Redarc vs Ctek

[Colin Hughes]

Thanks guys. I will read through the article mentioned above today. While I was out driving yesterday, I put the battery voltage screen up on the dash. It runs at 14.4 when driving. When I stop, it starts to drop and when the start/stop turns the engine off, it drops even more and goes down to around 8.5 when it restarts. If I turn off the start/stop, it stays at 14.4 constantly. If I don't use the stop/start, it seems it's almost like not having a smart alt.

 

[dwh]

The stop/start won't really change anything.

You push the battery up above 14v to get it charged in a timely fashion, but a fully charged 12v lead-acid battery will come to rest at around 12.8v, so anytime you stop charging, the voltage will start to fall. That's normal. It'll happen faster with the truck loads (radio/ heater blower, etc.), running but the engine off.

The voltage will sag under heavy load, so when the engine restarts, dropping momentarily even as low as 8.5v isn't surprising.

The only effect it will have in regards to the ACR and aux battery is to cause the ACR to frequently disconnect/reconnect, which will make recharging the aux battery take a lot longer to reach full charge.

Again, I wouldn't rig it to use the force tie as a start boost anyway, and especially not with that stop/start turned on.


But if you wanted to use the stop/start, you might very well be better off with a DC-DC charger such as CTEK, Sterling or Redarc.

 

[Colin Hughes]

Well, I think after all the advise and the article link, I'll give my Surepower a try. I have it, can't hurt to give it a shot and I'll hook the MPPT controller and panel up too so when I'm stopped, I can deploy the solar. I'll just turn the stop/start off. If it doesn't work, it was worth a shot. It also means I only need to run one wire from the engine bay to the rear of the Jeep which is less work too.

 

[unsung]

If I were to go with a Redarc DC-DC does it isolate the 2nd batt if I were to leave my lights on and kill my primary battery? Can the secondary be used to then start the vehicle? Is there an in cab monitoring system available?

I like that I can theoretically camp for days and keep my secondary charged with a solar panel.

I am about to buy one but the more I read the more indecisive I seem to be.

 

[DiploStrat]

If I were to go with a Redarc DC-DC does it isolate the 2nd batt if I were to leave my lights on and kill my primary battery?

Yes. And CTEK and Sterling B2B's all provide the same isolation function. But if leaving the lights on will kill your battery you need to redesign your system.

Can the secondary be used to then start the vehicle? Is there an in cab monitoring system available?

None of these units provide a self-jump capability. The REDARC supports remote tell tale LED's and some Sterlings have large remote panels. Whether any of this is useful or not is debatable.

I like that I can theoretically camp for days and keep my secondary charged with a solar panel.

Nothing theoretical as long as the system is sized correctly and you have enough sunlight. Some of us do this all the time.

I am about to buy one but the more I read the more indecisive I seem to be.

Simple process:

-- Size your system to your needs.

-- Determine the type of battery you want to use - FLA or LiFePO4.

-- Determine your vehicle's charging voltage. This will tell you whether you need a relay based system or a B2B.

-- Buy the system that best fits your needs.

 

[unsung]

The lights on was just an expression on a what if my main was dead. I will look into this a bit more, my secondary is https://www.batteriesplus.com/productdetails/sli35agmdp and my vehicle is a 2007 Land Cruiser. Thanks.

 

[DiploStrat]

The lights on was just an expression on a what if my main was dead. I will look into this a bit more, my secondary is https://www.batteriesplus.com/productdetails/sli35agmdp and my vehicle is a 2007 Land Cruiser. Thanks.

Understand about the lights, but my point is that you need to have enough power for your loads, whatever they may be. Relying on a battery isolator to get you home is a bit like relying on a fuse to keep you safe when your house circuit is overloaded.

In this case, the battery you are considering is a hybrid, which will offer only about 30Ah of power, applying the 50% rule. You can, of course, trade useful capacity for life, but you might be better off using a real deep-cycle battery which might give you closer to 50Ah.

I don't know about US Land Cruisers. Many overseas Land Cruisers run at about 13.9v, so they are the prime market for B2B's.

 

[carbon60]

I don't know about US Land Cruisers. Many overseas Land Cruisers run at about 13.9v, so they are the prime market for B2B's.

It really annoys me that I rarely see anything above 13.8v on my '94 HDJ81, which is a 12v system that uses a solenoid to feed a 24v starter from two factory batteries under the hood. I need to replace one of the main wires, which appears to have drop, and get a third house battery.

 

[DiploStrat]

24v? Is this a diesel Cruiser? I use a REDARC DCBC 1240D to charge a 12v camper bank from a 24v starter battery, so it may be that I know exactly what you are trying to do.

 

[carbon60]

24v? Is this a diesel Cruiser? I use a REDARC DCBC 1240D to charge a 12v camper bank from a 24v starter battery, so it may be that I know exactly what you are trying to do.

Yeah, it's a diesel. But it's a 12v system, so everything but the starter is 12v. Has two 12v starter batteries in parallel.

A.

 

[dwh]

2 x 12v in parallel is 12v. They'd have to be in series to get 24v.

 

[carbon60]

2 x 12v in parallel is 12v. They'd have to be in series to get 24v.

Yes, as I mentioned above, maybe with a lack of clarity: "(…) a 12v system that uses a solenoid to feed a 24v starter (…)".

I wonder if that Toyota uses a series/parallel relay like my Tractor?
12V system, but 24V starter.

Yup, that's exactly what it does. Funny, I've heard people call my beloved truck a tractor, before…

A.

 

[DiploStrat]

So, given that Toyotas are known to have low voltage, you are probably a strong candidate for a REDARC or Sterling B2B. Where are you going to mount that camper battery?

Side note. I used to own a diesel Land Cruiser. Bought used in Djibouti and had it at a second car for about three years. I confess that I never raised the hood other than to change the oil - never noticed the starter/electrical system!

 

[carbon60]

So, given that Toyotas are known to have low voltage, you are probably a strong candidate for a REDARC or Sterling B2B. Where are you going to mount that camper battery?

Except I already have two giant batteries sitting under the hood. Seems a little ridiculous to get yet another. I have seen a few threads on 'mud where guys replace the starter with a 12V model and tear out all the extra wiring. Then you can use a deep cycle on one side and a DC-DC charger. But the 24V start is so nice when it's -25ºC…

Also, I think I have a wiring corrosion issue: with batteries somewhat discharged, I get 14.4V between the alternator and the block, but 13.8V between either positive post and the block. I'm thinking the solenoid might be the culprit. I should fix that before doing anything else.

Side note. I used to own a diesel Land Cruiser. Bought used in Djibouti and had it at a second car for about three years. I confess that I never raised the hood other than to change the oil - never noticed the starter/electrical system!

They are incredibly reliable. That said, I managed to blow mine up…

 

[shoredreamer]

@unsung The BCDC will isolate your 2 batteries. But in the scenario of you killing your start battery and needing to jumpstart your vehicle with your second house battery, the BCDC can not do this alone. You would need to add a REDARC SBI12, 100A fuse on each lead going to the SBI12 and run a momentary switch to the cab to join the batteries and start the vehicle. There are plenty other relays and switches to join your batteries to do the same job as the SBI as well but the SBI has a few features included and is pretty compact.