dc power converter problem PLEASE HELP QUICK

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C

canadianmedic2

Joined
Dec 26, 2005
Threads
25
Messages
94
Location
Coquitlam, BC
Hey Guys,

I have a problem with my truck, I think I have it figured out but just checking to be on the safe side.

First a little background, I have an 88 HJ61VX with a 12HT and 24 volt wiring. When I bought the truck it had a 24-12 volt power converter but it lacks power and amp ratings. I decided that when it came time to install my new vhf/uhf radio that I was going to add a dedicated 24-12 power converter for the radio and the previous power converter could still run my cd player and cigarette lighter plugs.

The new power converter has the 24 volt power to the positive terminal of one battery. The 24 volt ground is connected to the frame. Finally the 12 volt power and ground are connected to the radio.

I just installed the radio and power converter yesterday and it seems to kill my battery or so it would seem. Yesterday I had to jump the truck, it was just clicking when I tried to turn it over, and today the same problem. But the weird thing is that the voltage meter shows just under 24 volts. It definity sounds like a battery problem to me.

The only solution that I can think of is to install a on / off switch wired before the new power converter. My theory is that the battery is draining through the power converter to the ground.

Any suggestions?

PS this is my daily driver -- need to fix quick
 
follow up

I just jumped the truck and it's at least running now. I disconnected the power to the converter. I did read a voltage of 12.6vdc on one battery and 10.24vdc on the other.

still looking for a solution.

Canadianmedic2
 
I think your probelm is in how you connected the converter to ONE battery. Your 24v system is that way due to the voltages being in series from TWO 12v batteries. Headlights are a great example. your heads are 12v but can tap off of one battery because they tap off of one battery each, and therefore drain both batteries equally. For your 24v converter to not drain only one of the batteries, you need to connect it to both batteries.

I am still fairly new to this, but that's what I have read.

Anyone else with any advice?

K
 
Sounds like a load balance issue. Along with Breck--did you connect it to the high side or low side battery? The batteries are wired in series, so find the one whose + terminal goes into a wiring loom for the truck, ie don't use the + that is connected to the - terminal of the other battery. Get your 24v from the + of the aforementioned (high side) battery. To confirm this you should get a 24v reading off this + terminal and a ground point.

If you look in the FAQ section at the top of the board there are several threads on 24v electrical issues, and specifically on voltage converters. Also, using the search function will return other threads.

Sounds like nice truck and set up.

HTH
B
 
Ok sooo here's what I've found. I took the voltmeter out again and put in a 2 positional switch prior to the converter to act as a disconnect / connect switch. I have the converter wired on the high side of the battery, and grounded to the frame. I'm getting the proper 24vdc to the converter and 13.6vdc to the radio, but I believe that the frame of the truck is getting charged, and discharging the batteries. Under this assumption I installed the 2way switch but a weird thing happened. The converter acts like a capacitor and my radio still works for a little while, i'm assuming from residual voltage. I guess the true test is going to be whether the truck starts on it's own tomorrow.

Breck, I'm just curious but what sort of cruiser are you driving? I know cruisers vary quite a bit from place to place, but my cruiser has 24volt headlights. You've sparked my interest, does your cruiser have 12v lights? I'm relatively new to cruisers.

Canadianmedic2
 
The electrical guru here is Stone--hopefully he is still hanging around MUD and will chime in.

What is the brand of converter? The Solar converters are the gold standard because they can function both as converters and load balancers. Are the batteries relatively new? Which battery is dying, the high or low side? Does the radio draw current through the converter even when it is switched off? In the latter case your new in series switch might of course stop the problem.

I believe that one problem with straight converters that don't load balance is once your batteries are out of balance, it will kill the weaker battery. It's also recommended that batteries be replaced in pairs to restore balanced voltage.

BTW I have dual 12v headlights in my BJ42 with the evil center tap relay. But you've got the later, JDM issue headlights.

B
 
Thanks for the generosity, Brendan...but I ain't no "guru". :D Just finding my way around these issues like a lot of people here. :D :beer:

Basically what Brendan has mentioned already, but I would start by taking those batteries and charging them up separately to full charge and take a voltage reading off of them. THere's a good chance that the low-side battery has had some sort of draw on it and has sulfated. The best scenario is to always start with two fresh batteries that are as close to being equal as possible.

