Need to replace Genset Battery: stick withLead-Acid or not?

[Old_Skewler]

I have a Kohler 14kW Generator currently tied to a 450 CCA 12V lead-acid battery and a small 15W solar PV to keep the battery charged.

I need to replace the battery, it finally died today. Kohler does not specify ideal battery capacity for the generator, nothing on the owner's manual. I bought the generator used, so I do not know which battery size it originally had.

Two questions:

1. which battery type is most suitable for coupling to this generator? I am likely to use the generator to around 40F temperature.
2. Which size battery should I get?

Thanks in advance!

 

[RCinFLA]

If outside, subject to high and low temps, I would stick with lead-acid for starting battery. Don't just directly connect PV panel without at least a cheap PWM charge controller. Set float voltage to about 13.25v.

 

[chrisski]

I have a Kohler 14kW Generator currently tied to a 450 CCA 12V lead-acid battery

I like the idea of lead acid.

I'm not familiar with how many amps a motor actually takes to crank, but when I see 450 CCA, I assume that the engine needs at least that much to spin around. Finding a BMS to deliver that much will be difficult. That could require two 12 volt batteries in parallel each with DALY 250 amp BMS. You'd also need to be sure the cells can deliver enough amperage also. Maybe the number is not 450, but it probably is more than 100 amps.

If cold is a factor, below freezing, the lithium may be below charging or even being able to use them when lead acid would be fine.

I bought the generator used, so I do not know which battery size it originally had.

IME batteries come in certain standard sizes, like a group 27 battery. Within that group, there's some differences like amp hours or CCA, but its not huge. With lack of documentation, I'd go to a autoparts store or battery plus online and get the most AH and CCA available if its not ridiculously more expensive than others. If the battery fit loose in the holder, I have even sized up for more power. This doesn't necessarily mean A Group 28 is the next size up from the group 27, but you can get dimensions of each group.

The other thing I will recommend if buying online is checking to make sure the battery you're getting has the same terminals. My Trojan battery has on option for about six different terminals.

 

[Old_Skewler]

Don't just directly connect PV panel without at least a cheap PWM charge controller. Set float voltage to about 13.25v.

Hmm... This I didn't know was required. Could you clarify the following:

1. Why isn't it a good idea to directly connect a solar panel to a 12v battery?

2. Which charge controller would suffice for this job?

Thanks in advance!

 

[Old_Skewler]

That could require two 12 volt batteries in parallel each with DALY 250 amp BMS.

The battery compartment in the generator only holds one battery, so I am sure a single battery should be able to handle it.

If cold is a factor, below freezing, the lithium may be below charging or even being able to use them when lead acid would be fine.

Yes, it seems like lead acid is the way to go.

Just to be safe, I'll reach out to Kohler and see which battery size they recommend for the genset.

Thanks for the feedback!

 

[Old_Skewler]

Don't just directly connect PV panel without at least a cheap PWM charge controller. Set float voltage to about 13.25v.

I took your advice and did some research on PWM controllers. All of them are at least 7A.

The solar panel I have connected to the genset starter is only a 7W and 600mA. And to be honest, not a lot of sun exposure where the panel sits - I tried moving it around and cleaning it.

 

[RCinFLA]

I took your advice and did some research on PWM controllers. All of them are at least 7A.

The solar panel I have connected to the genset starter is only a 7W and 600mA. And to be honest, not a lot of sun exposure where the panel sits - I tried moving it around and cleaning it.

Two issues not having a PV controller. 600 mA when battery fully charged will eventually damage battery, even lead-acid and definitely LFP. The PV panel has some leakage current at night or low light so it will be discharging battery at night unless you have at least a blocking diode in panel path.

I am pretty sure you can find a small inexpensive PWM 12v controller. Otherwise, you would be better off with a small battery tender charger plugged into inverter AC. It probably consumes a lot less power then inverter idle power.

 

[Old_Skewler]

Two issues not having a PV controller. 600 mA when battery fully charged will eventually damage battery, even lead-acid and definitely LFP. The PV panel has some leakage current at night or low light so it will be discharging battery at night unless you have at least a blocking diode in panel path.

According to the manufacturer:

• A built-in blocking diode prevents power loss at night

I am pretty sure you can find a small inexpensive PWM 12v controller. Otherwise, you would be better off with a small battery tender charger plugged into inverter AC. It probably consumes a lot less power then inverter idle power.

Got it. I'll try Ebay now.

Thanks for clarifying.

 

[pvdude]

I use a lead acid battery for our Diesel generator, a large battery (730CCA) was needed.
To keep it charged, I bought a kit from Northern Tool.
The kit consisted of a 15 watt PV panel and a cheap charge controller of some mystery type.

Panel is still working fine 5 years later, but the mystery controller gave up after a year or so.
I found a better charge controller on Amazon, it has been working fine for a few years now!

 

[Old_Skewler]

The kit consisted of a 15 watt PV panel

Okay, so this answer part of my question: I was under the impression for such small wattage panels (7W or 15W) that a controller would not work. But it seems like still works.

Thanks for sharing your setup!

 

[RCinFLA]

Okay, so this answer part of my question: I was under the impression for such small wattage panels (7W or 15W) that a controller would not work. But it seems like still works.

Thanks for sharing your setup!

PWM controllers do not do high speed switching like an MPPT controller so their overhead power consumption is very low, pretty much regardless of amperage size.

 

[Affordable DC Generators]

What Kohler model? A lot of the residentials fit a specific size group 51 which is ridiculous money for the size. Others use a group 26 which is half the price but wont fit the side cavity.

Just go lead acid, its cheap and works. Just be sure to clean the terminals every year.