APU Tri-pac not charging batteries

I have a 2500 watt inverter...with two led bars...one volts other watts...I would like to purchase a 3500 watt inverter...the one I have has trouble with a 700 watt microwave...and I barely have anything else on when using the MW. Not doing anything with new inverter until I upgrade my APU alternator...but need to save money the TK alternator expensive.

 

Yes I installed it myself.... It is identical to the 65 amp except the cooling fins behind the pully. I used the original wiring except for the ground wire from the alt to the ground lug. I upgraded it to an 8 gage wire. I have heard that the newest tripacs have the option of a duel wire alt but the part number I posted is a direct replacement...

 

The cooling fins are behind the pully... The fins on my original alt are straight (from shaft to outer edge)... the ones on the replacement are slanted... Thermoking parts counter can get you a tripac fin plate. I don't have a pic because you have to drop the lower pan off the unit to get to the alt.

 

Talk to an RV dealer about a battery Isolator... I have one on my rv that allows me to keep 1 battery from not being discharged.. but it allows all to charge at the same time. it can be set up for any combination of batteries. I have 2 deep cycles for lighting, and 1 for engine/generator starting. Hope this helps.

 

Sarge where did you buy the 120amp alternator and how much if i may ask? I tried searching the part number in goog but very limited choices. I think my alt is dead and want to replace it. How hard is this to do? I crawled under the turck and it looks like the whole bottom cover will come off with a few bolts and unhook the exhaust from it? thx in adv, chris

 

Chris, I bought mine at Thermoking. They are a little pricey. I paid $385 for it because I didn't have a core. They are easy to install... Your right, disconnect the exhaust fromt the side, remove the 4 bolts and remove the bottom cover. Be sure to disconnect all the Tripac power cables from the batteries (4).. the just 2 bolts and the wiring from the back of the alt. You will need an impact wrench and I think it's a 15/16" socket to remove the pully... REMEMBER, you must use the cooling fins off the old one or you will burn the new one up due to overheating. This is also a good time to replace the belt... I don't buy the belts from Thermoking, I get the from a local parts house. Alot cheaper, just take the old one in and they can match it up, then write the number down somewhere, I wrote it on the inside of the top cover... Hope this helps...

 

Sounds to me like what you're describing in an AGM (absorbed glass mat) battery. They are a true start-deep cycle battery. The numbers put out are extremely impressive, and those batteries weigh about 70lbs each vs half of that for a regular battery. And they are ###### expensive lol. I started a post about them a short while back, but there wasn't much interest in them. Probably because of the cost associated.

 

i had the same problem.lasted for 6 monthes.then i asked the mechanic to disconnect each battery,and test 1 x 1. 1 was dead,killing the others,by becoming a load,like a light. when tested together the voltage , and amps seem ok. this hapened at the t.a. laredo. great staff there,by the way,just dont pay service call to the f.j.

 

i talked to thermoking today and he said if my apu isnt giving any codes and working fine other than the charging that i have a wiring problem..My apu works fine ac,invertor,etc I crawled under the truck again today and checked what i could with just access panel off and dont see anything. i also checked all battery connections. Tech also said i should just stick to the 65 amp alternator which is what im going to do as i dont put much load on it.

i dont know what else to check, i think i will wait till i get home in a couple weeks and take the bottom cover off and drive up to autozone and see if they will let me hook up the tester and check it. If it is indeed bad im going to take it off and see if the autozone or local alternator shop has one similar i can make fit,hate to pay dealer prices, 385 seems very high to me, i found some expired ebay ads where the 65amp ones sold for 70$-120$, probably refurb but thats ok... thx for the reply

chris

 

you may show good voltage at the alternator on the TriPac, but poor voltage at the batteries due to a bad ground with the APU.

You can't use a simple replacement alternator as the ThermoKing one has lots of extra wires on it that are related to the voltage sensing circuits that turn it on and off based on the voltage.