too big a battery?

[BJ Navara]

So the time has come to buy a new tub battery.
I am running an Evakool fridge freezer, a couple of leds and that's about it.

old battery was 120 amphour deep cycle/cranker combo fed by a Redarc BCDC 1225.

So, as I understand it, the bigger the amphours, the longer it will take for the redarc to top it up, is that right?

I am looking at a 105ah deep cycle AGM as an alternative on the basis that it will recharge faster.

If that is a goer, the next question is whether Giant (from China) is a realistic supplier - so much cheaper than the Aussie Century that seems identical in every spec, and with a much longer warranty....

Love to know what you think

 

[happy john]

Yes the more A/H the longer to recharge and a AGM will recharge a little quicker than a wet cell deep cycle. I'd look at the Ctek charger to look after it properly. In the heat lately my cranker gets 13.7 with the a/c on yet the aux is charged to 14.5 via the Ctek.

The same Giant 120a/h battery is used after 4 years in the link below, I run a 21ltr Engel as a frezzer, and a 40 ltr as fridge. Never had a power issue and I can add another 120a/h if needed via a Anderson plug.
http://www.navara.asia/showthread.php?t=22631

 

[Czechmate]

https://www.anacondastores.com/camp...ZHiAa3L6uDD4CBZBj91GRhmDBR_IYxWraMaAiRB8P8HAQ

I bought this exide deep cycle from sprint auto for 399 a few months ago. Has been good running a 40 litre national luna fridge freezer in 40+ degree weather
Made in USA, and has a long extended warranty if you register it online

 

[Old.Tony]

The problem with buying a smaller battery so that it charges faster is that the smaller battery also holds less charge - so your gear won't last as long.

I have a 75Ah Optima D31A in my tub and while it was just the Engel and the LED strip in the awning, I had no worries. I've added a 40L Stirling that I use as a freezer and the 75Ah isn't enough now. I'm going to upgrade my solar panel from 120W to 200W and am looking to replace the 75Ah with a 100Ah battery.

The time to charge isn't as important to me as how long the battery lasts. Increasing the capacity makes the time-to-charge longer, but it also means that my equipment runs longer between charges.

 

[BJ Navara]

Yes the more A/H the longer to recharge and a AGM will recharge a little quicker than a wet cell deep cycle. I'd look at the Ctek charger to look after it properly. In the heat lately my cranker gets 13.7 with the a/c on yet the aux is charged to 14.5 via the Ctek.

The same Giant 120a/h battery is used after 4 years in the link below, I run a 21ltr Engel as a frezzer, and a 40 ltr as fridge. Never had a power issue and I can add another 120a/h if needed via a Anderson plug.
http://www.navara.asia/showthread.php?t=22631

As the red arc is in and it wasn't cheap it will be staying for now.
I haven't seen bad comment on the Giant so far, and it's considerably cheaper.
Good to see its working for you

 

[BJ Navara]

The problem with buying a smaller battery so that it charges faster is that the smaller battery also holds less charge - so your gear won't last as long.

I have a 75Ah Optima D31A in my tub and while it was just the Engel and the LED strip in the awning, I had no worries. I've added a 40L Stirling that I use as a freezer and the 75Ah isn't enough now. I'm going to upgrade my solar panel from 120W to 200W and am looking to replace the 75Ah with a 100Ah battery.

The time to charge isn't as important to me as how long the battery lasts. Increasing the capacity makes the time-to-charge longer, but it also means that my equipment runs longer between charges.

Gday old Tony, my concern was that if it doesn't get fully topped up, the Evakool is very precious about battery drop and goes on strike.
So trying to walk the line between a big battery I can't get to full charge and a smaller one that needs less time...
Battery bloke did the math and reckoned the 105ah would walk it in, but I suppose in the grand scheme of things the bcdc redarc will deal with 120ah just as well?

 

[BJ Navara]

https://www.anacondastores.com/camp...ZHiAa3L6uDD4CBZBj91GRhmDBR_IYxWraMaAiRB8P8HAQ

I bought this exide deep cycle from sprint auto for 399 a few months ago. Has been good running a 40 litre national luna fridge freezer in 40+ degree weather
Made in USA, and has a long extended warranty if you register it online

Thanks for the link! I will take a look!

 

[Old.Tony]

Gday old Tony, my concern was that if it doesn't get fully topped up, the Evakool is very precious about battery drop and goes on strike.
So trying to walk the line between a big battery I can't get to full charge and a smaller one that needs less time...
Battery bloke did the math and reckoned the 105ah would walk it in, but I suppose in the grand scheme of things the bcdc redarc will deal with 120ah just as well?

