Replacement for Lead Acid battery - Page 1
Forum section: electronics / projects

author: Bloch
author_rank: Unknown
timestamp: December 02, 2012, 11:57:55 am
content: Today i use a LC-R127R2P and LC-RA1212P 12Volt 7,2Ah and 12Ah.The battery drives a 10Watt dc/dc converter that needs 10-36 Volt InThat i am looking for is a lighter battery.I did look on the comments (EEVblog #393 - LiPo) that they cant be stored fully charged. That will not work for me.So I was hoping some one did have some advice that to do and not to do.

author: SeanB
author_rank: Super Contributor
timestamp: December 02, 2012, 12:08:47 pm
content: What life and what battery life do you want? Use a few of Dave's latest 5AH lithium cells in series with the associated charger to recharge them. 6 in series will be a little lighter than the SLA, and will have more energy, though you will have to make up the 6 cell pack yourself along with the charge lead.

author: T4P
author_rank: Super Contributor
timestamp: December 02, 2012, 12:31:48 pm
content: Be careful with series charging, you can lead to all sorts of cell balancing issues so either you charge them individually or you charge and tap each cell off and monitor voltage of each cell, thus have to balance as in discharge another cell now and then

author: Bloch
author_rank: Unknown
timestamp: December 02, 2012, 12:52:40 pm
content: It is for remote measurements. It will be used daily /weekly. And for life the batteries can be replaced /checked every 6/12 month.so maybe a 4 cellhttp://www.hobbyking.com/hobbyking/store/__18560__Turnigy_5000mAh_1S_20C_Lipoly_Single_Cell_.htmlandcharge to 4 Voltdischarge to 3 voltTo bad that rs and farnell dont have them.

author: muvideo
author_rank: Frequent Contributor
timestamp: December 02, 2012, 06:22:30 pm
content: Quote from: Bloch on December 02, 2012, 12:52:40 pmHello.Storage voltage:Li-ion (or Li-po) charged to 4.1V retain almost full capacity, and should have longer life thanif fully charged to 4.2. Will you charge them in service? If they will be slowly discharged and thenperiodically recharged they should fare well, since they will stay in high voltage for breaf periods,for most of the discharge the voltage will be less than 4V per cell.If they will be charged during service, I wouldn't use the Li-po or Li-ion, because of safety reasons,if they fail (for example charged in high temperatures) they will catch fire.hobbyking:If you want to use the cells from hobbyking, maybe you can buy assembled packs, that will simplifyyour work, they come with connectors that you can plug into the cheap chargers* they sell.They have a nice battery finder applet:http://www.hobbyking.com/hobbyking/store/lithium_polymer_battery_configuration.asp?You can select voltage, capacity and warehouse.LiFePO4:Maybe for your use the Li iron phosphate chemistry can be better, less density but much moresafe, at least they dont catch fire, and in series of 4 have almost the same voltage range of 12V Pb batteries:http://www.ev-power.eu/LiFePO4-small-cells/I never bought from them, but I'm thinking to try some.*Charger: the cheap RC ones take care also of the balancing, and can be set to charge many chemistries,and also Ni and Pb.Fabio.

author: peter.mitchell
author_rank: Super Contributor
timestamp: December 03, 2012, 02:11:47 am
content: Quote from: Bloch on December 02, 2012, 12:52:40 pmThis particular pack has the same cells in it as the one Dave used,http://www.hobbyking.com/hobbyking/store/__15521__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack.htmlit has a hard(er) case which is weak, but better then raw cells, it is also 4 cells, for $22.60us rather than one cell for $8.98us, it has a tap at every cell so you can balance the pack also 75~Wh and 600~g