Question on CT smart charger

Submitted: Friday, Oct 28, 2005 at 19:58
ThreadID: 27640 Views:2849 Replies:5 FollowUps:3
This Thread has been Archived
I intend to have 3*100Ah AGM batteries in a CT. I am tossing up between a 20A smart charger and a 40A smart charger. It occurred to me though that if the 240V at caravan parks is limited to 10A like home power plugs, then your maximum draw is 2400W which is 12V*20A. If this is true, a 40A smart charger is overkill as it could not supply that current with the 240V limitation. Am I correct, or are caravan outlets more than 2400W?
Back Expand Un-Read 0 Moderator

Reply By: Eric Experience. - Friday, Oct 28, 2005 at 20:11

Friday, Oct 28, 2005 at 20:11
Sky pilot.
You will have no problems with power your charger should only draw 2 amps.
You need a serius charger for what you are doing, I suggest you talk to a computor shop and try to get an old UPS supply, some banks etc, change them often as a precaution, the chargers in the ups are superior to any unit you will find in a auto shop,
Eric
AnswerID: 136834

Reply By: Grungle - Friday, Oct 28, 2005 at 20:45

Friday, Oct 28, 2005 at 20:45
Hi Sky Pilot,

I have 4 x 100 Ahr batteries in the CT and charge them with a 30A 3 stage smart charger I bought off Ebay for $370 (Durst brand). Charges them fast and @ just under the 30A from a standard house power point or 1000W gennie during its boost stage. Go the biggest you can afford but remember that batteries are designed to charge at a specific rate (C10, C20 etc). check the rate as specified by the manufacturer of your batteries.

BTW I have a write up on my system on my website

Regards
David
AnswerID: 136841

Follow Up By: Sky Pilot - Friday, Oct 28, 2005 at 22:04

Friday, Oct 28, 2005 at 22:04
Thats one heck of a smart system David. It is what I'd love, but wouldn't have the confidence to bite off. Why do you feed the Honda generator backto the chargers rather than straight into the batteries?
0
FollowupID: 390614

Follow Up By: Grungle - Saturday, Oct 29, 2005 at 09:03

Saturday, Oct 29, 2005 at 09:03
The Honda Gennie only has a 12v 8A DC output which is good for nothing really. The voltage is about 12.5v which is insufficient for battery charging as the batteries need 14.2v for a bulk of the charge and then float at 13.5v. There is no better way to charge a battery than a 3 stage smart charger.

You don't have to spend an arm and a leg either. My system cost $400 for 4 batteries (2 years old but from a mainframe UPS system so well looked after - life of these are 7 years), $370 for a 3 stage 30A 240v battery charger from eBay (Durst Brand - New - Australian made with warranty), $120 for a 3 stage 20A solar regulator from eBay (Manson Brand - New - with warranty - works great so far) with the solar panel being the dearest at $770 as a web special from Solar Panel Express. The Honda gennie was a swap for a PDA phone. Good quality, high amperage cabling was around $100 including connectors and anderson plugs (which are $12 on eBay for a pair).

Design what you want for the type of camping you do and also the space you have to install it all. Then shop around and ask people what brands they use and how it all perfoms. Buying my system with new items and well known brands would cost around $4000+. The good thing about buying from eBay is that you have other customers there that have purchased the goods before you and you can message and ask how the product is.

The only thing I would be careful with is buying secondhand batteries. I was lucky with mine as I got to thoroughly check one before buying plus I knew the history.

My last (first) bit advice would be to buy a book on the subject. The best by far is Collyn Rivers book, Motorhome Electrics & Caravans Too!

Regards
David
0
FollowupID: 390636

Reply By: Member - Paul P (Bris) - Friday, Oct 28, 2005 at 20:46

Friday, Oct 28, 2005 at 20:46
G'day

The 40amp is fine on 240 volt 10amps. You could go bigger if you wish without exceeding the 240volt 10amp supply. A lot to charge (battery/amp hour wise). A ten amp charger will take a long time to bring your 300amp hours back up even if only 50% discharged.

I would assume a good brand smart charger is your choice? eg Xantrex or similiar. Have a look at Absorbed Power in Manly Brisbane also.

Regards

Paul

Paul
AnswerID: 136842

Reply By: drivesafe - Friday, Oct 28, 2005 at 21:07

Friday, Oct 28, 2005 at 21:07
Hi Sky Pilot, under Australian Wiring Standards Regulations, all caravan parks are supposed to have 16 amp power outlets so your going to have heaps to play with.

Cheers
AnswerID: 136847

Reply By: Member - Stephen (WA) - Friday, Oct 28, 2005 at 22:45

Friday, Oct 28, 2005 at 22:45
Hi Sky-Pilot,

No drama - you're out by a facor of 10. 2,400W is 12V at 200 amps (not 20A).

I let my decimal points wander places they shouldn't as well sometimes.

Hope this has eased your worries about the supply capacity.

Regards
Stephen J.
VKS737 - Mobile 2735

Lifetime Member
My Profile  My Position  Send Message

AnswerID: 136861

Follow Up By: Sky Pilot - Saturday, Oct 29, 2005 at 06:57

Saturday, Oct 29, 2005 at 06:57
Doh! Whoops sorry. You're right Stephen. I thought my theory of conservation of energy was right - just miscalculated how much energy there was to conserve:-)
0
FollowupID: 390626

Sponsored Links

Popular Products (9)