Ctek D250s versus Redarc

[sparra04]

my system is a bit different as i have 2 batteries linked
so if i suffer cable damage i still have the potential to have cable live at BOTH ends, until both fuses blow
better to be safe than sorry
tony what size fuse would you reccomend ??
all my research suggested 100 amp fuse
and most kits come with 100 amp megafuses
good luck with the build rusty
its looking good

 

[Old.Tony]

Getting the fuse size right is important. If the fuse is too small, it will still let power through but it will heat up, increasing its resistance and lowering the voltage on the other side. If it's far too small, when your fridge compressor starts the fuse will blow.

If it's too large, a problem could occur and the fuse won't blow when it needs to. Here's how I'd pick the fuse.

For the aux battery run from the front: I'd rate the fuse on BOTH ends at the rated output of the isolator.

If the aux battery is in an isolated chamber in the tub together with all of its outputs, I'd just fuse each of the outputs depending on what was going in them.

Cigarette-style outputs (multipurpose) = 20A fuse. Fridge would be the fuse above the manufacturer's rated maximum draw with a little room to spare (because compressor startup rush current could exceed their rated maximum by a bit) - so a 4A Engel would get a 10A fuse not a 5A. Don't worry about inverters, they're internally fused - and if yours isn't, next time you buy one make sure it is self-fused and electrically isolated.

 

[Nobby]

A fuse/breaker should be fitted from the starting battery (as close to the starting battery as posible) to suit the current rating of the cable being used or the equipment to be run, then a 40amp before the charger (as close to the charger as posible). The first fuse/breaker protects the cable running to the 40amp in case of damage, and the 40amp protects the charger.

When I have installed these, I usually run a Fuse/breaker rated to the cable being used to avoid voltage drops just after the starting battery, then a fuse/breaker rated to the equipment being used.

 

[RustyNav09]

alrite last question before i put my coin down on one fo these units. so far its heading directly towards the ctek. some website say that its better coupling the ctek smartpass unit with the d250s dual unit, why? is it really necessary? if the 250sdual does everything the smartpass can do then whats the point?

Already ordered the 40amp auto reset breakers. Just gotta work out how I'm gonna wire it in. Should be easy though

rusty

 

[Old.Tony]

I'm not sure the SmartPass is essential. It will prevent you from using the auxiliary battery down to the point where you're damaging the battery, but I couldn't justify buying one, especially for $300+.

 

[RustyNav09]

Sweet ordering it tomoz. I like the screw type fittings gf ctek unit has. Means I can reuse my wire I have already used without having to change to many terminals.

 

[Nobby]

Mate, you do not require a smartpass with the 250s for a dual battery system in a 4wd. It's more designed for battery banks.

The big diference, with out getting to technical, between the redarc and the ctek is that the redarc compensates for voltage drops in the system.

I've installed both units and used both units for different requirements. If you were going to fit it in a caravan or a trailer i'd go with the redarc due to the voltage drop and the ability to run smaller cable, but for what you want it for, the ctek is perfect and cheaper.

One of the benefits I like with the ctek is that when you connect a solar pannel it will maintain both batteries.

If you want more info i can Pm you my number and you can give me a call if you like.

Nobby

 

[user 1102]

Believe the Smartpass will charge at up to 80 Amps at Alternator voltage, then the D250S will continue to charge at up to 20 Amps to 14.4 Volts.
Will recharge flat battery quicker with both.

 

[joffo81]

Hi everyone, I know i'm dredging up an old thread but i'd just like some clarification from those in the know before I install a ctek dual! I'm planning to run the ctek to charge my aux battery in the tub via the alternator or solar panel (fixed to roof rack).

I already have a redarc SBI12 isolator separating the starter from the auxillary batteries. My question is............can I leave the isolator in place and just run the ctek dual between the isolator and aux battery? I realise that the redarc isolator is not needed with the ctek but for ease of intallation and removal (if needed at a later date) of the ctek I would like to leave the redarc where it is!

