Amperetime / CHINS 12V 100AH enough to start RV Generator?

[eXodus]

5500w? I'm guessing about a 11hp engine. I just replaced the 6 year old battery in my 18hp lawn mower. On sale, the new battery was $20. Why not just buy a lawn mower starter battery? beats possibly harming something expensive.

Yeah, I was thinking sometimes along those lines.

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But it's not $20 but $45 bucks. still a lot cheaper I agree. So then I got the issue that my RV has a single stage converter (charger) which puts out 13.7V

That thing is very likely killing my lead batteries. But would be ideal to float a lithium battery.

Same goes for build quality, I am going to guess the internals are way up there in robustness, I would love to see a teardown. You are right though not sure if its worth it at double the price not without more long term data on how they hold up, thats what sold me on spending nearly 2x a normal AGM was there well known reputation for lasting a very long time, if I purchased now I would most likely go with a Chins/Ampertime or equivalent.

Will did a Chins Teardown.

 

[jharrell]

Will did a Chins Teardown.

Yep which is why I am considering, it has ok build quality and a good price, but no low temp disconnect which I am sure the Lifeline has plus most likely much better internal build quality on par or better than Battleborn and bluetooth monitoring.

 

[eXodus]

This is one reason I prefer a 12v house system its much easier to interface with the chassis for alternator charging and vis versa for emergency starting and keeping chassis charged. 12v does need larger conductors for high power (I have 4/0 for my 3000w inverter) and inverter pretty much top out at 3000w for 12v, but thats plenty for my 30ft Class A. Even a large 10kwh could be made 12v no problem, only issue is making sure the alternator can handle a discharged battery.

I'm going back and forth with this.

The interface is easier with 12V, full agreement. Yet when you go north of 2000W, 12V gets a lot more expensive.

24V
Growatt 3000W 24V $700
Signature solar 5kwh Battery $1500 2x

Total: $3700 + wiring


12V
Victron Multiplus 3000W 12V $1300
Amperetime 12V 300AH 3.6kwh $1200 x 3

Total: $4900 + wiring + larger alternator

 

[eXodus]

Yep which is why I am considering, it has ok build quality and a good price, but no low temp disconnect which I am sure the Lifeline has plus most likely much better internal build quality on par or better than Battleborn and bluetooth monitoring.

I live in and camp Florida,

No Low temp disconnect needed this is an non - issue for me.

 

[jharrell]

I live in and camp Florida,

No Low temp disconnect needed this is an non - issue for me.

I am FL too, but have camped in freezing temps before, although the batteries under the steps never hit 32f even in low 20's outside temps. Just one of those things I don't want to worry about, such a simple thing to add not sure why these cheaper batteries can't do it right, the typically already have a temp probe on the battery.

I wouldn't skimp on the inverter / charger, a nicer one will be much more robust (low frequency vs high), have better monitoring and more flexible programming and is basically the core of the system. I like my Magnum Hybrid 3000w, I bought it 6 years ago knowing it could be programmed for any battery chemistry in the future and I like the integrated shunt battery monitor. Victron is also top tier I might go with them if a where purchasing now, with more choices for monitoring and other secondary equipment but their documentation always annoys me compared to Magnum much less complete. A second tier choice would be Samlex.

On your pricing you are forgetting the DC-DC conversion needed if you want alternator charging or emergency starting from the 24v system.

 

[eXodus]

On your pricing you are forgetting the DC-DC conversion needed if you want alternator charging or emergency starting from the 24v system.

I would for maximum redundancy keep both 12V house and chassis systems in place and additional add the 24V - three distinct systems.

The 24V system would only interact through the 120V charger with the 12V systems.

Victron makes 12 -> 24V Charger. But when I look at my usecase - most of my charging of the large 24V bank will be either:
- Solar (1600w+)
- shore
- generator

I don't drive long enough (1-2h) in Florida that alternator charging makes any sense. I would need to get a much larger alternator.

