Split Charge Relays vs DC-DC Chargers: Which One Is Right For You?
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- čas přidán 8. 09. 2024
- We get asked quite often which split charge system should I use, so in this video we explain the differences and why you should choose a particular one for your vehicle
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I have had my Ctek 250S + Smartpass in my boat since 2011 together with a solar panel. It works flawlessly and I have it connected all year round, to my 19 Ah (!) start battery and my 150 Ah AGM battery. The little sun that comes in wintertime keeps the batteries fully charged all year round.
Thank you for your cristal clear explanations. I have read that DC-DC charger can be put in parallel onto a same battery bank so as to increase the total amount of charge current. On my opinion, that could also be a way to have a redundancy in case one of the DC-DC charger fails. Of course, the price might be prohibitive.
Down side of the Smart Voltage Sensitive relay is the variable voltage alternators in newer cars can sit charge voltages to the start battery below the relay trigger voltage. The DC-DC chargers work much better than relying on voltage differential in the solenoid systems.
I started my dual battery charging system with a huge marine rotary switch. I think its more accurate, easier to use and allows for any combination of charging and isolation and has no complicated electronics and wiring that can fail.
As long as you remember to isolate the starter and auxiliary batteries when parked up so you don't drain both then happy days
However personally I think that leaves a big margin for human error
@@OverlandExplorersUK I leave the House battery connected and starter disconnected when over-nighting as that's what I will be using all night. I don't care if it goes flat because the Starter is fully charged. I've used that system for more than 20 years. It's dead simple and works perfectly. I had a CA-CA starter and an AGM House. The alternator doesn't care which one it charges and 'adjusts' depending on the battery type.
I've wired the van with a fully electronic switch but if there is even a hint of reliability issues, I'll be throwing it all out and going back to a marine switch. I also carry one of those light weight portable LIIO started batteries as a third starter option.
You mention 'human error'. It's no different to making sure you have fuel in your tank. You can design for stupid.
Fantastic explanation on the relays
But wow, the price of them AGM batteries then the cost of a specialist charger for them. Love my little dolbo with it's no thrills alternator and it's cheap arss leisure batteries. I have a voltage sensing relay and a MPPT solar charge controller wired in parallel across the battery. Keeps things simple, cheap and works a treat.
If you're just using the solenoid and are worried that when the ignition is switched on you would have dual connectivity even if the engine wasn't running, one solution would be to install an oil pressure switch and wire it in series with the feed wire to switch the solenoid. Thus is you don't have oil pressure the switch will not throw, even if the ignition is on or somehow was left on accidently. Some vehicles with fuel injection have this system wired into the fuel pump, so in the event of an accident and the engine stops turning, or gets damaged you won't be spraying fuel on a damaged engine and creating a fire hazard. I you could locate this feed wire and route it, (fused), to a 12v relay to shunt power to feed the solenoid you could skip the oil plumbing for the pressure switch. It's usually a terminal on your own engine's oil pressure switch. I have installed this on the electric choke of my 350 sbc, ( 84 chevy van), so for the same reason in case of an event to cut off electricity to my carburetor. It's a little complicated but the switch is only 4 or 5 dollars. To keep the ability to use the leisure battery to jump start you main battery, you could wire a toggle switch near the solenoid to switch on the solenoid relay. Be sure to power it from the terminal on the relay that goes to the leisure battery because if your main battery was dead it wouldn't switch the relay. if you wanted to install a switch for that on your dash, use a momentary contact switch so you don't worry about leaving it on and connected
dually.......................................................................................................................................................................just saying' Mike
Nice job I like the ctek charger it has all work good Great product
God bless
Re opening 4WD shots.
I didn't know the UK even had any dirt roads ... let alone hills/mountains. 😉
Hi from Australia -- land of many dirt roads, potholes, hill climb gravel driveways, and 4WDa in every posh suburb ready for the supermarket trip. 🙄
Thanks...your a Spitfire for my problem👍🏾🙏🏾👌!!!!!
