Battery replacment January 05, 2021, 12:29:24 pm I need to replace my batteries. The existing Batteries are US (US125 XC) batteries and I do not think they performed as well as the Costco batteries they replaced. I never felt that good about the batteries and wished I would have bought Trojans. I am thinking I will replace with 2-6V Trojans and want to buy some real good one as we do Winter dry camping. There are 2 factory installed 75 Watt solar panels. Any input out there on capacity and type would be appreciated. Thanks, Matt
Re: Battery replacment Reply #1 – January 05, 2021, 12:49:55 pm There is limited variability in A-hr rating for models that will fit - standard is about 225 A-hr. But, solar siting is critical in winter. Avoid trees like the plague, especially to the south. Note what items on your roof will shade the solar with the sun low in the sky, and pick a site to minimize that. Finally, if your converter is factory standard, upgrade to a multi-stage unit that can do a fast battery recharge running the generator.Steve 1 Likes
Re: Battery replacment Reply #2 – January 05, 2021, 01:15:59 pm Steve is correct, there are only a few Trojan 6 Volt Deep-Cycle Flooded batteries that will fit.GC2 T-105 225 A-Hr GC2 T-125 240 A-Hr GC2H T-145 260 A-Hr Trojan Battery GuideBe advised the T-145 is about 7/8" taller than the standard GC2 battery spec (hence the "H") and might be too tall. Terminal configuration and cable attachment choice may also come into play.Charles 1 Likes
Re: Battery replacment Reply #3 – January 05, 2021, 02:04:36 pm I think the T145 will fit and I believe the LD battery compartments are all the same size. Thanks for that information.
Re: Battery replacment Reply #4 – January 05, 2021, 02:12:27 pm Quote from: Charles & Donna - January 05, 2021, 01:15:59 pm GC2H T-145 260 A-Hr Trojan Battery GuideBe advised the T-145 is about 7/8" taller than the standard GC2 battery spec (hence the "H") and might be too tall. Terminal configuration and cable attachment choice may also come into play.A T-145 installation usually requires removing the battery slide, to provide the needed overhead clearance.On a cost per amp/hour of capacity, the T105s are the best value.The T-125 has bigger plates but less reserve water, they need more frequent watering.Larry 1 Likes
Re: Battery replacment Reply #5 – January 05, 2021, 04:44:42 pm Thanks for that. So the T105s are probably best. I have 2- 75 W solar panels on the roof (2002 MB). What is your opinion on replacing those with 2 higher wattage panels. Like 2 -150's. They are nearly identical in size. I was in contact with AM solar in Oregon and they communicated that my wiring and controller were adequate for this change. Seems like maybe a reasonable improvement. What do you think?Thank you,Matt
Re: Battery replacment Reply #6 – January 05, 2021, 07:22:50 pm Quote from: Matt Jones - January 05, 2021, 04:44:42 pmThanks for that. So the T105s are probably best. I have 2- 75 W solar panels on the roof (2002 MB). What is your opinion on replacing those with 2 higher wattage panels. Like 2 -150's. They are nearly identical in size. I was in contact with AM solar in Oregon and they communicated that my wiring and controller were adequate for this change. Seems like maybe a reasonable improvement. What do you think?I agree your wiring and controller are adequate but ..... <smile> there is always a but. The wiring and controller in a 2002 MB is just enough to be able to add a set of 150solar panels but you'll be not getting the full benefit of them. With an updated three stage charge controller and heavy wiring you harvest just about all the watts your panels are gathering. May I suggest one of these bad boys -- Solar Charge Controllers - Victron EnergyYes they are more $$$ but you do get what ya pay for.glen
Re: Battery replacment Reply #7 – January 05, 2021, 07:39:01 pm Quote from: Matt Jones - January 05, 2021, 04:44:42 pmThanks for that. So the T105s are probably best. I have 2- 75 W solar panels on the roof (2002 MB). What is your opinion on replacing those with 2 higher wattage panels. Like 2 -150's. They are nearly identical in size. I was in contact with AM solar in Oregon and they communicated that my wiring and controller were adequate for this change. Seems like maybe a reasonable improvement. What do you think?It really depends on your needs and desires, your camping style, and how much money you're willing to spend. There isn't a one size fits all answer. If your current system is meeting your needs, I would stay with it. If it meets your needs most of the time, I'd stick with it.If you're constantly changing your behavior or passing up activities due to power needs, the upgrade could make it so that you don't have to do that anymore.Anyone with a 2002 era coach can get a lot of bang for their buck in the electrical system by switching to LED lighting, upgrading to a newer charger/inverter and using modern electronics. That can be more cost effective than adding more solar (and it works in the dark!)You might also bump the output from your current panels by switching from a PWM to a MPPT based charge controller. The good thing about working with AM Solar is that they can give you a price. Only you can decide if that price is worth it to you.Rich 3 Likes
Re: Battery replacment Reply #8 – January 05, 2021, 10:24:12 pm In our 2003 MB we replaced the original charge controller with AM Solar's MPPT Blue Sky Solar Boost 3000i and we have been happy with it. Also, AM Solar was really helpful and available. We have the factory installed solar panels and replacement T105s. I think we would benefit from more battery power but that's what we have for now.Barb