I'm going through about 3kwh a day during my winter camping. I could probably charge at home go 3 days before I need to recharge at all.

On my old campervan I had 4,5kwh and 200w of solar - and that was plenty for 5 years.

 

[jharrell]

I would for maximum redundancy keep both 12V house and chassis systems in place and additional add the 24V - three distinct systems.

The 24V system would only interact through the 120V charger with the 12V systems.

Victron makes 12 -> 24V Charger. But when I look at my usecase - most of my charging of the large 24V bank will be either:
- Solar (1600w+)
- shore
- generator

I don't drive long enough (1-2h) in Florida that alternator charging makes any sense. I would need to get a much larger alternator.

I'm going through about 3kwh a day during my winter camping. I could probably charge at home go 3 days before I need to recharge at all.

On my old campervan I had 4,5kwh and 200w of solar - and that was plenty for 5 years.

In that case I would just stick with a single cheap dual purpose lead house battery. It would be hard for me to give up alternator charging we do cross country 8 hour per day driving trips a few times a year, its mostly used for running the fridge while driving, but nice to have as a backup, but you can easily add a 12-24 charger later. I also like keeping chassis charged with solar, but if you do 120v to 12v charger then have a chassis ACR/BIRD that will be taken care of.

 

[eXodus]

In that case I would just stick with a single cheap dual purpose lead house battery. It would be hard for me to give up alternator charging we do cross country 8 hour per day driving trips a few times a year, its mostly used for running the fridge while driving, but nice to have as a backup, but you can easily add a 12-24 charger later. I also like keeping chassis charged with solar, but if you do 120v to 12v charger then have a chassis ACR/BIRD that will be taken care of.

with that massive battery I'm planning on - it shouldn't be an issue running the fridge on electric.
The absorption fridge needs about 300w peak and about 150-200wh an hour. So for driving days that's like 0.5-1kwh

As soon as setup camp I put the fridge on propane and don't worry about it anymore. I'm spending like 50-60$ a year on propane to run the fridge, furnace, water heater and cooking. Not worth putting in a large powerbank for those application. Propane is very cost effective in making stuff warm (or cold like in the fridge)

With a 12V LFP I'm still going to have alternator charging on the house side.

I got a small 12V to 12V "charge controller" to charge the chassis battery (2A) I mean they say it's controller, but it's nothing more then a few diodes as soon as the house battery has voltage above the chassis battery - it's trickle charging it and then turns it off after a while.

 

[jharrell]

That is a large battery are you planning on running the air conditioner off it? If so get a good inverter and you will want to get a soft starter like a Micro-air Easystart, otherwise not sure why you would want 10kwh .

Again I wouldn't waste the money on a 12v LFP you won't be deep cycling that system, the big battery will keep it floating most of the time, maybe just a AGM for longer life but a dual purpose marine will be cheap and easy to replace as needed.

Propane fridges are bad on electricity (just a heating element) but yes when I am boon docking mine is on propane to minimize electrical usage, but with a huge battery and lots of solar a dc fridge would be better for many reasons. Usually the fridge is always on driving due to heat soaking of the RV so its pretty much constant draw from alternator unless Im running the generator for roof ac. With enough solar on the roof shouldn't matter, my 320w gets around 200 driving in the sun so I still like the alternator.

 

[eXodus]

That is a large battery are you planning on running the air conditioner off it? If so get a good inverter and you will want to get a soft starter like a Micro-air Easystart, otherwise not sure why you would want 10kwh .

I'm a prepper by nature, and had many power outages where I live.

So the large battery should support a few scenarios:
- just random outages (few hours usually) to run the fridge and Window A/C in the main house
- Cooling the RV down after the day to sleep

Usually when I go camping the nights are nice but RV takes on a bunch of heat over the day. So I need to cool that down a bit.

