Ctek charger- getting a small shock
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Category: General Forums
Forum Name: The Boat Shed
Forum Description: Discuss all things boating.
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=124840
Printed Date: 10 Jun 2026 at 1:36am
Topic: Ctek charger- getting a small shock
Posted By: :Hunter:
Subject: Ctek charger- getting a small shock
Date Posted: 18 Jul 2017 at 12:12pm
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I have two ctek charges wired up to two different alloy boats, one a 575 Surtees and the other a F14 Frewza. Surtees has a normal hooked up single 12v battery and a battery switch. Frewza has a stand alone small 12v battery only used for lighting and sounder. Both have the quick attachment wired onto the battery. I have noticed that I get a small shock off both boats when the ctek is connected only. Only enough to feel on my arm or if I have a cut on my hands. Does anyone else get this? Anyone got any suggestions how to fix it? |
Replies:
Posted By: MB
Date Posted: 18 Jul 2017 at 12:24pm
| I've just discovered exactly the same thing. Very low voltage/current (not sure which is the correct term!). Can't feel it with palm of my hand, but can on the underside of my arm. |
Posted By: OuttaHere
Date Posted: 18 Jul 2017 at 4:52pm
| I feel like this can only be bad for an alloy boat. |
Posted By: :Hunter:
Date Posted: 18 Jul 2017 at 6:12pm
| Yep wouldn't think it would be good. Have emailed ctek direct bit no response yet. Interesting if others are getting the same thing. |
Posted By: MacSkipper
Date Posted: 18 Jul 2017 at 6:15pm
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I don't but then I have a Mac plastic boat. Do you have a battery isolation switch and is battery isolated from boat by this (is it working?) have you tried cleaning battery (remove battery and clean with soapy water around and under it) in case of salt buildup conducting leakage to boat? ------------- Good fishing trip nothing breaks, great trip catch fish. |
Posted By: DIY
Date Posted: 18 Jul 2017 at 6:46pm
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I had the same thing happen on my glass boat, I had the cowling off the motor and touched my arm on the engine itself and felt a slight tingle. The isolator was off and battery charging. Wondering if there is some voltage floating round the negative/ground. ------------- Oh what a smasher - two eggs and a rasher! |
Posted By: MB
Date Posted: 18 Jul 2017 at 8:13pm
| By the way, I have a jet ski, so not an alloy hull! I get the shocks from touching metal components/accessories. |
Posted By: Steps
Date Posted: 19 Jul 2017 at 8:54am
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When you have the chargers connected, is the isolation switch turned off? I dont use a ctek charger.. I do run trickle maintance chargers...have put a double, fused marine cig socket unit in the top of the battery box direct to the battery terminals. This by passes the isolation switch which means the rest of the boat/ engine etc is isolated when in charge. Or can run stuff when switch off Rozboons comment above... I feel like this can only be bad for an alloy boat. is far more significant than just alloy boats but corrosion on boat wiring terminals, and the engines etc |
Posted By: :Hunter:
Date Posted: 19 Jul 2017 at 12:54pm
| Yep mine are wired directly to the battery, with isolation switch off. Shock can be felt anywhere on the boat and even the trailer. Still no reply from ctek |
Posted By: Steps
Date Posted: 19 Jul 2017 at 4:11pm
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Yep mine are wired directly to the battery, with isolation switch off. I suggest, (process of elimination) remove and isolate battery terminals.. the +ve 1st.. check if have issue... then -ve and check. If still there, ground the hull directly to earth. That will remove any static electricity stored in the hull. It does sound as if likely to have a static/ capacitance issue Now check.. If still there, check battery top is clean, no salt moisture between the terminals, and check there is no water in the bottom of the battery box. If still there, dismantle and clean (if possible the isolating switch. A a side note is your isolating switch a double.. ie isolates both +ve and ground? With battery now totally isolated, all that leaves make sure the |
Posted By: MikeAqua
Date Posted: 20 Jul 2017 at 8:31am
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I had discernible charge from the (-) terminal on one of the batteries in my (alloy) boat. I couldn't isolated a voltage leak at all. It even persisted when I disconnected all the terminals from that battery. My battery lockers are alloy with no room for battery boxes So I fitted offcuts of plastic tube matting underneath the batteries. Problem solved. This suggested to me that voltage can leak throguh the plastic casing of battery. In your situation I would be slightly concerned that the leak may be from the AC side. I'd have one of the chargers tested. |
Posted By: MikeAqua
Date Posted: 20 Jul 2017 at 8:45am
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The other thing is ... are you charging these boats at the same property? I am not sparky but based on problems I have experienced with electrical systems before. Could it be an issue with the earthing on the properties power supply? What happens if you plug the CTek in via an RCD when charging? |
Posted By: :Hunter:
Date Posted: 20 Jul 2017 at 9:24am
| Nope two totally different properties, one running through an rcd with no issues |