Re: Battery replacment Reply #9 – January 06, 2021, 03:47:46 am Quote from: Matt Jones - January 05, 2021, 04:44:42 pmThanks for that. So the T105s are probably best. I have 2- 75 W solar panels on the roof (2002 MB). What is your opinion on replacing those with 2 higher wattage panels. Like 2 -150's. They are nearly identical in size. I was in contact with AM solar in Oregon and they communicated that my wiring and controller were adequate for this change. Why not add two more, leaving the existing panels in place? You have already paid for them. Our LD came with one panel and now has five. For maximum efficiency, the lead-in cable should be upgraded.Glen's suggestion to modernize the controller is a good idea and will charge the battery faster.Larry
Re: Battery replacment Reply #10 – January 06, 2021, 12:40:06 pm Thank you all for the good advice, as usual. I recall someone telling me that it is not a good idea to have panels of different wattage connected together And wondering how effective my 20 year old panels are. So since the 150's are about the same size as the existing 75's and 300 W is all my wiring can handle I thought it would make sense to swap. I also thought I could use the existing structural connection between the roof and panel. I experimented on a bright day covering on panel and checking the amps then covering the other panel and checked the amps and the output was not close to being uniform. Also with both panels exposed it was underperforming although I do not recall the exact output - something like 3 amps. The personLD said I should be getting more.
Re: Battery replacment Reply #11 – January 06, 2021, 01:33:26 pm Hi Matt. Well many installations involve different sizes and wattages of panels in parallel, (and series too in certain instances). The panels need to be the same voltages. So all cells are about .6 volts, they are connected in series inside the panel. For RV use usually four rows of nine cells, for a total of 36. That is about 22 volts open circuit. The power per panel depends on surface area. 150 watt panels with 36 cells will be twice the area as 75 watt panels with 36 cells. The efficiency of cells hasn't changed much. Monocrystalline cells are the best efficiency, and when cut and placed in the panel with no empty areas (depends on how they are cut) will have the best efficiency. Polycrystalline cells are less expensive. If you have a house with more roof than you can afford cells for, the Polycrystalline are a good choice. But not for RV's with limited roof space. Amorphous are lowest efficiency, the silicon is essentially 'painted' on, and while it does work 'sort of' I think those aren't a good choice. Some large house panels might have 66 cells or more in series, and are meant for higher power systems in the multiple kilowatt ranges. Modern MPPT controllers can handle the higher voltages. You could keep your present two 75 watt panels (150 watts total) and add one 150 watt panel. The total current may require an upgrade of your RV-30S; I think that is the original controller you have. The SB3000i can handle up to 29 Amps. When you measured 3 amps, That is OK. The theoretical wattage ratings aren't what you get. Panels have to be clean, pointed directly at the sun. Atmosphere clean and clear, and amperage is measured into a dead short. Real world power delivery falls short of that. Panels aren't clean, the sun isn't as bright as it seems, the sun is at some latitude angle since you aren't at the equator. Wiring can decrease the watts harvested at maximum insolation. The controller takes some power to run, and if the batteries aren't dead, they won't absorb power as easily. There is usually shadows on the panels, even really small antenna, or power 'lines' will reduce power. Tree branches, and leaves cast real shadows, etc. For you, one new panel, and a modern MPPT controller are a good start. When you put up more panel wattage, then you need to think about more batteries, Then re-wiring to improve efficiency. So you need to consider what type of camping you do, and what your power demands are versus what you want. And first you should upgrade your power converter, if you will be running your generator, or be plugged into shore power often. RonB edit. Yes with 20 year old panels, they've had a lot of time to deteriorate. Water intrusion and poor electrical connections. The panels themselves should last much longer than the motorhome. My 48 watt panels (x3) are about 30 years old, I bought them used, and are still in good shape. The rubber seals could start leaking anytime. The most I've ever gotten was about 9 amps in with a Solar Boost 2000 MPPT controller. 2 Likes
Re: Battery replacment Reply #12 – January 06, 2021, 05:42:18 pm It's very easy to go down the rabbit hole of solar power and panels. My I suggest this set of vidsElectricity for Dummies - Mobile Solar Power Made Easy!I have a few others but this is a good start.glen 1 Likes
Re: Battery replacment Reply #13 – January 06, 2021, 05:42:26 pm I agree with everything Ron said, and want to reinforce what he and others have said about replacing the RV-30. Solar controllers have come a long way since 2002! The RV-30 is an obsolete design that wastes power. Get an MPPT controller, and you'll squeeze more power out of the panels you have now and any you may add in the future.
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