Battery Question

Thanks for the explanation, interesting system . I will have some other questions when I have a chance to think a little more about it .

ticki2 wrote:

pianotuna wrote:


Take it out of storage at -37 and let me know how that works for you.

I sure would like to know your routine after you take your camper out of storage at -37 to warm the interior up to a reasonable temperature , with what heat source , and how long it takes .

Thanks for the question.

I have a decent size battery bank. The solar system maintains and charges the house, generator, and starter batteries. The charging is temperature controlled. This means the batteries are fully charged and kept at float.

Here is a step by step.

1. put magnetic heater on the bottom of the Yamaha generator.
2. turn on inverter to power the heater
3. wait 30 minutes
4. start the generator (sio2 equipped)
5. start electric heaters and plug in block heater for engine to the limits of the generator--which is also recharging the teleco batteries.
6. start furnace
7. furnace runs constantly for about 2 hours, as do the electric heaters.
8. start engine.

The various electric heat sources consist of heated electric carpets, oil filled heaters, 1 radiant heater (good for thawing compartment doors and the like), 2 fan based heaters. I protect the fridge with a 60 watt light bulb controlled by a themocube. I have fans in the fridge chimney and they restrict air flow somewhat in the winter time.

In the -30ties I'm able to heat 100% electrically, if there is sufficient shore power. The furnace set to cycle on should the power fail. The power needed is 4300 watts (continuous) with a peak load of 7100 watts. Total consumption for 24 hours is about 129 KWH.

To do this on a thirty amp RV I've added two auxiliary shore power cords, (15 amp and 20 amp). I have a "break out box" for 50 amp that has a 30 amp outlet on one leg and twin 20 amp outlets on the other leg. Each outlet has its own breaker.

Because power drops by the square of the voltage, I use an autoformer on the 30 amp service to provide sufficient voltage to keep the electric heaters working at peak output.

I have a hybrid inverter/charger which I operate in load support mode. I do limit the amperage on a 15 amp shore power to 13. On 30 amp the limit is 24 amps--or just about the same output as the Yamaha generator.

I've done some "back yard" experiments that document heating time and energy use both before and after modifications I've made. They exist somewhere on the boards. Try the winter camping thread on the full time forum?

I'd be delighted to answer any questions you or anyone else has.

StirCrazy wrote:

ticki2 wrote:

pianotuna wrote:


Take it out of storage at -37 and let me know how that works for you.

I sure would like to know your routine after you take your camper out of storage at -37 to warm the interior up to a reasonable temperature , with what heat source , and how long it takes .

he has a motorhome, lots of room and payload capability for batteries, probably just starts the furnace while he drives. the weight and spae limitations of a camper mean nothing to him.


Steve

I am well aware of his rv , it is listed in his signature . I imagine he would heat the interior with the engine heater , at least at first . A truck camper does not have that ability , it would have to rely on the furnace or electric if shore power was available.. I also know from experience it takes a lot of heat to warm up the interior of a camper starting at -37C . That is why I was curios how the poster was accomplishing the above .

Bradymydog wrote:

pianotuna wrote:

adamis wrote:
I don't understand these arguments at all...

If you have a LiFePo4 battery and camp in extreme cold weather, move the battery to inside the camper. Problem solved...

Take it out of storage at -37 and let me know how that works for you.

It is fine if one were full time.

I'm still waiting for FWC to describe the power system he uses.

If I were to take mine out of storage at -37, assuming the batteries had some % of charge remaining, I would:

1. Shut off/disconnect any charging devices - solar, shore power, DC-DC charger, no genny running.

2. Start the furnace. My 2 BB batteries are inside the conditioned space and have a heat duct discharge adjacent to the batteries. Let the furnace run for 24 hrs. while monitoring the battery temp via my Victron BM712 and an external digital thermostat next to the batts. My external digital thermo switch, serves a double duty as my Victron DC/DC charger generates considerable heat, so I installed 2 small 4" fans which are set to come on at 30C. My BB batts do not have built in heaters which are available.