Posted By: :Hunter:
Date Posted: 20 Jul 2017 at 9:32am
| Appreciate the suggestions. The voltage leak in only when the ctek charger is connected though. No issue or leakage once it's unplugged or even just switched off at the wall. |
Posted By: Kevin.S
Date Posted: 20 Jul 2017 at 10:14am
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Is it the quick connector with the led indicators on it? I had one of those and it caused me lots of problems. Battery kept going down, wouldn't charge. Ended up getting the battery changed, tried charger on another battery but both battery and charger were OK. Eventually threw the quick connector away and haven't had any problems since. |
Posted By: MikeAqua
Date Posted: 20 Jul 2017 at 10:33am
That's that theory dead then  .Seem unlikely that two chargers would be the problem. I'd now suspect: - (1) Quick connector as suggested by Kevin; and/or (2) Leakage through battery casing. What is the battery sitting on? Another question: does this happen during all phases of charging? For example - does the problem disappear or lessen during the trickle phase? |
:Hunter: wrote:Posted By: MB
Date Posted: 20 Jul 2017 at 11:39am
mine does.
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Posted By: :Hunter:
Date Posted: 20 Jul 2017 at 1:17pm
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Quick connectors but with no lights. Out of interest I tried using the alligator clips that came with the charger onto the battery, and still the same problem. Can feel the shock at all times of the charging cycle, but disappears as soon as the charger is disconnected or even just turned off at the wall.
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Posted By: MikeAqua
Date Posted: 20 Jul 2017 at 2:03pm
If the quick connector was still attached to the battery terminals it could still be a leakage path while you are charging via alligator clips. |
Posted By: Titahi
Date Posted: 20 Jul 2017 at 3:36pm
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A process of elimination might source the issue... Connect a voltage meter to -ve of battery and positive to the hull, connect the ctek and turn it on, to give an indication of the leakage voltage. Remove the fuse in every circuit in the boat, in theory the voltage should drop to zero, then replace each fuse one at time checking to see if the voltage on the meter attached to the hull increases... I suspect you have a leakage through a circuit, this process might help identify which circuit... ------------- "I love standing by the ocean and just knowing what its for" |
Posted By: Steps
Date Posted: 20 Jul 2017 at 5:37pm
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A process of elimination might source the issue... Yep as suggested further back in essence same method... only when plugged in at 240v source and turned on... I have a feeling it is an issue in the house wiring.. a poor earth / ground.. possible loose terminal in the wall switch or where that circuit connects back to the earth bar or neutral terminals in the switch board... or between the actual grounding point. All of these are meant to be checked by an electrician if ANY work is done in the home/ establishment. Often what happens over the yrs, the copper wire in the terminals compresses causing a loose terminal...in this case a poor ground.. If was the phase, wires heat up building can burn down. This is assuming the CTek unit is not faulty. The other is "eliminate" by Titahi s method or mine further back. a possible leak due to salt deposits and moisture on the battery case 'shorting' to the engine alloy boat creating in effect a huge capacitor since the boat trailer will be isolated from ground on rubber tyres. |
Posted By: smudge
Date Posted: 20 Jul 2017 at 7:12pm
I'm a sparky and can't quite understand why that is. Maybe I'm a dumb sparky  .Titahi has a pretty good systematic approach here and that is what I would try. ------------- Best gurnard fisherman in my street |
Posted By: :Hunter:
Date Posted: 20 Jul 2017 at 7:31pm
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I doubt there is an issue with the house wiring due to it being two different houses and two different boats. In relation to the voltage meter and fuses, wouldn't the isolation switch prevent the current running through the boat? |
Posted By: DIY
Date Posted: 20 Jul 2017 at 9:52pm
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Can't help wondering if it is just the way it works and is not actually a problem. Mine has always done it and have not noticed any problems. I'm a sparky as well and just checked the charger, it's double insulated so doesn't have an earth pin. Cant see it would have anything to do with the house wiring. Maybe being an electronic/smart charger it uses some weird frequency or something to monitor the battery perhaps down the negative??? ------------- Oh what a smasher - two eggs and a rasher! |
Posted By: MacSkipper
Date Posted: 21 Jul 2017 at 6:43am
Ah but does the isolation switch work? and as said earlier does it isolate both plus and negative? Probably only plus side, could be a grounding issue then or could be as above is characteristic of charger - but doesn't seem right to me as stray voltages will cause electrolysis I would have thought. ------------- Good fishing trip nothing breaks, great trip catch fish. |
Posted By: Steps
Date Posted: 21 Jul 2017 at 9:17am
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In relation to the voltage meter and fuses, wouldn't the isolation switch prevent the current running through the boat?
