B&S mower - replacement of 10.8V li-ion battery with 12V gel battery

Hi to all

Equipment:
Stiga 53seq 4 b mower with Briggs & Stratton 775 IS (instart) engine - electric start
battery 10.8 V 1.45 Ah / 15.7 Wh.

Is it possible to replace the set with a 12 V gel battery, e.g. 9 Ah for about PLN 100 instead of a 10.8 V battery? It's a shame to spend PLN 350 on a battery that will fail after 2 years. How do you think it could be done? Will the starter fail at higher voltage? What's the best way to go about it?

I would be very grateful for any tips.

From the voltage point of view, this is not a problem (li-po 10.8 is actually 10.8 V- 12.6V). The question is, will it be fine for you without being reworked. Aku li-po certainly had security either in the mower or only in the battery, I do not know. Unless they are NI-Cd batteries, then it will be easier, but if the voltage above 12 V will not affect the starter, I do not know.

What technology is the original Li-Ion, LiPo, NiMH battery in? An output voltage of 10.8V would suggest either of the above. Knowing this, you can also consider regeneration, it should be cheaper. There are many companies that deal with this, or by yourself, if you have the appropriate skills.
As for the replacement for a 12 V gel battery, it is difficult to say whether it will hurt.
Is only the starter powered from the 10.8 V battery, or is it also the ignition module? Is this battery charged while the mower is in operation or with a separate charger?
The first thing to keep in mind is the higher voltage, which was already mentioned by jarcecz.
The voltage of such a freshly charged 12 V gel battery can range from 13.8 to approx. 14.5 V (depending on the charger).
And the voltage of the original charged battery is probably approx. 12.6 V.
The difference is small, the starter motor itself should withstand such a difference in voltage, if it is not used too intensively, it may theoretically overheat.

Thanks for the answers.

It is a lithium-ion battery with an external battery, such as in e.g. screwdrivers. I was wondering whether I should add a stabilizer L7912 12 V 1.5 A, then maybe the problem with higher voltage would be solved, but I read it, because I don't know anything about it. I'm just trying to save some money, the battery costs PLN 50 and it's a 350 contraption. As for overheating, the starter spins up to 5 seconds, so it shouldn't overheat at this time.

I would like to add that the battery died a month after the 2-year warranty.

Give up these stabilizers, do you know what current the starter draws? A charged gel battery is 12.3-12.6 V, not 14. Plug in the gel and check.

I do not know what current it consumes, there is no sticker, and unfortunately it is not described in spare parts. I guess the size of this current does not make much difference whether the battery will be 4 Ah or 7 Ah?

Gentlemen, I am trying to connect the battery, but I noticed that the mower has a microswitch and that 4 wires come out of the battery. I am asking you to take a look at the diagram and suggest how to connect it to the battery, where there is only plus and minus. I especially don't know what the cable goes from the battery to the microswitch and how to connect it to the battery.

1. Scheme



2. Photo of the microswitch with 2 plugs coming out - for the ignition key and for the battery as shown in the diagram.

This microswitch is what it can do, what is it attached to, a cable, a lever?
Pictures of the rest of the electrics would be nice, this battery with "external battery" too. Does the battery itself also have four contacts? From the diagram, it can be concluded that there is an additional relay or electronics to activate the starter. Rather, the inrush current should not be applied to the microswitch.

I expressed myself a bit vaguely when talking about the external battery, let me explain:

this is the battery:


this is what the charger looks like:


this is what the microswitch looks like:


This is how the wires coming from the battery look like:


1 and 2 are connected and 1 goes to the starter and 2 to the ignition switch
3 (red) to the starter
4 for microswitch v7-6c37e9-036, exactly like on this page: Link

according to the information on this page, this switch is at a maximum of 15 A. I suspect that the microswitch with this plate connected in some way with the motor gives the current to the coil at the right moment.

here again the diagram:


I repeat the question, how to connect it via a gel battery without damaging the starter and, above all, the microswitch with these parameters:

jogma wrote:

I repeat the question, how to connect it via a gel battery without damaging the starter and, above all, the microswitch with these parameters

Connect the battery in accordance with the polarity directly to the starter, through a solid switch or relay, e.g. dedicated to starters in scooters, motorcycles. Maybe a solid switch is enough, it is not known how much current the starter consumes.
This is when it comes to turning the starter itself. But it is not known if this is enough for the mower to start. Something else needs to be done with the wires to the coil, and it is not known what the microswitch is for.
The pictures of the original battery probably show plus and minus signs and two additional pins, maybe it is a Li-Ion balancer connector or maybe something else. The diagram does not show where these individual pins are connected, where plus or minus. The microswitch also has a specific contact arrangement, and the diagram does not show how it is connected. Without this equipment in front of you and without remote measurements, it is difficult to advise well.

There are 4 contacts from the battery, the two extreme ones are plus and minus (there is, say, 1 V on them) for the starter. The circuit is broken by a switch that closes when we grab the handle and release the brake. Now we turn to firing. In this case, it is solved in the battery, there is a microcontroller and when pressed firing (red start), the voltage from the battery PLUS to the connector next to it is applied, and then the system also tells two MOSFETs (such small relays) that they open and voltage 10, 8 V goes to the starter. The starter is like a 12-volt, and a 12-volt battery will do, but to bypass this system with MOSFETs, you will have to add a relay under the firing button. To do, is there anyone willing to sell an old battery? It may be broken, in parts ?

