any sparkys in here? got a power question

[theoneandonlyfat]

lets just say SWIM wanted to grow 24 turnip plants that would require a total of 150 litres a day. If he were to run 2 of the pumps below, what size/type battery would he need and how long would it last? the garden will be about 2m above the water source.

 

Lets say swim used this battery:

 

High performance Supreme heavey duty DEEP CYCLE battery (model: 24DC36) -- Made in USA

 

12V 85Ah

 

160RC 730CA

 

Dimensions: 283(L)x171(W)x238(H)

 

Weight: 22.3Kg

 

Model: 24DC36

with this pump:

 

Bilge Pumps Submersible - Johnson

Description: Johnson's cartridge pump concept (L450 L550 & L750) makes cleaning easier. Lift the tab on the top, give the cartridge a twist and pull it out. L1600 & L2200 uses liquid cooled, 12 pole motor with double ball bearings for extended service life

 

Code Size Type Voltage Wattage Unit $USD $AUD(i) ADD

PUE470 53L/min L450 700gph 12v DC 2 amps EACH $27.14 $36.85 <<

 

 

 

Now swim knows nothing about electricity, but if he runs 2x 2 amp pumps for 15mins a day, does that mean he will use 1amp hour a day, and if the battery is rated at 85 amp hours will it last for 85 days???? this doesnt seem right to swim.

 

thanks,

fatboy

Edited September 8, 2008 by theoneandonlyfat

[Frazz]

Get a small solar panel(12vJaycar,etc) and it will continuously trickle charge your battery , problem solved provided direct sunlight hits solar panel

 

[theoneandonlyfat]

SWIM would like to avoid a solar panel if possible. can it be done by just swaping the battery once a week and recharging??

 

or should i tell swim he's dreaming??

[Al B. Fuct]

Now swim knows nothing about electricity, but if he runs 2x 2 amp pumps for 15mins a day, does that mean he will use 1amp hour a day, and if the battery is rated at 85 amp hours will it last for 85 days???? this doesnt seem right to swim.

 

yep, 4A for 15 mins is 1AH. 85AH would indeed appear to be enough to support that draw for 85 days. A deep cycle battery is supposed to hold its cell voltage closer to charged level despite discharge, falling off sharply at full discharge, so it's the right kind of battery for the job. I think I'd mock it up in a bucket on the garage floor and test it to be sure.

 

I like the solar panel idea. However, I don't like that they'd be really visible in surrounding veg due to being covered with a sheet of glass, usually. However, so would a trail worn to the site to swap batteries.

[brick]

yep, 4A for 15 mins is 1AH. 85AH would indeed appear to be enough to support that draw for 85 days. A deep cycle battery is supposed to hold its cell voltage closer to charged level despite discharge, falling off sharply at full discharge, so it's the right kind of battery for the job. I think I'd mock it up in a bucket on the garage floor and test it to be sure.

 

I like the solar panel idea. However, I don't like that they'd be really visible in surrounding veg due to being covered with a sheet of glass, usually. However, so would a trail worn to the site to swap batteries.

 

Another problem that may occur is if the nights get cold I mean below 10oc that will shorten the battery life.

[Al B. Fuct]

Good point, lead acid batts like to be warm-ish, ideally about 26-27C. There's a formula somewhere for derating the CCA of a car batt as temps fall below there, damned if I can find it right this sec. A deep cycle batt won't transfer as much stored energy at low temps as it will closer to 26C, so some derating of the AH is to be expected.

[Al B. Fuct]

Everything you could ever want to know about marine lead acid batts.

 

http://www.marine-electronics.net/techarti...y_faq/b_faq.htm

 

 

 

http://www.marine-electronics.net/techarticle/battery_faq/image011.gif

 

CAPACITY vs. TEMPERATURE °C

[danoz]

No nothing about elec swim but no a thing or two about batteries.

In my opinion. ....

You cant run it to 85 amps batteries rates at 85 start to flatten at 75 and are flat by 85 problem is completely draining a lead acid battery stuffs its chemistry i think they say you can get away with three complete flattenings of a new battery before its damaged. Therefore i would try to calculate to swap recharge what ever at like 70 amps to be sure.

 

Another option and it means more money is a gel cel lead acid like for a caravan these dont leak acid and are a sealed unit. furthermore no worries operating at low temp they are made for it. Downside is cost closed cell lead acid batts are fucking expensive > $300 for a 100amp hour caravan battery. waeco and engel batteries are also examples of sealed lead acid but these offer shit value with 30 amp hour cost > $200

[Al B. Fuct]

better idea yet on the gel cells!

[theoneandonlyfat]

ok thanks for all the replies everyone, the gel cells seem to expensive gonna go with something like the one i posted.

 

seeing as the deep cycle batteries operate best at 26degrees, should swim set the timer to operate the pump during the hottest part of the day?

 

also if this battery is left out bush, will it need to be kept out of the rain or are they weather proof??