Man that was great! Thanks for the really informative video. I've been researching this subject for a while now and I wish I'd found this video weeks ago.
i know it's kind of randomly asking but does anybody know of a good site to stream newly released movies online ?
@Orlando Grayson Flixportal :P
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@Orlando Grayson no problem xD
Great! Thanks! Just what I needed to learn. Installing one lifepo4 200ah as hous battery in my boat. Starter battery is one AGM. Two engines and thereby two alternators. These will now go parallel to the starter battery. Between start and LifePO4 + I attach one Cyrix Battery Combiner. After the combiner a dc to dc charger to regulate the amps into the LifePO4 battery (200ah)
If I have understood the set up properly it dosnt sound like you need that battery combiner
Just put the DC charger between the starter and lithium batteries and you will be good to go
@@OverlandExplorersUK Thanks for your feedback. My thought was the combinder will stop potential charging from starter battery when the engines are not running and after heavy usage from the house battery (LifePO4). If not necessary I'll return the combiner. Agian thanks for your feedback, much appreciated!
I have a atv which runs electric hydrolic pump from a second battery. Would a dc to dc charger keep the secind battery charged when the ATV engine is running. And would i still be able to use those battery operated electric attachments at same time
Thanks
Thank you!
Most Australians are using the dual input REDARC BCDC1225D in their 4WD’s or camper trailers. 🦘🇦🇺
That's because of the "tax load" on import systems. Redarc is an Australian brand so works out a lot cheaper
great video and explanation.
Use accessory terminal from ignition switch.... not ignition position then the solenoid/relay won't be energized while cranking.
I run Two Ham Radios in my vehicle. I have a second battery whose ONLY job is to run the radios, and charge the phone and the laptop. I have it isolated from the vehicle main when its fully charged up. I have had one instance where the main battery went south, and I used the second battery to Jump start my rig. BETTER THAN CALLING FOR HELP!
What type of charger are you using? De K2SCH
how do you know what size fuses you need.
So your saying my starter battery has to match my leisure batteries ?
Mate, thanks for that. I have a Ctek dc/dc charger running my solar panels and I’m looking at getting the Smartpass connected as well but the problem is, my truck runs on 24volts. Can I use a 24volt to 12 volt reducer off the alternator to bypass this problem?
Do not go split charge at all is my opinion... Only if the batteries are the same. Lead acid start battery, well then you can charge lead acid start battery. AGM-Start , then you can charge AGM-Start;
I would never connect a proper AGM Leisure battery to my start battery via split relay as it requires proper voltage.. (MAX 14.2 for my part) most chargers go 14.4..
Especially if you have euro 5/6 with smart alternator a dc-dc charger is a MUST:. (I'd say it's a must either way to get proper charge)
Thanks for the video. Defo going to go with what you suggest. Though when searching I've found a CTEK D250SE and a CTEK 250SA. Whats the difference ? Also seen people with two units - CTEK attached to each other with bars. My plan is to have only one 200ah/220ah AGM leisure battery.. ( with a smart alternator - and thanks again for clearly explaining how they work.)
As in your video, is one CTEK unit all I need, and not two linked together ?
The SE is the newest version with the ability to charge lithium batteries I believe however they are very similar units
The additional unit is called a SMARTPASS and ups the output of the unit from 20 amps for just the 250 to 60 amps (I think) which Is required for large battery capacity
I cant remember what the maximum capacity they recommend before upgrading to the SMARTPASS, the information will be on the CTEK website
@@OverlandExplorersUK Thanks again.. Yes I've seen the SMARTPASS is used for large battery banks.. I now understand I won't be needing it - A SMARTPASS.. As I'll only be using the one 200 - 220ah AGM. Then add solar to it later. Looks a great bit of kit !
ty, I'm glad I watched this video...... here's what I had planned , just incase my situation is different, I'll ask you : I have a 2013 jeep with a 160 amp alternator. my plan was to run the starter battery through a smart splitter to make sure my jeep battery was charged up first., then run a 6 awg wire to the trailer's deep cycle battery. Will this work to charge my trailer battery after long drive or will I be hurting the 160 alternator? It came with my jeep as part of a tow package from factory
I wouldn't disconnect the starter battery from the alternator at any point, this may disturb some of the vehicle systems, I would take a feed off your starter battery to a dc charger fitted in the trailer itself, have an anderson connector to connect the power to the trailer
Will the ctek charge a lead crystal battery mate?
