7 for LVC and 4.2 for the HVC.

 

[wesnewell]

2.7V is way too low for lvc for lico. I'd recommend 3.3V minimum for a 20ah pack and 3.4V minimum for a 10ah pack. With 3.5V being better imo. 3.5V will let you use up to 96% of the charge. At 2.7V you've long gone over the cliff and your pack will get so out of balance it will take days to get it back in balance, if you haven't already ruined a bunch of cells or incinerated the pack from thermal runaway.