# Battery problems in my Generac



## ToolLover (Jan 13, 2020)

The later model Generac's have a LED that gives a warning when the battery has problems.
It does not however tell you what is wrong with the battery.
So, I get the yellow LED warning.
Add to that the start LED is lit, the stop LED is lit.
I check the battery with the charger on and it is 14.95 VDC.
Well the charger is working so I disconnect the ground cable and recheck the battery: 12.58 VDC.
I am thinking the Computer or charger must be screwed up.
I was advised to let the generator sit without power overnight.
Another experienced diagnosis was that the battery had a bad cell causing the overcharge.
I call my buddy at the station. He tells me that the battery has a bad cell causing the over charge.
The Battery is only 21 months since install.
I installed the new battery this morning and everything is back to normal.
It was a trip, and frustrating to say the least, but it is fixed.


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## iowagold (Jan 22, 2020)

yea...
are you still using the oem charger??
or did you go the after market charger yet?
click here for the battery charger page
we have switched over to the little solar brand charger on the cars and trucks as well as the eu7000is generators now.
they work perfect..
and so far we have yet to over cook a battery..
yea some of the oem chargers are not "smart chargers"
and they can trash a good battery in a short time by over volt or over current charge...
yo might want to look in to the newer battery tech...
pricy but they are good the new lithium battery's work well on the gens.
click here for the generator batteries page


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## exmar (Jun 29, 2015)

Gotta love a happy ending!


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## iowagold (Jan 22, 2020)

lol ex!


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## speedy2019 (Jan 29, 2019)

Will a lithium batter work on a gen that recharges the battery when the gen is in operation?


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## tabora (Sep 6, 2018)

speedy2019 said:


> Will a lithium batter work on a gen that recharges the battery when the gen is in operation?


The answer is a qualified maybe. The charging rates for them can be quite different...

The maintenance charging for a Lithium battery is very different than a lead/acid battery. It must be charged with a voltage of 14V minimum to 15V maximum, and requires a special charger, like the OptiMate Lithium 4S. Per TecMate: _*Lead-acid and lithium batteries operate the same in the vehicle ONLY within the range of 13 to 14.4V.* Below that it changes : a lithium (LiFePO4) is close to 0% at 12.8V, it has no useful power left to give, around the same voltage where the sealed AGM lead-acid battery is at full charge (12.7 to 12.9V)!_​


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## iowagold (Jan 22, 2020)

some have the charge manager controller inside the battery.
depends on the make and model of the battery.
the best is to get a lithium battery that is designed for automotive use.
most of those have the controller on board.

and yes use a lithium automatic charger with a lithium battery!

and disable the oem charger connections.
or modify the oem charger for the lithium upgrade (that is what we do).

works well for us.


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## ToolLover (Jan 13, 2020)

Re Iowagold: The later model Generac's have a built in charger.
Previously there was a small charger in the Generac TS.
I had to remove the TS charger and use the wire to put 120 VAC into the Generator panel.
Now I am curious: How do you disable the add on charger when the engine is running and charging the battery? Relay? By removing the utility supply?


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## speedy2019 (Jan 29, 2019)

I have had my gen for just under 2yrs now and its only been used for 20mins for its monthly runs as we havent had any power cuts and even with the gen being used very little its keeping the battery charged well.

It normally takes about 2-3secs of holding the key, so Im guessing that stressing the battery a bit... But Last time the gen didnt want to go at all as it took like 10secs for it to fire up and it wasnt that cold at all.. I was a tad wrorried that the battery was going to die before it started, as I cannot use the pull rope as Im not fast enough.


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## ToolLover (Jan 13, 2020)

You did not say if it is a standby unit or what.
If it is a standby generator, after two years you should have had to reset the yellow indicator at least once.
That yellow LED Indicates battery check, battery low or battery over charge.
If you cannot reset the LED, best get a battery. The gremlins inside as just too smart.


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## tabora (Sep 6, 2018)

ToolLover said:


> You did not say if it is a standby unit or what.


@speedy2019 doesn't have a Generac. He has a Chinese-built Böhmer (in the U.K.)...








Böhmer-AG 6500W-e Portable Petrol Generator







unionmart.co.uk




Oddly, it's model is 6500W, but it's 2800W Startup / 2600W Constant Output.


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## iowagold (Jan 22, 2020)

ToolLover said:


> Re Iowagold: The later model Generac's have a built in charger.
> Previously there was a small charger in the Generac TS.
> I had to remove the TS charger and use the wire to put 120 VAC into the Generator panel.
> Now I am curious: How do you disable the add on charger when the engine is running and charging the battery? Relay? By removing the utility supply?


pm me TL


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## Brian Baird (4 mo ago)

ToolLover said:


> The later model Generac's have a LED that gives a warning when the battery has problems.
> It does not however tell you what is wrong with the battery.
> So, I get the yellow LED warning.
> Add to that the start LED is lit, the stop LED is lit.
> ...


That 14.95 is way to high for any 12 volt battery. The charger is killing it. Likely either made gas out of all the water or corroded the positive plates until they fall apart. Either way will kill it easily in 21 months. You need to check out your charger. It should sit at 13.2 volts for a battery that is only rarely used. Any higher and you WILL kill it. I have several lead acid batteries on some of my electronics gadgetry, to keep it going when the electric fails. The power supplies are a constant voltage at 13.1-13.2 volts. My batteries last for years. Don't tell me a battery will not charge until it's at 13.6. I know it won't charge up very fast, but it will charge. Takes about 4 days to go from empty to full. Automotive alternators do run at 13.6 to 14.2 so that they can charge up quick. But you don't let your car run and keep the battery at that voltage 24/7. You shut it off and the battery gets to rest. A trickle charger is a great way to kill any battery. If the generator's "maintainer" is not adjustable, disconnect it and see if you can just use a plug-in battery maintainer. Get a good one that actually shuts off when the battery is full.


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