How To Change Battery In Generac Generator

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Today we will be showing you how to change battery in Generac generatorWe are replacing this battery because it no longer holds a charge at all. As we have left the battery tender on overnight and when we remove the battery tender and try and start it it doesn’t even click. We will be showing you on this XG series and the battery is located in the panel right above the muffler on the handle side.


So to start we are going to need a 3/16 allen wrench or key that way we can remove the 8 3/16 bolts from the front and back panel. There are four in each panel two at each end. For the front panel well just wiggle it free and let it hang down as all our connections are in the panel and we don’t want to disconnect them or pull on our choke cable. The back panel has nothing in it so we can remove that panel completely.


Once we have the front and rear panels removed we can grab a 1/2 ratcheting wrench and remove the two gas tank bolts that hold the tank into the panel that we need to remove to gain access to the battery right next to the handles. Once we have those two removed we can loosen the other side four or five turns. Next we can zip tie the gas tank to the generator frame to hold it up that way when we do remove that panel the gas tank won’t fall. You can zip tile right though where the bolts go through.


Once we have our gas tank tied in place we can grab a 3/8 wrench and remove the 3/8 bolt from the bottom of the panel right above the muffler as that hold the heat shield in place. Once we have the 3/8 bolt removed we can now grab that 1/2 ratcheting wrench and remove the two 1/2 bolts that hold the panel to the generator frame so we can gain access to the battery. There is one on each side of the panel. You will want the wrench as a ratchet and socket will push the front panel away where you could damage the choke cable or accidentally disconnect your wiring. Hold the panel as the weight of the battery will pull the panel downward.


Once we have the two 1/2 bolts removed we can roll it or well keep one end kind of sitting in the generator as we don’t want to pull on our connections. You can have someone hold the panel or zip tie it to the frame so you don’t pull on the wires. Next we can grab a 1/4 ratchet and a 5/16 socket and wrench. We can use that to disconnect both our battery cables. Once we have both the negative and the positive terminals removed we can add a 3″ 1/4 extension and loosen the two 5/16 bolts that hold our battery bracket in position.


Once we have the battery bracket loose we can lift the old battery out and remove it. Next we can open or unpackage our new battery and slide it into our battery bracket. The battery part is 0G9449 12v sealed battery. With the battery slide back into our battery bracket we can tighten the two 5/16 bolts to hold the bracket in position. Next we can reconnect a battery terminal leads. When reconnecting them also make sure that your battery tender leads get reconnected as well. Once we have them started by hand we can snug them up with the ratchet and socket.

Now that we have our battery reinstalled we can rotate the battery panel back in position within the generator frame. You will want to make sure that the heat shield is resting on top of the bottom side of the panel. Well align the holes and then reinstall the two 1/2 bolts on each side of the panel. Once we have them started by hand we can use the 1/2 ratcheting wrench and tighten them up.


Now that we have that panel attached to the generator frame we can now cut the zip tie holding the gas tank up and let it come down and rest on top of the panel we just reinstalled. Next we can reinstall the two 1/2 bolts we removed from the gas tank and tighten them with the 1/2 wrench. Be sure to also tighten the other two as tanks bolts and we loosened them 4-5 turns to let the gas tank pivot.


Next we can reattach the back panel. You will want to make sure that the spacers are in position and that you have the lettering the right way. Well hold that in position and start all the 3/16 allen head bolts. Once we have them all started we can take the allen wrench and snug them up.

Once we have the back panel on we can reinstall the front panel. Before you push it back up and into position be sure to reconnect or attach your battery tender leads. Once we have them reconnected we can lift and get the front panel in the correct position. Once we have it where it needs to be we can start all the 3/16 allen head bolts by hand. Once all started by hand we can snug them down with the allen wrench.


Once we have that front panel on we can now reinstall the 3/8 bolt to hold our heat shield to the side panel by the muffler. Once we have that 3/8 bolt install we are now ready to test the battery to see if it will start the generator.


So well push the generator outside or to a well ventilated area. Check our oil and see if it starts. This one started right up so this battery works and we have connected everything correctly.


Something you might want to do is get a weekly timer and plug that into the wall and then the battery tender into it and set it to charge the battery a few hours once a week. That way you know the battery is getting charged every so often to ensure that when you need the generator it will be ready to go. Another thing you could do is get a battery tender junior and wire that in as you replace the battery. The battery tender JR is better because it will give you an idea of battery charge level, if its charging the battery and it can be plugged in or powered all the time and it won’t overcharge the battery as it will cycle on and off as it needs to.



So that’s it we have just shown you how to replace the battery on your portable generac generator.










This video was extremely well done! I just changed the battery on my Generac 8700 which is the 10000 Watt version of this generator. It it configured exactly the same way and the steps outlined in this video are perfect. There is one extra nut holding the heat shield in place on the 8700 model. It is attached to the bolt that holds the end cover in place so when you remove that bolt, you first remove the nut supporting the heat shield. When replacing the battery, I also attached the leads for a Deltran Battery Tender Junior so that I can continuously charge this new battery. As Generac owners know, there is no Smart Charge option for the Generac and you have to remember to charge the battery through the dumb charging port periodically. Eventually you forget and the battery is toast. Should be good to go for a long time now. Thanks for the video.

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