Vern Crawford, of Centerpoint, TX, has a full kilowatt of solar on his GMC and 5 or 6 Battleborns beneath the couch. He didn't even plug in at Tallahassee last year. Loaned me his 30a cord for extension and gave away his Onan while there.
House Battery Compartment Restoration
- Thread starter JSanford
- Start date
I thought 2 100ah Battle Born would be overkill, but it is easy to add more down the road. 100ah of Lithium is way more power than 100ah of lead acid.
admittedly I'm still learning about the best battery system for my coach but not sure why you say the above?
Will one 100AH lithium battery give better service than 2 CG 6v's rated at 230AH? I'm not talking long-term here, just usability on say a week long camping trip ....
Larry
I am not sure about all the science behind it, but Lithium has more usable energy and more nominal voltage than a lead acid battery of the same size. The one Battle Born I have will easily last us six days dry camping running all the standard GMC 12v equipment like fans and lights (bulbs converted to LED).
230ah of lead acid would probably be more usable capacity than 100ah of lithium.
One 100Ah lithium (LFP) battery is about equivalent to two GC's lead acid's (LA) @ 230Ah because unless you want to severely shorten the GC battery life, you are limited to using only about 50% of their charge (approx. 115Ah). LFP batteries can be discharged to about 90% without harm.
Also:
- LFP batteries have a much flatter voltage discharge curve and operate about 1 volt higher (13's vs 12's).
- LFP batteries as much lighter and smaller for the same capacity... less than 1/2 the weight.
- LFP batteries have a much lower internal resistance so their output voltage drops very little under load.
- LFP batteries can be recharged in a much shorter time, 2-3hours from 90% depth of discharge (DOD) vs about 6 hours @ 50 % DOD for LA batteries.
- LFP batteries will return about 98% of the charging power consumed, where LA batteries are only 80-85%, rest is lost as heat.
- LFP batteries are happy when left partially charged (store at about 40-60% charged). LA batteries need to be immediately recharged after use and kept charged.
- LFP batteries are happy if you only recharge them to 80-90%. They have an even longer life if operated between 20-90% state of charge. LA batteries need to be fully charged and kept charged.
- LFP batteries don't off-gas, LA batteries emit explosive hydrogen while being charged.
- LFP batteries don't have a liquid electrolyte so they can be mounted in any position... upside-down is not recommended though.
- Because LFP batteries do not off-gas, their connection terminals do not corrode.
- LFP batteries are much safer than LA because of the last several points above.
Also be sure to buy a converter/charger that is designed to charge LFP batteries. They require a different charge curve than LA batteries.
Larry, I bought two 100Ah LFP batteries from Alberta Lithium battery for $450Cdn. That was less than two CG batteries. So far I am loving them!
I installed a LI-BIM 225 Battery Isolation Manager which cycles the connection between the engine alternator and the living area battery when the engine is running to prevent the aleternator from overheating. I have spent two full camping seasons with my lithium setup and my original 1977 Delcotron is still alive!
You can see everything I changed on mine when I converted from lead acid to lithium https://www.gmcmotorhome.org/threads/lithium-conversion-of-living-area-12v-system.703/
I would say the biggest positive (there are many) about lithium Ion is the much faster charge time and the biggest negative (other than cost) is the fragility in cold weather environments. If you're looking for something to abuse and not think about (mostly because they are cheap to replace), go with two 6v Golf Cart batteries from Costco and a decent charger that will "take care of" your batteries without a lot of input from you (like Progressive Dynamics). If you are looking to maximize your stay, consider the Lithium Ion, but realize there is a premium in the tech (not just the battery, but the controller, etc., as well). Many people get a lot of seasons (five or more) out of the golf cart battery setup (unless you kill them by over draining them), and your cost is only about $350 including the charger. If you can find AGM batteries (they are only slightly more expensive than typical lead/acid but are in short supply right now), they are a sealed wet cell (you don't have to add water over time), and do a little better in the cold and with freezing temps. Some you can also mount in any orientation (on their side, etc.), so they can be easier to "cram" into tight spaces.
An alternator is a fixed voltage output device with the current limited only by wiring resistance and the internal resistance of the alternator itself. A BIM is simply a low duty cycle PWM regulator. It connects the alternator to the House Battery for 15 mins, then OFF for 20 mins to prevent overheating the alternator. So the alternator will deliver its maximum current for 15 minutes, then have 20 minutes to cool when it only powers the chassis requirements (Chassis Battery charging, headlights & running lights, dash heater fans etc)
A better choice in my opinion is a DC-DC charger. They take the alternator (chassis battery) power and convert it to the proper voltage/current charging profile for whichever battery chemistry you are using. So the Maximum current is limited and the battery is not overcharged. You can use them for either lead-acid or litium battery technology. The power drawn from the alternator is set to a reasonable level depending on the output rating of DC-DC charger. With my unit there is even an input which will put it into a slower charge mode with the maximum current set at 50% of the unit's rating. In my case its a 20Amp charger, so the slow mode reduces that to 10Amps.
