Thank you.
An excellent write up.
An excellent write up.
T-Max Dual Battery Install
- Thread starter KlausVanWinkle
- Start date
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Great Write Up ! If you accidently short the green wire out of control module to 0volt ground , trying emergency override or testing your new install, trying to get coil to pull in, you will destroy the Mosfet output. Typical symptom is the control module always has the solenoid on as soon as green wire connected, no green link light on module. Emergency jump requires you remove the green from control module, then jump coil to 0V gnd. You can repair module if your an electronic hobbyist/Eng or know one. Part you need is any old n channel 3055 type mosfet in a dpak surface mount package.
The original is extinct part PHD3055E.
I used Rohm RSD220NO6TLCT. Fit's exact , 22amp instead of original 10.9amp. I bought from digikey.com
If you need schematic and repair details of the PCB.
Including Fuse reset and advanced install schematic,
Alternate source part numbers and suppliers,
Also install schematic update for features like flyback diode
for coil etc...
PM me on FB , I'll send you pdfs by your email address.
The original is extinct part PHD3055E.
I used Rohm RSD220NO6TLCT. Fit's exact , 22amp instead of original 10.9amp. I bought from digikey.com
If you need schematic and repair details of the PCB.
Including Fuse reset and advanced install schematic,
Alternate source part numbers and suppliers,
Also install schematic update for features like flyback diode
for coil etc...
PM me on FB , I'll send you pdfs by your email address.
Repair info for T-Max DBS02 PCB, my schematic dual battery 2013 Sierra GMC
anyone know if the t-max is still being made or has it been discontinued for new model
so the way you have it installed if your primary battery voltage drops can you use aux to jump start from the controller you've installed in the glove box?
screendoor
SILVER Star
This may or may not help - I have used my aux battery to start the engine when my main battery was low and having a hard time turning over. I pressed the "manually link" button and was able to get it going with no problem. However, I recall that if the main battery was too low, then the "manually link" button didn't work properly. Hope that helps.
Ed Driscoll's post above has a picture with text that describes how to force the batteries to connect by cutting the green wire and touching it to the negative terminal - T-Max Dual Battery Install
I did solve the problem by putting a 50amp fuse connector between the 2 posts and removing the fuse so if i need to manually connect them i just have to insert fuse. and start. i believe the head unit has failed as when i use the link it does not activate a charge.
Thank you so much for your write up. Just finished my install yesterday!
Question, i drove the car today and the system is always linked right after start up.
Is that normal? Is there no way to unlink the battery from the controller? The instructions weren't very clear and the Grammer and spelling were horrible.
Question, i drove the car today and the system is always linked right after start up.
Is that normal? Is there no way to unlink the battery from the controller? The instructions weren't very clear and the Grammer and spelling were horrible.
Okay so been looking at mine more. Mine is not linked on startup but driving it around it is until I turn off the truck. I may have mine backwards but I don't think so. Also when I put my truck on a battery charger I can hear the solenoid clicking. I assumed it's linking them because of the voltage?
Last edited:
fireball
SILVER Star
Sounds like it is working as intended. When on the charger, you'll want to have a way to manually disconnect the batteries so you can charge each individually.
Do you have a suggestion on how to do that?
So im having an issue now, i just went to Colorado for a week and my dash cam killed my battery. No problem, just hit link and start. Nope. Both are dead. So my system isn't doing the one thing i installed it to do.
I've installed it exactly how the op did. Any reasons why?
I've installed it exactly how the op did. Any reasons why?
Do you have anything hooked up to your other battery that may have drained it?
Nope. Nada. Not a thing.
Positive fused from main battery to solenoid, then on to the aux battery that's also fused.
Ground from aux to main battery. Aux to body, main to body.
On a side note, instead of messing with the green wire to turn on and off the Solenoid manually. The other option is to remove the black jumper off the main battery lug (big lug) on the solenoid. Keep it installed on the small lug like the diagram shows and either use a relay or attach it to a keyed ignition source.
This way the solenoid will only operate when the key is on. This will eliminate the cycling in and off the the solenoid if you are using a charger or solar.
One other thing is that you can keep a pig tail to the main lug and with a female connector and have a male attached to the small lug so you can connect them incase you need to self jump start and the main battery is too low to trigger the solenoid.
This way the solenoid will only operate when the key is on. This will eliminate the cycling in and off the the solenoid if you are using a charger or solar.
One other thing is that you can keep a pig tail to the main lug and with a female connector and have a male attached to the small lug so you can connect them incase you need to self jump start and the main battery is too low to trigger the solenoid.