Would leaving the isolator before the ctek affect the charging of the auxillary in a major way or will the ctek just boost the voltage it receives when it recieves it?

Because I will have a solar panel mounted permanently and hooked to the ctek, my aux battery should be receiving a charge (sun dependent) until the redarc isolator allows charge through to the ctek when driving.

What are your thoughts/opinions/experiences?

 

[Old.Tony]

I don't think it's a bad thing leaving the isolator in the mix. Basically what it's going to do is wait until the starter has enough charge then it'll hand some power to the C-Tek to charge the aux.

That's not a bad way of doing it. It means you can leave your ignition in "ACC" to listen to the radio and not have the aux battery sucking the life out of the starter. Adding the solar panel is just pure smart.

The only things I'd ensure are that there's a fuse between the Redarc isolator and the cable run heading to the rear (protects the isolator and the cable). Make it about 40A, mounted close to the isolator. The other thing I'd do is make sure the cable between the isolator and C-Tek is at least 8G, if not 4G - reduces voltage drop, makes the system more efficient.

 

[joffo81]

Excellent - thanks for your reply Old Tony! Looks like it ticks all the boxes for me. Now I just need to order some gear and do the install.

 

[user 1102]

My Dual Battery Setup

Finished off my setup today, planning on giving it a go this long weekend. Has a Optima D31A battery, CTEK D250S Dual Charger, BAINTECH Universal Panel and a custom battery tray. Ran 8 B&S twin cable with a 50A Anderson plug so I can disconnect with the plan to plug into a camper trailer with battery later.

 

[Old.Tony]

^ Now that's a tidy setup.

 

[mike1303]

^ Now that's a tidy setup.

Have a look at the new redarc bms1215s2 Tony... Their new fan dangle system.... And that price!!!!

 

[Old.Tony]

Holy sweet Mary mother of ... hopefully it comes with a nice chain so you can wear it around your neck when you go to nerd discos.

They have a 1230 as well. At $1700. Wow.

 

[mike1303]

You seen what it does though?
Pretty much plug everything in and let it go!!

 

[Old.Tony]

If money was no object I'd consider it, for sure. Since $ are tight, if I had to start again I'd grab a D250S and the cheapo battery monitor that I have now (only a few $ on eBay).

 

[rsgooch]

If money was no object I'd consider it, for sure. Since $ are tight, if I had to start again I'd grab a D250S and the cheapo battery monitor that I have now (only a few $ on eBay).

Hey Tony what battery monitor are you using? Does it have shunt?

 

[Old.Tony]

Yes mine has a shunt. It's not exactly this model but it's close to it. The caveat is that it doesn't work well over long distances measuring current - here's why (for those that are interested).

Shunts are fantastic for measuring current, because at a given power level, there'll be a given voltage drop over the shunt. A shunt is a precisely manufactured piece of metal that has a large capacity and a very accurate resistance under load.

When a certain amount of current (amps) is passed through the shunt, the voltage drops by a certain amount. It's a tiny voltage difference. This variation is lost on the cable over about 2m. I had mine connected directly to my battery and it worked perfectly but now there's about 6m of cable from the back into the cabin I'm only getting volts - that's ok, I can tell roughly what is happening to my battery just by seeing that.

Connections are:

One side of shunt - negative battery post, along with negative wire to meter
Other side of shunt - meter sensor wire and negative out to devices
Red wire from meter - battery positive

How to tell what's happening to your battery: typically a battery that's fully charged and not being charged/floated will hold around 12.8V unless you put a load on it. If the voltage is higher than 12.8V the battery is probably being charged, and if it's less the battery is probably being discharged (or has been!).

 

[75 GRC]

Like this shunt not installed at the time my photo.

The shunt is a great option.
It tells you exactly what amps you are drawing.

^^^^^^
Agree with Tony