Yuasa Battery Acid Filling Tip

I went to install the sulfuric acid into my new Yuasa AGM battery I bought for my 07 Bandit to replace the original battery yesterday, and it came with a slick 6 compartment acid container that you press down onto the cell openings which have angled tubes that are part of the battery housing, which puncture the foil seals over each of the 6 tubes containing the acid.

The instructions state that if the fluid does not drain into the battery by itself to tap the container to help the acid flow down into the battery, but what I quickly found out is that the acid will did flow into the battery by itself without constantly tapping the container, and even doing that repeatedly for over a minute only about 1/6 of the acid had drained into the cells, so I quickly figured out what was needed to speed things up was to vent each of the cells on the acid container.

So I took a sharp single edge razor and made a cut in the top of each of the cells on the plastic acid container, and by the time I vented the last acid cell all the other cells were emptied, and the whole thing took about 30 seconds to fill the battery. I don't know why Yuasa doesn't tell you to do this, or have little vent nipples on the top of each acid cell that you can just snip off to vent them.

I had to aid mine the same way when I replaced the battery on the Bandit and again on the KLR. I just use the tip of my knife blade. I had replaced the Bandit battery as a safeguard after 65,000 miles and 5 years due to fixing to do a long trip last summer.

ooppps, that's an absolute no no! The filler is designed to "slowly" fill the battery over a controlled amount of time. If it did not foam up and leak out during filling, consider yourself lucky.

AGM stands for "Absorbed Glass Mat". After the battery is full of the acid it needs to sit quietly and undisturbed for at least 30 minutes, an hour or more is preferred, to allow the material inside the battery to "evenly" soak up the acid. Then it needs to be charged with an appropriate charger, that could take as long as 14 hours.

I deal with these batteries on a daily basis. I cannot begin to tell you how many fail prematurely because they were not initially handled correctly.

I demonstrated this several times to co-workers and customers. I have one of those battery testers that measures the internal resistance of the battery and displays it in percentage of battery health. When you fill the battery and apply the tester it is rarely above 85%. Putting it directly in the vehicle and cranking, further weakens it, then the charging system of the vehicle pumps in current way to fast and damages the battery, thus shortening its overall life span.

If filled and charged correctly the tester will show more than 110% and the battery does not need a huge current to get it back to 100% when installed in the vehicle. I seen these batteries fail in less than a year when handled incorrectly at initial fill. On the other hand I've seen them last as much as 10 years when handled properly and well maintained.

The last dealer I worked at had an on going issue with these batteries failing. As a dealer there is enough mark up on the batteries, and the return percentage is so low, there is no warranty from Yausa. What I found was that the parts guys were doing what most people do. Either selling the battery directly in the box and letting the customer do it or they would install the acid for the customer. In the shop, because of "time" the mechanics would just fill the battery and immediately install it, crank and park. This is by far the worst thing to do. After several demonstrations with an improperly filled battery and one done properly (used the tester, multi meter and a carbon pile load tester) I finally convinced management to buy the correct style of charger for these batteries and they in-turn allowed service and sales enough time for the batteries to soak and charge. Our battery warranty rate went from 37% to less than 1%.

I love these forums for exactly this reason, thanks for the info and explaination Chris

I second that Barry. Chris, thank you for your contribution!!!!!

So, what kind of charger do we need for an AGM? Is a battery tender ok? Is the key to charging to limit the amps?

SL350 said:

So, what kind of charger do we need for an AGM? Is a battery tender ok? Is the key to charging to limit the amps?

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My Schumacher charger lets you choose what type of battery you are charging :
Standard
AGM
GEL
Deep-Cycle

Been using a Battery Tender on everything thing since they came out. Not a problem yet. Only short battery life I've had in the past 40 or so years on motorcycle comes with the KLR and the vibration. I padded the compartment last battery change and this batt is still doing a fine job after 3 years. Before I was getting about 2 years. Been using AGMs since they came out.

Thanks for the input, and I did not have a problem with it foaming or over flowing when I filled it, and I did let it sit for over an hour before charging it.

MetrickMetal said:

Thanks for the input, and I did not have a problem with it foaming or over flowing when I filled it, and I did let it sit for over an hour before charging it.

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Hear that, we used to leave them for at least 2 hours before charging when I work in a shop. My last ones stayed on the bench for about 6 hours or so before hooking up the battery tender. I was not in a hurry.

I just got off the phone with Yuasa customer service, and the guy I talked to said that I was ok letting the battery sit for a little over 1 hour before putting it on my battery tender charger over night, and then going on a 100 mile ride yesterday.

I also asked him what the standing voltage should be, and he said that on a brand new battery after having been properly charged before use, and after not have been ridden for a couple of hours, the standing voltage should be between 12.8v and 13v, and I just checked mine and it at 12.94v measured with my Fluke model 112 VOM, so it looks like I good to go.

I will remember though next time to let the acid slowing enter the battery.

Thanks for the heads up!!!!!!!!!

achesley said:

Thanks for the heads up!!!!!!!!!

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If you go onto Yuasa's website, all they sell is a 1 amp battery charger / maintainer for their power sport batteries, and the customer service guy I talked to said that letting a new battery charge over night with a battery tender type charger is fine.