Battery Questions

5 replies in 1/2 hour - very impressive.

I am using those batteries because that is what came with the camper, so when bought new batteries, that is what I went with. Probably not the best reason.

I can charge the batteries with the on-board generator. With the new converter, it charges at around 35 Amps. I thought about getting the higher Amp PD unit, but my old converter was the only rated at 32 Amps, so I was concerned about the wiring.

Solar panels might be a challenge in Oregon - we tend not to see the Sun between November and May.

We replaced all of the lights with LED's (draw dropped from 1.5 Amps to 0.1 Amps per bulb). Blower on fan for heater draws about 5 Amps. So even if that is running 100% for 10 hours at night, that would be 5 Amp-hours. So 1 1/2 hours of running the generator in the AM should fix that.

And since the noise in the parking lot is loud when they are plowing snow, I can actually run the generator at night without anyone even noticing....

That setup may work fine. How long are your boondocking outings? Be sure you maintain your batteries in fully charged state when home (don't let them sit discharged after trip) , and always leave for the trips with brim full batteries.

Also, explore LEDs for most used interior lights.

OK Andy,

Your approach is very good, but I have some problems here. You do not say if you have an installed APU (genset). If you do, you have now made things much easier.

I suggest that you do not "stress test" the system as that will not tell you anything that the Xantrex LinkLite does not already display. It will probably damage your house bank if you do. Any time any lead/acid battery (here after referred to as jars) is discharged below about 50% (~12.0V) it will be damaged and will not cover easily and may never recover completely.

Note 1- You do not have 300AH available. You do have closer to 150. Your good battery monitor will tell you that.

Note 2- If you added one more jar to the existing bank, expect problems. The jars in the bank will never balance charging and discharging. There is no cure. 12V jars just never play well when in parallel. I can actually tell you, but I do not have time for that much writing today. Be cautious, if things get at all strange please break up the bank. If (when) one cell in one jar goes bad, it can draw power off the others. Something bad can happen. Keep some baking soda handy.

The best answer is put up with what you have until the Xantrex starts to tell that the bank efficiency has started to drop. Then, if you find you need that capacity, the smart move would be to find two BIG golf cart batteries. These are 6Veach (put two in series) and 200+ to ~300AH. They really are truly deep cycle. When combined with your 4635, they will do real well for a very long time.

Me?? I'm a ship's engineer by trade and up until the depression, I did a lot of work on other people's expensive yachts. The advice is always free unless you don't listen, then I charge big time to clean things up.

Matt

Those are cheap, not true deep-cycle batteries. Whether they live up to their ratings remains to be seen.

If you go to bed with them fully charged, you should be ok. Batteries lose capacity with drops in temps.

My golden rule is to never ever let my battery bank drop below 12.0VDC which is pretty close to the 50% charge state when camping off the power grid. Have enough batteries in the bank to make it until the next morning at 8AM where you are allowed to run a generator to run your PD4600 smart mode charger to get back up to the 90% charge state before you use the batteries again. I use a PD9260C smart mode charger to charge my 255AH battery bank.

If you need to re-charge the batteries in a short three hour time frame then you will need to get 14.4VDC from your Converter/charger unit with enough capacity to give you 17-20AMPS DC CURRENT for each battery in the bank. My 255AHs setup will draw around 55AMPS when first hit with 14.4VDC and then start tapering back from there as they start taking on charge. this senerial will take around three hours charge time to get my 255AH 50% depleted battery bank back up to their 90% charge state. It will take a good 12 hours to get the battery bank up to its 100% charge state. I can do this 50% to 90% charge state cycle for around 12-14 times and not do any harm to my batteries. I will however have to charge them to a full 100% charge state right away after doing this otherwise I will start doing damage to the batteries.

As stated above in other posts your PD4635 is going to be a bit small to re-charge a couple of high AH rated batteries if you need to do them within a short three time frame due to generator run time restrictions. For me I have to always start my day/night run off my batteries at the 90% charge state if I want them to not drop below the 50% charge state by 8AM the next morning.

Works for me doing this...

Roy Ken

One of the first tests I did was to determine amp usage of all the 12-volt electrical items. Installed LED lights, and was able to determine how long we can camp with different usage scenarios - and keep the batteries at or above 50% discharge. BTW, our furnace fan uses about 7amps.

The 46 35 is a good charger, but I probably would have suggested the 46 45 with 10 more amps output.

300 AH is going to be pretty good for boondocking. It will take a while to fully charge all those batteries with the generator, but if you happen to have a portable charger, it will help add more amps quicker.

At least with your motorhome, you can start the engine at night, and that alternator will put out 100+ amps to run everything and charge the battery in 10 minutes enough to get you through the rest of the night. You might consider upgrading your alternator to battery wire.

What I did was buy a 100 amp rated forklift relay from Grainger.com part # 6C017 - it has a coil rated to run full time, silver allow contacts rated for 100,000 on-off cycles at 100 amps! I ran a #4 wire from my alternator to the relay to the battery + 12 terminal. Then I can energize it two ways (with a three way on-off-on switch. One is from power from my radio that is only on when the engine is running. THe other is power from the battery, so I can energize it anytime.

This way the wire from the alternator to the battery is rated at 100+ amps, with very little voltage drop. Then you can make sure that the engine is fully charging the battery, even if the factory relay is now in bad shape, and has oxidation on the contacts, and is not giving the full factory rating anymore. I know that my factory relay went bad because I was using my inverter and then drove home about 90 miles, and the battery did not fully charge. My E-meter told me so. The solar filled it the next day. I did not want to look for or replace the factory relay, so I upgraded as described.

If you really want to be able to dry camp for a week at a time, without worry about the battery, consider a pair of 140 watt solar panels and a Olympic Catalytic heater. I dry camped for 2 weeks with a 400W solar and 6,000 Btu Olympic heater in 19F weather, no problems. I also have 4 golf cart batteries, and like to watch a lot of Direct TV, so I can use 100 AH daily on TV and laptop via a inverter.

SunElec.com Look for 12 volt nominal panels, with aluminum frames, and also buy a PWM controller. I saw 140W for $229 a few weeks ago.

My E-meter tells me that my RV draws 0.8 amps 24/7, and will increase to 1.2 amps for the hours that the refrigerator is running, so about 35 AH daily to run the RV. This is about what 1 of my 120 watt solar panels will collect in one day.

If you are charging from a generator, you might consider a 30 - 40 amp battery charger that is portable. Make sure that you are looking at the 'charge rating' not the 'engine start rating' - that is only good for 15 seconds, then must be shut off for a total of about 20 minutes. Harbor Freight sells some, wait for a sale, or get the 20% off coupons they offer via e-mail.

Good luck,

Fred.

Good luck,

Fred.

How are you charging the batteries? Do you have a generator? Or are you running the engine (if charging system is capable of charging engine and house batteries)? Are your 12 volt batteries truly deep cycle? Me personally, I would have gone with 6 volt batteries, which are meant to recycle over and over again. I doubt you can run a heater for long solely on battery power, in fact, I would only run a heater with the generator on and leave the house batteries for other uses.