# Generac XT8500EFI



## SKT_33 (Mar 30, 2021)

Hi all, 

Forgive me if this has been asked before, I am new to the forums and owning a generator in general. 

I recently bought a Generac XT8500EFI from Costco and had a transfer switch installed at the house. My first Generac XT8500EFI had a ton of issues and was returned as DOA. the new one seems to be working ok and starts, however, the manual says to charge the battery once a month for 12-18 hours. I charged the battery for about 20 hours and started the generator no problem. 2 weeks later I tried again and saw the light flashing which appears to mean the battery needs charging as there is not enough juice. Is this common for the battery to deplete that fast that it would not allow the generator to turn on? I have added the battery to a battery tender which should solve this problem, but I read in the manual not to over charge the battery. I am not sure if the tender will "overcharge" the battery as it allows the battery to get to 80% and then recharge but I just want to make sure the generator is working in a time of need and not be stuck without power.

Any input or advice would be greatly appreciated. 

thank you,
Steven


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## ToolLover (Jan 13, 2020)

I think you need a trickle charger installed full time. They are about $25 on Amazon.


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## Old man here (Nov 5, 2020)

SKT_33 said:


> Hi all,
> 
> Forgive me if this has been asked before, I am new to the forums and owning a generator in general.
> 
> ...


Is that the "Battery Tender" brand? If so, leave it hooked up all the time.


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## SKT_33 (Mar 30, 2021)

Old man here said:


> Is that the "Battery Tender" brand? If so, leave it hooked up all the time.


 Yes! it will charge 6v or 12v batteries and I currently have the battery for the generator hooked up so I would just need to connect the battery back to generator if power goes out. I just wanted to make sure that is ok and that is what most are doing with these generators.


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## exmar (Jun 29, 2015)

A lot of Generacs are infamous for weak or failed battery chargers. Battery tender/trickle charger, etc. is what most folks leave connected. That is a construction generator, if you have it connected by a TS, you may/may not have to disconnect the internal jumper between ground and neutral to avoid having two grounds on the electrical supply (NEC) however, if you've tried it and it works should be fine. Make sure when you're in an outage that you feed the battery tender/trickle charger to keep the battery up. You'll be shutting it down to refuel, check oil, etc. those batteries only have one good start and "maybe" a second one. Trying to jump the battery in the dark ain't fun.


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## speedy2019 (Jan 29, 2019)

I really dont know why all generators with electric starts doesnt recharge the battery while its running... I bought a cheap £300 2800watt gen 2yrs ago and that if any wouldn't have this feature with it being cheap, but it does. I have only really run the the gen for about 10-20mins monthly so far, but its enough to keep the battery topped up and the battery still seems as strong at turning over the engine as when it was new.
Electric Key Start Generator | Bohmer-AG - 6500W-e Portable Generator


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## Airstreamer67 (Oct 3, 2020)

It is quite amazing that generators which have electric starting and otherwise might depend on a battery would not include a 12VDC circuit to charge the batteries. My 25-year-old genset sure does


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## exmar (Jun 29, 2015)

Over the years, hanging out in various forums, small engine, lawn and garden tractor, tiller, etc. The one thing I've heard repeatedly is that very obvious and needed things are left off in order to meet a "price point" and be competitive. e.g. The reason that the less expensive small tractors don't have a drain plug on the transmission is to allow a "beverage holder" to be added to the fender. Obviously market research discovered that the public was more interested in having a cold beer while mowing than being able to service the machine. :-(


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## iowagold (Jan 22, 2020)

SKT_33 said:


> Yes! it will charge 6v or 12v batteries and I currently have the battery for the generator hooked up so I would just need to connect the battery back to generator if power goes out. I just wanted to make sure that is ok and that is what most are doing with these generators.


you can do a battery switch fr the generator main power for no draw when sitting. just to make sure to have a tender or a tender style charger running 7/24.

the late model batteries are junk... with the new lower lead design they have higher internal resistance that just sitting not used or connected they run down. and in a short time!.
so the good answer is to make sure to have some sort of GOOD battery charger maintainer onboard 7/24 in all battery units.
cars, trucks, heavy equipment, small equipment, and yes our gen sets with electric start!
pm me if you need links to good chargers.


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## Airstreamer67 (Oct 3, 2020)

I've never liked the idea of leaving live battery chargers on all the time on a bunch of equipment batteries that are left unused and unsupervised over periods of time.

My problem is the potential malfunctions that could occur to the battery chargers and inside the lead-acid batteries themselves. The threat of fire or explosions etc is low, but not nonexistent.

As an alternative, I disconnect batteries from the machines when they are not being run regularly, and check the water and charge the batteries every few months as the voltage slowly dissipates over time. On my irregularly run vehicles, I install knife-blade disconnects to make the job easier.