JWID.
I have quite a good charger/converter ATM, (an Iota DLS 55A) and have just found out that my fridge fan that has been sucking steady amperage 24/7 is somewhat surplus to reqs.
This changes the scenario a little so I think if I get rid of the fridge fan, I'll be OK for the moment. My Onan works pretty well too, so plenty of time to consider other style batteries ....plus, possibly by next spring prices may take a tumble as quantity and competition increases.
Larry
Jeremy,
Nice work!
Is the life span of the lithium affected by the high temperatures next to the generator? Also, can you still use the boost function for starting if you have lithium in the back and lead in the front, without causing harm to the lithium battery?
Russell
Nice work!
Is the life span of the lithium affected by the high temperatures next to the generator? Also, can you still use the boost function for starting if you have lithium in the back and lead in the front, without causing harm to the lithium battery?
Russell
Russell,
The Battle Born I got will operate up to 135º and can be stored at temps up to 140º so it should not have any issue in the stock battery compartment. The bigger concern for owners in colder climates is the lithium batteries will not charge at temps below 24º
Yes you can still use the boost function in combination with the lead acid chassis battery without harming the Battle Born battery.
Battle Born makes that battery in a vertical configuration…I was going to put 3 or 4 of them in there… then I found this.
Here’s the link to Battle Born verticals: https://battlebornbatteries.com/product/100ah-12v-gc2-lifepo4-deep-cycle-battery/
Here’s what I’m going to maneuver into that battery place—just have to undo the aluminum divider, once past that, there is width… should have pictures next week…. But it’s $1000, and 460ah…. Well rated.
Group 8D is the original size battery for the GMC, so you should not need to make any modifactions to install a 8D LFP.
BattleBorn are great batteries, but there are lots of quality options these days. The 100ah provides more power than we can use on an average camping trip, but if I were doing the project today I would get a 8D LFP.
BattleBorn’s have got th
Once past this opening, I have 11.5” in that bay. But getting past the opening, I thought I’d need to undo the aluminum baffle to slide it in. Once past that—seems I’m good to go!. Haven’t done it yet—but the $1000 for 460ah price per Ah, has me pretty willing to unfasten that panel.
Attachments
10 BattleBorn batteries in parallel. Two are in the engine compartment. These are under the couch. 1000 AH.
My 77 has been extended two feet and has storage compartments towards the back end. Yesterday as I was winterizing the coach I found that cover hidden on driver's side. I didn't know it was there.
Check out my 7/17/22 post #85 on page #5 of "Converting to LiFePO4 batteries and Sailor Man's LiFePO4". Also #186, #187 and #188 (10/25/22) on page #10.
Post #213 0n page #11 shows how I initially intended to use my (2) BattleBorn GC3 24vdc batteries wired in series to form an 48vdc 270aH battery bank in conjunction with a Firman 3042 dual fuel inverter generator.
With this stack, a busbar connection between the two batteries would be a series connection for 48vdc.
Flip the top battery and the busbar would be a parallel connection and you could get either a 12vdc or 24vdc barrel bank if you chose either 12vdc or 24vdc batteries.
Please not the BattleBorn bracket fasteners.
But alas, read post #235 on page #12 (02/19/23) in which BattleBorn said that I could not get my 48vsc out of the BattleBorn batteries.
You could use this configuration is you want either 12vdc or 24vdc and the Firman.
This is the current installation.
Post #213 0n page #11 shows how I initially intended to use my (2) BattleBorn GC3 24vdc batteries wired in series to form an 48vdc 270aH battery bank in conjunction with a Firman 3042 dual fuel inverter generator.
With this stack, a busbar connection between the two batteries would be a series connection for 48vdc.
Flip the top battery and the busbar would be a parallel connection and you could get either a 12vdc or 24vdc barrel bank if you chose either 12vdc or 24vdc batteries.
Please not the BattleBorn bracket fasteners.
But alas, read post #235 on page #12 (02/19/23) in which BattleBorn said that I could not get my 48vsc out of the BattleBorn batteries.
You could use this configuration is you want either 12vdc or 24vdc and the Firman.
This is the current installation.
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That'd be cool to see pictures or understand how that got extended 2'!
I'd always thought about cutting 2' off the 260 keeping the longer wheelbase--like the Hot Wheels Car version of the GMC RV. But then I just put down the crack pipe... going to love it the way it is. (This one at least.)