 

[eXodus]

Again I wouldn't waste the money on a 12v LFP you won't be deep cycling that system, the big battery will keep it floating most of the time, maybe just a AGM for longer life but a dual purpose marine will be cheap and easy to replace as needed.

I've just looked into AGMs.
Some of them got a higher float voltage, 13.8V which is much better match to my existing 12V charger.

The charger puts out 13.7-8V at float and basically boils the flooded Lead batteries which like to float at 13.2V

Next reason for the LFP was - where my batteries are mounted behind the bumper - it's really difficult - to impossible to check the water levels.
But AGM would also solve that. Would save $200-600 on LFP and when go with a AGM and don't have to worry about the generator start. Since those things can pump out 2000A and put the money towards a 12V to 24V DC-DC for the large system.

Thanks for the idea, will investigate further

 

[eXodus]

Again I wouldn't waste the money on a 12v LFP you won't be deep cycling that system, the big battery will keep it floating most of the time, maybe just a AGM for longer life but a dual purpose marine will be cheap and easy to replace as needed.

just bought two 95AH AGM batteries

Got them local for $100 a piece. 2x 95ah AGM for $200 not bad.

Has pretty good voltage match for my RV Converter and should have no issues starting the generator.
Just get them charged and balanced and the put them in tomorrow.

Saving the money for the large lithium system, which shall then keep them topped of.

 

[BrunoTPM]

Another consideration - Most motorhomes have an emergency start feature that links the chassis and house batteries together to be able to start the motorhome's engine if you have a low / failing / discharged or almost dead chassis battery. Not clear how well that feature would work with LFP House batteries / BMS as it takes a lot more juice to start the motorhome than to start the generator. For reference, the spec for the Chassis battery on my 2008 Class C is for a group 65 starting battery with 650 - 750 CCA. It typically starts with about 3-4 seconds of cranking from the Chassis battery. Thoughts?

 

[Hedges]

my 2x 12V deepcycle batteries in my RV are just about to die. I got a 5500w Onan generator, which starts from those batteries.

Is that a large old 2-cylinder Onan, or something smaller? What kind of starter?

My trencher has an Onan, about 800cc and 18 HP or so.
I tried a used small Optima battery from my Honda Civic in it, wouldn't crank even though still starts the Civic (which has gear reduction starter motor.)
Full-size Optima or other car battery will start the Onan, which has a full-size automotive starter.

Your mileage may vary. Lithium can deliver a lot of current, but BMS may not let it.

 

[eXodus]

Is that a large old 2-cylinder Onan, or something smaller? What kind of starter?

My trencher has an Onan, about 800cc and 18 HP or so.
I tried a used small Optima battery from my Honda Civic in it, wouldn't crank even though still starts the Civic (which has gear reduction starter motor.)
Full-size Optima or other car battery will start the Onan, which has a full-size automotive starter.

Your mileage may vary. Lithium can deliver a lot of current, but BMS may not let it.

It is a large 2 cylinder Onan. Pretty heavy duty.

Like I posted earlier, I bought a pair of AGM.

My LFP setup is 24v and does all the large power uses, like microwave or A/C and I just left the 12v in lead. I think with the falling batteries prices, I will just replace the Onan in a few years with a ton of batteries.

The compartment should house somewhere 20-30kwh of batteries and is designed to carry a 350lbs generator.

 

[GSXR1000]

Another consideration - Most motorhomes have an emergency start feature that links the chassis and house batteries together to be able to start the motorhome's engine if you have a low / failing / discharged or almost dead chassis battery. Not clear how well that feature would work with LFP House batteries / BMS as it takes a lot more juice to start the motorhome than to start the generator. For reference, the spec for the Chassis battery on my 2008 Class C is for a group 65 starting battery with 650 - 750 CCA. It typically starts with about 3-4 seconds of cranking from the Chassis battery. Thoughts?

I would say engage the switch without starting for several minutes to charge the coach battery

 

[One Old Guy]

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