Like Mac above.. often with isolation switches off, there is often still a low voltage.. which is why I suggest way back to eliminate by disconnection of terminals. Salt/ moisture.. doesn't take much conduct current, be it a little driven into a isolation switch r simply between terminals on a battery or down the side to surrounding area.. its noted the battery is not in a battery box. you would be surprised even on a battery in a car.. just how much leakage there is between terminals on the battery. Also mentioned above, throw in ground isolation, salt water and doesnt take much to create a giant high voltage, low current capacitor To establish what is causing out of several possibilities requires process of isolation |
Posted By: MikeAqua
Date Posted: 21 Jul 2017 at 10:37am
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I suspect there is always some leakage from the DC system into these particular boats. When the charger is connected the amount of energy being pumped into the battery (and by extension the DC system) makes the voltage more apparent. A multimeter between (-) terminal and an alloy surface on the boat (scratch the oxidation off) will test this. For fault finding start with the most common systems first: - 1) If the battery is sitting on alloy, isolate from the alloy. 2) Disconnect everything from a battery and charge it via alligator clips. 3) Repeat (2) with the c-tek charging socket connected to the battery. 4) Reconnect the wider DC system to the battery but disconnect the main cables from your (+) and (-) buses. 5) Disconnect all devices from both buses. Reconnect one device at a time, then disconnect it again and move onto the next device. 6) If you identify a problem device try testing with only the positive or negative lead connected and see if you can identify which one is the problem. Hopefully you don't have to go as far as (5) and (6) |
Posted By: dontpanic
Date Posted: 22 Jul 2017 at 8:56am
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I had this problem as well on our Fibreglass trailer boat, a light tingle from around the transom only when the charger was plugged in. I latter realised the battery boxes were holding water so the batteries were sitting in a bath of rain water, I drilled holes in the battery boxes and have noticed that the tingle has disapeared also.
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Posted By: MacSkipper
Date Posted: 22 Jul 2017 at 10:56am
------------- Good fishing trip nothing breaks, great trip catch fish. |
Posted By: dontpanic
Date Posted: 22 Jul 2017 at 11:25am
| I should have also noted our charger is not a CTEK brand it is an Ultipower, installed by the previous owner. http://waveinverter.co.nz/Battery-Charger/Ultipower-12V-8A-Charger" rel="nofollow - http://waveinverter.co.nz/Battery-Charger/Ultipower-12V-8A-Charger |
Posted By: dmck
Date Posted: 25 Apr 2021 at 9:23pm
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I've only just joined this site so I'm late in contributing to this post. The 'small shock' is coming from the CTek. A fairly high voltage ripple occurs across BOTH terminals when the Ctek is charging, but it cannot provide current(load) and so is safe. All you feel is the 'tingle'. As it is across both terminals it is transferred to the metal hull, so if you touch the hull and an earthed 'outside' object eg a metal shed frame, you may feel it. Simplest solution, clip a wire on to the hull and on to the shed. I did extensive testing some years ago and referred it to the CTek manufacturer. They are aware of the effect and assure everyone it is safe. My tests indicate it IS safe... it is just disconcerting. I dont know if any other 'brands' have similar effects.