Just an alternative way to do things.


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## SKT_33 (Mar 30, 2021)

exmar said:


> A lot of Generacs are infamous for weak or failed battery chargers. Battery tender/trickle charger, etc. is what most folks leave connected. That is a construction generator, if you have it connected by a TS, you may/may not have to disconnect the internal jumper between ground and neutral to avoid having two grounds on the electrical supply (NEC) however, if you've tried it and it works should be fine. Make sure when you're in an outage that you feed the battery tender/trickle charger to keep the battery up. You'll be shutting it down to refuel, check oil, etc. those batteries only have one good start and "maybe" a second one. Trying to jump the battery in the dark ain't fun.


Thank you for the info. Super dumb question and apologies for my ignorance, but if I lose power and start the generator, can I plug the charger it came with into the outlet of the generator to keep the battery charged so in the event the outage lasts over 10-12 hours and I need to shut down the generator to refill with gas the battery will be charged up or will that not work? I looked in the manual but it doesnt mention anything on this so was curious and cant seem to find an answer. 

Again apologies for the "dumb" questions this stuff is all new to me.


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## ToolLover (Jan 13, 2020)

Back to Iowagold's comment about today's batteries.
I installed a new 16KW Generac two years ago.
At that time I installed a new Kmart battery.
Less than a year later the Generac started telling me there was a battery problem.
1 1/2 years later the Generac refused to allow a reset for a battery problem.
I replaced it after learning the Kmart battery had an internal resistance problem.
Use your own judgement, but for now on I buy only batteries that are warrantied for five years.


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## Old man here (Nov 5, 2020)

Whoa, stop the misinformation here!
Direct from the manual, the generator will charge the battery while the generator is running.


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## SKT_33 (Mar 30, 2021)

Old man here said:


> Whoa, stop the misinformation here!
> Direct from the manual, the generator will charge the battery while the generator is running.
> View attachment 9019


Thank you for this! This is great news. I have seen conflicting info that these batteries dont charge while they run and I missed this in the manual. Thank you again for confirming this. I think my best bet is leave the battery on the trickle charger, start the unit once a month for about 20-30 minutes and once every three months or so connect to the transfer switch and make the generator "work"

Thank you all for your input. This has put my mind at ease!


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## Old man here (Nov 5, 2020)

SKT_33 said:


> Thank you for this! This is great news. I have seen conflicting info that these batteries dont charge while they run and I missed this in the manual. Thank you again for confirming this. I think my best bet is leave the battery on the trickle charger, start the unit once a month for about 20-30 minutes and once every three months or so connect to the transfer switch and make the generator "work"
> 
> Thank you all for your input. This has put my mind at ease!


You want to have at least a small load on the generator while it is running. I always use two ceramic heaters when I exercise mine. One plugged into each leg to balance the load.
Also, your battery may just be bad. If a battery sets in a discharged state very long, it will be ruined. It is hard to say how long the generator set in a warehouse or store or how old the battery was when the factory installed it in the generator.
I would buy a new battery just to be on the safe side.


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## exmar (Jun 29, 2015)

Old man, my comment was "weak or failed...." a battery maintainer precludes this.


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## speedy2019 (Jan 29, 2019)

I have never charged my battery manually, I just start up the gen monthly and put a light load on the gen for 10-20mins and that seems to keep the battery in good shape and battery is 2yrs old now with gen being stored 24/7 outside with just a cover over it.


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## Gerunzo (3 mo ago)

iowagold said:


> you can do a battery switch fr the generator main power for no draw when sitting. just to make sure to have a tender or a tender style charger running 7/24.
> 
> the late model batteries are junk... with the new lower lead design they have higher internal resistance that just sitting not used or connected they run down. and in a short time!.
> so the good answer is to make sure to have some sort of GOOD battery charger maintainer onboard 7/24 in all battery units.
> ...


My solution to a battery discharge situation is a battery switch on the positive lead, you can also add a solar panel to keep battery topped off while battery is disconnected through switch
I have my unit mounted in a plastic shed with a small exhaust fan for the carbon monoxide detector. Mild modification to exhaust with flex exhaust pipe and metal dryer port.


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## sledman8002002 (Jan 28, 2021)

Gerunzo said:


> solution to a battery discharge situation is a battery switch on the positive lead


I'm a big fan of the battery switch/breaker as well. Been using them for years on every boat with a battery I've owned, (my plow truck and a few ATV's as well).
I also recently added a breaker to both of my elec start gen's due to finding a dead battery on one of them that the rocker style start/power switch had inadvertently been turned on/left on for a few weeks.
*To note...*A breaker (as pictured) will make absolutely no difference in keeping a battery alive when the battery a poor example piece to begin with.


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