12v system with new charger

Submitted: Wednesday, Mar 09, 2011 at 16:12

ThreadID: 84899 Views:2530 Replies:3 FollowUps:6

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Battery Power

In this article we explain why you might need an additional power source independent of the starting battery installed into your vehicle and we look in detail at types of batteries,

kevmac....(WA)

Finally finished rewiring 12 volt system on my caravan and installed a new "Supercrap"(as some of you refer to them as) 20 amp multi stage charger.plugged the 240v in and charged 120a/h battery to full capacity( strange as already thought was there off my old charger). Turned off power 8.30pm and went to bed.
On way to work at 7.30am turned power back on and checked charger and to my happiness was only charging at absorption rate. Had wife check it at 10.30am and was already on float rate. Sheer bliss for me. Means now that should only have to run generator max of 3 - 4 hrs twice a day now, instead of 12 - 13 hrs per day.

Maybe even get away with running generator say 4 - 5 hrs once a day, does that sound about right??

Forgot to mention was just running Waeco 110 ltr 12 upright fridge which allegedly draws on average around 3a/hrs. Note on this occassion fridge was on from hot. I run LED lights with alleged drain of 0.23a/hrs.

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Reply By: Member -Dodger - Wednesday, Mar 09, 2011 at 16:23

Wednesday, Mar 09, 2011 at 16:23

Kev
Your just about there, now get yourself a portable 120watt solar setup and the Generator would hardly be required.

I used to have a handle on life, but it broke.

Cheers Dodg.

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AnswerID: 447775

Follow Up By: kevmac....(WA) - Wednesday, Mar 09, 2011 at 18:06

Wednesday, Mar 09, 2011 at 18:06

This is a long work in progress until current generator(no pun intended) stuffs up. Between now and then yes i will weigh up all options of power generation.
Maybe i will win Lotto soon and all problems will be solved.

FollowupID: 720088

Reply By: Battery Value Pty Ltd - Wednesday, Mar 09, 2011 at 18:17

Wednesday, Mar 09, 2011 at 18:17

Hello kevmac,

there's a couple of tests I recommend to do:

Start with a fully charged battery.
Wire a voltmeter across its terminals.

Then connect the fridge and charger to the battery and plug the charger in 240VAC.
Put the fridge on max setting and leave the door open so that the compressor runs continuously.
Note the start time and keep an eye on the voltmeter readings.

If your charger goes into absorption (14.4V) straight away and stays there for a couple of hours before switching back to float (13.6V), the absorption-float switchover is timed electronically.
If it stays on absorption all day long, the switch-over is charging/load current dependent.

Both charging methods have their 'issues':
timed: battery always receives the same amount of (over)charging as soon as the charger is switched on, even if battery's fully charged already.
Charging/load current: battery always receives absorption (over)charge as soon as fridge compressor draws current, even if battery's already full and charger should be in float mode.

Good chargers offer charging/load dependent switch-over, with selectable max absorption times as an override.
Selectable power supply mode (fixed 13.8V output) also helps to overcome this.

cheers, Peter

AnswerID: 447784

Follow Up By: hazo - Wednesday, Mar 09, 2011 at 19:24

Wednesday, Mar 09, 2011 at 19:24

I had exactly the same problem that Battery Value mentioned.

Every time my compressor fridge (Waeco HDC 190) fired up the smart charger would go into absorbtion mode, ended up stuffing my two Trojan Deep cycle batteries in less than 2 years!

Both battery casings swelled considerably due to excessive overcharging.

I now have full solar and that takes care of all my batterys needs without overcharging when on mains power.

I also fitted a relay and Anderson plug so fridge is powered from car when mobile and caravan batteries are again charged just by solar.

FollowupID: 720092

Follow Up By: paulnsw - Thursday, Mar 10, 2011 at 11:47

Thursday, Mar 10, 2011 at 11:47

If you use a Xantrex Truecharge2 they recognise the load on the battery and act as a power supply with the load connected and dont overcharge and ruin the battery.

FollowupID: 720164

Reply By: PatrolEv - Wednesday, Mar 09, 2011 at 19:37

Wednesday, Mar 09, 2011 at 19:37

Hi Kevmac,

Good stuff mate, glad it works.

I am seriously considering changing my old 3 way fridge for a 110L upright Waeco 12v, do you find it a good fridge? I have a waeco 50L car fridge and use that more than my 3 way because it gets things cold fast and keeps them cold.

I am looking at adding another battery and putting some solar on the roof ooooof the van to keep it plus my other things running. Do you think 3amps per hour is genuine?

Cheers
Ev

AnswerID: 447789

Follow Up By: paulnsw - Thursday, Mar 10, 2011 at 11:52

Thursday, Mar 10, 2011 at 11:52

Swapped the 3 say fridge over to a Waeco 110L 18 months past. Good fridge and holds 3C middle of summer. 3A is genuine and in winter less. Fortunately received great advice how to setup solar, solar regulator and batteries. Dont own or need a noisy bloody generator.

FollowupID: 720165