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Posted By: ofthesea
Date Posted: 26 Apr 2021 at 10:54am
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I've never had this but I only touch the terminals while in the boat and typically the tyres are dry on dry concrete. Are you outside the boat and earthing yourself, that would explain things. A but like getting out of a vehicle without holding the door and getting a shock when you close the car door
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Posted By: Big -Dave
Date Posted: 30 Apr 2021 at 5:28pm
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The charder is a switch mode power supply, not an old double isolated transformer. It is quite possible that a reference voltage to earth (and neutral), will be present. If things are damp, and yoh have a small cut etc in your hand, you will feel 5 volts. Crikey, you certainly feel 9 volts off an alarm battery on your tongue. Not dangerous, but never the less, you can feel it. ------------- you can't fix an idiot with duct tape, but it does muffle them for a while... |
Posted By: MB
Date Posted: 23 Nov 2021 at 9:20pm
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Thread resurrection. This is still going on for me, got a bit of a wake up when my puku touched a stainless steel accessory on the ski this evening I have little understanding of things electrical, but I ran a wire from the ski to the garage floor thinking it would solve the problem, but it doesn't. No drama, just wondered if anyone had any more thoughts?
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Posted By: MacSkipper
Date Posted: 24 Nov 2021 at 3:25pm
------------- Good fishing trip nothing breaks, great trip catch fish. |
Posted By: MB
Date Posted: 24 Nov 2021 at 11:20pm
Yes.
Correct, no isolation switch on the ski. Guess the next logical move would be to try it with the battery in situ, but disconnected from the ski. Although, I'm not sure how useful that information will be given my lack of electrical knowledge.
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Posted By: Steps
Date Posted: 25 Nov 2021 at 8:13am
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Are you one of those who tend to be sensitive (maybe wrong word) to getting static shocks off cars and such? My wife sometimes on some cars can get an very audible 'crack' and a kick like off the solar anti cat/ dog electric fence around the veggie garden. Yet at best over decades at best on very rare occasions I may get a very faint kick. Im also wondering.. If one gets a tingle off a household tap or metal are, it usually means that there is a bad grounding connection between the item, switch board/ and the grounding pole / strap in the ground. Cant rem (without going out to the boat) if my ctek on the a/c side has a ground wire.. There is only +ve and -ve DC on the battery side , and dont know if the -ve is actually connected to a ground (if exists ) inside the ctek. Only happens when ctek is connected and on ? You dont get the occasional tingle or crack off the ski any other time... say after towing it to the ramp still up on the hard.. dry? |
Posted By: MB
Date Posted: 25 Nov 2021 at 9:25am
No and it's more sustained than static, as in it goes on as long as you make contact.
No.
Don't know if it's relevant, but the power point is on the ceiling of the garage.
Yes.
No. Cheers!
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Posted By: Steps
Date Posted: 25 Nov 2021 at 10:44am
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Cant rem (without going out to the boat) if my ctek on the a/c side has a
ground wire.. There is only +ve and -ve DC on the battery side , and
dont know if the -ve is actually connected to a ground (if exists )
inside the ctek. Don't know if it's relevant, but the power point is on the ceiling of the garage. Hmm so its all the time, a continuous tingle... Garage.. assume metal... If not sure how to, get an electrical to check that the garage circuits, walls, anything metal is actually grounded correctly. And side note: if had ANY work done on house or garage by an electrician, by law he must also check the grounding. That is how important grounding metal parts is.. But so often they dont. |
Posted By: Titahi
Date Posted: 25 Nov 2021 at 11:19am
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Steps I have no idea how you came to be worried about the earth/bonding of the garage? the stainless steel in the jetski is described as providing the leaking voltage. As Cteks are double insulated they dont use an earth pin in the plug. The voltage on the negative ( @ battery)is different to the voltage of the ground your standing on (potential voltage) Disconnect +ve and -ve from jetski circuits when charging if it bothers you... ------------- "I love standing by the ocean and just knowing what its for" |
Posted By: MB
Date Posted: 25 Nov 2021 at 2:30pm
Thanks for the reply. Its doesn't really bother me, but I worry a little about corrosion as per the earlier comments in this thread and fire risk. My concerns may be unfounded though.
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