You're correct about needing a full charge, but it's actually not as vital for the fridge as it is for the battery's longevity. If a 105 will handle it that's great, but remember that it's only when the battery is new that it will do that. As they age, their capacity diminishes.

As for how much charge the RedArc can handle ... it's pretty much unlimited, really. One of the campers in another forum I'm on has a battery bank of around 1200Ah. Motorhomes often have capacities of 400Ah and greater and Redarc controllers are sometimes used.

C-Tek is good (maybe better as a smart charging device) but the Redarc isn't bad and more than adequate.

Here's an important test for you to conduct.

Disconnect the battery terminal from the auxiliary battery and connect a multimeter set to DC Volts (50) to the two battery clamps. Have someone start the car and hold the revs at around 1500rpm while you watch the multimeter.

What voltage do you see on the multimeter?

 

[BJ Navara]

It's all in pieces at present as the new drawer setup is only now being wired back up.

 

[BJ Navara]

Fridge data says that at ambient43C it will use 2.3A per hour worst case.
Everything else is worst case the same.
Using Century battery brochure estimator calculator -
So say 5A X 12v is 60 watts.
Drawing for say 10 hours flat out is 600 Wh, plus 30% buffer makes it 780Wh.

So at 80% of battery discharge, battery capacity needs to be 780 divided by 10 (12v X .8) or 78Ah
On that basis 105 Ah battery seems fine.

BUT, is it realistic to draw to 80% of discharge? Does that mean 80% left or 80% gone?

 

[happy john]

I'm a little confused by your maths, does the Everkool use the Danfoss/Seacorp compressor as in the Waeco?.

 

[BJ Navara]

I'm a little confused by your maths, does the Everkool use the Danfoss/Seacorp compressor as in the Waeco?.

Yep.Their website in FAQs says worst case with the freezer at -19 and outside temp at 43, it will draw 2.3 amps per hour

 

[happy john]

Aarhh thought so, it's a good compressor but very voltage sensitive. I'd never use 80% of capacity as it will kill the battery quickly and you may find it will not have enough grunt to power the fridge. I just use a digital volt meter, the 120 watt panel just powers both fridges in full sunlight and I have a 160watt on order that will be used when needed.

I keep an eye on the voltage and when I see 12.3 under load it's time for a drive or idle for 30 mins.

 

[happy john]

Have a read here.
http://www.powerstream.com/battery-capacity-calculations.htm

 

[bods]

Ideally you don't want to run it below 50% soc otherwise you will shorten the life of the battery.

The redarc controller you have will be fine as it is the same thing as the ctek charger anyway. It might be worth investing in a solar panel, especially if you go camping a lot. Either mounted to the roof or on a stand so you can move it around. Just wire up an anderson plug in the vehicle that feeds the second battery and make sure you get a regulated panel. That way if you want it portable, you can just get it out when you need it. If you don't want a normal solid panel, those solar blankets aren't a bad idea, they are getting cheaper too.

 

[Czechmate]

This is a bit off topic but since Secop has been mentioned I'll post it anyway
I recently bought a national luna fridge with "danfoss" compressor marked on the box
When i got home i looked in the side panel at the compressor and found the brand "Secop" and model "BD35F"
Secop bought danfoss years ago
I emailed Secop in England, Slovenia and Austria asking about the changes to the danfoss compressor
They all replied with the same answer, the design is the same, but now its manufactured in china by Secop
:\

 

[happy john]

This is a bit off topic but since Secop has been mentioned I'll post it anyway
I recently bought a national luna fridge with "danfoss" compressor marked on the box
When i got home i looked in the side panel at the compressor and found the brand "Secop" and model "BD35F"
Secop bought danfoss years ago
I emailed Secop in England, Slovenia and Austria asking about the changes to the danfoss compressor
They all replied with the same answer, the design is the same, but now its manufactured in china by Secop
:\

As far as I know nothing has changed, they have had the factory in China since 2008. There's a big contract to supply Kings Fridges with the same compressor.

 

[MANNING]

As far as I know nothing has changed, they have had the factory in China since 2008. There's a big contract to supply Kings Fridges with the same compressor.

https://www.productsafety.gov.au/re...odel-akf60-portable-compressor-fridge-freezer

 

[happy john]

They have fixed it after that Manning thanks for the link.

 

[happy john]

I paid $1150 in 1992 for my Engel. Just a tad more now for the same thing.