Try and hook up your converter directly to the ground terminal of your low-side battery. See if you can find any 12V draw coming from your low-side battery at all. Many times, people will hook up the Memory (yellow) wire of their radios directly to the low side battery and have the radio's ignition wire going through the ignition controlled converter so that the radio shuts off with the ignition. Only thing is that radio memory still draws minimal current, and depending on the condition of your battery, you may not have problems for a long time, but eventually a load imbalance will result. Another thing to note on this subject is that a lot (if not all) of the newer radios will pull their amplifier current through the memory wire because it's a direct battery hookup (and you will notice some radio harnesses will have a thicker memory wire than the ignition wire) and use the ignition wire only to switch the unit...meaning that while the radio is on it is pulling a lot of current from your low-side battery.

Anyway, just something to look out for. Your HJ61 will have 24V headlights, not the 12V ones going through a funky dimmer like the Canadian BJ42.
 
Stone, I'm glad you're here, I think I've solved the converter problem, but I've got more problems now. I went to work last night, and the truck didn't start...again. I pulled out the multimeter again and both batteries have sufficent voltage, and I have all of my accessories working fine. It just makes a clicking noise when I try to turn it over. I'm guessing starter problem. Am I correct in this assumption? If so, do you know where I can get a JDM starter?

Thanks for the help
Canadianmedic2
 
canadianmedic2 said:
I went to work last night, and the truck didn't start...again. I pulled out the multimeter again and both batteries have sufficent voltage, and I have all of my accessories working fine. It just makes a clicking noise when I try to turn it over. I'm guessing starter problem. Am I correct in this assumption? If so, do you know where I can get a JDM starter?Thanks for the help Canadianmedic2
Click to expand...

Before spending money on a new or rebuilt starter, have your batteries fully charged and load tested. Load testing is the critical part here. You can show full voltage and have a few dodgy cells, which will not get enough juice to do anything except click the relays. I bet as Stone suggests there is a dodgy battery (your lowside one) which is sulphated and/or has a few bad cells, and with the colder weather has finally made itself known.

hth's

gb
 
A couple of times on my cruiser I have had those same clicking noises you are refering to and my cruiser will not start batter voltage is fine. If I directly connect my jumper cables from the positive battery to where the starter switching wire is on the starter It starts straight away. You might try this next time the cruiser does not start although I think everyone might be right about the need to get the batteries load tested.
 
That sounds like a plan I will definitely get the batteries load tested. Both batteries look relatively new. Last night I didn't do too much it was 3am when I was trying to get it started. I'll try a proper 2 vehicle jump and fully charge both batteries, prior to starting it.
Canadianmedic2
 
Medic:

If Kiwi's idea of jumping the starter directly solves your clicking problem, you may also want to look at your starter relay. Better yet, first make sure that all of your battery terminal connections are clean and tight, and that there is also a good chassis ground...if no one has mentioned this first step already.

Keep us posted...

Stone
 
I have a 1981 BJ44 JDM from new Zealand. I am still working my way around it too. I was using the example of the 12V headlights that were put on the CDN spec cruisers. I assume Toyota did this because headlights can be replaced fairly easily by owners while starters and glows which do better with 24v, would be taken in for servicing.

Kraig
 
BreckenridgeCruiser said:
I have a 1981 BJ44 JDM from new Zealand. I am still working my way around it too. I was using the example of the 12V headlights that were put on the CDN spec cruisers. I assume Toyota did this because headlights can be replaced fairly easily by owners while starters and glows which do better with 24v, would be taken in for servicing.

Kraig
Click to expand...

Hi Kraig:

I could be wrong about this, but I was under the impression that the reason why Toyota put the weird and sometimes troublesome 12V headlights in a 24V system in their Canadian diesel Land Cruisers was because they had to to meet some strange Ministry of Transport requirement.

Stone
 
I was just guessing. Your reason sounds better than mine!

Stone, do you know anything about B and 2B injection pumps? I put a post up about my fuel issue!

Thanks!
 
Breckenridge:

I'm still wet behind the ears regarding Cruisers...luckily there's lots on here who are experts at them though... I know you'll find the answer you're looking for.

Knorrena:

Sulfated is when you get the buildup on the plates in the cells of your battery when a battery is deeply discharged. If there's a lot of sulfation, then you get a bad cell, and if there's enough bad cells the battery refuses to take a charge. Deep cycle batteries resist sulfation better than regular batteries. My deep cycle battery charger has a feature where it gives zaps of high amerage pulses to de-sulfate the battery before giving it a recharge.
 
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