Great source thanks
How to make a cheap isolated dual-battery setup for $50
- Thread starter evldave
- Start date
DaveInDenver
Middle Income Semi-Redneck
Your link is to the manufacturing and wholesale website. For low volume, e.g. individual purchases, the website is different.
I absolutely agree, great resource.
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Too bad their site is badly coded, I tried visiting it and there seems to be something wrong with their location based redirect, it either thinks I am in South Africa (I'm in Utah, USA) or if I try from my cell on TMobile it just says I'm in "-" and still redirects me.
Sent them an email about it, but it'll probably be a bit before they fix it.
Sent from my SM-N975U using Tapatalk
ryanoddi
New member
Wondering if anyone can help me troubleshoot/pinpoint an issue I’m having with my system. I built it off of the basic plan from post #1. Only difference being the house batteries are two 35ah 12v agm batteries wired in parallel.
I’ve had this system since 2014 and it’s worked well enough for my needs. But, I had the hood open and I noticed that the solenoid has some rust around the small + terminal that goes to the keyed source. Not sure if that should be concerning or not. You’ll also notice the 4ga wire in this photo, it’s actually bulging just past the heat shrink, where it’s very firm rather than soft, like it was when new.
In the second photo, it looks like a chunk was taken out rather than melted but I don’t know what could have done that.
I’ve had this exact system in 3 separate vehicles so something may have happened from the latest re-install into my 4Runner. The system appears to still be functioning. I put my multi-meter on before starting the vehicle, house batteries were at 12.65v. After starting and running a few minutes they got up to 12.7 before I shut it down. I’m disconnecting for the time being so no further damage can occur until I fix it. Any ideas what would be causing the 4ga wire to firm up like that?
Thanks!
I’ve had this system since 2014 and it’s worked well enough for my needs. But, I had the hood open and I noticed that the solenoid has some rust around the small + terminal that goes to the keyed source. Not sure if that should be concerning or not. You’ll also notice the 4ga wire in this photo, it’s actually bulging just past the heat shrink, where it’s very firm rather than soft, like it was when new.
In the second photo, it looks like a chunk was taken out rather than melted but I don’t know what could have done that.
I’ve had this exact system in 3 separate vehicles so something may have happened from the latest re-install into my 4Runner. The system appears to still be functioning. I put my multi-meter on before starting the vehicle, house batteries were at 12.65v. After starting and running a few minutes they got up to 12.7 before I shut it down. I’m disconnecting for the time being so no further damage can occur until I fix it. Any ideas what would be causing the 4ga wire to firm up like that?
Thanks!
Hillbilly Heaven
Explorer
Water intrusion and you now have green copper sulfate inside the jacket. Also rodents have chewed the heat shrink and jacket on the other cable.
another_mike
Adventurer
Isn’t the solenoid installed upside down also? Usually the instructions say dimple must be down.
transalper
Explorer
You are the man! Thank you for this - it is exactly the cheap inspiration I needed to set up a dual battery!!
ryanoddi
New member
Ok should the entire length of cable be replaced or will it be safe to cut it just a bit past where the corrosion stops?
Didn’t know rodents eat cables... that’s a new one for me. I’ll replace that then, it’s a short run so I have enough extra.
Going to dig into there a bit more this week, check for other chewed wires/hoses. Not sure of the quality of the cable either. It’s been too long to find a receipt.
Solenoid did not actually come with instructions. Have had it installed this orientation for 3 rigs/6 years/45k miles collectively, no issues whatsoever until now. Could be incorrect but checking through the questions on the amazon listing just now didn’t yield much more than “how dumb are you? If you need instructions you shouldn’t be installing” not helpful.
another_mike
Adventurer
Perform the following tests to to determine present wiring health:
Drain the house batteries down to about 12vdc, so that they need charging.
Connect your voltmeter test leads to the two large posts on the solenoid.
Start the engine. The voltmeter should read almost zero volts dc. Any voltage read here subtracts from the voltage seen by the house batteries. The contact's resistance causes that small voltage, and reduces current flow to the house batteries.
Place one dc voltmeter test lead on the starting battery's positive post. Place the other test lead on either house battery's positive post. You may need to lengthen your voltmeter lead/s.
There is basically a single wire conductor, separated by the solenoid's contacts/large terminals from one battery to the other. With the solenoid energized, contacts closed, there should be no more than a few tenths of a volts dc measured between batteries. The test leads connected from starting to house battery positive terminals shows total voltage drop/loss across all connections.
A clamp-on DC ammeter to read house battery charging current is very handy to actually know amp flow.
Drain the house batteries down to about 12vdc, so that they need charging.
Connect your voltmeter test leads to the two large posts on the solenoid.
Start the engine. The voltmeter should read almost zero volts dc. Any voltage read here subtracts from the voltage seen by the house batteries. The contact's resistance causes that small voltage, and reduces current flow to the house batteries.
Place one dc voltmeter test lead on the starting battery's positive post. Place the other test lead on either house battery's positive post. You may need to lengthen your voltmeter lead/s.
There is basically a single wire conductor, separated by the solenoid's contacts/large terminals from one battery to the other. With the solenoid energized, contacts closed, there should be no more than a few tenths of a volts dc measured between batteries. The test leads connected from starting to house battery positive terminals shows total voltage drop/loss across all connections.
A clamp-on DC ammeter to read house battery charging current is very handy to actually know amp flow.
another_mike
Adventurer
I knew I read it somewhere when installing mine. No idea the reason behind it.
Working on a balanced 24v dual battery system for my big rig.
The Smart isolator has performed well on my FJC for several years and lots of driven miles. It has also saved my hide several times due to how I split the system - separating the starter battery from everything else.
So here's what I'm in the process of now... The Bussman provides a 100A 12v tap and equalizes the draw on that bank's batteries.
The 24v starter always draws from the other bank, unless the Smart isolator is closed in which case it draws from all 4 batteries.
In addition there is a 60W 24v PV panel and Victron 75/15 as a battery maintainer for when parked extended time.
This is totally separated from any part of the habitat electrical, or the 28v 3.5k diesel genny.
The Smart isolator has performed well on my FJC for several years and lots of driven miles. It has also saved my hide several times due to how I split the system - separating the starter battery from everything else.
So here's what I'm in the process of now... The Bussman provides a 100A 12v tap and equalizes the draw on that bank's batteries.
The 24v starter always draws from the other bank, unless the Smart isolator is closed in which case it draws from all 4 batteries.
In addition there is a 60W 24v PV panel and Victron 75/15 as a battery maintainer for when parked extended time.
This is totally separated from any part of the habitat electrical, or the 28v 3.5k diesel genny.
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