I have a question, how to check the battery? Do you need to shorten the two internal pins or give some voltage? I want to charge it with an external source, because firing sometimes works and sometimes doesn't.

The battery is IS12B.
Pins: - | TH | E | +

jogma wrote:

this is the battery:

Enter on the Allegro: 18650 plaques.
You will replace with an ordinary soldering iron.

But nobody asked about it and it is not that simple, because there are 3.6 V cells and high-current ones.

Very simple. And on the Allegro you have 20 and 30 amps.

As I know it, but it's worth mentioning so as not to make yourself a torch from the battery.
However, I asked for something completely different.

kris86k wrote:

Do you need to shorten the two internal pins or give some voltage?

If you don't want to go into space, don't touch them. Any actions are only positive and negative. If, after charging, they do not have at least 12 V, the battery is repairable.

I see you haven't read the topic from the beginning. This is not a typical battery. The current is "released" only after the signal is sent to the appropriate pin through the internal mosfets in the battery. That's the problem.
I regenerate my batteries and do not need basic advice. I know Li-Ion quite well, I know how to test, replace, weld, solder etc.
It is a pity that such an experienced forum user litter the topic without even getting acquainted with it.

kris86k wrote:

I regenerate my batteries and do not need basic advice

With such experience, you have not dismantled this battery yet? Show me what's inside.
If you don't turn the starter sometimes, check if it can be turned by hand. Because it doesn't have to be the fault of the battery.

The equipment does not belong to me, I do not have it in place. Took the battery to check but it came out zonk. The mower itself is under warranty (the warranty is 3 years, more than two years have passed), but the battery is probably over, but I'm not sure about it, so I haven't touched it yet. The equipment would go to the service, but the service requires the mower to be sent to them (another city) and there is a problem to pack because the mower is quite large.
A colleague of emdi90 wrote that the signal is fed from the plus to the next connector, but I do not fully understand what it means. Plus with the pin next to it is shorted and then the voltage appears on the pins?
I know that the voltage to the starter is supplied directly from the batteries marked as + and - but the voltage is not there. There are 3 pins in the mower. Two external and one additional internal at + marked as E.

There is nothing on the Internet about this battery, and nothing follows from the pictures above. I would give the mower voltage from a normal car battery and see what will happen. I do not want to believe that there is a relay in the battery. The charger would also have to turn on this relay for charging. Some paranoia. In addition, this battery is without a balancer, so the service life is short.

The battery may have a built-in balancer, and a separate circuit, as one of my colleagues writes, switches the voltage on with mosfets.
There are already many batteries so that the balancer with the charger is inside, and only the power supply is connected. Sometimes even an ordinary DC circular "bush-pin" connector.
Here, the solution is perhaps due to the fear of short circuits and fire. The risk of short-circuiting 3 pins at once is much less than two.
The charger can turn on the battery in the same way as the lawn mower, unfortunately I do not have it at hand at the moment.

I have the same problem with this engine. I bought a mower used without a charger with a discharged or maybe even damaged battery. Quickly, to check if the mower works, I connected the 12 V batteries from the screwdriver to the + and - contacts and it fired, but the starter with this connection is spinning all the time.

If you get acquainted with the topic, everything becomes clear.
Write what you want to achieve. The easiest way is to buy a new battery, but I guess you want to avoid it.

At the moment, I wanted to find a way to charge the battery, for example using a DeWalt 10.8V charger. I want to avoid both buying a new battery and a charger that is not cheap. If it turns out that the battery is damaged, I will remodel the installation in the mower for DeWalt batteries, because I have some equipment of this brand and it would be the most advantageous for me.

As far as I remember correctly, there are three pins in the mower. Check if after pressing the start lever and the starter button there is a short circuit between any of the plus or minus pins with the third pin. Press and release the button, then you will see a change on the gauge as it may show something without even pressing the starter button.
It's best to also open the battery and take photos.

For me, this battery is between + and - about 0.1 V. The mower stopped today, the LEDs show 100% charge. After inserting it into the charger after 5 minutes, it already showed that the battery was charged.
How to check this battery, is it dead, or maybe a charger, starter, etc.?
Stiga Twinclip mower.

If you have any experience with electronics, try this: set the mower to start (I don't know how it works on your model), probably two people will be needed. On the mower's pins, which are marked as + and - on the battery, connect the power supply directly from a 12 V battery with a minimum capacity of 10 A, it must be a battery, an ordinary power supply is not enough. It can be a scooter battery, car battery, etc. Watch out for short circuits and correct polarity connection! The starter should crank without depressing the starter button. If the mower starts, the battery or the starter button / system is to blame.
Just because the battery shows 0.1V doesn't mean it's damaged.
Be sure to let me know how it went.

The battery is functional, one of the cables in the plug is damaged, which connects to the cable from the starter button.
I am trying to patch it up, because I do not see such cables to buy with such a tubular connector, and the cable is probably damaged at the plug itself.

Then tell me where this conclusion came from, maybe it will be useful to someone in the future.

I checked the batteries (5 years old) in another mower in the store, then found this broken cable.
I patched it and it works.
Regards.