Since the CETK is an MPPT DC to DC charger, and will accept input from Solar panels, what is the high voltage limit on the Solar Panel input. The reason I ask, is because I want to run my solar panels in series, and therefore my voltage will be as high as 90 volts. The Renogy DC to DC MPPT charger only allows a maximum of 25 volts, and therefore, if I go with Renogy, I will have to hook my solar panels up in parallel. Can you advise?
Sounds like you will need a dedicated solar regulator that can deal with the higher voltages you wish to use
question I have a 2008 dodge ram 6.7 diesel with 2 lead acid batteries and want to put a longer lasting battery bank on camper like gmv type or lith ion but these require different charge rate and voltage so would I need a dc-dc charger or what as I don't want to burn out alternater also on my truck the computer controls charging voltage depending on ambient temp from 13.5 -14.6. thinks RT
If your battery types are differnt to your starter batteries you will definitely need a dc to dc chargers
If using lithum ensure you get a charger that has a lithum charging profile as they have differnt needs to other types
Hi,
I have a Ctek 250s installed in my hilux, what type size of solar panel would you recommend for here in the uk
With Solar, especially in the UK, more is better to capture as much sunlight as possible
We run a relatively small 75w panel on the roof, which means we don't get a massive input from the solar but its enough to keep the fridge from draining the batteries which is really our only constant draw
I guess it all depends on what space you have to put panels on, of course you could always go down the route of "Portable Panels" and set them up when you get to camp
Without seeing a plan of electrical consumption, battery capacity or how long between engine starts you need to achieve I couldn't say exactly how much solar you need
If you would like some advice on your system in particular then put up a post on our forum www.uk-overlanders.co.uk so you will get more then just my advice
UK-Overlanders thanks for the quick reply, it’s really only a fridge that I will be running, thanks again for the info
No mention of Euro 5 alternators? I still cannot get a straight answer on whether my Euro 5 engine can take a smart relay. It doesmt have start stop function or anything like that.
Dont think you will get a straight answer
Euro 5 is an emission standard not an alternator standard so euro 5 engine may or may not have smart low output alternators as it will depend on the manufacturer
As a rule of thumb though a 2010 onwards vehicle has a high likelihood of having a smart alternator so I would opt for a DC-DC charger
my truck is 12 v and my camper has a 24 v ,[220 Amp hours] battery bank for a 5000 watt pure sine inverter UPS, for the ac in the camper. right now i need to charge it with solar or 110 AC. it would be nice to charge it with my truck . everything i find to make 12 v to 24 v ,is low amp charging. help . idea's for more amps at 24 v from my 12 v truck.
Only thing I could think of off the top of my head would be to run an inverter in the truck powered when you turn on the ignition and run a 24v battery charger off the inverter then connect the trailer with an Anderson connector
Hello Jake would this be any good for my campervan build ie a 2014 Mercedes sprinter van I aim to have around 200ah of leisure battery , thanks for any help
It would work great with that setup :)
What if I already have a good MPPT controller, but I only need the wall and alternator functions ?
There is a simple/cheaper version that does pretty much the same ?
Better? maybe look at the REDARC manager 30 but it definitely won't be cheaper
I would suggest hooking your solar up to your starter battery and running the dc dc charger to your aux battery
This is our set up, we also have a built in 240v ctek charger hooked up to the aux battery only but since installing solar we haven't needed to use it
@@OverlandExplorersUK I live pretty much full time in my small camper van, when everything runs fine, so I depend more on service battery, since happen to stay still long time and 97% off grid.
Connecting the solar panel on starting battery should probably work better for those who drive constantly, with shorter camping stops.
My MPPT regulator shows me all details on display, but this device don't have such thing, so makes no sense to eliminate old regulator and use CTEK one, as I was thinking before.
