I would like to add a couple more deep cycle batteries to my 5th wheel. Given the batteries are heavy I just want to make sure the storage compartment is robust enough for another 100+ pounds that would be concentrated in a small area.
Added batteries in the front compartment of a Grand Design 27RL?
- Thread starter oldryder
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Tom
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Check if there's sufficient (steel) support for the battery bay.
xrated
Well-known member
Or switch to LiFePO batteries and get more AH for a lot less weight.
Kirk
Well-known member
I would think that if the space is large enough to add batteries that it would also be strong enough to do so.
The trouble is you can't just fit lifepo batteries. Other items need upgrading as well, not least the tow truck wiring from the alternator.
Gizmo
Well-known member
I agree with TonyL, besides the operational superiority of lifepo batteries the weight difference is significant.
Gary RV_Wizard
Site Team
I think this Lithium upgrade problem (restriction?) is often overstated, but it is something that needs to be considered carefully before jumping into the change. There are LiFePO4 batteries designed with a BMS that facilitates dropping them into a lead-acid system with minimal issues, existing chargers that are compatible with LiFEPO4 even is not optimal, and simple ways to make sure the tow vehicle alternator does get over-taxed.
Gary's points are all valid and for me personally, that's why I stick with lead acid. Adding batteries needed no more than secure fixing and additional wiring connections. The other issue for us is we have to leave our fifth wheel for at least 6 months at a time. I'm not sure how the lithium batteries would cope stored in a possibly cold region with no charging options.
Lou Schneider
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Don't forget about providing sufficient airflow to carry away the acid fumes and explosive hydrogen and oxygen gasses produced by lead acid batteries. The floor of the battery compartment in my trailer is open to the outside air for just this purpose.
As far as the compartment holding the weight, lead is heavy. I doubt you'll find many items concentrating the same weight in a comparable footprint.
Lithium batteries don't have any of these problems. They store fine in cold weather, self discharging less than lead acid. You just can't charge them if they're below freezing and most Lithium batteries self protect against this
As far as the compartment holding the weight, lead is heavy. I doubt you'll find many items concentrating the same weight in a comparable footprint.
Lithium batteries don't have any of these problems. They store fine in cold weather, self discharging less than lead acid. You just can't charge them if they're below freezing and most Lithium batteries self protect against this
xrated
Well-known member
I have zero charging from my truck to the LFP battery in my camper.....I've disconnected it in the trailer. I have enough battery capacity with 302AH that my fridge (a twin compressor 12VDC unit from JC Refrigeration) could run for approx. 40 hours before the battery needs to be recharged......and I can assure you, I won't be driving anywhere, anytime for 40 hours straight. And as far as replacing the Converter/Charger, yes I did do that on mine because I have zero solar on my trailer and zero plans of installing any. The normal FLA type Converter/Charger will get the LFP battery to 80% or a bit more. That would still be around 240AH and the fridge will use right at 145AH in a 24 hr period of time.....still far less than I'm ever going to drive in a day's time.
Gary RV_Wizard
Site Team
A current-limiting breaker between the tow vehicle and the trailer would protect the alternator from overload. An auto-rest type would make it convenient if it did happen to trip, e.g. when you first hook up while the batteries are discharged.
dktool
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A D.C. to D.C. charger is all that is needed to bridge the gap between LP's and the alternator.
I used this one in the 20A version, and you can pump your solar thru it if needed.
12V 20A 40A DC to DC Charger On-Board MPPT Solar Panel Battery Charger for RV | eBay
ã99% Efficiency MPPTã. With IP65 level waterproof. Provides proper charging for AGM/GEL, Lead acid, Lithium and Calcium batteries. Solar Panel Kit. Solar Battery System. The addition of stater battery and leisure battery isolation achieves greater safety performance.
www.ebay.com
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MoInEd
Well-known member
I have 200ah LifePo batteries and 300w solar on the roof. They keep the batteries always charged before we head out. We almost always boondock and the combination of solar and batteries works great. Never had to charge the batteries by plugging in.
rbrdriver
Well-known member
I am glad I saw that post from Gary about possibly overloading an alternator on tow vehicle if one switches to lithium batteries. I have a large fifth wheel I tow with my Ram, and also a smaller travel trailer, both which I installed lithium batteries. Is there an issue with alternators being overtaxed? I haven't noticed anything yet, but how would I know unless my alternator suddenly fried or something......
Gary RV_Wizard
Site Team
Nobody is saying it cannot be done. The point is that you MAY need to do some hardware upgrades/additions to accommodate LiFEeO4 batteries, so you need to educate yourself about what you have vs what is needed before you make a decision to change battery chemistry type.A D.C. to D.C. charger is all that is needed to bridge the gap between LP's and the alternator.
I used this one in the 20A version, and you can pump your solar thru it if needed.
12V 20A 40A DC to DC Charger On-Board MPPT Solar Panel Battery Charger for RV | eBay
ã99% Efficiency MPPTã. With IP65 level waterproof. Provides proper charging for AGM/GEL, Lead acid, Lithium and Calcium batteries. Solar Panel Kit. Solar Battery System. The addition of stater battery and leisure battery isolation achieves greater safety performance.www.ebay.com
And for the many folks who have to ask others what kind of batteries to get or how to wire them correctly, advice like "add a DC-to-DC charger" probably sounds like the proverbial "rocket science".
Lou Schneider
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Lithium batteries can suck more current than lead acid batteries while charging. The amount of current depends on the voltage reaching the batteries and can overtax a vehicle alternator if you have a large battery pack (more than about 300 a/h) and short, fat cables producing minimal voltage loss between the vehicle alternator and the batteries. You'll find this in a motorhome but not in a truck and trailer.
In a truck and trailer, the voltage drop along the long, relatively thin wire between the vehicle alternator and the trailer batteries will self-regulate the charging current, dropping the voltage reaching the batteries and keeping the charging current at acceptable levels. Maybe even lower than you'd want.
You can install a DC to DC charger at the trailer battery but the primary effect will be to boost the incoming voltage from the tow vehicle and keep the charging current at the converter's rated output, not limit the current as would happen in a motorhome.
rbrdriver
Well-known member
So it sounds like I'm good then. Thanks.
Gary RV_Wizard
Site Team
Probably, but somebody needs to look at the specifics of both the vehicle charging and the trailer onboard charging to be sure. When deeply discharged, the bigger battery bank will cause the existing onboard charger to operate near or at its peak amp load and shed more heat. You might, for example, find that it gets too hot for the existing cooling air flow. Or that the charging time is unacceptably long due to the 50% increase in amp-hours needed. "Look before you leap", as the old adage says.
