Community Forums

jx450 · 06-20-2022, 11:56 AM

Our new to us 2018 DRV JX450 has 4x6V FLA L16 batteries, that are in need of replacement. These are OEM, generic black case, with no markings of any kind to indicate capacity. I'm guessing in the ballpark of 350AH each. For the same money I can get 4x12v 100ah Lithium. My charger and controller will support Lithium. Will I have problems starting my Onan 5500 genset? That's my only concern with the Lithium. Most camping will be with hookups, but there are those times when the genny needs to run.

billy_RV · 06-20-2022, 12:08 PM

Make sure your converter supports Lithium.

jx450 · 06-20-2022, 12:31 PM

Magnum Energy ME-ARC50 w/ MS2812 inverter/charger

Marine359 · 06-20-2022, 12:31 PM

LiFePo4 batteries all have a mfg spec called max continuous output amperage. A 100ah battery may or may not have 100 amps max continuous output. An Onan 5500 needs up to 80 amps to start. So, two LFP in parallel will normally provide up to 200 amps continuous; more than enough to start your Onan.

Isaac-1 · 06-20-2022, 01:04 PM

I would also suggest you look at getting a pair of 200AH or even 300AH Lithium batteries instead of 4 100AH as it will simplify wiring, though look closely at the BMS output rating, a lot of cheap 200 and 300AH batteries have the same 100A BMS as you typically find in the 100AH models, the better ones will have 150A BMS or perhaps higher, I have not been keeping up with the market the last 6 months or so since buying a pair of 200AH batteries last November.

jx450 · 06-20-2022, 01:43 PM

I'd love to go with the 200ah or 300ah batteries, but they have a sigficantly different footprint than the 100ah. I am space constrained in my battery compartments, and could get creative and expand the passenger side, but the driver side compartment has no room to expand it. There't plenty of room in the generator compartment, above the generator, but not sure if that's a good idea.

Isaac-1 · 06-20-2022, 04:54 PM

That would probably be very bad, when I upgraded to LiFePo4 batteries I moved them inside the coach into a hard to access lower kitchen cabinet. As a general rule LiFePo4 batteries like the same temperature ranges that people do, also since they don't vent acidic gases there is no reason to not mount them in the living space. In a worst case thermal runaway / fire event it probably would not matter if they were in the living space or not in the end.

oscarvan · 06-20-2022, 04:56 PM

Quote:

Originally Posted by jx450

I'm guessing in the ballpark of 350AH each.

I'm guessing in the ballpark of 350Ah total. A 350Ah 6 volt battery is a large heavy battery. You may be looking at minutes discharge at specified amperage.

darrellr · 06-20-2022, 08:52 PM

Quote:

Originally Posted by Marine359

An Onan 5500 needs up to 80 amps to start. So, two LFP in parallel will normally provide up to 200 amps continuous; more than enough to start your Onan.

My Onan 5500 draws a lot more an 80amps for a short period to start. However, as you said, I used 2x100ah lfp batteries and they start my Onan 5500 LP generator just fine.

Marine359 · 06-21-2022, 06:50 AM

Yes, start-up surge amperage is 100 amps. But battery surge amperage is normally twice max continuous output. So, 2x 100ah can deliver up to 400amps surge for 30 seconds. This video thoroughly and definitively gives the answer for Onan 5500LP:

https://youtu.be/MqFV_FPFMes

Kid Gloves · 06-21-2022, 07:16 AM

Quote:

Originally Posted by oscarvan

I'm guessing in the ballpark of 350Ah total. A 350Ah 6 volt battery is a large heavy battery. You may be looking at minutes discharge at specified amperage.

In the OP’s case, they stated 6V, L16 batteries. Those are large, heavy batteries, perhaps 120lb/ea. 350-400Ah’s is a fairly common rating for such a battery.

inthepines · 06-21-2022, 07:33 AM

I looked at the dimensions of your l16 batteries.The 390ah 6v l16 battery dimensions are 11.61 in x 7 in x 16.77 in and you need 2 for 12v.
So that is about 22 x 14 x 33 is my math right?

a 200ah lifepo4 is about 20x9.5x8.6 So it seems that you can fit 2 200ah lifepos in the same space.
Other posters are right about some 200ah batteries only have a 100ah BMS and can only support above 100ah for a short very short duration.
1 200ah battery is about 77 lbs depending on manufacturer, I've seen some weigh less.

darrellr · 06-21-2022, 03:09 PM

Quote:

Originally Posted by Marine359

Yes, start-up surge amperage is 100 amps. But battery surge amperage is normally twice max continuous output. So, 2x 100ah can deliver up to 400amps surge for 30 seconds. This video thoroughly and definitively gives the answer for Onan 5500LP:

https://youtu.be/MqFV_FPFMes

One note: That monitor is not quick enough to measure the peak current draw. If you watch that on a scope you will likely see a short peak of over 250-300 amps. That is the peak that would be a concern with a single battery. Two batteries, as in the video, should be fine.

I run 2 100ah LFP in my RV and don't have any concerns with starting the generator. Then again, I have not tried to start my generator much below 32 degrees Fahrenheit.

jx450 · 06-23-2022, 08:25 AM

Thanks to all for the great responses. Yes, these are the large, heavy, L16 6v, setup as 2s2p. One pair per battery bay (so logically a 12v in each bay, parallel bay to bay). There are plenty of pos/neg connections in each bay, which doesn't exactly follow what I understand is best practice for parallel connections.

They are each 10x7, side by side, making each pair 10x14. The battery bays are small (19x14 or so), and won't accomodate the 20" length of a 200ah lithium. So for now I'm going with 100ah (~ 13" x 7"), which I can make fit. When it's time to upgrade these, I'll do some creative construction that will allow me to handle the 20" batteries. Maybe prices will drop and we can go with 4x400ah and solar, so we can boondock as long as we want.