After restoring the van, I might consider lithium batteries and then, this DC-DC might get paid by just protecting the alternator.
Great Vlog, thank you !
@@syncrovanCos think you may of misunderstood how our set up works
The solar controller is connected to the starter battery, once there is enough solar power to activate the DC to DC charger then both the starter battery and aux battery will be receiving charge just like it would if the engine was running
This has an added benefit that the aux battery receives exactly the charge it needs which could be differnt to the starter battery
This would benefit you if your staying in one place for an extended period of time as your will have peice of mind that your starter battery will never be ran flat accidently by leaving an interior light on or similar
@@OverlandExplorersUK Although I understand in big line, not sure I get it all right !
You refer to the secondary solar controller, or should I connect the CTeck solar controller to the starter battery ?
All my living lights and accessories, including the stereo, are connected to the service battery.
I just bought the CTeck and should be ready to install in few days. Crazy expensive, so hopefully, I'm not gonna be disappointed.
Do you have an additional display that shows you the status of battery and solar energy, or just trusting that the cteck will do everything by itself ?
@@syncrovanCos no I don't use the solar input of the CTEK, I have a separate MPPT controller which is connected to the starter battery
We have a simple national luna battery dual monitor in the cab and then use the MPPT controller monitor to keep an eye on things in the back
Will the 250s operate with smart alternator?
Yes, its the only ideal option if you have a smart alternator
What category is the Cyrix-Li-CT by Victron in? Is that s smart relay?
Yes that would be classed as a smart relay
@@OverlandExplorersUK OK. Do you know how a device like Cyrix-Li-CT regulates the amount of Amps going to the aux. battery? It can't be sending 120A on an "empty" LiFePO4 because the batt's built-in BMS might be cutting off the charging at 50 or 100A.
@@PrimalMiltos it doesn't regulate amps at all thats the issue with them
To regulate amperage would would need a DC-DC charger other wise your battery is getting what the alternator is giving out
@@OverlandExplorersUK Yes that's their operating principle BUT it appears that Victron has a model AGM Cyrix-CT for $45 and a new model for LifePO4 the Cyrix-Li-CT for $75. These can connect to their (expensive) Victron BMV-712 and be "controlled" by it? There is a YT upload on this but I still can't grasp what this bi-directional Victron Cyrix device can achive versus a "regular" relay.
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can you fit these then ad an charger for your battery off your site electrics
You can simply fit a normal mains powered battery charger to your starter battery and it will charge as normal
@classic camper if you hook the wall charger to the starter battery then yes it will charge both starter and leisure battery
Hi, you said that using a VSR both the starter and leisure batteries must be the same type etc. Can you absolutely confirm this as I know quite a few people who have done van conversions with lead acid starter batteries and AGM leisure batteries with no problems (except one instance of reverse charging accidentally in exceptional circumstances)
It is highly recommended that they are the same type when using a VSR, it wont cause any immediate danger to the batteries by connecting two different types however you will be reducing the life of the AGM battery by alot as it's not getting the charge it needs
Bottom line is why bother paying for an AGM battery if your not going to get the performance benefits because it's not getting the correct charge
7:23 dc-dc charger is not split relay! It's the better alternative to split-relay..
Isn't that exactly what he said? Even the title says split vs. dc-dc... What are you trying to say?
@@Steve_MFr oh sorry, didn't know you were deaf. He called it a split charge system. And it's not,it's a dc-dc charger, not a split system. Split implies 1 charger but two things being charged.
@@AndreasEUR No, lieber Andreas, I am NFD - not deaf. I went back and checked again, and I found what you meant. You put the WFTS - wrong time stamp - in your original comment. I assume what you meant is at 7:14 where he says "which means we are on to our final split-charge system". But if you listen - carefefeckinfully - following your time stamp, he goes on to say that DC-DC is not like relays and that the batteries are in no way connected.
Granted, his explanations aren't very concise and clear, but you really are a pedantic little sauger, aren't you?
You're so dull, I couldn't listen through to the end!