3. Once I'm confident the internal battery temp is above 32F/0C, I'd start charging them.

Note: If attempting to charge cold batteries, according Tony discussions with BB, the BB internal battery monitor will disconnect at 25F to prevent damage to the batteries. To reset the internal BM, just disconnect/reconnect the negative battery cable.

On a side note, the coldest I've ever experienced was during an extended business trip to Prince Albert, SK. I'm not sure I'd personally want to camp in that weather but with adequate preparation, it should be possible.

if you bought quality LFP you wouldn't need to disconect the sources of power as the BMS would have already done that internaly. most have a internal reset, dont know for sure why battle born went with one that needs a total reset of the BMS... maybe when they started it was all there was..

the one I have ordered disconects at what ever I set it at so I could put it at -3C and set the reconect at 0C so when it hits -3 it will automaticly shut off charging ability and when it warms up to 0 it alows charging again.

there are newer ones you can buy that have heaters built into the battery case and the BMS will automaticly shut off charging of the battery but reroute the power supply to the heaters untill they hit a spicifc temp then start charging the batteries. so if you have solar, in the morning when the sun starts coming out and you have 0.5amps of power, this could be warming the battery for an hour then when the real Amps start flowing you charging. for a truck camer who boondocks in the winter I like this setup if you dont want to move the batteries inside the conditiond space. just do some nice foam insulation around the batteries to mak the warming more efficient and I dont think it would ever be to cold to camp.

Steve

ticki2 wrote:

pianotuna wrote:


Take it out of storage at -37 and let me know how that works for you.

I sure would like to know your routine after you take your camper out of storage at -37 to warm the interior up to a reasonable temperature , with what heat source , and how long it takes .

he has a motorhome, lots of room and payload capability for batteries, probably just starts the furnace while he drives. the weight and spae limitations of a camper mean nothing to him.


Steve

Or Bradymydog you could simply buy SiO2 batteries and store them where ever you wish. No fussing about them. 1/2 the initial purchase price and equivalent cost per cycle as Li.

pianotuna wrote:


Take it out of storage at -37 and let me know how that works for you.

I sure would like to know your routine after you take your camper out of storage at -37 to warm the interior up to a reasonable temperature , with what heat source , and how long it takes .

I decided against Lithiums due to non ability to charge in freezing temperatures. I got a good price on agms and my converter works on agm's but NOT Lithium, so check all the other stuff to be sure it is compatible with your choice or be prepared to upgrade.

pianotuna wrote:

adamis wrote:
I don't understand these arguments at all...

If you have a LiFePo4 battery and camp in extreme cold weather, move the battery to inside the camper. Problem solved...

Take it out of storage at -37 and let me know how that works for you.

It is fine if one were full time.

I'm still waiting for FWC to describe the power system he uses.

If I were to take mine out of storage at -37, assuming the batteries had some % of charge remaining, I would:

1. Shut off/disconnect any charging devices - solar, shore power, DC-DC charger, no genny running.

2. Start the furnace. My 2 BB batteries are inside the conditioned space and have a heat duct discharge adjacent to the batteries. Let the furnace run for 24 hrs. while monitoring the battery temp via my Victron BM712 and an external digital thermostat next to the batts. My external digital thermo switch, serves a double duty as my Victron DC/DC charger generates considerable heat, so I installed 2 small 4" fans which are set to come on at 30C. My BB batts do not have built in heaters which are available.

3. Once I'm confident the internal battery temp is above 32F/0C, I'd start charging them.

Note: If attempting to charge cold batteries, according Tony discussions with BB, the BB internal battery monitor will disconnect at 25F to prevent damage to the batteries. To reset the internal BM, just disconnect/reconnect the negative battery cable.

On a side note, the coldest I've ever experienced was during an extended business trip to Prince Albert, SK. I'm not sure I'd personally want to camp in that weather but with adequate preparation, it should be possible.

adamis wrote:
I don't understand these arguments at all...

If you have a LiFePo4 battery and camp in extreme cold weather, move the battery to inside the camper. Problem solved...

Take it out of storage at -37 and let me know how that works for you.

It is fine if one were full time.

I'm still waiting for FWC to describe the power system he uses.